Pub Date : 2025-01-25DOI: 10.1016/j.polymer.2025.128074
J. Oller-Iscar, Andrés R. Tejedor, Marisol Ripoll, Jorge Ramírez
This work investigates the effects of tangent polar activity on the conformational and dynamic properties of entangled polymer melts through Langevin molecular dynamics simulations. We examine systems composed of all self-propelled, monodisperse linear chains, so that constraint release is considered. The range of activities explored here includes values where the active reptation theory is applicable, as well as higher activities that challenge the validity of the theory. Chain conformations exhibit a moderate increase in coil size increase, which becomes more pronounced at higher activity levels. Under these conditions, a local bond alignment along the chain contour appears together with a non-homogeneous segmental stretching, and orientation and stretching of the tube. Dynamically, polar activity induces a molecular-weight-independent diffusion coefficient, a transient superdiffusive behavior, and an end-to-end relaxation time inversely proportional to the molecular weight. Finally, our results are summarized in a diagram that classifies the various regimes of behavior observed in the simulations. Overall, these findings provide valuable insights into the complex interplay between activity and entanglements, advancing our understanding of active polymer systems and their potential applications across various fields.
{"title":"Computational study of active polar polymer melts: From active reptation to activity induced local alignment","authors":"J. Oller-Iscar, Andrés R. Tejedor, Marisol Ripoll, Jorge Ramírez","doi":"10.1016/j.polymer.2025.128074","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128074","url":null,"abstract":"This work investigates the effects of tangent polar activity on the conformational and dynamic properties of entangled polymer melts through Langevin molecular dynamics simulations. We examine systems composed of all self-propelled, monodisperse linear chains, so that constraint release is considered. The range of activities explored here includes values where the active reptation theory is applicable, as well as higher activities that challenge the validity of the theory. Chain conformations exhibit a moderate increase in coil size increase, which becomes more pronounced at higher activity levels. Under these conditions, a local bond alignment along the chain contour appears together with a non-homogeneous segmental stretching, and orientation and stretching of the tube. Dynamically, polar activity induces a molecular-weight-independent diffusion coefficient, a transient superdiffusive behavior, and an end-to-end relaxation time inversely proportional to the molecular weight. Finally, our results are summarized in a diagram that classifies the various regimes of behavior observed in the simulations. Overall, these findings provide valuable insights into the complex interplay between activity and entanglements, advancing our understanding of active polymer systems and their potential applications across various fields.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"58 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031184","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 : 2025-01-25DOI: 10.1016/j.polymer.2025.128083
Mine Begum Alanalp, Ali Durmus
In this study, an amine functionalized thermoplastic elastomer was easily synthesized by a semi-batch reactive melt compounding method in an internal mixer at 165 °C using maleic anhydride grafted styrene-block-ethylene/butylene-block-styrene copolymer (SEBS-g-MAh) as elastomer phase and 3-amino-1,2,4-triazole (TA) as cyclic amine compound. Then a metal salt, zinc nitrate (Zn(NO3)2), was introduced into the melt mixer to form metal-ligand interactions between amine functionalized TPE. Structural, mechanical, rheological, and viscoelastic properties of functional TPE were characterized by various analytical methods such as FTIR, DMA, rotational rheometer, and tensile test. FTIR analysis confirmed that the primary amine groups of cyclic amine compound reacted with maleic anhydride of SEBS-g-MAh to form maleimid groups. Formation of metal-ligand interactions in the modified TPE structure was also shown with various rheological measurements such as strain-dependent, frequency-dependent, and time-dependent test procedures and different mathematical models. It was shown that the strong metal-ligand interactions provided the modified TPE, temperature-induced self-healing property.
