Pub Date : 2025-01-15DOI: 10.1016/j.polymer.2025.128068
Daize Mo, Zhuang Ren, Kuirong Deng, Pengjie Chao
The benzoselenadiazole-based D-A-D polymers have demonstrated significant potential in organic solar cells, due to its lower optical band gap, more red-shifted absorption spectra, good processing ability, and higher hole transport. However, its application in the electrochromic field is relatively limited so far. Therefore, this work presents the design and synthesis of four difluorinated D-A-D monomers. These monomers incorporate difluorobenzoselenadiazole as their electron-withdrawing segment, with thiophene and 3,4-ethylenedioxythiophene (EDOT) serving as the electron-donor components. These monomers were polymerized into D-A-D polymers via electrochemical deposition method, and their optoelectronic properties were systematically investigated. The elongation of the π-conjugated systems of monomers, along with the stronger electron donating ability of the EDOT unit, further reduced the oxidation potential of Se-Th-EDOT to 0.65 V. This change was accompanied by a blue shift in the electronic spectra and a red shift in the emission spectra. Among the polymers, those derived from EDOT-containing monomers exhibited superior performance, including enhanced redox stability, and a notable shift in hue, evolving from green to a sky-blue shade when oxidized. Notably, the P(Se-Th-EDOT) exhibited remarkable electrochromic performances, featuring an optical contrast of 33.21%, response times within the range of 0.4 to 0.80 s, and a coloration efficiency reaching to 160.08 cm2 C-1. Devices based on P(Se-Th-EDOT) further shown improved coloration efficiency (228.66 cm2C-1) and rapid response times (0.05-0.28 s). The research outcomes underscore the suitability of D-A polymers that incorporate difluorinated benzoselenadiazole for the advancement of state-of-the-art electrochromic applications.
{"title":"Difluorinated benzoselenadiazole: a new promising electron withdrawing acceptor unit for building efficient D-A type electrochromic polymers","authors":"Daize Mo, Zhuang Ren, Kuirong Deng, Pengjie Chao","doi":"10.1016/j.polymer.2025.128068","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128068","url":null,"abstract":"The benzoselenadiazole-based D-A-D polymers have demonstrated significant potential in organic solar cells, due to its lower optical band gap, more red-shifted absorption spectra, good processing ability, and higher hole transport. However, its application in the electrochromic field is relatively limited so far. Therefore, this work presents the design and synthesis of four difluorinated D-A-D monomers. These monomers incorporate difluorobenzoselenadiazole as their electron-withdrawing segment, with thiophene and 3,4-ethylenedioxythiophene (EDOT) serving as the electron-donor components. These monomers were polymerized into D-A-D polymers via electrochemical deposition method, and their optoelectronic properties were systematically investigated. The elongation of the π-conjugated systems of monomers, along with the stronger electron donating ability of the EDOT unit, further reduced the oxidation potential of Se-Th-EDOT to 0.65 V. This change was accompanied by a blue shift in the electronic spectra and a red shift in the emission spectra. Among the polymers, those derived from EDOT-containing monomers exhibited superior performance, including enhanced redox stability, and a notable shift in hue, evolving from green to a sky-blue shade when oxidized. Notably, the P(Se-Th-EDOT) exhibited remarkable electrochromic performances, featuring an optical contrast of 33.21%, response times within the range of 0.4 to 0.80 s, and a coloration efficiency reaching to 160.08 cm<sup>2</sup> C<sup>-1</sup>. Devices based on P(Se-Th-EDOT) further shown improved coloration efficiency (228.66 cm<sup>2</sup>C<sup>-1</sup>) and rapid response times (0.05-0.28 s). The research outcomes underscore the suitability of D-A polymers that incorporate difluorinated benzoselenadiazole for the advancement of state-of-the-art electrochromic applications.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"9 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-14DOI: 10.1016/j.polymer.2025.128060
Jia Zhao, Haiyan Zhu, Huiyu Bai, Weifu Dong
Conductive hydrogels, due to their flexibility and conductivity, offer potential for wearable bioelectronics. Enhanced conductivity in these hydrogels stems from the conducting network of reactive particles, notably polypyrrole (PPy). Nevertheless, the hydrophobicity, brittleness, and opacity of conjugated π PPy hinder its application in conducting hydrogels for flexible, wearable, and transparent electronics. Herein, PPy-decorated cellulose nanocrystals (CNC-PPy) hydrophilic complexes are initially synthesized by in situ polymerization of pyrrole (Py) onto CNC. Subsequently, an ion-electron conductive PCPF hydrogel with a multi-crosslinked network structure is developed using polyvinyl alcohol bearing styrylpyridinium group (PVA-SbQ) and CNC-PPy under UV irradiation and ammonium persulfate (APS)-induced gelation, followed by ferric chloride (FeCl3) immersion. APS both initiates polymerization and disrupts PPy π-π stacking, enhancing mechanical properties and transparency. The unique synergy effect of CNC-PPy and FeCl3 contribute to superior mechanical (tensile strength of 370 ± 17 KPa and elongation at break of 702 ± 18 %), electrical (4.50 mS.cm-1) and strain sensitivity (GF = 1.43). Furthermore, it effectively monitors large deformations, like joint bending, and small deformations such as pulse. Thus, our approach offers a promising strategy for developing PVA-based hydrogels with exceptional mechanical and electrical properties while maintaining transparency, rendering them ideal for flexible sensors.
