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1.	Jönsson, Christina, et al. (author) Biocatalysis in the Recycling Landscape for Synthetic Polymers and Plastics towards Circular Textiles 2021 In: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 14:19, s. 4028-4040 Journal article (peer-reviewed)abstract Although recovery of fibers from used textiles with retained material quality is desired, separation of individual components from polymer blends used in today's complex textile materials is currently not available at viable scale. Biotechnology could provide a solution to this pressing problem by enabling selective depolymerization of recyclable fibers of natural and synthetic origin, to isolate constituents or even recover monomers. We compiled experimental data for biocatalytic polymer degradation with a focus on synthetic polymers with hydrolysable links and calculated conversion rates to explore this path The analysis emphasizes that we urgently need major research efforts: beyond cellulose-based fibers, biotechnological-assisted depolymerization of plastics so far only works for polyethylene terephthalate, with degradation of a few other relevant synthetic polymer chains being reported. In contrast, by analyzing market data and emerging trends for synthetic fibers in the textile industry, in combination with numbers from used garment collection and sorting plants, it was shown that the use of difficult-to-recycle blended materials is rapidly growing. If the lack of recycling technology and production trend for fiber blends remains, a volume of more than 3400 Mt of waste will have been accumulated by 2030. This work highlights the urgent need to transform the textile industry from a biocatalytic perspective.
2.	Hosseini, Seyedehsan, 1994 (author) Additive-Driven Improvements in Interfacial Properties and Processing of TMP-Polymer Composites 2023 Doctoral thesis (other academic/artistic)abstract Efforts to address environmental concerns have resulted in new regulations designed to plan the reduction of plastic and synthetic polymer usage, necessitating the search for sustainable natural alternatives with comparable cost-effectiveness and mechanical performance. Thermomechanical pulp (TMP) fibres are one of the most affordable natural fibres that have no chemical refining in production, production have a high yield of 90-98% and TMP fibres have been demonstrated to improve the mechanical characteristics (strength, stiffness and toughness) of wood-polymer composites (WPCs) compared to the pure polymer. The integration of TMP fibres with non-polar synthetic polymers remains a challenge due to surface polarity differences. This PhD thesis aims to ease the processing of TMP fibre composites through the incorporation of additives. The hypothesis posits that incorporating magnesium stearate (MgSt), molybdenum disulfide (MoS2) and alkyl ketene dimer (AKD) as additives in TMP composites will enhance interfacial properties, resulting in improved processability and flow behaviour at high temperatures. MoS2 is known for its interaction with lignin, which exists in TMP and MgSt is recognised for its ability to improve flow in pharmaceutical processing when combined with cellulose, also a component of TMP. AKD modifies the hydrophilic properties of lignocellulosic surfaces. The experimental work explores the effect of these additives on the properties of TMP composites of ethylene acrylic acid copolymer (EAA) and polypropylene (PP) matrices. The dynamic mechanical analysis (DMA) and mechanical analysis results reveal that MoS2 exhibits superior interaction with TMP fibres, yielding enhanced interfacial properties compared to MgSt in between EAA and TMP fibres. Rheological studies elucidate the transition from a fluid-like state to a network-like structure upon the incorporation of TMP into the PP matrix. The incorporation of AKD with C18 reduces the viscosity of TMP-PP composites and PP itself, and, as determined through theoretical Hansen solubility parameter (HSP) calculations, increases compatibility between cellulose in TMP fibres and PP. The addition of AKD influences both the colour (lighter) and shape (smoother surface) of the extrudate filaments in the TMP-PP composites, indicative of improved processing. In addition, frictional analysis demonstrates the reduction of the coefficient of friction (COF) between metal and TMP fibre by MgSt and AKD treatments.
3.	Lei, Yu, et al. (author) Graphene and Beyond: Recent Advances in Two-Dimensional Materials Synthesis, Properties, and Devices 2022 In: ACS Nanoscience Au. - : American Chemical Society (ACS). - 2694-2496. ; 2:6, s. 450-485 Research review (peer-reviewed)abstract Since the isolation of graphene in 2004, two-dimensional (2D) materials research has rapidly evolved into an entire subdiscipline in the physical sciences with a wide range of emergent applications. The unique 2D structure offers an open canvas to tailor and functionalize 2D materials through layer number, defects, morphology, moiré pattern, strain, and other control knobs. Through this review, we aim to highlight the most recent discoveries in the following topics: theory-guided synthesis for enhanced control of 2D morphologies, quality, yield, as well as insights toward novel 2D materials; defect engineering to control and understand the role of various defects, including in situ and ex situ methods; and properties and applications that are related to moiré engineering, strain engineering, and artificial intelligence. Finally, we also provide our perspective on the challenges and opportunities in this fascinating field.
4.	Hosseini, Seyedehsan, 1994, et al. (author) Alkyl ketene dimer modification of thermomechanical pulp promotes processability with polypropylene 2024 In: Polymer Composites. - 1548-0569 .- 0272-8397. ; 45:1, s. 825-835 Journal article (peer-reviewed)abstract Alkyl ketene dimers (AKDs) are known to efficiently react with cellulose with a dual polarity in their structure: a polar component and a nonpolar component. AKD of three different carbon chain lengths, 4, 10, and 16 carbons have been synthesized, and thermomechanical pulp (TMP) fibers were modified by them. The modification of TMP fibers with AKD resulted in an increased water contact angle, showing the presence of the AKDs on the TMP fibers and a new carbonyl peak in the IR spectra, suggesting modification of the TMP fibers with AKD groups. Calculating the Hansen solubility parameters of AKD and AKD conjugated to TMP in polypropylene (PP) indicates improved compatibility, especially of longer chain AKD and TMP AKD. The rheological studies of the composites showed that the AKD with the longest carbon chain decreases the melt viscosity of the PP-TMP-AKD composite, which combined with the shape and the color of the extruded composite filaments indicates improved flow properties and reduced stress build up during processing. The research findings demonstrate the ability of AKD to enhance the dispersibility and compatibility of natural fibers with PP.
5.	Townsend, Philip, 1991, et al. (author) Stochastic modelling of 3D fiber structures imaged with X-ray microtomography 2021 In: Computational materials science. - : Elsevier B.V.. - 0927-0256 .- 1879-0801. ; 194 Journal article (peer-reviewed)abstract Many products incorporate into their design fibrous material with particular levels of permeability as a way to control the retention and flow of liquid. The production and experimental testing of these materials can be expensive and time consuming, particularly if it needs to be optimised to a desired level of absorbency. We consider a parametric virtual fiber model as a replacement for the real material to facilitate studying the relationship between structure and properties in a cheaper and more convenient manner. 3D image data sets of a sample fibrous material are obtained using X-ray microtomography and the individual fibers isolated. The segmented fibers are used to estimate the parameters of a 3D stochastic model for generating softcore virtual fiber structures. We use several spatial measures to show the consistency between the real and virtual structures, and demonstrate with lattice Boltzmann simulations that our virtual structure has good agreement with respect to the permeability of the physical material. © 2021 The Author(s)
6.	Peterson, Joel, 1959-, et al. (author) Mechanical-Property-Based Comparison of Paper Yarn with Cotton, Viscose, and Polyester Yarns 2021 In: Journal of Natural Fibers. - : Taylor & Francis Group. - 1544-0478 .- 1544-046X. ; 18:4, s. 492-501 Journal article (peer-reviewed)abstract Cotton and oil-based fibre consumption is highly problematic because the growth of these materials often requires fertilisers and toxic pesticides. Less environmentally damaging alternative fibres are urgently required. This study investigates Manila-hemp paper-yarn textile fabrics. Manila-hemp (abacá) is a species of banana grown as a commercial crop in the Philippines, Ecuador, and Costa Rica. Knitted structures of paper, cotton, viscose, and polyester yarns are tested and compared. Tensile strength tests are also performed. Paper yarn shows low shrinkage and no pilling, which are excellent characteristics for use in the textile and clothing industries. However, its poor handleability/knittability, high stiffness, and hard grip must be resolved for the widespread application of paper yarn in the textile industry in the future.
