{"title":"Cover Image, Volume 61, Issue 20","authors":"","doi":"10.1002/pol.20230694","DOIUrl":"https://doi.org/10.1002/pol.20230694","url":null,"abstract":"<p>Pushing the limits of synthetic polymers in terms of stiffness and strength, aromatic polyamide fibers – like Kevlar® – are used for demanding applications. Damage mechanisms and crack propagation are observed <i>in situ</i> and unveil a widespread damage over the entire length of the fiber. These observations make it possible to draw a novel scenario of fracture. To shed light on the crucial role of microfibril cooperativity in fracture toughness, a slight twist is applied to the single fiber to promote tortuosity and frictional contacts between microfibrils. Statistical fracture analysis demonstrated the beneficial impact of such torsion on early failure events. Alba Marcellan created the cover image. DOI: 10.1002/pol.20230400\u0000 \u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":199,"journal":{"name":"Journal of Polymer Science Part A: Polymer Chemistry","volume":"61 20","pages":"i"},"PeriodicalIF":2.702,"publicationDate":"2023-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/pol.20230694","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41229882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Emerging researchers interview—Ji Liu, Southern University of Science and Technology","authors":"Journal of Polymer Science Editorial Office","doi":"10.1002/pol.20230675","DOIUrl":"https://doi.org/10.1002/pol.20230675","url":null,"abstract":"","PeriodicalId":199,"journal":{"name":"Journal of Polymer Science Part A: Polymer Chemistry","volume":"61 19","pages":"2231-2232"},"PeriodicalIF":2.702,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/pol.20230675","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41085101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cover Image, Volume 61, Issue 19","authors":"","doi":"10.1002/pol.20230684","DOIUrl":"https://doi.org/10.1002/pol.20230684","url":null,"abstract":"<p>The cover image by first author Kosuke Terayama represents nanoparticles composed of conjugated polymers (Pdots). Each monomer unit is a different color, highlighting the bright near-infrared fluorescent polymer due to the electronic interactions of the conjugated monomer units. A vague cellular image is depicted in the background because of the potential application of Pdots for clinical diagnosis and therapeutic evaluation. (DOI: 10.1002/pol.20230421)\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":199,"journal":{"name":"Journal of Polymer Science Part A: Polymer Chemistry","volume":"61 19","pages":"i"},"PeriodicalIF":2.702,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/pol.20230684","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41085096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cover Image, Volume 61, Issue 18","authors":"","doi":"10.1002/pol.20230610","DOIUrl":"https://doi.org/10.1002/pol.20230610","url":null,"abstract":"<p>The cover by Johannes Berg shows the schematic representation of calcium alginate consisting of mannuronic acid (green) and guluronic acid (red), cross-linked by calcium cations (yellow). An interpenetrating additional polymer is polyethyleneimine (blue), thereby constituting a composite hydrogel. Positively charged methylene blue is selectively adsorbed in the alginate hydrogel due to its negatively charged polymer backbone. Along with that, negatively charged congo red is selectively adsorbed by the positively charged polyethyleneimine. (DOI: 10.1002/pol.20230215)\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":199,"journal":{"name":"Journal of Polymer Science Part A: Polymer Chemistry","volume":"61 18","pages":"i"},"PeriodicalIF":2.702,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/pol.20230610","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6921935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cover Image, Volume 61, Issue 17","authors":"","doi":"10.1002/pol.20230585","DOIUrl":"https://doi.org/10.1002/pol.20230585","url":null,"abstract":"<p>The cover image by Daisuke Aoki shows how the properties of biobased furan polymers are tuned by the Diels–Alder reaction with the tailor-made modification agents. (DOI: 10.1002/pol.20230316)\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":199,"journal":{"name":"Journal of Polymer Science Part A: Polymer Chemistry","volume":"61 17","pages":"i"},"PeriodicalIF":2.702,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/pol.20230585","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5659704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Inside Cover","authors":"","doi":"10.1002/pol.20230513","DOIUrl":"https://doi.org/10.1002/pol.20230513","url":null,"abstract":"<p>Microfluidics are key tools for designing uniform polymer microgels via emulsion templates, although usually limited to microliter quantities. 3D printing forms a promising basis to fabricate flow cells in a single process step, enabling the integration of various functional microfluidic units in one device, e.g., to address the demand for large quantities of microgels for particle-based inks in extrusion-based 3D printing or for constructing supragels. Here, parallelized droplet formation and splitting are combined in one reusable 3D-printed flow cell to form polymer microparticles at milliliter-per-hour scale. Cover art designed by Martin Schumann. (DOI: 10.1002/pol.20230213)\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":199,"journal":{"name":"Journal of Polymer Science Part A: Polymer Chemistry","volume":"61 16","pages":"ii"},"PeriodicalIF":2.702,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/pol.20230513","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6244837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Clotilde Richard, Bruno Bresson, Maxime Bès, Laura Schittecatte, Solène Le Roux, Nizar Didane, François Bataille, Sébastien Joannès, Alba Marcellan