{"title":"Easy synthesis of self-healing thermoplastic elastomer (TPE) via functionalization of styrene block copolymer (SEBS) with a cyclic amine compound in melt state and rheological assessment of non-covalent dynamic interactions","authors":"Mine Begum Alanalp, Ali Durmus","doi":"10.1016/j.polymer.2025.128083","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128083","url":null,"abstract":"In this study, an amine functionalized thermoplastic elastomer was easily synthesized by a semi-batch reactive melt compounding method in an internal mixer at 165 °C using maleic anhydride grafted styrene-<em>block</em>-ethylene/butylene-<em>block</em>-styrene copolymer (SEBS-g-MAh) as elastomer phase and 3-amino-1,2,4-triazole (TA) as cyclic amine compound. Then a metal salt, zinc nitrate (Zn(NO<sub>3</sub>)<sub>2</sub>), was introduced into the melt mixer to form metal-ligand interactions between amine functionalized TPE. Structural, mechanical, rheological, and viscoelastic properties of functional TPE were characterized by various analytical methods such as FTIR, DMA, rotational rheometer, and tensile test. FTIR analysis confirmed that the primary amine groups of cyclic amine compound reacted with maleic anhydride of SEBS-g-MAh to form maleimid groups. Formation of metal-ligand interactions in the modified TPE structure was also shown with various rheological measurements such as strain-dependent, frequency-dependent, and time-dependent test procedures and different mathematical models. It was shown that the strong metal-ligand interactions provided the modified TPE, temperature-induced self-healing property.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"26 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031182","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}
Adhesive interfaces with epoxy resin (adhesive joints and composites) play a critical role in bulk mechanical properties (e.g., load transfer), and it is important to elucidate the strength development mechanism near adhesive interfaces. However, the mechanical properties of epoxy resins on adhesive interfaces are known to be different from those of bulk resin and macroscopic adhesive interfaces because of a difference in the cross-linking ratio of epoxy resin. Since it is difficult to clarify the cross-linking ratio near the adhesive interface and to measure mechanical properties, it is important to establish nano-mechanical testing and simulation methods that can investigate mechanical properties and molecular structure around an adhesive interface. In this study, nanoindentation tests using atomic force microscopy (AFM) and molecular dynamics (MD) simulations that can reproduce the AFM tests were conducted on two-component epoxy resins to clarify the mechanical properties near the nanoscale adhesive interface and to investigate the mechanism of adhesive strength development. MD simulations employed a coarse-graining method that extends the spatial scale to cover the experimental scale of AFM nanoindentation. Furthermore, the mechanical properties of the adhesive interface were investigated from the viewpoint of deformation of molecular chains. It was found that at the interface, nanoindentation showed deformation in the adhesive due to reduction of cross-linking ratio. Coarse-grained (CG) MD simulations also simulated such deformation behavior in order to discuss molecular chain structure in deformation.
{"title":"Coarse-Grained Molecular Dynamics Simulations of Nano-Deformation Behavior of Epoxy Adhesives’ Interface during Atomic Force Microscopy (AFM) Mechanical Testing","authors":"Masayoshi Ogawa, Ayumu Morimura, Ikko Haba, Akio Yonezu","doi":"10.1016/j.polymer.2025.128071","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128071","url":null,"abstract":"Adhesive interfaces with epoxy resin (adhesive joints and composites) play a critical role in bulk mechanical properties (e.g., load transfer), and it is important to elucidate the strength development mechanism near adhesive interfaces. However, the mechanical properties of epoxy resins on adhesive interfaces are known to be different from those of bulk resin and macroscopic adhesive interfaces because of a difference in the cross-linking ratio of epoxy resin. Since it is difficult to clarify the cross-linking ratio near the adhesive interface and to measure mechanical properties, it is important to establish nano-mechanical testing and simulation methods that can investigate mechanical properties and molecular structure around an adhesive