| 1. |
- Adatia, Karishma K., et al.
(författare)
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Structure–property relations of amphiphilic poly(furfuryl glycidyl ether)-block-poly(ethylene glycol) macromonomers at the air–water interface
- 2020
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry. - 1759-9954 .- 1759-9962. ; 11:35, s. 5659-5668
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Tidskriftsartikel (refereegranskat)abstract
- To deepen our knowledge of the film formation and the structure–property relations of poly(furfuryl glycidyl ether)-block-poly(ethylene glycol) (PFGEp-b-PEGq) macromonomers at the air–water interface, we synthesized PFGEp-b-PEGq in six different block lengths. The molar mass of the PFGEp-b-PEGq macromonomers varied from ∼2000 g mol−1 to ∼7000 g mol−1 and included a wide range of hydrophilic–lipophilic balance (HLB) values between 3.6 and 13.9. Surface pressure–area (π–A) isotherms of these amphiphilic macromonomers revealed that the block lengths and the molar mass influence the isotherm shape and onset. Smaller, more hydrophobic macromonomers (HLB < 8) showed a steeper surface pressure increase in the liquid condensed phase compared to larger, more hydrophilic macromonomers with HLB > 8. The molecular area for isotherm onsets increased almost linearly with growing molar mass of the macromonomers. Static and dynamic film stability measurements demonstrated limited stability of all macromonomer monolayers at the air–water interface. The more hydrophilic macromonomers PFGE8-b-PEG79, PFGE18-b-PEG66 and PFGE13-b-PEG111 (HLB > 8) showed higher film stability compared to the more hydrophobic macromonomers (HLB < 8). Hysteresis experiments displayed an almost linear increase of the film degradation with rising HLB values of the macromonomers. Due to partial film recovery of our macromonomers, we propose an interplay between a reversible folding and an irreversible submersion mechanism for the macromonomer monolayers at the air–water interface. The molecular structure and the film forming ability of the macromonomers at the air–water interface indicate that they are promising surface functionalization reagents for materials formed from aqueous solutions, such as hydrogels. In this regard, PFGE10-b-PEG9 is the most promising hydrogel surface functionalization reagent, because it can introduce the highest number of functional groups per surface area.
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| 2. |
- Ai, Chenxiang, et al.
(författare)
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One-pot construction of nitrogen-rich polymeric ionic porous networks for effective CO2 capture and fixation
- 2022
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 13:1, s. 121-129
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Tidskriftsartikel (refereegranskat)abstract
- Facile preparation of ionic porous networks (IPNs) with large and permanent porosity is highly desirable for CO2 capture and transformation but remains a challenge. Here we report a one-pot base-mediated construction of nitrogen-rich IPNs through a combination of nucleophilic substitution and quaternisation chemistry from H-imidazole. This strategy, as proven by the model reactions of 1H-imidazole or 1-methyl-1H-imidazole with cyanuric chloride, allows for fine regulation of porosity and physicochemical properties, leading to nitrogen-rich IPNs featuring abundant ionic units and radicals. The as-prepared networks, termed IPN-CSUs, efficiently capture CO2 (80.1 cc g−1 at 273 K/1 bar) with an ideal CO2/N2 selectivity of 139.7. They can also effectively catalyse the cycloaddition reaction between CO2 and epoxides with high yields of up to 99% under mild conditions (0.1 MPa, 298 K), suggesting their possible applications in the fields of both selective molecular separation and conversion. Unlike the previously known strategies generally involving single coupling chemistry, our strategy combining two coupling routes in one pot appears to be unique and potentially applicable to other building blocks.
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| 3. |
- Alexakis, Alexandros Efraim, et al.
(författare)
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Bimodal nanolatexes prepared via polymerization-induced self-assembly : losing control in a controlled manner
- 2023
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 14:19, s. 2308-2316
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Tidskriftsartikel (refereegranskat)abstract
- The combination of reversible addition-fragmentation chain-transfer (RAFT) polymerization with polymerization-induced self-assembly (PISA) is known to yield monodisperse nanolatexes. Interestingly, based on the results of the current study, reproducible bimodal nanolatexes were shown to be the result of chain extension of protonated poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) with methyl methacrylate (MMA) in water when aiming for a longer hydrophobic block, for which we provide the first imaging data to our knowledge. The bimodality was found to be induced by the hydrophilic Z-group of the RAFT agent, which has been reported in the literature to be the cause of bimodal molecular weight distributions in RAFT-mediated PISA in emulsion polymerization. Moreover, the advantages of such reproducible bimodal size distribution nanolatexes in coating applications were investigated briefly, underlining the possibilities of their one-pot synthesis. It was found that when bimodal nanolatexes are adsorbed onto cellulose filter paper, the contact angle against water is higher compared to chemically similar monomodal nanolatexes. Also, the morphological arrangement was found to be dependent on the drying protocol. This study aims to expand our understanding on bimodality and the identification of parameters that could promote it on demand to target high-end applications.