{"title":"Mechanisms of damage and fracture of aramid fibers: Focus on the role of microfibril cooperativity in fracture toughness","authors":"Clotilde Richard, Bruno Bresson, Maxime Bès, Laura Schittecatte, Solène Le Roux, Nizar Didane, François Bataille, Sébastien Joannès, Alba Marcellan","doi":"10.1002/pol.20230400","DOIUrl":"https://doi.org/10.1002/pol.20230400","url":null,"abstract":"<p>Pushing the limits of synthetic polymers in terms of stiffness and strength, aromatic polyamide fibers–like Kevlar®–are used for demanding applications in the form of fiber assemblies as ropes. The unique mechanical performance of aramid fiber is intimately linked to its hierarchical structure and orientation, induced during the spinning process. Surprisingly, after nearly 60 years of heavy use, very little is known about damage mechanisms and rational explanation of such high resistance. We report an experimental investigation of the fiber damage mechanisms at the single fiber scale (diameter ≅ 10 μm) with the aim to establish a link with the microstructure. Damage mechanisms and crack propagation are observed in situ for the first time and unveil a widespread damage over the entire length of the fiber in the form of a network of transverse and longitudinal cracks. These observations make it possible to draw a novel scenario of fracture that mitigates the small strain failure hypothesis. To shed light on the crucial role of microfibril cooperativity in fracture toughness, a slight twist is applied to the single fiber to promote tortuosity and frictional contacts between microfibrils. Statistical fracture analysis demonstrated the beneficial impact of such torsion on early failure events, since lowest fracture stresses are shifted to higher stresses.</p>","PeriodicalId":199,"journal":{"name":"Journal of Polymer Science Part A: Polymer Chemistry","volume":"61 20","pages":"2549-2558"},"PeriodicalIF":2.702,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/pol.20230400","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41229673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Poly(L-lactide)-b-poly(ε-caprolactone)-b-poly(D,L-lactide) copolymers with enhanced toughness and strength by regulating crystallization and phase separation","authors":"Yipeng Chen, Jiangang Zhang, Yuesheng Zhang, Wen Cao, Xiong Liu, Jianna Bao, Xianming Zhang, Wenxing Chen","doi":"10.1002/pol.20230425","DOIUrl":"https://doi.org/10.1002/pol.20230425","url":null,"abstract":"<p>Copolymerizing poly(lactide) with other materials to obtain better comprehensive performance is a effective way to expand its application range. In this work, the precursors of hydroxyl terminated (poly(L-lactide) [PLLA], poly(ε-caprolactone) [PCL], poly(D,L-lactide) [PDLLA]) were prepared, and PLLA-PCL-PDLLA copolymer were synthesized by chain extension. The effects of the proportion and molecular weight of each component and the amount of chain extender on crystallization, phase structures, mechanical properties and thermal stabilities of PLLA-PCL-PDLLA copolymer were studied in detail. Based on small-angle X-ray scattering results, the competition between crystallization and microphase separation was regulated by the composition and chain length of prepolymers. As the ratio of PLLA/PDLLA was 1:1, crystallization was prevailing and no obvious peak was observed in SAXS pattern. The tensile test results showed that as the ratio of PLLA/PDLLA increased from 1:1 to 1:5, the elongation at break of the copolymer changed from 1.8% to 343%. By using shorter length of PCL and PLLA segments in chain extension, improvement in strength and flexibility were obtained due to moderate degree of crystallization and microphase separation. This work used biodegradable materials to prepare extraordinary toughness copolymers without losing the biocompatibility, which may provide a feasible method for obtaining high toughness and biodegradable PLA-based materials.</p>","PeriodicalId":199,"journal":{"name":"Journal of Polymer Science Part A: Polymer Chemistry","volume":"61 19","pages":"2303-2315"},"PeriodicalIF":2.702,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41085114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Structural design of conjugated polymers for fluorescence bioimaging in the second near-infrared window","authors":"Kosuke Terayama, Satoshi Habuchi, Tsuyoshi Michinobu","doi":"10.1002/pol.20230421","DOIUrl":"https://doi.org/10.1002/pol.20230421","url":null,"abstract":"<p>Fluorescence imaging in the second near-infrared (NIR-II) region has become one of the most powerful tools in clinical diagnosis and therapy assessment because of its high spatial resolution, rapid feedback, radiation safety, and low cost. Conjugated polymer nanoparticles (Pdots) based on donor-acceptor (D-A) polymers are some of the most promising fluorescent probes which have many superior characteristics, such as a high fluorescence brightness, good photostability, facile functionalization, and low cytotoxicity. While there has been tremendous progress in developing fluorescent polymers for use in the NIR-II wavelength range, the types of monomer structures used as building blocks for NIR-II fluorophores are still limited compared to those for organic solar cells and organic transistors. This review summarizes the NIR-II fluorescent polymers reported in the past few decades. The donor/acceptor unit structures of the polymers are systematically classified and discussed, which will provide new insights into the logical molecular design of donor/acceptor units for the development of high-brightness NIR-II Pdots.</p>","PeriodicalId":199,"journal":{"name":"Journal of Polymer Science Part A: Polymer Chemistry","volume":"61 19","pages":"2276-2291"},"PeriodicalIF":2.702,"publicationDate":"2023-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/pol.20230421","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41085069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}