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Elastomer Mechanics of Cross-Linked Linear-Ring Polymer Blends
IF 5.8 Q1 POLYMER SCIENCE Pub Date : 2025-04-01 DOI: 10.1021/acsmacrolett.5c00095
Siteng Zhang, Thomas C. O’Connor, Gary S. Grest, Ting Ge
Cross-linking a blend of linear and ring polymers creates a new topology-based dual-network elastomer in which the two components differ significantly in their topology. We use molecular simulations and topological analysis to examine key mechanical properties as functions of ring polymer volume fraction ϕR. For ϕR < ϕR*, where the rings begin to overlap, the network shear modulus G and the maximum stretch ratio λp are weakly dependent on ϕR. For ϕR > ϕR*, entanglements trapped in the network are diluted as the rings overlap, leading to a significant decrease in G and an increase in λp with increasing ϕR. The peak tensile stress, σp, exhibits a maximum around ϕR*, indicating an enhancement of network strength due to the stronger cohesion from the entanglements between linear and ring polymers.
{"title":"Elastomer Mechanics of Cross-Linked Linear-Ring Polymer Blends","authors":"Siteng Zhang, Thomas C. O’Connor, Gary S. Grest, Ting Ge","doi":"10.1021/acsmacrolett.5c00095","DOIUrl":"https://doi.org/10.1021/acsmacrolett.5c00095","url":null,"abstract":"Cross-linking a blend of linear and ring polymers creates a new topology-based dual-network elastomer in which the two components differ significantly in their topology. We use molecular simulations and topological analysis to examine key mechanical properties as functions of ring polymer volume fraction ϕ<sub>R</sub>. For ϕ<sub>R</sub> &lt; ϕ<sub>R</sub><sup>*</sup>, where the rings begin to overlap, the network shear modulus <i>G</i> and the maximum stretch ratio λ<sub>p</sub> are weakly dependent on ϕ<sub>R</sub>. For ϕ<sub>R</sub> &gt; ϕ<sub>R</sub><sup>*</sup>, entanglements trapped in the network are diluted as the rings overlap, leading to a significant decrease in <i>G</i> and an increase in λ<sub>p</sub> with increasing ϕ<sub>R</sub>. The peak tensile stress, σ<sub>p</sub>, exhibits a maximum around ϕ<sub>R</sub><sup>*</sup>, indicating an enhancement of network strength due to the stronger cohesion from the entanglements between linear and ring polymers.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"75 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143758275","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}
引用次数: 0
Direct Measurements of Overlooked Long-Range Interactions near Zwitterionic and Nonionic Polymer Brushes
IF 5.8 Q1 POLYMER SCIENCE Pub Date : 2025-03-31 DOI: 10.1021/acsmacrolett.5c00043
Jiahao Wu, Feng Cao, Manjia Li, Wei Liu, Kohji Ohno, To Ngai
Current research on the antifouling mechanisms of “electrically neutral” polymer brushes predominantly emphasizes thermodynamically unfavorable short-range interactions. However, our study reveals the critical importance of long-range interactions. By utilizing zwitterionic poly(carboxybetaine methacrylate) (PCBMA) and nonionic poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA) brushes as model systems, we employed total internal reflection microscopy (TIRM) to directly measure interactions with contaminants. Surprisingly, even seemingly neutral polymers exhibit significant electrostatic interactions with nearby contaminants─a fact that has been largely overlooked in this field. Our findings challenge the prevailing assumption of charge absence on surfaces grafted with antifouling polymer brushes and investigate how external stimuli (such as ionic strength and polymer conformation) affect these long-range interactions. In conclusion, this study presents a novel approach to exploring long-range interactions near polymer-grafted surfaces, offering valuable insights for the development of antifouling materials and biomedical applications in the future.