{"title":"Tough ion-electron conductive hydrogels with multi-crosslinked network for strain sensors","authors":"Jia Zhao, Haiyan Zhu, Huiyu Bai, Weifu Dong","doi":"10.1016/j.polymer.2025.128060","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128060","url":null,"abstract":"Conductive hydrogels, due to their flexibility and conductivity, offer potential for wearable bioelectronics. Enhanced conductivity in these hydrogels stems from the conducting network of reactive particles, notably polypyrrole (PPy). Nevertheless, the hydrophobicity, brittleness, and opacity of conjugated π PPy hinder its application in conducting hydrogels for flexible, wearable, and transparent electronics. Herein, PPy-decorated cellulose nanocrystals (CNC-PPy) hydrophilic complexes are initially synthesized by <em>in situ</em> polymerization of pyrrole (Py) onto CNC. Subsequently, an ion-electron conductive PCPF hydrogel with a multi-crosslinked network structure is developed using polyvinyl alcohol bearing styrylpyridinium group (PVA-SbQ) and CNC-PPy under UV irradiation and ammonium persulfate (APS)-induced gelation, followed by ferric chloride (FeCl<sub>3</sub>) immersion. APS both initiates polymerization and disrupts PPy π-π stacking, enhancing mechanical properties and transparency. The unique synergy effect of CNC-PPy and FeCl<sub>3</sub> contribute to superior mechanical (tensile strength of 370 ± 17 KPa and elongation at break of 702 ± 18 %), electrical (4.50 mS.cm<sup>-1</sup>) and strain sensitivity (GF = 1.43). Furthermore, it effectively monitors large deformations, like joint bending, and small deformations such as pulse. Thus, our approach offers a promising strategy for developing PVA-based hydrogels with exceptional mechanical and electrical properties while maintaining transparency, rendering them ideal for flexible sensors.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"12 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-13DOI: 10.1016/j.polymer.2025.128056
Sandra M. Cassemiro, Cristiano Zanlorenzi, Denis A. Turchetti, Francineide L. de Araújo, Roberto M. Faria, Alexandre Marletta, Leni Akcelrud
A published theoretical approach for forecasting the photovoltaic behavior of D-A copolymers, relying on the frontier levels of donor–acceptor (D–A) type copolymer was tested experimentally. The pair [5,11-bis(2-ethylhexyl) dihydroindolo [3,2-b]-carbazole] (D)/ [3,6-Bis(4-octylthiophen-2-yl)-1,2,4,5-tetrazine] (A) was chosen to prepare the DA copolymer (PIC-TTz), based on an extensive theoretical study that has considered 2080 DA possible combinations. The energy levels, estimated by cyclic voltammetry joined with absorption spectra revealed that the polymer have appropriate energy levels for organic photovoltaic application. Polymer photovoltaic devices based on blends of the copolymer and PC71BM showed a high open-circuit voltage (>0.9 V) under the illumination of AM 1.5 (100 mWcm-2). The determined power conversion efficiency (PCE) was 1.12%, and this result is discussed in light of the photophysical behavior not considered in the theoretical approach. It was demonstrated that although promising, the theory can be used as a guide, but not enough to substitute bench work.