7.	Hu, Enyi, et al. (author) Junction and energy band on novel semiconductor-based fuel cells 2021 In: iScience. - : Elsevier BV. - 2589-0042. ; 24:3 Research review (peer-reviewed)abstract Fuel cells are highly efficient and green power sources. The typical membrane electrode assembly is necessary for common electrochemical devices. Recent research and development in solid oxide fuel cells have opened up many new opportunities based on the semiconductor or its heterostructure materials. Semiconductor-based fuel cells (SBFCs) realize the fuel cell functionality in a much more straightforward way. This work aims to discuss new strategies and scientific principles of SBFCs by reviewing various novel junction types/interfaces, i.e., bulk and planar p-n junction, Schottky junction, and n-i type interface contact. New designing methodologies of SBFCs from energy band/alignment and built-in electric field (BIEF), which block the internal electronic transport while assisting interfacial superionic transport and subsequently enhance device performance, are comprehensively reviewed. This work highlights the recent advances of SBFCs and provides new methodology and understanding with significant importance for both fundamental and applied R&D on new-generation fuel cell materials and technologies.
8.	Zubritskaya, Irina, 1984, et al. (author) Dynamically Tunable Optical Cavities with Embedded Nematic Liquid Crystalline Networks 2023 In: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 35:13 Journal article (peer-reviewed)abstract Tunable metal–insulator–metal (MIM) Fabry–Pérot (FP) cavities that can dynamically control light enable novel sensing, imaging and display applications. However, the realization of dynamic cavities incorporating stimuli-responsive materials poses a significant engineering challenge. Current approaches rely on refractive index modulation and suffer from low dynamic tunability, high losses, and limited spectral ranges, and require liquid and hazardous materials for operation. To overcome these challenges, a new tuning mechanism employing reversible mechanical adaptations of a polymer network is proposed, and dynamic tuning of optical resonances is demonstrated. Solid-state temperature-responsive optical coatings are developed by preparing a monodomain nematic liquid crystalline network (LCN) and are incorporated between metallic mirrors to form active optical microcavities. LCN microcavities offer large, reversible and highly linear spectral tuning of FP resonances reaching wavelength-shifts up to 40 nm via thermomechanical actuation while featuring outstanding repeatability and precision over more than 100 heating–cooling cycles. This degree of tunability allows for reversible switching between the reflective and the absorbing states of the device over the entire visible and near-infrared spectral regions, reaching large changes in reflectance with modulation efficiency ΔR = 79%.
9.	Öberg Månsson, Ingrid, 1991- (author) Electroanalytical devices with fluidic control using textile materials and methods 2020 Licentiate thesis (other academic/artistic)abstract This thesis, written by Ingrid Öberg Månsson at KTH Royal Institute of Technology and entitled “Electroanalytical devices with fluidic control using textile materials and methods”, presents experimental studies on the development of textile based electronic devices and biosensors. One of the reasons why this is of interest is the growing demand for integrated smart products for wearable health monitoring or energy harvesting. To enable such products, new interdisciplinary fields arise combining traditional textile technology and electronics.Textile based devices have garnered much interest in recent years due to their innate ability to incorporate function directly into, for example, clothing or bandages by textile processes such as weaving, knitting or stitching. However, many modifications of yarns required for such applications are not available on an industrial scale. The major objective of this work has been to study how to achieve the performance necessary to create electronic textile devices by either coating yarns with conductive material or using commercially available conductive yarns that are functionalized to create sensing elements.Further, liquid transport within textile materials has been studied to be able to control the contact area between electrolyte and electrodes in electrochemical devices such as sensors and transistors. Yarns with specially designed cross-sections, traditionally used in sportswear to wick sweat away from the body and enhance evaporation, was used to transport electrolyte liquids to come in contact with yarn electrodes. The defined area of the junction where the fluidic yarn meets the conductive yarn was shown to increase stability of the measurements and the reproducibility between devices.The results presented in the two publications of this thesis as well as additional results presented in the thesis itself show the promising potential of using textile materials to integrate electronic and electrochemical functionality in our everyday life. This is shown by using basic textile materials and processing techniques to fabricate complex devices for various application areas such as sensors and diagnostics as well as electrical and energy harvesting components.
10.	Johannisson, Wilhelm, et al. (author) A screen-printing method for manufacturing of current collectors for structural batteries 2021 In: Multifunctional Materials. - : IOP Publishing. - 2399-7532. ; 4:3, s. 035002- Journal article (peer-reviewed)abstract Structural carbon fibre composite batteries are a type of multifunctional batteries that combine the energy storage capability of a battery with the load-carrying ability of a structural material. To extract the current from the structural battery cell, current collectors are needed. However, current collectors are expensive, hard to connect to the electrode material and add mass to the system. Further, attaching the current collector to the carbon fibre electrode must not affect the electrochemical properties negatively or requires time-consuming, manual steps. This paper presents a proof-of-concept method for screen-printing of current collectors for structural carbon fibre composite batteries using silver conductive paste. Current collectors are screen-printed directly on spread carbon fibre tows and a polycarbonate carrier film. Experimental results show that the electrochemical performance of carbon fibre vs lithium metal half-cells with the screen-printed collectors is similar to reference half-cells using metal foil and silver adhered metal-foil collectors. The screen-printed current collectors fulfil the requirements for electrical conductivity, adhesion to the fibres and flexible handling of the fibre electrode. The screen-printing process is highly automatable and allows for cost-efficient upscaling to large scale manufacturing of arbitrary and complex current collector shapes. Hence, the screen-printing process shows a promising route to realization of high performing current collectors in structural batteries and potentially in other types of energy storage solutions.
11.	Schellenberger, Steffen, 1981-, et al. (author) An Outdoor Aging Study to Investigate the Release of Per- And Polyfluoroalkyl Substances (PFAS) from Functional Textiles 2022 In: Environmental Science and Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 56, s. 3471- Journal article (peer-reviewed)abstract The emission of per- and polyfluoroalkyl substances (PFAS) from functional textiles was investigated via an outdoor weathering experiment in Sydney, Australia. Polyamide (PA) textile fabrics treated with different water-repellent, side-chain fluorinated polymers (SFPs) were exposed on a rooftop to multiple natural stressors, including direct sunlight, precipitation, wind, and heat for 6-months. After weathering, additional stress was applied to the fabrics through abrasion and washing. Textile characterization using a multiplatform analytical approach revealed loss of both PFAS-containing textile fragments (e.g., microfibers) as well as formation and loss of low molecular weight PFAS, both of which occurred throughout weathering. These changes were accompanied by a loss of color and water repellency of the textile. The potential formation of perfluoroalkyl acids (PFAAs) from mobile residuals was quantified by oxidative conversion of extracts from unweathered textiles. Each SFP-textile finish emitted a distinct PFAA pattern following weathering, and in some cases the concentrations exceeded regulatory limits for textiles. In addition to transformation of residual low molecular weight PFAA-precursors, release of polymeric PFAS from degradation and loss of textile fibers/particles contributed to overall PFAS emissions during weathering. © 2022 The Authors.
12.	Dahlbom, Maja, et al. (author) Sustainable clothing futures - Mapping of textile actors in sorting and recycling of textiles in Europe 2023 Reports (other academic/artistic)abstract This report is as a part of the research project Sustainable clothing futures, and have, through literature and market studies and interviews, identified actors working with sorting and recycling of textiles, with capacities of 560 000 tons and 1.3 million tons per year, respectively.In the interviews, it was clear that an up scale of the capacities is possible, but is depending on several factors, technological development amongst others.
13.	Tadesse Abate, Molla (author) Supercritical CO2 technology in resource-effectiveproduction of functional and smart textiles 2020 Doctoral thesis (other academic/artistic)abstract The demand for functional and smart textiles has risen nowadays due to the lifestyle change of human beings. Along with this, the production of functional and smart textiles is consistently increasing. However, the conventional dyeing and finishing methods used to produce the functional textiles have issues such as the requirement of a large amount of fresh-water, energy, and chemicals and the associated wastewater pollution which poses harmful effect to humans, animals, and the environment. Moreover, due to the stringent environmental legislation on effluent release and hence the necessity of wastewater treatment, it has also become an economic problem for the textile industry. Thus, the textile industry has nowadays focused on alternative green technologies and eco-friendly chemical agents to minimize these problems. In this regard, supercritical carbon dioxide (scCO2) dyeing technique is a promising alternative to conventional aqueous-based methods as it avoids the use of water, uses less energy, and fewer chemicals minimizing the waste generation which is important to improve the ecological footprint and reduced production cost. Owing to these important attributes, scCO2 dyeing has been investigated in the last three decades as an environmentally benign process and now it is commercially successful in an industrial scale for dyeing polyester fibres. Thus, employing this technique to textile functionalization can bring additional economic and environmental benefits for the textile dyeing and finishing industry. Nevertheless, only a few attempts have been made so far in using this technology for textile finishing despite having promising potentials.This thesis used scCO2 dyeing technology intending to explore its potential to the production of functional and smart textiles. To fulfil this, firstly, different functional dyes and functional finishing agents of interest suitable for scCO2 media were selected based on literature data and some screening experiments. Based on this, chitosan very low molecular weight and lactate derivatives, curcumin natural dye, and two commercial photochromic dyes based on spirooxazine and naphthopyran dye classes were selected. Secondly, these agents were incorporated into the polyester fabric using scCO2 impregnation technique to impart range functionalities such as antimicrobial, antioxidant, UV protecting and smart UV-sensor fabrics. Moreover, the functional and colour performances of these functional textiles and the effects of the processing variables on the functional/colour properties were explored. Besides, the thesis includes the production of pH sensing functional fabric with a halochromic molecule using photo grafting technique as an alternative resource-efficient method.The results showed that scCO2 is a viable technique for the production of functional polyester fabric in a resource-efficient and eco-friendly way. Dyed polyester fabric with additional functionalities such as antimicrobial, antioxidant, UV protection, and UV sensing properties were realised in a single step. The fabrics developed have demonstrated desirable colour and functional properties without affecting each other confirming compatibility. Moreover, the functional fabrics exhibited the required durability and fastness properties sufficient for various applications. This thesis contributes towards widening the application of supercritical CO2 dyeing technique further and paves a way for sustainable production of functional and smart textiles in a resource-efficient and eco-friendly way. Moreover, the functionalization of cotton fabric with a pH indicator dye using the photo-grafting technique was successful and exhibited good halochromic property towards different pH environments with potential application in several smart textile areas.
