| 1. |
- Donahue, Mary, et al.
(författare)
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Tailoring PEDOT properties for applications in bioelectronics
- 2020
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Ingår i: Materials science & engineering. R, Reports. - : Elsevier. - 0927-796X .- 1879-212X. ; 140
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Tidskriftsartikel (refereegranskat)abstract
- Resulting from its wide range of beneficial properties, the conjugated conducting polymer poly(3,4‐ethylenedioxythiophene) (PEDOT) is a promising material in a number of emerging applications. These material properties, particularly promising in the field of bioelectronics, include its well‐known high‐degree of mechanical flexibility, stability, and high conductivity. However, perhaps the most advantageous property is its ease of fabrication: namely, low‐cost and straight‐forward deposition processes. PEDOT processing is generally carried out at low temperatures with simple deposition techniques, allowing for significant customization of the material properties through, as highlighted in this review, both process parameter variation and the addition of numerous additives. Here we aim to review the role of PEDOT in addressing an assortment of mechanical and electronic requirements as a function of the conditions used to cast or polymerize the films, and the addition of additives such as surfactants and secondary dopants. Contemporary bioelectronic research examples investigating and utilizing the effects of these modifications will be highlighted.
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| 2. |
- Gouné, M., et al.
(författare)
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Overview of the current issues in austenite to ferrite transformation and the role of migrating interfaces therein for low alloyed steels
- 2015
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Ingår i: Materials science & engineering. R, Reports. - : Elsevier BV. - 0927-796X .- 1879-212X. ; 92, s. 1-38
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Forskningsöversikt (refereegranskat)abstract
- Solid state phase transformations in metals, and more precisely the science of transformation interfaces, is a key point to understand the formation of nano/microstructure, and thus, as a result, many physical properties such as mechanical properties, conductivity, thermoelectric and magnetic properties of materials. Steels are by far the most widely used metallic alloys, and a deep understanding of their microstructure is essential to tailor their service properties. The transformation of high temperature parent austenite to ferrite is one of the main issues controlling the final microstructures, and for more than a century, this has driven metallurgists to investigate in detail this solid state transformation, and, particularly, the details of austenite to ferrite interface migration. In this paper, we review the evolution of the different concepts and experiments developed in the last century to investigate this transformation mechanism. After a brief introduction, most of the physical models developed, which reduce the α/γ interface into a mathematical body with its own properties, are reviewed and discussed with regard to experimental data. The increased availability of highly sophisticated experimental and modelling tools in recent decades has considerably clarified the perceptions of transformation interfaces. These recent advances are presented, and their contribution to the field of migrating austenite-ferrite interfaces are highlighted in a third section. In the fourth section, the latest developments in experimental methods, which now allow the quasi atomistic direct characterization of the interface chemistry, are presented. The observed conditions at the interfaces can be compared with model predictions, which is believed to be a critical step for the refinement of the theoretical concepts guiding the understanding of the interface migration. Finally, in the concluding section, the present situation of the field is summarized, and some perspectives regarding the expected future developments are sketched.
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| 3. |
- Lund, Anja, 1971, et al.
(författare)
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Electrically conducting fibres for e-textiles: An open playground for conjugated polymers and carbon nanomaterials
- 2018
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Ingår i: Materials Science and Engineering: R: Reports. - : Elsevier BV. - 0927-796X .- 1879-212X. ; 126, s. 1-29
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Forskningsöversikt (refereegranskat)abstract
- Conducting fibres and yams promise to become an essential part of the next generation of wearable electronics that seamlessly integrate electronic function into one of the most versatile and most widely used form of materials: textiles. This review explores the many types of conducting fibres and yarns that can be realised with conjugated polymers and carbon materials, including carbon black, carbon nanotubes and graphene. We discuss how the interplay of materials properties and the chosen processing technique lead to fibres with a wide range of electrical and mechanical properties. Depending on the choice of conjugated polymer, carbon nanotube, graphene, polymer blend, or nanocomposite the electrical conductivity can vary from less than 10(-3) to more than 10(3) S cm(-1), accompanied by an increase in Young's modulus from 10 s of MPa to 100 s of GPa. Further, we discuss how conducting fibres can be integrated into electronic textiles (e-textiles) through e.g. weaving and knitting. Then, we provide an overview of some of the envisaged functionalities, such as sensing, data processing and storage, as well as energy harvesting e.g. by using the piezoelectric, thermoelectric, triboelectric or photovoltaic effect. Finally, we critically discuss sustainability aspects such as the supply of materials, their toxicity, the embodied energy of fibre and textile production and recyclability, which currently are not adequately considered but must be taken into account to ready carbon based conducting fibres for truly practical e-textile applications.
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| 4. |
- Salaneck, William R, et al.
(författare)
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The electronic structure of polymer-metal interfaces studied by ultraviolet photoelectron spectroscopy
- 2001
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Ingår i: Materials science & engineering. R, Reports. - 0927-796X .- 1879-212X. ; 34:3, s. 121-146
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Forskningsöversikt (refereegranskat)abstract
- Ultraviolet photoelectron spectroscopy has come of age. UPS can take its place beside its older, better-known sister, ESCA (or XPS) as a surface sensitive method which has become more useful in learning certain specific things about interfaces at distances significantly larger than the typical electron elastic mean-free-paths dictated by the photon energies employed, In particular, the emergence of UPS as a real tool for interfacial studies has been applications driven, evolving after needs within polymer-based electronics applications. The situation is clarified through the use of several examples, drawn from the applications-spectroscopy literature. (C) 2001 Published by Elsevier Science B.V.
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| 5. |
- Wilson, Stephen A., et al.