interface. In this study, nanoindentation tests using atomic force microscopy (AFM) and molecular dynamics (MD) simulations that can reproduce the AFM tests were conducted on two-component epoxy resins to clarify the mechanical properties near the nanoscale adhesive interface and to investigate the mechanism of adhesive strength development. MD simulations employed a coarse-graining method that extends the spatial scale to cover the experimental scale of AFM nanoindentation. Furthermore, the mechanical properties of the adhesive interface were investigated from the viewpoint of deformation of molecular chains. It was found that at the interface, nanoindentation showed deformation in the adhesive due to reduction of cross-linking ratio. Coarse-grained (CG) MD simulations also simulated such deformation behavior in order to discuss molecular chain structure in deformation.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"45 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031179","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 : 2025-01-25DOI: 10.1016/j.polymer.2025.128084
Pu Zhou, Hao-Nan Zhang, Guo-Ao Wang, Qing-Hui Yang, Hang-Kai Qi, Meng-Bo Luo
The adsorption and diffusion behaviors of a polymer chain within a narrow slit composed of two patch-patterned surfaces is studied using Langevin dynamics simulations. The surfaces consist of a neutral area interspersed with periodic attractive patches of size L and period d. The mismatch of the upper and lower surfaces is denoted by Δx and Δy along x- and y-directions. For both the perfectly matched system (Δx = Δy = 0) and the mismatched system (Δx = 0.5d, Δy = 0) with moderate sized patches, the polymer chain mainly adopts an upper-lower adsorption state, i.e., it is adsorbed on both surfaces simultaneously. However, for the mismatched system with Δx = Δy = 0.5d, a single-surface adsorption state where the polymer is adsorbed on only one surface is primarily observed. On the other hand, the polymer chain does not undergo diffusion in the matched case, but exhibits normal diffusion on a long time scale in mismatched cases. The translational diffusion coefficient increases when the patch mismatch changes from Δx = 0.5d, Δy = 0 to Δx = Δy = 0.5d, which is attributed to an increased frequency of changes in the adsorption state. The polymer chain diffuses via a patch-exchange mode, that is, it exchanges patches between an upper-lower adsorption state and a single-surface adsorption state. The effect of patch period and slit height is also studied. These findings underscore the pivotal role of patch mismatch in modulating polymer adsorption and diffusion behaviors.
{"title":"Adsorption and diffusion of a polymer chain within a thin slit composed of two patch-patterned surfaces","authors":"Pu Zhou, Hao-Nan Zhang, Guo-Ao Wang, Qing-Hui Yang, Hang-Kai Qi, Meng-Bo Luo","doi":"10.1016/j.polymer.2025.128084","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128084","url":null,"abstract":"The adsorption and diffusion behaviors of a polymer chain within a narrow slit composed of two patch-patterned surfaces is studied using Langevin dynamics simulations. The surfaces consist of a neutral area interspersed with periodic attractive patches of size <em>L</em> and period <em>d</em>. The mismatch of the upper and lower surfaces is denoted by Δ<em>x</em> and Δ<em>y</em> along <em>x-</em> and <em>y-</em>directions. For both the perfectly matched system (Δ<em>x</em> = Δ<em>y</em> = 0) and the mismatched system (Δ<em>x</em> = 0.5<em>d</em>, Δ<em>y</em> = 0) with moderate sized patches, the polymer chain mainly adopts an upper-lower adsorption state, i.e., it is adsorbed on both surfaces simultaneously. However, for the mismatched system with Δ<em>x</em> = Δ<em>y</em> = 0.5<em>d</em>, a single-surface adsorption state where the polymer is adsorbed on only one surface is primarily observed. On the other hand, the polymer chain does not undergo diffusion in the matched case, but exhibits normal diffusion on a long time scale in mismatched cases. The translational diffusion coefficient increases when the patch mismatch changes from Δ<em>x</em> = 0.5<em>d</em>, Δ<em>y</em> = 0 to Δ<em>x</em> = Δ<em>y</em> = 0.5<em>d</em>, which is attributed to an increased frequency of changes in the adsorption state. The polymer chain diffuses via a patch-exchange mode, that is, it exchanges patches between an upper-lower adsorption state and a single-surface adsorption state. The effect of patch period and slit height is also studied. These findings underscore the pivotal role of patch mismatch in modulating polymer adsorption and diffusion behaviors.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"16 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031180","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}