14.	Xu, Yunsheng, et al. (author) Methacrylated lignosulfonate as compatibilizer for flax fiber reinforced biocomposites with soybean-derived polyester matrix 2020 In: Composites Communications. - : Elsevier BV. - 2452-2139. Journal article (peer-reviewed)abstract The poor adhesion between natural fibers and polymer matrix restricts the mechanical performance of natural fiber reinforced composites. Here, lignosulfonate was methacrylated and evaluated as a potential compatibilizer for flax fiber reinforced soybean-derived polyester thermosets. Significant improvement in both tensile and flexural properties of the fiber composites were achieved when the flax fiber mat was treated with methacrylated lignosulfonate solution. In particular, the flexural modulus and flexural strength more than doubled from 2.6 to 6.7 GPa and from 36 MPa to 76.8 MPa, respectively when the fibers were soaked in 5 wt % MLS solution. The SEM analysis revealed improved fiber-matrix interface and lower extent of fiber pull-out in the methacrylated lignosulfonate treated fiber composites, which correlates with the improved mechanical properties.
15.	Pal, Rudrajeet, Biträdande Professor, et al. (author) Demystifying process-level scalability challenges in fashion remanufacturing : An interdependence perspective 2021 In: Journal of Cleaner Production. - : Elsevier Ltd. - 0959-6526 .- 1879-1786. ; 286 Journal article (peer-reviewed)abstract The purpose of this paper is to determine how process-level challenges can be solved in order improve scalability of fashion remanufacturing. In order to do so, and prescribe solutions, the paper first conducts a systematic literature review to reveal three categories of process-level challenges that are related to sourcing of input material, process throughput time, and skillset requirement. These categories further guided us in conducting case study with a Swedish charity-owned fashion remanufacturer for exploring how the challenges are addressed and solved in order to achieve process-level scalability. First, our study reveals a systematized approach to determine product-process categories defined by production volume and degree of remanufacturing. Second, by exploring the process-level challenges of six different remanufactured product groups in the case study organization we identify process-level requirements for scalability, and challenges when these are unmet. The findings show that in fashion remanufacturing (particularly disassembly and reassembly), low degree of coupling, high level of formalization of activities and low skill specificity can be ways to attain process-level scalability. Overall, this highlights the need to build lower interdependence between disassembly and reassembly during fashion remanufacturing.
16.	Farjana, Sadia, 1983, et al. (author) Low Loss Gap Waveguide Transmission line and Transitions at 220-320 GHz Using Dry Film Micromachining 2021 In: IEEE Transactions on Components, Packaging and Manufacturing Technology. - 2156-3985 .- 2156-3950. ; 11:11, s. 2012-2021 Journal article (peer-reviewed)abstract This paper presents a novel microfabrication technique to manufacture gap waveguide components operating at sub-millimeter wave (sub-mmWave) frequency range. The conventional metal waveguide component manufacturing has a low resolution and low throughput and is not suitable for applications above 100 GHz. The micromachining techniques have matured and applied in various applications. Several micromachining techniques have been developed to address the specification requirements of different fields. Conventional micromachining techniques suffer from fabrication issues such as non-vertical sidewall, non-uniform surface, and time-consuming fabrication process. The proposed dry film photoresist offers significant amount of benefits such as fewer processing steps, reduced production cost, shorter prototyping time over existing micromachine techniques. To validate the proposed fabrication method, SUEX dry film photoresist is used to demonstrate three gap waveguide transmission lines. Different transitions from rectangular waveguide (RW) to gap waveguide (GW) have also been designed to characterize the newly fabricated gap waveguide components with a standard measurement setup. All the designed and fabricated device operates from 220 GHz to 320 GHz. The fabricated devices showed a good agreement with the simulation result over this frequency band and the measured average insertion losses were in the order of 0.048 dB/mm and 0.075 dB/mm for groove gap waveguide and ridge gap waveguide respectively. Thus, dry film photoresist provides fabrication precision of the structures and consequently opens the path for low-cost fabrication of high-frequency waveguide components.
17.	Nierstrasz, Vincent, 1967- (author) Resource effective textile processes forfunctional and smart textiles 2022 Conference paper (other academic/artistic)
18.	Ghai, Viney, 1989, et al. (author) Orientation of graphene nano sheets in magnetic fields 2024 In: Progress in Materials Science. - 0079-6425. ; 143 Research review (peer-reviewed)abstract Aligning anisotropic nanoparticles using external fields is one of the major obstacles to unlocking their enormous potential for novel applications. The most famous such example is graphene, a 2D family of nanomaterials that has received enormous attention since its discovery. Using graphene to enhance mechanical, thermal, electric or gas barrier properties, imparting antibacterial properties etc., relies to a great extent on the ability to control their orientation inside a matrix material, i.e., polymers. Here we summarize the latest advances on graphene orientation using magnetic fields. The review covers the underlying physics for graphene interaction with magnetic fields, theoretical continuum mechanics framework for inducing orientation, typical magnetic field orientation setups, and a summary of latest advances in their use to enhance the performance of materials. Current trends, limitations of current alignment techniques are highlighted and major challenges in the field are identified.
19.	da Costa, Marcus Vinicius Tavares, et al. (author) Prediction of loss of barrier properties in cracked thin coatings on polymer substrates subjected to tensile strain 2021 In: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 426 Journal article (peer-reviewed)abstract Thin brittle coatings on polymer films are a potentially useful material combination for food packaging applications. The brittle coatings inevitably risk cracking when the package is converted. This strain-induced cracking leads to a loss of the key barrier properties. In design of packaging materials, it would be useful to predict the loss of the oxygen transmission rate (OTR) as a function of the applied tensile strain, which are linked by the crack opening and crack spacing in the coating. Previous works have presented a model that predicts the effect of strain on the OTR in the presence of cracks in the coating. This work uses an improved numerical model based on finite element method (FEM) to predict the oxygen permeability more accurately, especially for thin coatings with high crack densities. The numerical predictions show reasonable correspondence with experimental results for SiOx coatings. These results as well as predictions for previously tested metal-oxide coated polymer films show a significant increase in OTR at crack onset, which suggests that efforts should be made to make the coatings more ductile with higher crack onset strains if the barrier performance should be maintained in converted packages. The quantitative link from deformation over the damage state to barrier properties indicate that mechanics could provide a tool to aid the design of improved food packages with retained barrier capacity.