{"title":"Theoretical and Experimental Photovoltaic Behaviors of an s-Tetrazine Based D-A Copolymer","authors":"Sandra M. Cassemiro, Cristiano Zanlorenzi, Denis A. Turchetti, Francineide L. de Araújo, Roberto M. Faria, Alexandre Marletta, Leni Akcelrud","doi":"10.1016/j.polymer.2025.128056","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128056","url":null,"abstract":"A published theoretical approach for forecasting the photovoltaic behavior of D-A copolymers, relying on the frontier levels of donor–acceptor (D–A) type copolymer was tested experimentally. The pair [5,11-bis(2-ethylhexyl) dihydroindolo [3,2-b]-carbazole] (D)/ [3,6-Bis(4-octylthiophen-2-yl)-1,2,4,5-tetrazine] (A) was chosen to prepare the DA copolymer (<strong>PIC-TTz</strong>), based on an extensive theoretical study that has considered 2080 DA possible combinations. The energy levels, estimated by cyclic voltammetry joined with absorption spectra revealed that the polymer have appropriate energy levels for organic photovoltaic application. Polymer photovoltaic devices based on blends of the copolymer and PC<sub>71</sub>BM showed a high open-circuit voltage (>0.9 V) under the illumination of AM 1.5 (100 mWcm<sup>-2</sup>). The determined power conversion efficiency (PCE) was 1.12%, and this result is discussed in light of the photophysical behavior not considered in the theoretical approach. It was demonstrated that although promising, the theory can be used as a guide, but not enough to substitute bench work.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"21 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142968470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-13DOI: 10.1016/j.polymer.2025.128058
Yifeng Li, Xuan Li, Hui Du, Yu Wang, Ping Zhu, Xia Dong, Dujin Wang
This study investigates the structural evolution under thermal treatment in an inert atmosphere of polyether-block-amide (PEBA) based on PA1012 and PTMO. Thermal analysis, nuclear magnetic resonance (NMR), in-situ small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD), rheology, and in situ infrared spectroscopy are employed to characterize the structure evolution, with a focus on both chemical and physical aspects. After the thermal treatment at 260°C for 60 minutes in nitrogen atmosphere, the chemical analyses of the sample show minimal reactions at the repeating unit scale, with only slight post-condensation. The main finding in this work is the suppression of crystallization in polyamide hard segments. Other key physical performances like glass transition temperature (Tg) and Brill transition temperature (TB) are largely unaffected, with the TB only shifts from 64°C to 61°C detected by WAXD. The observed changes are attributed to the formation of a denser non-chemical-crosslinking network structure, which reduces crystallization temperatures. Rheological measurements indicate that this network is reversible and can be disrupted by shear. This research enhances understanding of PEBA’s non-chemical-crosslinking network structure and its potential for controllable processing and functional design in high-performance materials.
{"title":"The Formation and Disruption of Reversible Physical Crosslinking Structure of Polyether-block-amide under High Temperature","authors":"Yifeng Li, Xuan Li, Hui Du, Yu Wang, Ping Zhu, Xia Dong, Dujin Wang","doi":"10.1016/j.polymer.2025.128058","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128058","url":null,"abstract":"This study investigates the structural evolution under thermal treatment in an inert atmosphere of polyether-block-amide (PEBA) based on PA1012 and PTMO. Thermal analysis, nuclear magnetic resonance (NMR), in-situ small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD), rheology, and in situ infrared spectroscopy are employed to characterize the structure evolution, with a focus on both chemical and physical aspects. After the thermal treatment at 260°C for 60 minutes in nitrogen atmosphere, the chemical analyses of the sample show minimal reactions at the repeating unit scale, with only slight post-condensation. The main finding in this work is the suppression of crystallization in polyamide hard segments. Other key physical performances like glass transition temperature (T<sub>g</sub>) and Brill transition temperature (T<sub>B</sub>) are largely unaffected, with the T<sub>B</sub> only shifts from 64°C to 61°C detected by WAXD. The observed changes are attributed to the formation of a denser non-chemical-crosslinking network structure, which reduces crystallization temperatures. Rheological measurements indicate that this network is reversible and can be disrupted by shear. This research enhances understanding of PEBA’s non-chemical-crosslinking network structure and its potential for controllable processing and functional design in high-performance materials.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"52 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rapid development of conductive hydrogels shows great potentials in the field of flexible sensors. Accordingly, the research on the hydrogel sensors with great self-healing property for long-term durability is noticeably essential. In the present study, curcumin (Cur)-involved polyacrylic acid (PAA) and polyethyleneimine (PEI) based hydrogels noted as PAA/PEI-Al-Cur were constructed. The effect of curcumin on the mechanical properties of the hydrogels was firstly studied. The introduction of curcumin could effectively improve the mechanical properties that the tensile strength of the prepared PAA/PEI-Al-Cur hydrogel could reach as high as 119.0 kPa. The existence of Al3+ and the porous network structure of the hydrogel entrust to a high conductivity (σ=1.11 S/m). Thus, the hydrogel could be applied as both strain sensor and pressure sensor to detect different deformations and various human activities including large-scale human movements and subtle facial expressions. It is worth noting that the self-healing ability of the hydrogels could be regulated by the amount of introduced curcumin that the optimal dose exhibited ultrafast self-healing ability and the mechanism was illustrated. More to the point, the healed hydrogel could be applied as the sensor to repeatedly and stably perform sensing behavior as the original one. This work provides an effective construction strategy to prepare novel conductive hydrogels for flexible sensors.