Developing superior flame-retardant and low dielectric epoxy resins used in electronics remains a great challenge. Herein, two cycloaliphatic epoxy molecules (CFP, CFDP) were designed by incorporating phosphaphenanthrene (DOPO) into a cyclic silicon resin (CFS) through one-pot solvent-free process. CFP and CFDP exhibited self-catalyzed ability toward anhydride hardener (MHHPA) . Both CFP/MHHPA and CFDP/MHHPA resins achieved UL-94 V-0 rating with limited oxygen index of 26.5% and 36.5% owning to the emission of silicon/phosphorus-containing segments in gas phase and enhancement of carbonation ability. Moreover, incorporating DOPO well-maintained the thermal stability and enhanced char yield in air, thus significantly suppressing heat release during combustion. Meanwhile, CFP and CFDP imparted epoxy resins with excellent dielectric properties. The dielectric loss of CFP/MHHPA and CFDP/MHHPA was 0.005 and 0.006 at 10 MHz, and dielectric constant was remained at 3.36. This work offers a facile and practical way to fabricate multifunctional epoxy resins used in electronic field.
{"title":"One-pot solvent-free synthesis of self-catalyzed phosphorus/silicon cycloaliphatic epoxy resin with excellent flame-retardant and dielectric property","authors":"Yonghao Lv, Hongyan Li, Zhu-Bao Shao, Zhiming Jiang","doi":"10.1016/j.polymer.2025.128087","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128087","url":null,"abstract":"Developing superior flame-retardant and low dielectric epoxy resins used in electronics remains a great challenge. Herein, two cycloaliphatic epoxy molecules (CFP, CFDP) were designed by incorporating phosphaphenanthrene (DOPO) into a cyclic silicon resin (CFS) through one-pot solvent-free process. CFP and CFDP exhibited self-catalyzed ability toward anhydride hardener (MHHPA) . Both CFP/MHHPA and CFDP/MHHPA resins achieved UL-94 V-0 rating with limited oxygen index of 26.5% and 36.5% owning to the emission of silicon/phosphorus-containing segments in gas phase and enhancement of carbonation ability. Moreover, incorporating DOPO well-maintained the thermal stability and enhanced char yield in air, thus significantly suppressing heat release during combustion. Meanwhile, CFP and CFDP imparted epoxy resins with excellent dielectric properties. The dielectric loss of CFP/MHHPA and CFDP/MHHPA was 0.005 and 0.006 at 10 MHz, and dielectric constant was remained at 3.36. This work offers a facile and practical way to fabricate multifunctional epoxy resins used in electronic field.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"11 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031186","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 : 2025-01-25DOI: 10.1016/j.polymer.2025.128077
Hao Ye, Jingying Xu, Yaru Wang, Mengyao Zhao, Wanjing Li, Xianglong Li, Bin Yang
Centrifugal spinning of nanofibers has garnered significant attention due to its numerous advantages and industrial potential. However, meeting diverse needs with a single material is challenging, and the production of mixed material fibers often compromises fiber quality due to miscibility issues with different materials. Therefore, this study introduces a novel approach for efficiently preparing side-by-side micro-nano composite fibers by modifying the cavity structure of the centrifugal spinneret. Based on the experimental analysis of fiber spinnability, we derive the motion equation of polymer solution in the spinneret and analyze how the position of cavity plate influences the force exerted on the polymer solution. The optimal spinneret structure was determined through simulation of the solution motion mechanism in various types of spinnerets. Subsequently, polyvinylpyrrolidone (PVP)/ethylene oxide (PEO) composite micro-nanofibers were prepared using a centrifugal spinning device for experimental validation. The results indicate that the left and right cavity structure results in a significant disparity in flow between the two cavities at the nozzle, rendering it unsuitable for producing juxtaposed micro-nano composite fibers. The upper and lower cavity configuration does not impact the flow rate of the two cavities, making it suitable for stable and efficient preparation of side-by-side micro-nano composite fibers.