(författare)
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New materials for micro-scale sensors and actuators An engineering review
- 2007
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Ingår i: Materials science & engineering. R, Reports. - : Elsevier BV. - 0927-796X .- 1879-212X. ; 56:06-jan, s. 1-129
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Forskningsöversikt (refereegranskat)abstract
- This paper provides a detailed overview of developments in transducer materials technology relating to their current and future applications in micro-scale devices. Recent advances in piezoelectric, magnetostrictive and shape-memory alloy systems are discussed and emerging transducer materials such as magnetic nanoparticles, expandable micro-spheres and conductive polymers are introduced. Materials properties, transducer mechanisms and end applications are described and the potential for integration of the materials with ancillary systems components is viewed as an essential consideration. The review concludes with a short discussion of structural polymers that are extending the range of micro-fabrication techniques available to designers and production engineers beyond the limitations of silicon fabrication technology.
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| 6. |
- Beretta, Davide, et al.
(författare)
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Thermoelectrics: From history, a window to the future
- 2019
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Ingår i: Materials Science and Engineering: R: Reports. - : Elsevier BV. - 0927-796X. ; 138
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Forskningsöversikt (refereegranskat)abstract
- Thermoelectricity offers a sustainable path to recover and convert waste heat into readily available electric energy, and has been studied for more than two centuries. From the controversy between Galvani and Volta on the Animal Electricity, dating back to the end of the XVIII century and anticipating Seebeck's observations, the understanding of the physical mechanisms evolved along with the development of the technology. In the XIX century Ørsted clarified some of the earliest observations of the thermoelectric phenomenon and proposed the first thermoelectric pile, while it was only after the studies on thermodynamics by Thomson, and Rayleigh's suggestion to exploit the Seebeck effect for power generation, that a diverse set of thermoelectric generators was developed. From such pioneering endeavors, technology evolved from massive, and sometimes unreliable, thermopiles to very reliable devices for sophisticated niche applications in the XX century, when Radioisotope Thermoelectric Generators for space missions and nuclear batteries for cardiac pacemakers were introduced. While some of the materials adopted to realize the first thermoelectric generators are still investigated nowadays, novel concepts and improved understanding of materials growth, processing, and characterization developed during the last 30 years have provided new avenues for the enhancement of the thermoelectric conversion efficiency, for example through nanostructuration, and favored the development of new classes of thermoelectric materials. With increasing demand for sustainable energy conversion technologies, the latter aspect has become crucial for developing thermoelectrics based on abundant and non-toxic materials, which can be processed at economically viable scales, tailored for different ranges of temperature. This includes high temperature applications where a substantial amount of waste energy can be retrieved, as well as room temperature applications where small and local temperature differences offer the possibility of energy scavenging, as in micro harvesters meant for distributed electronics such as sensor networks. While large scale applications have yet to make it to the market, the richness of available and emerging thermoelectric technologies presents a scenario where thermoelectrics is poised to contribute to a future of sustainable future energy harvesting and management. This work reviews the broad field of thermoelectrics. Progress in thermoelectrics and milestones that led to the current state-of-the-art are presented by adopting an historical footprint. The review begins with an historical excursus on the major steps in the history of thermoelectrics, from the very early discovery to present technology. A panel on the theory of thermoelectric transport in the solid state reviews the transport theory in complex crystal structures and nanostructured materials. Then, the most promising thermoelectric material classes are discussed one by one in dedicated sections and subsections, carefully highlighting the technological solutions on materials growth that have represented a turning point in the research on thermoelectrics. Finally, perspectives and the future of the technology are discussed in the framework of sustainability and environmental compatibility. © 2018 Elsevier B.V.
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| 7. |
- Gregory, David A., et al.
(författare)
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Bacterial cellulose: A smart biomaterial with diverse applications
- 2021
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Ingår i: Materials Science and Engineering: R: Reports. - : Elsevier BV. - 0927-796X. ; 145
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Forskningsöversikt (refereegranskat)abstract
- Natural biomaterials have benefited the human civilisation for millennia. However, in recent years, designing of natural materials for a wide range of applications have become a focus of attention, spearheaded by sustain-ability. With advances in materials science, new ways of manufacturing, processing, and functionalising bio-materials for structural specificity has become feasible. Our review is focused on bacterial cellulose (BC), an exceptionally versatile natural biomaterial. BC is a unique nanofibrillar biomaterial extruded by microscopic single-cell bacterial factories utilising the chemical energy harvested from renewable substrates. BC is extra-cellular and is intrinsically pure, unlike other biopolymers that require extraction and purification. BC fibres are 100 times thinner than plant-derived cellulose and exist in a highly porous three-dimensional network that is highly biocompatible. Macro fibres fabricated from BC nanofibrils are stronger and stiffer, have high tensile strength values and can be used as substitutes for fossil fuel-derived synthetic fibres. The increased surface area to volume ratio allows stronger interactions with the components of composites that are derived from BC. The reactive hydroxyl groups on BC allows various chemical modifications for the development of functionalised BC with a plethora of & lsquo;smart & rsquo; applications. In this review we consolidate the current knowledge on the production and properties of BC and BC composites, and highlight the very recent advancements in bulk applications, including food, paper, packaging, superabsorbent polymers and the bio-concrete industries. The process simplicity of BC production has the potential for large scale low-cost applications in bioremediation. Furthermore, the emerging high value applications of BC will be in electrochemical energy storage devices as a battery separator, and in transparent display technologies will be explored. Finally, the extensive biomedical applications of BC are discussed including, wound healing, controlled drug delivery, cancer treatment, cell culture and artificial blood vessels. In a further development on this, additive manufacturing considers enhancing the capabilities for manufacturing complex scaffolds for biomedical applications. An outlook on the future directions of BC in these and other innovative areas is presented.
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