{"title":"Direct Measurements of Overlooked Long-Range Interactions near Zwitterionic and Nonionic Polymer Brushes","authors":"Jiahao Wu, Feng Cao, Manjia Li, Wei Liu, Kohji Ohno, To Ngai","doi":"10.1021/acsmacrolett.5c00043","DOIUrl":"https://doi.org/10.1021/acsmacrolett.5c00043","url":null,"abstract":"Current research on the antifouling mechanisms of “electrically neutral” polymer brushes predominantly emphasizes thermodynamically unfavorable short-range interactions. However, our study reveals the critical importance of long-range interactions. By utilizing zwitterionic poly(carboxybetaine methacrylate) (PCBMA) and nonionic poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA) brushes as model systems, we employed total internal reflection microscopy (TIRM) to directly measure interactions with contaminants. Surprisingly, even seemingly neutral polymers exhibit significant electrostatic interactions with nearby contaminants─a fact that has been largely overlooked in this field. Our findings challenge the prevailing assumption of charge absence on surfaces grafted with antifouling polymer brushes and investigate how external stimuli (such as ionic strength and polymer conformation) affect these long-range interactions. In conclusion, this study presents a novel approach to exploring long-range interactions near polymer-grafted surfaces, offering valuable insights for the development of antifouling materials and biomedical applications in the future.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"4 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143744863","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}
引用次数: 0
Tailoring Diels–Alder Cross-Linked Liquid Crystal Elastomers for Spatially Programmable Monolithic Actuators
IF 5.8 Q1 POLYMER SCIENCE Pub Date : 2025-03-30 DOI: 10.1021/acsmacrolett.5c00117
Yue Liu, Qing Yang, Qing Liu, Jun-Bo Hou, Jing Zhao, Ying Zhang, Qiongyao Peng, Zhi-Chao Jiang, Yao-Yu Xiao, Hongbo Zeng
Liquid crystal elastomers with thermo-reversible Diels–Alder cross-links (DALCEs) offer exceptional reprocessability and mild-temperature reprogrammability, enabling repeated fabrication of diverse actuators. However, optimizing their molecular design and refabrication protocols remains crucial to further unlocking their potential. This work systematically investigates DALCEs synthesized via aza-Michael addition reactions between RM82, furfurylamine, and various chain extenders (phenylethylamine, ethylamine, butylamine, hexylamine, octylamine, and 6-amino-1-hexanol). The effects of cross-linking density and chain extender selection on phase behavior, thermomechanical properties, and actuation performance have been thoroughly examined. The results show that a PEA-based formulation with moderate cross-linking density achieves the most balanced performance. Based on this optimized formulation, a novel (re)fabrication strategy is introduced by harnessing DALCEs’ intrinsic reprocessability, reprogrammability, and self-healing properties. This strategy employs multilevel fiber programming before monolithic actuator formation, enabling spatially controlled liquid crystal alignment and facilitating iterative actuator refinement through reconstruction. Consequently, complex morphing behaviors in disk films and stress-modulating functions in tubular actuators were demonstrated. This work establishes a versatile, easily synthesized material platform for spatially programmable, dynamic monolithic actuators, paving the way for advanced applications in soft robotics and adaptive devices.
{"title":"Tailoring Diels–Alder Cross-Linked Liquid Crystal Elastomers for Spatially Programmable Monolithic Actuators","authors":"Yue Liu, Qing Yang, Qing Liu, Jun-Bo Hou, Jing Zhao, Ying Zhang, Qiongyao Peng, Zhi-Chao Jiang, Yao-Yu Xiao, Hongbo Zeng","doi":"10.1021/acsmacrolett.5c00117","DOIUrl":"https://doi.org/10.1021/acsmacrolett.5c00117","url":null,"abstract":"Liquid crystal elastomers with thermo-reversible Diels–Alder cross-links (DALCEs) offer exceptional reprocessability and mild-temperature reprogrammability, enabling repeated fabrication of diverse actuators. However, optimizing their molecular design and refabrication protocols remains crucial to further unlocking their potential. This work systematically investigates DALCEs synthesized via aza-Michael addition reactions between RM82, furfurylamine, and various chain extenders (phenylethylamine, ethylamine, butylamine, hexylamine, octylamine, and 6-amino-1-hexanol). The effects of cross-linking density and chain extender selection on phase behavior, thermomechanical properties, and actuation performance have been thoroughly examined. The results show that a PEA-based formulation with moderate cross-linking density achieves the most balanced performance. Based on this optimized formulation, a novel (re)fabrication strategy is introduced by harnessing DALCEs’ intrinsic reprocessability, reprogrammability, and self-healing properties. This strategy employs multilevel fiber programming before monolithic actuator formation, enabling spatially controlled liquid crystal alignment and facilitating iterative actuator refinement through reconstruction. Consequently, complex morphing behaviors in disk films and stress-modulating functions in tubular actuators were demonstrated. This work establishes a versatile, easily synthesized material platform for spatially programmable, dynamic monolithic actuators, paving the way for advanced applications in soft robotics and adaptive devices.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"69 1","pages":"495-501"},"PeriodicalIF":5.8,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143736506","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}