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| 4. |
- Andrén, Oliver, et al.
(författare)
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Facile thiolation of hydroxyl functional polymers
- 2017
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry. - 1759-9954 .- 1759-9962. ; 8:34, s. 4996-5001
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Tidskriftsartikel (refereegranskat)abstract
- Sulfur is an important component in many biological systems. In the hands of an organic chemist it can provide an ample handle for a myriad of robust reactions including thiol-ene click chemistry. However, in polymer chemistry the thiol functionality is rarely attributed to the macromolecule due to unatainable synthetic protocols. Herein, we provide a simple and robust strategy to produce thiol-functional polymers. The chemistry capitalizes on an unsymmetrical disulfide that straightforwardly converts hydroxyl functional polymers to their thiolated counterpart. Finally, PEG hydrogels, using both thiol-ene and Michael addition, is used to showcase the possibilities presented by thiol functional polymers.
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| 5. |
- Arias, Veluska, et al.
(författare)
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Selective degradation in aliphatic block copolyesters by controlling the heterogeneity of the amorphous phase
- 2015
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 6:17, s. 3271-3282
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Tidskriftsartikel (refereegranskat)abstract
- Controlling the course of the degradation of aliphatic polyesters is a key question when designing new degradable materials. It is shown herein that it is possible to predetermine the degradation path of aliphatic block copolyesters by controlling the heterogeneity of the amorphous phase, which in turn regulates the availability of the hydrolyzable groups in the polyester backbone. To demonstrate these processes, we synthesized a set of degradable materials based on poly(l-lactide) (PLLA), poly(ε-decalactone) (PεDL) and poly(ε-caprolactone) (PCL) with varying compositions. The materials were subjected to hydrolysis for a six months period. The materials composed of PLLA and PεDL exhibited a heterogeneous amorphous phase, whereas the materials composed of PCL and PεDL presented a more homogeneous phase. The kinetics of the degradation indicated that the slowest degradation rate was observed for the more homogeneous compositions. The degradation path of the heterogeneous amorphous phase materials was driven by a random chain scission process, whereas the more homogeneous composition presented a degradation path driven by a more selective chain scission. The confinement of the amorphous phase by the more hydrolytically stable PεDL permitted a selective degradation of the available hydrolyzable groups. The random and more selective chain scission processes were further verified by using previously determined molecular modeling based on Monte Carlo procedures. Topographical images and thermal analyses of the materials under different degradation periods correlated with the proposed degradation paths. Detailed insights and the ability to predetermine the degradation pathways of aliphatic polyesters will continue to expand the great potential of renewable materials and their use in specific applications for a future sustainable society.
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| 6. |
- Asplund, Maria, et al.
(författare)
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Electroactive polymers for neural interfaces
- 2010
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Ingår i: Polymer chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 1:9, s. 1374-1391
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Forskningsöversikt (refereegranskat)abstract
- Development of electroactive conjugated polymers, for the purpose of recording and eliciting signals in the neural systems in humans, can be used to fashion the interfaces between the two signalling systems of electronics and neural systems. The design of desirable chemical, mechanical and electrical properties in the electroactive polymer electrodes, and the means of integration of these into biological systems, are here reviewed.
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| 7. |
- Auty, Sam E. R., et al.
(författare)
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One-pot' sequential deprotection/functionalisation of linear-dendritic hybrid polymers using a xanthate mediated thiol/Michael addition
- 2015
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 6:4, s. 573-582
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Tidskriftsartikel (refereegranskat)abstract
- Thiol-Michael addition chemistry is a powerful tool for the preparation of functional materials. In this first report of xanthate-functional linear-dendritic polymer hybrids, the preparation of four generations of xanthate-functionalised dendron atom transfer radical polymerisation macroinitiators is described using an orthogonal chemical strategy. The controlled polymerisation of tertiary butyl methacrylate is demonstrated to high conversion and without interference from the xanthate surface groups. Modification of the peripheral xanthate groups of dendrons at the hybrid polymer chain-end has been studied using a one-pot deprotection/functionalisation strategy and a range of commercially available and bespoke acrylate monomers to form complex polymer architectures from feedstock polymers, differing in the number of modified end groups and the surface chemistry of the dendron chain end.