{"title":"Study on the preparation of side-by-side micro-nano composite fibers by centrifugal spinning based on improved spinneret cavity structure","authors":"Hao Ye, Jingying Xu, Yaru Wang, Mengyao Zhao, Wanjing Li, Xianglong Li, Bin Yang","doi":"10.1016/j.polymer.2025.128077","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128077","url":null,"abstract":"Centrifugal spinning of nanofibers has garnered significant attention due to its numerous advantages and industrial potential. However, meeting diverse needs with a single material is challenging, and the production of mixed material fibers often compromises fiber quality due to miscibility issues with different materials. Therefore, this study introduces a novel approach for efficiently preparing side-by-side micro-nano composite fibers by modifying the cavity structure of the centrifugal spinneret. Based on the experimental analysis of fiber spinnability, we derive the motion equation of polymer solution in the spinneret and analyze how the position of cavity plate influences the force exerted on the polymer solution. The optimal spinneret structure was determined through simulation of the solution motion mechanism in various types of spinnerets. Subsequently, polyvinylpyrrolidone (PVP)/ethylene oxide (PEO) composite micro-nanofibers were prepared using a centrifugal spinning device for experimental validation. The results indicate that the left and right cavity structure results in a significant disparity in flow between the two cavities at the nozzle, rendering it unsuitable for producing juxtaposed micro-nano composite fibers. The upper and lower cavity configuration does not impact the flow rate of the two cavities, making it suitable for stable and efficient preparation of side-by-side micro-nano composite fibers.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"87 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031181","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 : 2025-01-25DOI: 10.1016/j.polymer.2025.128075
Yanyang He, Jiuming Xiong, Yufang Hu, Zhiyong Guo, Sui Wang, Jie Mao
Hydrogels with enhanced mechanical strength and fatigue resistance have attracted considerable attention in the development of advanced triboelectric nanogenerators(TENGs). Flexible electrode is the key to the preparation of TENG. However, the preparation process of traditional flexible electrode is complex, the mechanical strength is poor, and the cost is high. These factors limit its application and development. In this work, a composite material named AM/AMPS wood-based hydrogel (AWH) was reported, which was composed of acrylamide (AM)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) hydrogel and delignification wood. AWH combines the natural fiber structure of wood and the softness of hydrogel, and has excellent mechanical properties and fatigue resistance. AWH is assembled into a triboelectric nanogenerator (AWH-TENG), which has high power generation performance and low cost. The AWH-TENG has an open circuit voltage of 60 V and can light up 113 LED bulbs. At the same time, AWH is sensitive to mechanical stimuli, so we have carried out research on its application in the field of wearable motion monitoring and writing sensing and achieved good results. In addition, the writing sensing system based on AWH-TENG is expected to be combined with deep learning to develop a new handwriting recognition system.