引用次数: 0
Photocatalytic Decarboxylative Heck-Type Postpolymerization Modification of Polyacrylates
IF 5.8 Q1 POLYMER SCIENCE Pub Date : 2025-03-29 DOI: 10.1021/acsmacrolett.5c00115
Le Huang, Meng Chen, Wenyan Hao, Shan Tang
Postpolymerization modification of commodity polymers has emerged as a powerful strategy for synthesizing functional polymers that are challenging to obtain via direct polymerization. Moreover, it offers opportunities to upcycle existing polymers and enhance their material properties. In this work, we introduce a photocatalytic decarboxylative Heck-type approach to upcycle polyacrylates. By employing an acridine-based photocatalyst in combination with a cobaloxime catalyst, hydrolyzed polyacrylates with varying carboxylic acid contents were efficiently converted into polymers bearing olefin functionalities. The degree of olefin incorporation notably influenced the thermal properties of the resulting materials. Importantly, this protocol is applicable to a broad range of vinyl comonomers, yielding 1,3-diene copolymers with exclusive 1,2-insertion selectivity. Furthermore, a variety of terminal alkenes can be utilized to functionalize the acrylate copolymers, and subsequent thiol–ene click reactions further expand the versatility of the accessible polymers.
{"title":"Photocatalytic Decarboxylative Heck-Type Postpolymerization Modification of Polyacrylates","authors":"Le Huang, Meng Chen, Wenyan Hao, Shan Tang","doi":"10.1021/acsmacrolett.5c00115","DOIUrl":"https://doi.org/10.1021/acsmacrolett.5c00115","url":null,"abstract":"Postpolymerization modification of commodity polymers has emerged as a powerful strategy for synthesizing functional polymers that are challenging to obtain via direct polymerization. Moreover, it offers opportunities to upcycle existing polymers and enhance their material properties. In this work, we introduce a photocatalytic decarboxylative Heck-type approach to upcycle polyacrylates. By employing an acridine-based photocatalyst in combination with a cobaloxime catalyst, hydrolyzed polyacrylates with varying carboxylic acid contents were efficiently converted into polymers bearing olefin functionalities. The degree of olefin incorporation notably influenced the thermal properties of the resulting materials. Importantly, this protocol is applicable to a broad range of vinyl comonomers, yielding 1,3-diene copolymers with exclusive 1,2-insertion selectivity. Furthermore, a variety of terminal alkenes can be utilized to functionalize the acrylate copolymers, and subsequent thiol–ene click reactions further expand the versatility of the accessible polymers.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"101 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734222","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}
引用次数: 0
Electrostatically Stabilized Microstructures: From Clusters to Necklaces to Bulk Microphases
IF 5.8 Q1 POLYMER SCIENCE Pub Date : 2025-03-26 DOI: 10.1021/acsmacrolett.4c00834
Artem M. Rumyantsev, Albert Johner
This Viewpoint reveals the universality of the physical mechanisms controlling electrostatically stabilized microstructures in various systems of charged polymers with short-range attractive interactions. Key to this behavior is the competition of short-range attractions with long-range electrostatic repulsions. In dilute solutions of hydrophobic polyelectrolytes and charge-imbalanced polyampholytes, aggregation of single globules driven by the surface tension is restrained by net charge accumulation, stabilizing the finite cluster of the electrostatic blob size, Rcl ≃ ξe. Increasing net charge of the chain results in cluster disintegration to single globules and their further transition to beads-on-string necklaces with the bead size Dbead ≃ ξe. This intrachain microphase separation is analogous to that in semidilute solutions of these polymers, with the polymer-rich domain size of Dbead ≃ ξe. Similar diblock-copolymer-like microphases also form in blends of immiscible polyanions and polycations, with the extra incompatibility-dependent prefactor in the domain size of D ≃ χ+–1/6ξe originating from decoupling between the domain density and the surface tension. Scaling and the random phase approximation (RPA) approaches to electrostatic microphase separation in solutions and blends of ionic polymers are not contradictory and correspond to the limits of strong and weak segregation, respectively. Upon the addition of salt, both bulk and single-chain systems exhibit multicritical behavior (Lifshitz point) when the Debye radius, rD, the electrostatic blob, ξe, and the blob due to short-range attractions, ξatt, are all equal to each other, ξe ≃ ξattrD. These findings underscore the universality of characteristic lengths controlling the formation and disintegration of electrostatically stabilized microstructures across different systems.