导电性水凝胶的迅速发展在柔性传感器领域显示出巨大的潜力。因此，研究具有良好自愈性能的长期耐用水凝胶传感器显得尤为必要。本研究构建了以姜黄素（Cur）为主体的聚丙烯酸（PAA）和聚乙烯亚胺（PEI）为基础的PAA/PEI- al -Cur水凝胶。首次研究了姜黄素对水凝胶力学性能的影响。姜黄素的加入可有效改善PAA/PEI-Al-Cur水凝胶的力学性能，制备的PAA/PEI-Al-Cur水凝胶的拉伸强度可高达119.0 kPa。Al3+的存在和水凝胶的多孔网络结构使其具有较高的电导率（σ=1.11 S/m）。因此，水凝胶可以作为应变传感器和压力传感器来检测不同的变形和各种人体活动，包括大规模的人体运动和微妙的面部表情。值得注意的是，水凝胶的自愈能力可以通过姜黄素的加入量来调节，最佳剂量表现出超快的自愈能力，并阐明了其作用机制。更重要的是，愈合后的水凝胶可以作为传感器重复稳定地执行原始传感器的传感行为。本研究为柔性传感器制备新型导电水凝胶提供了一种有效的构建策略。
{"title":"Curcumin-involved self-healing hydrogels as flexible sensors","authors":"Xinyu Wei, Zeng Liu, Hongli Fang, Zhiyue Cui, Shu He, Wei Shao","doi":"10.1016/j.polymer.2025.128047","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128047","url":null,"abstract":"The rapid development of conductive hydrogels shows great potentials in the field of flexible sensors. Accordingly, the research on the hydrogel sensors with great self-healing property for long-term durability is noticeably essential. In the present study, curcumin (Cur)-involved polyacrylic acid (PAA) and polyethyleneimine (PEI) based hydrogels noted as PAA/PEI-Al-Cur were constructed. The effect of curcumin on the mechanical properties of the hydrogels was firstly studied. The introduction of curcumin could effectively improve the mechanical properties that the tensile strength of the prepared PAA/PEI-Al-Cur hydrogel could reach as high as 119.0 kPa. The existence of Al<sup>3+</sup> and the porous network structure of the hydrogel entrust to a high conductivity (σ=1.11 S/m). Thus, the hydrogel could be applied as both strain sensor and pressure sensor to detect different deformations and various human activities including large-scale human movements and subtle facial expressions. It is worth noting that the self-healing ability of the hydrogels could be regulated by the amount of introduced curcumin that the optimal dose exhibited ultrafast self-healing ability and the mechanism was illustrated. More to the point, the healed hydrogel could be applied as the sensor to repeatedly and stably perform sensing behavior as the original one. This work provides an effective construction strategy to prepare novel conductive hydrogels for flexible sensors.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"82 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142968411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hydrogels, due to their exceptional flexibility, elasticity, and stretchability, are extensively utilized in numerous fields, particularly in the use of flexible wearable devices. However, the prevalent issues of solvent evaporation and limited environmental tolerance in the application of hydrogels significantly constrain their utilization in the field of flexible sensing. In this study, we designed a special organic gel, utilizing PEG as the solvent instead of water and Zr4+ as the physical cross-linking agent, to facilitate the formation of a steady copolymer network (P(AA-co-HEA)/PEG) that exhibits excellent mechanical properties, such as high fracture stress (1 MPa) and low hysteresis (<7%), as well as good adhesion ability (30 kN/m2) and good solvent evaporation resistance. Moreover, the addition of Zr4+ and Zn2+ not only enhanced the mechanical properties of the gel but also endowed it with good electrical conductivity. The conductive gels are capable of accurately distinguishing various deformations (10−250% tensile strain) and successively outputting reliable electrical signals with good durability. Most importantly, the gel can be utilized to fabricate a variety of complex structures via digital light processing (DLP) 3D printing technology. In summary, this work introduces a novel approach for the development of highly stable flexible wearable devices, which has the potential to expand the applications of PEG-based gel materials.