{"title":"AM/AMPS delignified wood-based hydrogel with enhanced mechanical strength and fatigue resistance for wearable strain sensing and energy harvesting","authors":"Yanyang He, Jiuming Xiong, Yufang Hu, Zhiyong Guo, Sui Wang, Jie Mao","doi":"10.1016/j.polymer.2025.128075","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128075","url":null,"abstract":"Hydrogels with enhanced mechanical strength and fatigue resistance have attracted considerable attention in the development of advanced triboelectric nanogenerators(TENGs). Flexible electrode is the key to the preparation of TENG. However, the preparation process of traditional flexible electrode is complex, the mechanical strength is poor, and the cost is high. These factors limit its application and development. In this work, a composite material named AM/AMPS wood-based hydrogel (AWH) was reported, which was composed of acrylamide (AM)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) hydrogel and delignification wood. AWH combines the natural fiber structure of wood and the softness of hydrogel, and has excellent mechanical properties and fatigue resistance. AWH is assembled into a triboelectric nanogenerator (AWH-TENG), which has high power generation performance and low cost. The AWH-TENG has an open circuit voltage of 60 V and can light up 113 LED bulbs. At the same time, AWH is sensitive to mechanical stimuli, so we have carried out research on its application in the field of wearable motion monitoring and writing sensing and achieved good results. In addition, the writing sensing system based on AWH-TENG is expected to be combined with deep learning to develop a new handwriting recognition system.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"9 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031188","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 : 2025-01-24DOI: 10.1016/j.polymer.2025.128081
Bo Zhang, Xueqing Li, Ming Zeng, Jingguo Cao
Rapid development in 5G and electronic appliance fields places higher demands on the dielectric, thermal and mechanical properties of materials. Dielectric materials with excellent comprehensive properties have become an urgent need of the times. Emerging machine learning techniques could greatly accelerate the discovery of high-performance dielectric materials. However, it remains unknown whether traditional 2D fingerprints or descriptors can extract molecular structure information more completely. In this study, data on four types of properties of polyimide (PI), including dielectric constant, glass transition temperature, tensile modulus and coefficient of thermal expansion, were collected to construct a deep learning model-COMFO to explore polyimide dielectric materials with excellent comprehensive performance. Our COMFO model could extract the key feature information in the molecule from three perspective learning tasks as well as process and learn them. Specifically, the three learning tasks include extracting the feature information in the SMILES sequence using a large language model, the bidirectional encoder Transformer; extracting the information about the atoms and bonds of polymer molecules from molecular graph using the Attentive FP network; and extracting the information about the substructures of polymer molecules through molecular fingerprints. The multi-perspective feature extraction task gave our model a more excellent performance (R2>0.90). The performance of the model was confirmed by various ways, including experimental validation, MD simulation validation, and comparison with 12 other models. Design guidelines for low dielectric constant PIs were discovered by monomer structure analysis. High-throughput virtual screening of 158,022 unknown PIs was performed and three PIs with excellent comprehensive properties (especially dielectric properties) were identified. MD and DFT approaches verified and analyzed the properties of these three potential high-performance PIs. In the future, this research could also contribute to the forward development of materials in other fields.
{"title":"COMFO: Integrated Deep Learning Model Facilitates Discovery of Multifunctional Polyimide Materials","authors":"Bo Zhang, Xueqing Li, Ming Zeng, Jingguo Cao","doi":"10.1016/j.polymer.2025.128081","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128081","url":null,"abstract":"Rapid development in 5G and electronic appliance fields places higher demands on the dielectric, thermal and mechanical properties of materials. Dielectric materials with excellent comprehensive properties have become an urgent need of the times. Emerging machine learning techniques could greatly accelerate the discovery of high-performance dielectric materials. However, it remains unknown whether traditional 2D fingerprints or descriptors can extract molecular structure information more completely. In this study, data on four types of properties of polyimide (PI), including dielectric constant, glass transition temperature, tensile modulus and coefficient of thermal expansion, were collected to construct a deep learning model-COMFO to explore polyimide dielectric materials with excellent comprehensive performance. Our COMFO model could extract the key feature information in the molecule from three perspective learning tasks as well as process and learn them. Specifically, the three learning tasks include extracting the feature information in the SMILES sequence using a large language model, the bidirectional encoder Transformer; extracting the information about the atoms and bonds of polymer molecules from molecular graph using the Attentive FP network; and