20.	Samanta, Archana, 1990, et al. (author) Wet spinning of strong cellulosic fibres with incorporation of phase change material capsules stabilized by cellulose nanocrystals 2023 In: Carbohydrate Polymers. - : Elsevier Ltd. - 0144-8617 .- 1879-1344. ; 312 Journal article (peer-reviewed)abstract Incorporating a phase change material (PCM) into fibres allows the fabrication of smart textiles with thermo-regulating properties. Previously, such fibres have been made from thermoplastic polymers, usually petroleum-based and non-biodegradable, or from regenerated cellulose, such as viscose. Herein, strong fibres are developed from aqueous dispersions of nano-cellulose and dispersed microspheres with phase changing characteristics using a wet spinning technique employing a pH shift approach. Good distribution of the microspheres and proper compatibility with the cellulosic matrix was demonstrated by formulating the wax as a Pickering emulsion using cellulose nanocrystals (CNC) as stabilizing particles. The wax was subsequently incorporated into a dispersion of cellulose nanofibrils, the latter being responsible for the mechanical strength of the spun fibres. It was possible to produce fibres highly loaded with the microspheres (40 wt%) with a tenacity of 13 cN tex−1 (135 MPa). The fibres possessed good thermo-regulating features by absorbing and releasing heat without undergoing structural changes, while maintaining the PCM domain sizes intact. Finally, good washing fastness and PCM leak resistance were demonstrated, making the fibres suitable for thermo-regulative applications. Continuous fabrication of bio-based fibres with entrapped PCMs may find applications as reinforcements in composites or hybrid filaments. © 2023 The Authors
21.	Depalo, Francesco, et al. (author) Effects of dynamic axial stiffness of elastic moorings for a wave energy converter 2022 In: Ocean Engineering. - : Elsevier BV. - 0029-8018. ; 251 Journal article (peer-reviewed)abstract This work studies the effects of the dynamic axial stiffness of elastic moorings on the dynamic behaviour of a point absorber wave energy converter. Following two mooring analysis procedures, coupled dynamic analysis of a taut-moored WEC with three legs is performed using the FEM program DeepC in three irregular wave conditions. Two synthetic fibre rope materials are investigated, i.e. a normally stiff polyester and a wire-lay 3-strand nylon rope. The results of WEC motions and mooring tensions obtained from a quasi-static stiffness model and the dynamic stiffness model are compared and discussed. The former analysis applies the non-linear stiffness working curves of the ropes in the simulations, while the latter utilizes the dynamic stiffness expression with an iterative process following a practical mooring analysis procedure. For the nylon rope, the influence of the load amplitude on the dynamic stiffness and the WEC response is presented and analysed. It was found that the quasi-static stiffness model tends to underestimate the maximum mooring tensions, leading to 30%–40% lower results compared to the one accounting for the dynamic stiffness effects. For the studied WEC system, the nylon rope shows advantages over polyester, because of the lower mooring tensions and higher WEC motions.
22.	Hafid, Abdelakram, et al. (author) Sensorized T-Shirt with Intarsia-Knitted Conductive Textile Integrated Interconnections: Performance Assessment of Cardiac Measurements during Daily Living Activities 2023 In: Sensors. - 1424-8220. ; 23:22 Journal article (peer-reviewed)abstract The development of smart wearable solutions for monitoring daily life health status is increasingly popular, with chest straps and wristbands being predominant. This study introduces a novel sensorized T-shirt design with textile electrodes connected via a knitting technique to a Movesense device. We aimed to investigate the impact of stationary and movement actions on electrocardiography (ECG) and heart rate (HR) measurements using our sensorized T-shirt. Various activities of daily living (ADLs), including sitting, standing, walking, and mopping, were evaluated by comparing our T-shirt with a commercial chest strap. Our findings demonstrate measurement equivalence across ADLs, regardless of the sensing approach. By comparing ECG and HR measurements, we gained valuable insights into the influence of physical activity on sensorized T-shirt development for monitoring. Notably, the ECG signals exhibited remarkable similarity between our sensorized T-shirt and the chest strap, with closely aligned HR distributions during both stationary and movement actions. The average mean absolute percentage error was below 3%, affirming the agreement between the two solutions. These findings underscore the robustness and accuracy of our sensorized T-shirt in monitoring ECG and HR during diverse ADLs, emphasizing the significance of considering physical activity in cardiovascular monitoring research and the development of personal health applications.
23.	Chen, Jiajia, et al. (author) Characterization of Longitudinal Thermal Conductivity of Graphene Film 2021 In: 2021 22nd International Conference on Electronic Packaging Technology, ICEPT 2021. Conference paper (peer-reviewed)abstract The chase of high performance by chip manufacturers has greatly increased the power consumption of integrated circuits, which brings great challenges to the heat dissipation of electronics systems. It has also slowed down following up of the Moore's Law, and it is expected to hit the wall soon [1]. Graphene film with high in-plane thermal conductivity is one of the key materials to make it possible for electronics industry to continue to follow the Moore's Law. However, there are few studies focusing on the longitudinal thermal conductivity of graphene films. The purpose of this study is to investigate the longitudinal thermal conductivity of graphene films according to ASTM D5470 [2]. The results show that the longitudinal thermal conductivity of the pressed graphene film is greater than that of the unpressurized graphene film. The longitudinal thermal conductivity is 10.6 W/m· K for the unpressurized graphene film and 20.6 W/m· K for the pressed graphene film.
24.	Mehraeen, Shayan, et al. (author) Effect of Core Yarn on Linear Actuation of Electroactive Polymer Coated Yarn Actuators 2023 In: Advanced Materials Technologies. - : John Wiley & Sons. - 2365-709X. Journal article (peer-reviewed)abstract Smart textiles combine the features of conventional textiles with promising properties of smart materials such as electromechanically active polymers, resulting in textile actuators. Textile actuators comprise of individual yarn actuators, so understanding their electro-chemo-mechanical behavior is of great importance. Herein, this study investigates the effect of inherent structural and mechanical properties of commercial yarns, that form the core of the yarn actuators, on the linear actuation of the conducting-polymer-based yarn actuators. Commercial yarns were coated with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) to make them conductive. Then polypyrrole (PPy) that provides the electromechanical actuation is electropolymerized on the yarn surface under controlled conditions. The linear actuation of the yarn actuators is investigated in aqueous electrolyte under isotonic and isometric conditions. The yarn actuators generated an isotonic strain up to 0.99% and isometric force of 95 mN. The isometric strain achieved in this work is more than tenfold and threefold greater than the previously reported yarn actuators. The isometric actuation force shows an increase of nearly 11-fold over our previous results. Finally, a qualitative mechanical model is introduced to describe the actuation behavior of yarn actuators. The strain and force created by the yarn actuators make them promising candidates for wearable actuator technologies. © 2023 The Authors. Advanced Materials Technologies published by Wiley-VCH GmbH.
25.	Nierstrasz, Vincent, 1967- (author) Resource effective textile processes for functional and smart textiles 2023 Conference paper (peer-reviewed)
26.	Van Der Veen, Ike, et al. (author) Fate of Per- and Polyfluoroalkyl Substances from Durable Water-Repellent Clothing during Use 2022 In: Environmental Science and Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 56:9, s. 5886-5897 Journal article (peer-reviewed)abstract To make outdoor clothing water- or dirt-repellent, durable water-repellent (DWR) coatings based on side-chain fluorinated polymers (SFPs) are used. During use of outdoor clothing, per- and polyfluoroalkyl substances (PFASs) can be emitted from the DWR to the environment. In this study, the effects of aging, washing, and tumble drying on the concentration of extractable PFASs in the DWR of perfluorohexane-based short-chain SFPs (FC-6 chemistry) and of perfluorooctane-based long-chain SFPs (FC-8 chemistry) were assessed. For this purpose, polyamide (PA) and polyester (PES) fabrics were coated with FC-6- and FC-8-based DWRs. Results show that aging of the coated fabrics causes an increase in concentration and formation of perfluoroalkyl acids (PFAAs). The effect of aging on the volatile PFASs depends on the type of fabric. Washing causes a decrease in PFAA concentrations, and in general, volatile PFASs are partly washed out of the textiles. However, washing can also increase the extractable concentration of volatile PFASs in the fabrics. This effect becomes stronger by a combination of aging and washing. Tumble drying does not affect the PFAS concentrations in textiles. In conclusion, aging and washing of fabrics coated with the DWR based on SFPs release PFASs to the environment.
27.	Ye, Xinchen (author) Materials Based on Protein Nanofibrils 2021 Doctoral thesis (other academic/artistic)abstract Protein nanofibrils (PNFs) prepared from whey protein isolate (WPI) at low pH and elevated temperature were processed into materials, i.e. hydrogels, films, foams, and fibres, for different applications where they could potentially be sustainable alternatives to petroleum-based polymers. WPI was chosen as the starting material due to the high accessibility of whey as an industrial side-stream product from cheese manufacturing, and its ability to easily grow PNFs.PNFs grown in the presence of different metal ions were generally curved and short, and they formed hydrogels, in contrast to the straight ones fibrillated without metal ions. The effect of metal ions with different acidity was systematically studied with respect to fibrillation kinetics and gelation behaviour. The protein fibrillation was accelerated by the addition of metal ions. The strength of the hydrogel increased with increasing acidity of the metal ion at the same ion concentration, as long as the ion did not precipitate as hydroxide/oxide. Protein nanocomposite films were prepared by adding separately grown PNFs into a non-fibrillar protein matrix from the same WPI starting material. The glycerol-plasticized composite films obtained an increased elastic modulus and decreased strain at break with increasing content of PNFs. The produced PNF foams showed high-temperature resistance during aging at 150 °C for as long as one month (maximum testing time), far exceeding the properties of many petroleum-based thermoplastics. The aged foams were also able to retain their properties in different solutions that normally degrade/dissolve protein materials.PNFs were also organized into microfibres using a flow-focusing method. Genipin was added as a natural crosslinker to improve the mechanical properties of the obtained fibre. The crosslinked fibre (using only 2% genipin) obtained a significantly higher stiffness and strength at break as compared to the fibre assembled without genipin.