{"title":"DLP printing PEG-based gels with high elasticity and anti-dryness for customized flexible sensors","authors":"Guoqing Qin, Youjie Rong, Huijie Wang, Pengdi Cui, Zhuang Zhao, Xiaobo Huang","doi":"10.1016/j.polymer.2025.128049","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128049","url":null,"abstract":"Hydrogels, due to their exceptional flexibility, elasticity, and stretchability, are extensively utilized in numerous fields, particularly in the use of flexible wearable devices. However, the prevalent issues of solvent evaporation and limited environmental tolerance in the application of hydrogels significantly constrain their utilization in the field of flexible sensing. In this study, we designed a special organic gel, utilizing PEG as the solvent instead of water and Zr<sup>4+</sup> as the physical cross-linking agent, to facilitate the formation of a steady copolymer network (P(AA-co-HEA)/PEG) that exhibits excellent mechanical properties, such as high fracture stress (1 MPa) and low hysteresis (<7%), as well as good adhesion ability (30 kN/m<sup>2</sup>) and good solvent evaporation resistance. Moreover, the addition of Zr<sup>4+</sup> and Zn<sup>2+</sup> not only enhanced the mechanical properties of the gel but also endowed it with good electrical conductivity. The conductive gels are capable of accurately distinguishing various deformations (10−250% tensile strain) and successively outputting reliable electrical signals with good durability. Most importantly, the gel can be utilized to fabricate a variety of complex structures via digital light processing (DLP) 3D printing technology. In summary, this work introduces a novel approach for the development of highly stable flexible wearable devices, which has the potential to expand the applications of PEG-based gel materials.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"6 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We designed and synthesized two monomers, TTTPA and TETPA, by inserting the EDOT and thiophene unit as π-bridges between thiophene unit and nitro-substituted triphenylamine (TPA) through Stille coupling reaction, and the corresponding polymers PTTTPA and PTETPA were also prepared by electrochemical polymerization. Both TTTPA and TETPA displayed the red-shifted absorption spectra and lower onset oxidation potential, in particular, TETPA possessed a much lower initial oxidation potential of 0.68 V than its counterpart TTPA (1.00 V) without π-bridges. In addition, PTTTPA possessed the reversible and stable color change from yellow to gray between the neutral and oxidized state with a higher optical contrast of 27.1%, and exhibited a higher coloration efficiency of 134.43 cm2 C-1 when compared with PTTPA and PTETPA. These results demonstrated that the reasonable introduction of π-bridges could optimize the electrochromic performance of TPA-based polymer.
{"title":"Effect of different π bridges on electro-optic properties of D-A-D type conjugated polymers based on nitro-substituted triphenylamine derivatives","authors":"Pengjie Chao, Yuqing Liao, Donglin Shen, Daize Mo, Lanqing Li, Donghau Fan","doi":"10.1016/j.polymer.2025.128041","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128041","url":null,"abstract":"We designed and synthesized two monomers, TTTPA and TETPA, by inserting the EDOT and thiophene unit as π-bridges between thiophene unit and nitro-substituted triphenylamine (TPA) through Stille coupling reaction, and the corresponding polymers PTTTPA and PTETPA were also prepared by electrochemical polymerization. Both TTTPA and TETPA displayed the red-shifted absorption spectra and lower onset oxidation potential, in particular, TETPA possessed a much lower initial oxidation potential of 0.68 V than its counterpart TTPA (1.00 V) without π-bridges. In addition, PTTTPA possessed the reversible and stable color change from yellow to gray between the neutral and oxidized state with a higher optical contrast of 27.1%, and exhibited a higher coloration efficiency of 134.43 cm<sup>2</sup> C<sup>-1</sup> when compared with PTTPA and PTETPA. These results demonstrated that the reasonable introduction of π-bridges could optimize the electrochromic performance of TPA-based polymer.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"119 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-13DOI: 10.1016/j.polymer.2025.128057
Tao Li, Dongyang Cheng, Longhui Liu, Yijia Guan, Jianguo Liao, Dan Lu, Yungui Li