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| 8. |
- Bini, Kim, 1987, et al.
(författare)
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Broad spectrum absorption and low-voltage electrochromic operation from indacenodithieno[3,2-: B] thiophene-based copolymers
- 2019
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 10:16, s. 2004-2014
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Tidskriftsartikel (refereegranskat)abstract
- Electrochromic performance of conjugated polymers has quickly become an important design factor in a variety of applications. There is still significant need to develop highly stable materials with high optical contrast, desired colour switching and fast kinetics. Here, poly[indacenodithieno[3,2-b]thiophene-2,8-diyl] (PIDTT) is introduced as a new type of electrochromic polymer exhibiting a narrow absorption band, excellent electrochemical stability and fast colour switching kinetics between vibrant red (peak maximum at ∼550 nm) and transparent (peak maximum at ∼920 nm) within a low potential range of 0-0.8 V. To widen the spectral coverage of the well-functioning PIDTT over the entire visible range, a modified donor-acceptor approach is used by incorporating three different donor-acceptor-donor (DAD) segments into an indacenodithieno[3,2-b]thiophene (IDTT) based polymer backbone, so as to obtain three different alternating copolymers. This design motif is further rationalized by the maintained electrochemical stability of the new copolymers, and their full colour switching between black and transparent down to an ultra-low potential range of 0-0.6 V.
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| 9. |
- Carlsson, Linn, et al.
(författare)
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Modification of cellulose model surfaces by cationic polymer latexes prepared by RAFT-mediated surfactant-free emulsion polymerization
- 2014
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry. - 1759-9954 .- 1759-9962. ; 5:20, s. 6076-6086
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the successful surface modification of a model cellulose substrate by the preparation and subsequent physical adsorption of cationic polymer latexes. The first part of the work introduces novel charged polymer nanoparticles constituted of amphiphilic block copolymers based on cationic poly(N,N-dimethylaminoethyl methacrylate-co-methacrylic acid) (P(DMAEMA-co-MAA)) as the hydrophilic segment, and poly(methyl methacrylate) (PMMA) as the hydrophobic segment. First, RAFT polymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) in water was performed at pH 7, below its pKa. The simultaneous hydrolysis of DMAEMA led to the formation of a statistical copolymer incorporating mainly protonated DMAEMA units and some deprotonated methacrylic acid units at pH 7. The following step was the RAFT-mediated surfactant-free emulsion polymerization of methyl methacrylate (MMA) using P(DMAEMA-co-MAA) as a hydrophilic macromolecular RAFT agent. During the synthesis, the formed amphiphilic block copolymers self-assembled into cationic latex nanoparticles by polymerization-induced self-assembly (PISA). The nanoparticles were found to increase in size with increasing molar mass of the hydrophobic block. The cationic latexes were subsequently adsorbed to cellulose model surfaces in a quartz crystal microbalance equipment with dissipation (QCM-D). The adsorbed amount, in mg m-2, increased with increasing size of the nanoparticles. This approach allows for physical surface modification of cellulose, utilizing a water suspension of particles for which both the surface chemistry and the surface structure can be altered in a well-defined way.
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| 10. |
- Carlsson, Linn, et al.
(författare)
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Surface-initiated ring-opening metathesis polymerisation from cellulose fibres
- 2012
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Ingår i: POLYM CHEM-UK. - : Royal Society of Chemistry. - 1759-9954. ; 3:3, s. 727-733
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Tidskriftsartikel (refereegranskat)abstract
- In this study, cellulose fibres have been grafted utilizing surface-initiated ring-opening metathesis polymerisation (SI-ROMP). Initially, a Grubbs' type catalyst was immobilized onto filter paper whereafter SI-ROMP of norbornene was performed from the surface of the fibres at three different reaction temperatures, room temperature (RT), 0 degrees C and -18 degrees C, and for different reaction times. The evaluation of the grafted cellulose was performed by contact angle measurements, FT-Raman spectroscopy, FE-SEM and TGA. After the grafting, all samples were clearly hydrophobic with weight increases up to over 100%. The FT-Raman spectroscopy analysis showed significant structural changes after polymerization for cellulose substrates polymerized at 0 degrees C and RT, confirming that a polymer was grafted from the surface. FE-SEM images verified that these samples are covered by polynorbornene and that the fibrillar structure of the native cellulose disappeared. For the samples grafted at -18 degrees C, no significant changes were seen with these analysis methods. However, SI-ROMP appears to be a versatile method to modify cellulose fibres.
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