extracting the information about the substructures of polymer molecules through molecular fingerprints. The multi-perspective feature extraction task gave our model a more excellent performance (R<sup>2</sup>>0.90). The performance of the model was confirmed by various ways, including experimental validation, MD simulation validation, and comparison with 12 other models. Design guidelines for low dielectric constant PIs were discovered by monomer structure analysis. High-throughput virtual screening of 158,022 unknown PIs was performed and three PIs with excellent comprehensive properties (especially dielectric properties) were identified. MD and DFT approaches verified and analyzed the properties of these three potential high-performance PIs. In the future, this research could also contribute to the forward development of materials in other fields.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"97 4 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143026981","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 : 2025-01-23DOI: 10.1016/j.polymer.2025.128082
Chunhua Li, Yifu Ruan, GengXin Liu
Polymeric soft-nanoparticles (SNPs) synthesized via microemulsion polymerization, are widely used in both academia and industry. However, achieving a significantly smaller diameter still presents a challenge. Despite the use of excess surfactants, surface tension constraints prevent microemulsion droplets from decreasing in diameter below 20 nm. Still using conventional surfactants, we introduce a simple and efficient method for mass production of SNPs down to 10∼15 nm in diameter. The microemulsion is prepared by incorporating solvents that are good for both monomers and polymers. This method effectively yields significantly smaller SNPs. In the melts of such small SNPs, the Rouse-like viscous-dominant behavior is observed and fully mapped with respect to the diameter and degree of cross-linking. This was previously not observed in microemulsion polymerized SNPs. We assess the cold flow conditions by determining the ability to form transparent sheets from the powder at room temperature when subjected to pressure. It is governed by the diameter and degree of crosslinking. The ultrasmall SNPs thus have the potential to be used as fillers in various industries.
{"title":"Mass-produce sub-15 nm polymeric soft-nanoparticles and cold-flow conditions","authors":"Chunhua Li, Yifu Ruan, GengXin Liu","doi":"10.1016/j.polymer.2025.128082","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128082","url":null,"abstract":"Polymeric soft-nanoparticles (SNPs) synthesized via microemulsion polymerization, are widely used in both academia and industry. However, achieving a significantly smaller diameter still presents a challenge. Despite the use of excess surfactants, surface tension constraints prevent microemulsion droplets from decreasing in diameter below 20 nm. Still using conventional surfactants, we introduce a simple and efficient method for mass production of SNPs down to 10∼15 nm in diameter. The microemulsion is prepared by incorporating solvents that are good for both monomers and polymers. This method effectively yields significantly smaller SNPs. In the melts of such small SNPs, the Rouse-like viscous-dominant behavior is observed and fully mapped with respect to the diameter and degree of cross-linking. This was previously not observed in microemulsion polymerized SNPs. We assess the cold flow conditions by determining the ability to form transparent sheets from the powder at room temperature when subjected to pressure. It is governed by the diameter and degree of crosslinking. The ultrasmall SNPs thus have the potential to be used as fillers in various industries.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"18 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143026983","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 : 2025-01-23DOI: 10.1016/j.polymer.2025.128078
Jiahao Mao, Jierui Zhou, Yang Cao, Mukerrem Cakmak
This study examines the morphological evolution of melt-cast Poly(ethylene terephthalate) (PET) thin films under nonlinear deformation strategies, specifically stretching and cycling, to analyze their structural, mechanical, and electrical properties. Capacitor-grade thin films were melt-cast and subjected to uniaxial deformation using an instrumented stretching machine that applied programmable deformations. During deformation, real-time mechano-optical data, including birefringence, true strain, and true stress, were collected above the glass transition temperature (Tg).Stress-induced crystallization emerged as the primary mechanism during stretching, as thermally induced crystallization was suppressed due to high viscosity in the rubbery temperatures near Tg. Strain oscillations after steady deformations at various strain levels promoted crystallization and relaxed oriented amorphous chains. This process enhanced crystalline orientation and crystallinity, particularly in stretching and oscillation tests compared to stretching and holding tests. At higher deformation levels, the orientation of amorphous domains transitioned to oriented crystalline structures. Increased crystallinity and crystalline and amorphous chain orientation enhanced electrical breakdown. The strain oscillation played a crucial role in promoting crystallinity enhancement while minimizing amorphous chain orientation, leading to lower electrical breakdown. These results highlight the substantial influence of the amorphous phase and its chain orientation on the electrical breakdown of PET films.
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