Polymer blends represent a viable and efficient approach for improving the performance of functional materials and semiconducting devices. Herein, we systematically investigated how the poly(9-vinylcarbazole) (PVK) impacts the chain structure and β conformation of poly(9,9-dioctylfluorene) (PFO) in both the blended solutions and their spin-coated films. At room temperature, neither the solutions nor the films exhibited any β conformation or aggregates at any PVK content. Remarkably, after a cooling treatment at -60 °C and subsequent recovering to room temperature, an increase of the PVK content from its absence to an optimal 10 wt.% led to the formation of large, ordered aggregates with high content of β conformation. In contrast, a further increase of the PVK content from 10 wt.% to 70 wt.% significantly suppressed the formation of β conformation, aggregates, and ordered structures. We propose that at low PVK content (0-10 wt.%), PVK acts as a cross-linking agent through π-π stacking between its carbazole side groups and the PFO backbone to connect PFO aggregates, while at high level of PVK (10-70 wt.%), excessive PVK may disperse the PFO phase and inhibit chain’s self-folding. This work shows a facile method to control the formation of β conformation of polyfluorene in solutions and films, shining light on their future application in optoelectronic devices.
{"title":"Facile Control of PFO β Conformation in Blended Polymers","authors":"Tao Li, Dongyang Cheng, Longhui Liu, Yijia Guan, Jianguo Liao, Dan Lu, Yungui Li","doi":"10.1016/j.polymer.2025.128057","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128057","url":null,"abstract":"Polymer blends represent a viable and efficient approach for improving the performance of functional materials and semiconducting devices. Herein, we systematically investigated how the poly(9-vinylcarbazole) (PVK) impacts the chain structure and β conformation of poly(9,9-dioctylfluorene) (PFO) in both the blended solutions and their spin-coated films. At room temperature, neither the solutions nor the films exhibited any β conformation or aggregates at any PVK content. Remarkably, after a cooling treatment at -60 °C and subsequent recovering to room temperature, an increase of the PVK content from its absence to an optimal 10 wt.% led to the formation of large, ordered aggregates with high content of β conformation. In contrast, a further increase of the PVK content from 10 wt.% to 70 wt.% significantly suppressed the formation of β conformation, aggregates, and ordered structures. We propose that at low PVK content (0-10 wt.%), PVK acts as a cross-linking agent through π-π stacking between its carbazole side groups and the PFO backbone to connect PFO aggregates, while at high level of PVK (10-70 wt.%), excessive PVK may disperse the PFO phase and inhibit chain’s self-folding. This work shows a facile method to control the formation of β conformation of polyfluorene in solutions and films, shining light on their future application in optoelectronic devices.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"74 6 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.polymer.2025.128051
Gottfried Laschet, Jonathan Alms, Maximilian Müller, Markus Apel, Christian Hopmann
In injection molding processes of semi-crystalline polymers, inhomogeneous solidification of the melt occurs resulting in complex warpage of the final part. They present a strongly different cooling behavior at mold walls and in their center. Thus, locally different spherulite microstructures are formed in the component leading to residual stresses formed during the injection molding process. To determine the effect of these inhomogeneities on the local thermo-elastic and thermal properties, the injection molding of an isotactic polypropylene (α-iPP) stepped plate is investigated. The previously developed multiscale simulation scheme has been extended to address thermo-elastic homogenization of semi-crystalline polymers. A new Representative Volume Element (RVE) of the cross-hatched crystalline-amorphous α-iPP lamella is introduced at the nanoscale, leading to a stiffer and less anisotropic effective lamella behavior. Besides, a relationship between the local crystallization degree and the cooling rate is derived, based on DSC and Flash-DSC measurements. Corresponding to the local crystallization degree, a specific RVE either with or without secondary branches is designed. In this way, the effect of locally different crystallization degrees on the effective thermo-elastic and thermal properties of the effective semi-crystalline α-iPP lamella is first determined at the nanoscale. The predicted values for the effective elastic Young’s and shear moduli are smaller at mold walls and stiffer in the core area of the part than the corresponding modules, predicted with a constant, mean crystallization degree ξ over the plate thickness; whereas the mean effective thermal expansion αm decreases continuously with the crystallization degree ξ over the half plate section.
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