28.	Fager, Cecilia, 1990, et al. (author) Optimization of FIB-SEM Tomography and Reconstruction for Soft, Porous, and Poorly Conducting Materials 2020 In: Microscopy and Microanalysis. - 1431-9276 .- 1435-8115. ; 26:4, s. 837-845 Journal article (peer-reviewed)abstract Tomography using a focused ion beam (FIB) combined with a scanning electron microscope (SEM) is well-established for a wide range of conducting materials. However, performing FIB-SEM tomography on ion- and electron-beam-sensitive materials as well as poorly conducting soft materials remains challenging. Some common challenges include cross-sectioning artifacts, shadowing effects, and charging. Fully dense materials provide a planar cross section, whereas pores also expose subsurface areas of the planar cross-section surface. The image intensity of the subsurface areas gives rise to overlap between the grayscale intensity levels of the solid and pore areas, which complicates image processing and segmentation for three-dimensional (3D) reconstruction. To avoid the introduction of artifacts, the goal is to examine porous and poorly conducting soft materials as close as possible to their original state. This work presents a protocol for the optimization of FIB-SEM tomography parameters for porous and poorly conducting soft materials. The protocol reduces cross-sectioning artifacts, charging, and eliminates shadowing effects. In addition, it handles the subsurface and grayscale intensity overlap problems in image segmentation. The protocol was evaluated on porous polymer films which have both poor conductivity and pores. 3D reconstructions, with automated data segmentation, from three films with different porosities were successfully obtained.
29.	Gugole, Marika, 1993, et al. (author) High-Contrast Switching of Plasmonic Structural Colors: Inorganic versus Organic Electrochromism 2020 In: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 7:7, s. 1762-1772 Journal article (peer-reviewed)abstract Plasmonic structural colors have recently received a lot of attention. For many applications there is a need to actively tune the colors after preparing the nanostructures, preferably with as strong changes in the optical response as possible. However, to date, there is a lack of systematic investigations on how to enhance contrast in electrically induced color modulation. In this work we implement electrochromic films with plasmonic metasurfaces and compare systematically organic and inorganic materials, with the primary aim to maximize brightness and contrast in a reflective color display. We show nanostructures with good chromaticity and high polarization-insensitive reflectivity (-90%) that are electrochemically stable in a nonaqueous solvent. Methods are evaluated for reliable and uniform electropolymerization of the conductive polymer dimethylpropylenedioxythiophene (PProDOTMe2) on gold. The resulting organic films are well-described by Lambert-Beer formalism, and the highest achievable contrast is easily determined in transmission mode. The optical properties of the inorganic option (WO3) require full Fresnel models due to thin film interference, and the film thickness must be carefully selected in order to maintain the chromaticity of the metasurfaces. Still, the optimized fully inorganic device reaches the highest contrast of approximately 60% reflectivity change for all primary colors. The switching time is about an order of magnitude faster for the organic films (hundreds of ms). The bistability is very long (hours) for the inorganic devices and comparable for the polymers, which makes the power consumption essentially zero for maintaining the same state. Finally, we show that switching of the primary colors in optimized devices (both organic and inorganic) provides almost twice as high brightness and contrast compared to existing reflective display technologies with RGB subpixels created by color filters.
30.	Jiang, Bing-Xin, et al. (author) Fabrication and bonding of In bumps on Micro-LED with 8 μ m pixel pitch 2024 In: ENGINEERING RESEARCH EXPRESS. - 2631-8695. ; 6:2 Journal article (peer-reviewed)abstract Indium (In) is currently used to fabricate metal bumps on micro-light-emitting diode (Micro-LED) chips due to its excellent physical properties. However, as Micro-LED pixel size and pitch decrease, achieving high-quality In bumps on densely packed Micro-LED chips often presents more challenges. This paper describes the process of fabricating In bumps on micro-LEDs using thermal evaporation, highlighting an issue where In tends to grow laterally within the photoresist pattern, ultimately blocking the pattern and resulting in undersized and poorly dense In bumps on the Micro-LED chip. To address this issue, we conducted numerous experiments to study the height variation of In bumps within a range of photoresist aperture sizes (3 mu m -7 mu m) under two different resist thickness conditions (3.8 mu m and 4.8 mu m). The results showed that the resist thickness had a certain effect on the height of In bumps on the Micro-LED chip electrodes. Moreover, we found that, with the photoresist pattern size increasing under constant resist thickness conditions, the height and quality of the bumps significantly improved. Based on this finding, we rationalized the adjustment of the photoresist pattern size within a limited emission platform range to compensate for the height difference of In bumps caused by different resist thicknesses between the cathode and anode regions. Consequently, well-shaped and dense In bumps with a maximum height of up to 4.4 mu m were fabricated on 8 mu m pitch Micro-LED chips. Afterwards, we bonded the Micro-LED chip with indium bumps to the CMOS chip, and we found that we could successfully control the CMOS chip to drive the Micro-LED chip to display specific characters through the Flexible Printed Circuit (FPC). This work is of significant importance for the fabrication of In bumps on Micro-LED chips with pitches below 10 mu m and subsequent bonding processes.
31.	Das, Oisik, et al. (author) Naturally-occurring bromophenol to develop fire retardant gluten biopolymers 2020 In: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 243 Journal article (peer-reviewed)abstract The aim of the study was to impart fire retardancy in wheat gluten polymer through naturally-occurring additives such as lanosol. The fire properties of lanosol were compared with two other conventional brominated fire retardants (Tetrabromobisphenol A and Hexabromocyclododecane). Samples containing fire retardants and gluten were prepared through compression moulding process and then characterised for their fire and mechanical properties. All fire retardants enhanced the reaction-to-fire and thermal properties of gluten while generating V-0 (i.e. vertical position and self-extinguished) ratings in the UL-94 test. The presence of all the fire retardants increased the modulus of the gluten polymer but the fire retardant particles were detrimental for the tensile strength. Nevertheless, lanosol addition delayed ignition and lowered peak heat release rate of gluten by the maximum amount, thereby leading to relatively higher fire performance index (compared to the other fire retardants). Lanosol also allowed the gluten to create a dense char barrier layer during burning that impeded the transfer of heat and flammable volatiles. The fact that only 4 wt% lanosol was able to cause self-extinguishment under direct flame and reduce peak heat release rate by a significant 50% coupled with its inherent occurrence in nature, raises the question if lanosol can be a potential fire retardant in polymeric systems, although it is a bromophenol.
32.	Harnden, Ross, et al. (author) Multifunctional Carbon Fiber Composites : A Structural, Energy Harvesting, Strain-Sensing Material 2022 In: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 14:29, s. 33871-33880 Journal article (peer-reviewed)abstract Multifunctional structural materials are capable of reducing system level mass and increasing efficiency in load -carrying structures. Materials that are capable of harvesting energy from the surrounding environment are advantageous for autono-mous electrically powered systems. However, most energy harvesting materials are non-structural and add parasitic mass, reducing structural efficiency. Here, we show a structural energy harvesting composite material consisting of two carbon fiber (CF) layers embedded in a structural battery electrolyte (SBE) with a longitudinal modulus of 100 GPa-almost on par with commercial CF pre-pregs. Energy is harvested through mechanical deforma-tions using the piezo-electrochemical transducer (PECT) effect in lithiated CFs. The PECT effect creates a voltage difference between the two CF layers, driving a current when deformed. A specific power output of 18 nW/g is achieved. The PECT effect in the lithiated CFs is observed in tension and compression and can be used for strain sensing, enabling structural health monitoring with low added mass. The same material has previously been shown capable of shape morphing. The two additional functionalities presented here result in a material capable of four functions, further demonstrating the diverse possibilities for CF/SBE composites in multifunctional applications in the future.
33.	Hwang, Byungil, et al. (author) Machine-Washable Conductive Silk Yarns with a Composite Coating of Ag Nanowires and PEDOT:PSS 2020 In: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 12:24, s. 27537-27544 Journal article (peer-reviewed)abstract Electrically conducting fibers and yarns are critical components of future wearable electronic textile (e-textile) devices such as sensors, antennae, information processors, and energy harvesters. To achieve reliable wearable devices, the development of robust yarns with a high conductivity and excellent washability is urgently needed. In the present study, highly conductive and machine-washable silk yarns were developed utilizing a Ag nanowire and PEDOT:PSS composite coating. Ag nanowires were coated on the silk yarn via a dip-coating process followed by coating with the conjugated polymer:polyelectrolyte complex PEDOT:PSS. The PEDOT:PSS covered the Ag nanowire layers while electrostatically binding to the silk, which significantly improved the robustness of the yarn as compared with the Ag nanowire-coated reference yarns. The fabricated conductive silk yarns had an excellent bulk conductivity of up to ∼320 S/cm, which is largely retained even after several cycles of machine washing. To demonstrate that these yarns can be incorporated into e-textiles, the conductive yarns were used to construct an all-textile out-of-plane thermoelectric device and a Joule heating element in a woven heating fabric.
34.	Anuar Bahari, Shahril, et al. (author) Strength Performance and Microstructure Characteristic of Naturally-Bonded Fiberboard Composite from Malaysian Bamboo (Bambusa vulgaris) 2022 In: Journal of Renewable Materials. - : Tech Science Press. - 2164-6325 .- 2164-6341. ; 10:10, s. 2581-2591 Journal article (peer-reviewed)abstract This study investigated the mechanical properties and microstructural characteristics of fiberboard composite produced by naturally-bonded Malaysian bamboo fiber (Bambusa vulgaris). The components that obtained through soda pulping of bamboo culms such as fiber and black liquor, were used for the preparation of high-density fibreboard composite at two target densities of 850 and 950 kg/m3. The bamboo fiberboard composite (BFC) were then produced at 200°C and two pressing parameters of 125 and 175 s/mm. The mechanical properties, e.g., flexural strength and internal bonding (IB) of BFC samples were evaluated according to BS EN 310: 1993 and BS EN 319: 1993, respectively. It was found that the mechanical performance of the composite with 850 kg/m3 density was significantly higher than 950 kg/m3 ones, especially for the samples with 125 s/mm pressing parameter. Microstructure characteristic of the BFC samples illustrated that the fiber linkages were cracked in the composites with higher density, e.g., the composite with the density of 950 kg/m3 and also black liquor were slightly degraded at longer pressing time, which led to the reduction in mechanical properties, especially in IB strength.
35.	Darabi, Sozan, 1994, et al. (author) Green Conducting Cellulose Yarns for Machine-Sewn Electronic Textiles 2020 In: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 12:50, s. 56403-56412 Journal article (peer-reviewed)abstract The emergence of "green"electronics is a response to the pressing global situation where conventional electronics contribute to resource depletion and a global build-up of waste. For wearable applications, green electronic textile (e-textile) materials present an opportunity to unobtrusively incorporate sensing, energy harvesting, and other functionality into the clothes we wear. Here, we demonstrate electrically conducting wood-based yarns produced by a roll-to-roll coating process with an ink based on the biocompatible polymer:polyelectrolyte complex poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). The developed e-textile yarns display a, for cellulose yarns, record-high bulk conductivity of 36 Scm-1, which could be further increased to 181 Scm-1 by adding silver nanowires. The PEDOT:PSS-coated yarn could be machine washed at least five times without loss in conductivity. We demonstrate the electrochemical functionality of the yarn through incorporation into organic electrochemical transistors (OECTs). Moreover, by using a household sewing machine, we have manufactured an out-of-plane thermoelectric textile device, which can produce 0.2 μW at a temperature gradient of 37 K.
36.	Lund, Anja, 1971, et al. (author) Conducting materials as building blocks for electronic textiles 2021 In: MRS Bulletin. - : Springer Science and Business Media LLC. - 0883-7694 .- 1938-1425. ; 46:6, s. 491-501 Research review (peer-reviewed)abstract To realize the full gamut of functions that are envisaged for electronic textiles (e-textiles) a range of semiconducting, conducting and electrochemically active materials are needed. This article will discuss how metals, conducting polymers, carbon nanotubes, and two-dimensional (2D) materials, including graphene and MXenes, can be used in concert to create e-textile materials, from fibers and yarns to patterned fabrics. Many of the most promising architectures utilize several classes of materials (e.g., elastic fibers composed of a conducting material and a stretchable polymer, or textile devices constructed with conducting polymers or 2D materials and metal electrodes). While an increasing number of materials and devices display a promising degree of wash and wear resistance, sustainability aspects of e-textiles will require greater attention.
37.	Rosenstock Völtz, Luísa, et al. (author) The use of recycled materials towards sustainability: biocomposites manufactured in melt compounding 2022 In: ECCM 2022 - Proceedings of the 20th European Conference on Composite Materials. - Lausanne : EPFL Lausanne, Composite Construction Laboratory. - 9782970161400 ; , s. 600-607 Conference paper (other academic/artistic)abstract Currently, there is a need in developing sustainable materials with an emphasis on reusing and recycling, to meet the sustainable development goals outlined by the United Nations for 2030. This work aimed to use recycled materials, such as recycled jeans and recycled rubber to replace the additive used in commercial wood polymer composites (WPCs) (reference material) to make it more sustainable without affecting its technical performance. The feeding of the post-used jeans fabric directly into the extruder was accomplished successfully with an increase in strength, modulus, and impact properties when compared with the reference material. The fracture surfaces showed that the fiber pullout contributed to the enhancement in fracture toughness with the addition of recycled jeans, further the addition of recycled rubber led to the matrix modification keeping the toughness at the same level as the reference material.
38.	Darabi, Sozan, 1994, et al. (author) Polymer-Based n-Type Yarn for Organic Thermoelectric Textiles 2023 In: Advanced Electronic Materials. - : Wiley. - 2199-160X .- 2199-160X. ; 9:4 Journal article (peer-reviewed)abstract A conjugated-polymer-based n-type yarn for thermoelectric textiles is presented. Thermoelectric textile devices are intriguing power sources for wearable electronic devices. The use of yarns comprising conjugated polymers is desirable because of their potentially superior mechanical properties compared to other thermoelectric materials. While several examples of p-type conducting yarns exist, there is a lack of polymer-based n-type yarns. Here, a regenerated cellulose yarn is spray-coated with an n-type conducting-polymer-based ink composed of poly(benzimidazobenzophenanthroline) (BBL) and poly(ethyleneimine) (PEI). The n-type yarns display a bulk electrical conductivity of 8 × 10−3 S cm−1 and Seebeck coefficient of −79 µV K−1. A promising level of air-stability for at least 13 days can be achieved by applying an additional thermoplastic elastomer coating. A prototype in-plane thermoelectric textile, produced with the developed n-type yarns and p-type yarns, composed of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-coated regenerated cellulose, displays a stable device performance in air for at least 4 days with an open-circuit voltage per temperature difference of 1 mV °C−1. Evidently, polymer-based n-type yarns are a viable component for the construction of thermoelectric textile devices.
39.	Khalili, Pooria, 1985, et al. (author) Elastomer Characterization Method for Trapped Rubber Processing 2020 In: Polymers. - : MDPI AG. - 2073-4360. ; 12:3 Journal article (peer-reviewed)abstract The increasing high-volume demand for polymer matrix composites (PMCs) brings into focus the need for autoclave alternative processing. Trapped rubber processing (TRP) of PMCs is a method capable of achieving high pressures during polymer matrix composite processing by utilizing thermally induced volume change of a nearly incompressible material inside a closed cavity mold. Recent advances in rubber materials and computational technology have made this processing technique more attractive. Elastomers can be doped with nanoparticles to increase thermal conductivity and this can be further tailored for local variations in thermal conductivity for TRP. In addition, recent advances in computer processing allow for simulation of coupled thermomechanical processes for full part modeling. This study presents a method of experimentally characterizing prospective rubber materials. The experiments are designed to characterize the dynamic in situ change in temperature, the dynamic change in volume, and the resulting real-time change in surface pressure. The material characterization is specifically designed to minimize the number and difficulty of experimental tests while fully capturing the rubber behavior for the TRP scenario. The experimental characterization was developed to provide the necessary data for accurate thermomechanical material models of nearly incompressible elastomeric polymers for use in TRP virtual design and optimization.
40.	Lidén, Anna, 1994, et al. (author) Structure of Filter Cakes during the Electroassisted Filtration of Microfibrillated Cellulose 2022 In: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 1520-5045 .- 0888-5885. ; 61:43, s. 16247-16256 Journal article (peer-reviewed)abstract Microfibrillated cellulose (MFC) is a biobased material with unique properties that can be used in a multitude of applications. Water removal from the dilute product streams is, however, challenging and hinders its commercial attractiveness. One possible method of improving dewatering is the use of electroassisted filtration, in which an electric field is applied across part of the filter chamber. In this work, a bench-scale dead-end filter press, modified to allow for electroassisted filtration, was used to dewater a suspension of MFC produced via 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation. A filter cake was produced with a channeled structure related to the design of the anode mesh, indicating that the cellulose microfibrils were aligned in the direction of the electric field. This was investigated, qualitatively and quantitively, using scanning electron microscopy and wide-angle X-ray scattering, which showed a preferred orientation on a microscopic level but only a partial orientation on a molecular level (fc between 0.49 and 0.57). The influence of the density of the anode mesh, in terms of the structure/permeability of the filter cake and dewatering rate, was also evaluated using two different anode mesh densities (5 × 5 and 10 × 10 mm). It was not, however, found to have any major impact on the dewatering rate.
41.	Karlsson, Tobias, et al. (author) Sensing abilities of embedded vertically aligned carbon nanotube forests in structural composites: From nanoscale properties to mesoscale functionalities 2023 In: Composites Part B: Engineering. - : Elsevier BV. - 1359-8368 .- 1879-1069. ; 255 Journal article (peer-reviewed)abstract In this paper, Vertically Aligned Carbon Nanotube (VACNT) forests are embedded into two different glass fibre/epoxy composite systems to study their sensing abilities to strain and temperature. Through a bottom-up approach, performing studies of the VACNT forest and its individual carbon nanotubes on the nano-, micro-, and mesoscale, the observed thermoresistive effect is determined to be due to fluctuation-assisted tunnelling, and the linear piezoresistive effect due to the intrinsic piezoresistivity of individual carbon nanotubes. The VACNT forests offer great freedom of placement into the structure and reproducibility of sensing sensitivity in both composite systems, independent of conductivity and volume fraction, producing a robust sensor to strain and temperature.
42.	Ouyang, Yingwei, 1995 (author) Novel Thermoplastic Material Concepts for High Voltage Cable Insulation - Engineering Immiscible Blends for a Sustainable Future 2021 Doctoral thesis (other academic/artistic)abstract To cope with our growing demand for energy in a sustainable way, efficient long-distance power transmission via high voltage direct current (HVDC) cables is crucial – these cables facilitate the integration of renewable energy into our power networks. For reliable and efficient power transmission, underground and undersea cables require robust insulation materials that possess a high level of mechanical integrity, a low direct-current (DC) electrical conductivity and a high thermal conductivity at the elevated temperatures experienced during cable operation. There is growing interest in thermoplastic materials that fulfill these requirements since thermoplastics offer the possibility for mechanical recycling by melt-reprocessing, and allow for more energy efficient cable production. In this thesis, it is shown that thermoplastic blends of low-density polyethylene (LDPE) and isotactic polypropylene (iPP) can be engineered towards HVDC cable insulation applications despite the immiscibility between LDPE and iPP. Reactive compounding was explored as a strategy for compatibilising iPP and LDPE, resulting in a material concept that exhibited good thermomechanical properties while maintaining low DC electrical conductivity and thermoplasticity. Blends comprising iPP, LDPE and a styrenic copolymer were also investigated. This led to another thermoplastic material concept where the blend composition could be tuned to simultaneously attain appropriate mechanical stiffness, DC electrical conductivity and thermal conductivity. Further, the addition of aluminium oxide nanoparticles was found to reduce the already low DC electrical conductivity of such blends. The novel material concepts described in this thesis may facilitate the design of thermoplastic insulation materials for HVDC cables of the future.
43.	Wang, Ying, et al. (author) Epoxy composite with high thermal conductivity by constructing 3D-oriented carbon fiber and BN network structure 2021 In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 11:41, s. 25422-25430 Journal article (peer-reviewed)abstract As electronic devices tend to be integrated and high-powered, thermal conductivity is regarded as the crucial parameter of electronic components, which has become the main factor that limits the operating speed and service lifetime of electronic devices. However, constructing continuous thermal conductive paths for low content particle fillers and reducing interface thermal resistance between fillers and matrix are still two challenging issues for the preparation of thermally conductive composites. In this study, 3D-oriented carbon fiber (CF) thermal network structures filled with boron nitride flakes (BN) as thermal conductive bridges were successfully constructed. The epoxy composite was fabricated by thermal conductive material with a 3D oriented structure by the vacuum liquid impregnation method. This special 3D-oriented structure modified by BN (BN/CF) could efficiently broaden the heat conduction pathway and connected adjacent fibers, which leads to the reduction of thermal resistance. The thermal conductivity of the boron nitride/carbon fiber/epoxy resin composite (BN/CF/EP) with 5 vol% 10 mm CF and 40 vol% BN reaches up to 3.1 W m(-1) K-1, and its conductivity is only 2.5 x 10(-4) S cm(-1). This facile and high-efficient method could provide some useful advice for the thermal management material in the microelectronic field and aerospace industry.
44.	Eutionnat-Diffo, Prisca, 1992- (author) 3D printing of polymers onto textiles : An innovative approach to develop functional textiles 2020 Doctoral thesis (other academic/artistic)abstract This thesis aims at characterizing tridimensional (3D) printed polymers onto PET textile materials via fused deposition modeling (FDM) that uses both non-conductive and conductive polymers, optimizing their mechanical and electrical properties through statistical modeling and enhancing them with pre and post-treatments and the development of polymer blends. This research work supports the development of technical textiles through 3D printing that may have functionalities. The FDM process was considered in this thesis for its strong potential in terms of flexibility, resource-efficiency, cost-effectiveness tailored production and ecology compared to the existing conventional textile finishing processes, for instance, the digital and screen printings. The main challenge of this technology is to warranty optimized electrical and mechanical (bending, flexibility, tensile, abrasion, etc.) properties of the 3D printed polymer onto textiles for the materials to be used in textile industry. Therefore, the development of novel 3D printed polymers onto PET materials with improved properties is necessary.First of all, 3D printed non-conductive Polylactic Acid (PLA) and PLA filled with 2.5wt% Carbon-Black filled onto PET fabrics were purchased and manufactured through melt extrusion process respectively, to characterize their mechanical properties including adhesion, tensile, deformation, wash ability and abrasion. Then, the relationship between the textile structural characteristics and thermal properties and build platform temperature and these properties through statistical modeling was determined. Subsequently, different textile pre-treatments that include atmospheric plasma, grafting of acrylic acid and application of adhesives were suggested to enhance the adhesion properties of the 3D printed PLA onto PET fabrics. Lastly, novel biophasic blends using Low-Density Polyethylene (LDPE) / Propylene- Based Elastomer (PBE) filled with multi-walled carbon nanotubes (CNT) and high-structured carbon black (KB) were developed and manufactured to improve the flexibility, the stress and strain at rupture and the electrical properties of the 3D printed PLA onto PET fabric. The morphology, thermal and rheological properties of each blends are also accessed in order to understand the material behavior and enhanced mechanical and electrical properties.The findings demonstrated that the textile structure defined by its weft density and pattern and weft and warp yarn compositions has a significant impact on the adhesion, deformation, abrasion, tensile properties of 3D printed PLA onto PET fabrics. Compromises have to be found as porous and rough textiles with low thermal properties showed better wash-ability, adhesion and tensile properties and worse deformation and abrasion resistance. Statistical models between the textile properties and the 3D printed PLA onto PET materials and the properties were successfully developed and used to optimize them. The application of adhesives on treated PET with grafted acrylic acid did significantly improve the adhesion resistance and LDPE/PBE blends filled with CNT and KB that have co-continuous LDPE and PBE phases as well as CNT and KB selectively located at the interface and in the LDPE phase revealed enhanced deformation and tensile and electrical properties.
45.	Karlsson, Mattias E. (author) Fundamentals of Polyethylene Composites for HVDC Cable Insulation – Interfaces and Charge Carriers 2020 Doctoral thesis (other academic/artistic)abstract Power transmission over long distances by using high voltage direct current (HVDC) cables is important for the transition from fossil energy to using renewable energy sources, e.g. wind, solar and water. Higher operating voltages enable longer transmission lines but better insulation materials with a much lower conductivity than today´s crosslinked polyethylene (PE) are required to reach the goal of 1 MV by 2030. Nanocomposites consisting of small fractions of metal oxide nanoparticles in PE are promising insulation materials, showing ca. 100 times lower conductivity. The reasons for the better insulating properties are however not fully understood.The properties of PE and inorganic nanoparticles were studied in this project to evaluate the influence of different material parameters on the conductivity of the cable insulation material. For pristine PE, the polymer morphology and oxidation were found to have a significant impact on the conductivity. For PE nanocomposites, the particle/polymer interface was shown to adsorb polar molecules, which are present in PE cable insulation. A suggested hypothesis is that the adsorption on particle surfaces results in cleaning of the bulk polymer from impurities, which in turn contributes to decreased nanocomposite conductivity. Since the particle interface is believed to be decisive for the nanocomposite properties, the role of particle terminations was investigated in detail. Oxygen dominated particle terminations resulted in 2 times higher composite conductivity than with zinc dominated surfaces, while fully oxygen covered surfaces showed 10 times higher conductivity. Composite systems with micro-sized particles allowed for evaluating parameters independently, which is not possible for nanocomposites. Terminations of ‘PE-like’ hydrocarbon chains lowered the conductivity and these trends could also be transferred to similar zinc oxide nanocomposite systems.
46.	Seipel, Sina, 1987-, et al. (author) Effect of physical parameters and temperature on the piezo-electric jetting behaviour of UV-curable photochromic inks 2020 In: Scientific Reports. - London : Springer Nature. - 2045-2322. ; 10, s. 18841- Journal article (peer-reviewed)abstract Although resource-efficient processes like inkjet printing have a large potential to foster the development of smart and functional textiles, one bottleneck still is the development of functional inks. To make inkjet printing and UV curing given production techniques for smart and functional specialty products, e.g. photochromic textiles, deepened knowledge about the development, rheological behavior and jetting behavior of functional ink is needed. This paper focuses on the formulation and performance of UV-responsive and UV-curable inkjet inks, which are based on photochromic dyes and their application to produce UV-responsive textiles. Two commercial photochromic dyes—Reversacol Ruby Red (RR) and Sea Green (SG), which represent dyes of the naphthopyran and spirooxazine class, respectively, have been used to develop the inks. The photochromic inks are characterized according to their physical–chemical and rheological properties in respect to temperature. The influence of temperature on the drop formation of the inks in an industrial print head is analyzed using a high-speed camera, which reveals important information regarding challenges in ink jettability. It was found that the dye structure and type used in the ink can influence the jetting behavior of photochromic UV-curable ink. More pronounced temperature sensitivity of dyes can increase the temperature-related effects of drop formation as was observed for SG ink. The printability of the RR and SG inks is framed and underpinned by theoretical calculations of the Z number. Discrepancies are observed and discussed between existing theory of ink jettability and visual evaluation of the photochromic ink.
47.	Bengtsson, Jenny, et al. (author) Chemical Recycling of a Textile Blend from Polyester and Viscose, Part II : Mechanism and Reactivity during Alkaline Hydrolysis of Textile Polyester 2022 In: Sustainability. - : MDPI. - 2071-1050. ; 14:11 Journal article (peer-reviewed)abstract Chemical recycling of textiles holds the potential to yield materials of equal quality and value as products from virgin feedstock. Selective depolymerization of textile polyester (PET) from regenerated cellulose/PET blends, by means of alkaline hydrolysis, renders the monomers of PET while cellulose remains in fiber form. Here, we present the mechanism and reactivity of textile PET during alkaline hydrolysis. Part I of this article series focuses on the cellulose part and a possible industrialization of such a process. The kinetics and reaction mechanism for alkaline hydrolysis of polyester packaging materials or virgin bulk polyester are well described in the scientific literature; however, information on depolymerization of PET from textiles is sparse. We find that the reaction rate of hydrolysis is not affected by disintegrating the fabric to increase its surface area. We ascribe this to the yarn structure, where texturing and a low density assures a high accessibility even without disintegration. The reaction, similar to bulk polyester, is shown to be surface specific and proceeds via endwise peeling. Finally, we show that the reaction product terephthalic acid is pure and obtained in high yields. © 2022 by the authors.
48.	Bolinius, Dämien Johann (author) Siptex - Quality assurance report 2022 Reports (peer-reviewed)abstract Siptex (Swedish Innovation Platform for Textile Sorting) is a research project funded by Sweden’s Innovation Agency's Challenge-driven innovation initiative. As a new step in the textile value chain, Siptex aims to create the conditions for increased profitability in the handling of the ever-increasing amounts of textile waste that are collected for material recycling and an increase in fibre-to-fibre recycling of textiles. This report focuses on the work carried out in the work package called “Quality assurance”. There were two main goals within this work. The first goal was to enable the establishment of a range of quality assured products. The second goal was to increase the knowledge on hazardous chemicals in post-consumer textiles in general.Five different outbound products of specific fibre content have been developed based on market demand. The products are referred to as ReFab® by SYSAV and include Siptex sorted materials of different purities of cotton, polyester and acrylics. For the quality assurance process, a method was developed to take representative textile samples from the bales of post-consumer materials, using a hay sampler and an extensive shredding process to product homogenous samples of shredded textile fibres. In the Siptex project, a total of 15 samples per bale was considered to be both practical as well as likely to give a good representation of the contents in a certain bale. This number is the result of a small pilot study which is described in this report. This method can be supplemented by a more routine analysis in which samples are taken by hand to monitor sorting efficiencies. The increase the knowledge on hazardous chemicals in post-consumer textiles, the project investigated existing data on hazardous chemicals in post-consumer textiles and supplemented this with new data generated from chemical analyses on bales of Siptex sorted materials made of cotton, polyester, and acrylics. The analysis of the literature data and the results from the chemical analysis of Siptex samples, indicate that compliance with REACH due to presence of hazardous chemicals, likely is not an issue in the sorted post-consumer textiles. Post-consumer textiles also seem to clear Oeko-tex and AFIRM requirements for the majority of the chemical substances on these restricted substance lists. But not all samples clear all the requirements from Oeko-tex or AFIRM. Bales with polyester materials were found to be most likely in breach of Oeoko-tex or AFIRM requirements. Three remaining challenges were identified and discussed in the report. These include the need for more standards, further development of the colour sorting process and a need for more analyses and data-sharing on hazardous substances in post-consumer textiles.
49.	Ortiz Catalan, Max Jair, 1982, et al. (author) Chronic Use of a Sensitized Bionic Hand Does Not Remap the Sense of Touch 2020 In: Cell Reports. - : Elsevier BV. - 2211-1247. ; 33:12 Journal article (peer-reviewed)abstract Electrical stimulation of tactile nerve fibers can be used to restore touch through a bionic hand. Ortiz-Catalan et al. show that a mismatch between the location of the sensor on the bionic hand and the tactile experience is not resolved after long-term prosthesis use.
50.	Hörteborn, Erica, 1987 (author) Knitted architecture and wind: Designing loosely fitted architectural textiles for interaction with wind 2023 Doctoral thesis (other academic/artistic)abstract Utilising the textile’s ability to adapt to external forces such as the wind could lead to the creation of new design expressions and functional features within architecture. Prompted by architectural potentials of textiles deliberately designed to move and flex, this thesis aims to explore and demonstrate how such knitted textiles could contribute to enriched aesthetic expression and improved performance of architectural elements placed in windy environments. A key part of the research is the interaction of textile and wind, viewing it as a source of energy or force that could be used, diffused, or directed - to enrich and create a more comfortable urban environment. As such, this work is positioned at the intersection of three knowledge areas: architectural design, knitted textile design, and wind engineering. A research by design approach is used to conduct quantitative and qualitative investigations with design prototypes as main vehicles of inquiry. Specifically, a hybrid method of design-based research is applied, involving artistic making and qualitative evaluations of the design prototypes as well as scientific methods featuring quantitative textile performance measurements. Both physical and digital prototypes are utilised to probe the geometric expressions of knitted textiles and investigate the performative features of different knitted textile designs in relation to their wind reduction capacity. The main finding from the quantitative part of the study, encompassing wind tunnel experiments, is that loosely fitted knitted structures efficiently reduce wind velocities and high-energy eddies. Along with this, the qualitative investigations, involving a series of diversely designed knitted architectural prototypes, show that knitted textiles can be applied to design three-dimensional architectural structures that are aesthetically diverse and have a dynamic, ever-changing expression. Finally, the developed framework for designing loosely fitted textiles for interaction with wind seeks to provide architects with guidance concerning important aspects of such design, including the workflows, tools, and evaluation methods.

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