{"title":"Electrostatically Stabilized Microstructures: From Clusters to Necklaces to Bulk Microphases","authors":"Artem M. Rumyantsev, Albert Johner","doi":"10.1021/acsmacrolett.4c00834","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00834","url":null,"abstract":"This Viewpoint reveals the universality of the physical mechanisms controlling electrostatically stabilized microstructures in various systems of charged polymers with short-range attractive interactions. Key to this behavior is the competition of short-range attractions with long-range electrostatic repulsions. In dilute solutions of hydrophobic polyelectrolytes and charge-imbalanced polyampholytes, aggregation of single globules driven by the surface tension is restrained by net charge accumulation, stabilizing the finite cluster of the electrostatic blob size, <i>R</i><sub>cl</sub> ≃ ξ<sub>e</sub>. Increasing net charge of the chain results in cluster disintegration to single globules and their further transition to beads-on-string necklaces with the bead size <i>D</i><sub>bead</sub> ≃ ξ<sub>e</sub>. This intrachain microphase separation is analogous to that in semidilute solutions of these polymers, with the polymer-rich domain size of <i>D</i><sub>bead</sub> ≃ ξ<sub>e</sub>. Similar diblock-copolymer-like microphases also form in blends of immiscible polyanions and polycations, with the extra incompatibility-dependent prefactor in the domain size of <i>D</i> ≃ χ<sub>+–</sub><sup>1/6</sup>ξ<sub>e</sub> originating from decoupling between the domain density and the surface tension. Scaling and the random phase approximation (RPA) approaches to electrostatic microphase separation in solutions and blends of ionic polymers are not contradictory and correspond to the limits of strong and weak segregation, respectively. Upon the addition of salt, both bulk and single-chain systems exhibit multicritical behavior (Lifshitz point) when the Debye radius, <i>r</i><sub>D</sub>, the electrostatic blob, ξ<sub>e</sub>, and the blob due to short-range attractions, ξ<sub>att</sub>, are all equal to each other, ξ<sub>e</sub> ≃ ξ<sub>att</sub> ≃ <i>r</i><sub>D</sub>. These findings underscore the universality of characteristic lengths controlling the formation and disintegration of electrostatically stabilized microstructures across different systems.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"57 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703384","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}
引用次数: 0
Random Terpolymerization as a Design Strategy to Modulate Aggregation in NDI-Based Polymer Acceptors for All-Polymer Solar Cells
IF 5.8 Q1 POLYMER SCIENCE Pub Date : 2025-03-26 DOI: 10.1021/acsmacrolett.5c00122
Dasol Chung, Stephanie Samson, Sungmo Moon, Seyeon Yoon, Wei You, Sung Yun Son
Naphthalene diimide (NDI)-based conjugated polymers are prominent polymer acceptors in all-polymer solar cells (all-PSCs). However, these polymers tend to exhibit strong self-aggregation, which can cause excessive phase separation and hinder optimal donor–acceptor mixing in the bulk heterojunction blend. To address this issue, random terpolymerization was employed to modulate the aggregation of NDI-based polymer acceptors, aiming to enhance the corresponding device performance of all-PSCs. Four terpolymers (PNDI-T21, PNDI-T23, PNDI-T25, and PNDI-RT) were synthesized by incorporating 10 mol % thiophene derivatives into PNDI-T2, a reference polymer with a regular configuration. Increased thiophene content enhanced backbone planarity, leading to greater aggregation and crystallinity, while a highly randomized backbone reduced both. When used as polymer acceptors in all-PSCs, PNDI-T21, with the weakest aggregation, achieved the highest power conversion efficiency (5.3%), whereas PNDI-T25, with the strongest aggregation, showed the lowest efficiency (3.2%).
{"title":"Random Terpolymerization as a Design Strategy to Modulate Aggregation in NDI-Based Polymer Acceptors for All-Polymer Solar Cells","authors":"Dasol Chung, Stephanie Samson, Sungmo Moon, Seyeon Yoon, Wei You, Sung Yun Son","doi":"10.1021/acsmacrolett.5c00122","DOIUrl":"https://doi.org/10.1021/acsmacrolett.5c00122","url":null,"abstract":"Naphthalene diimide (NDI)-based conjugated polymers are prominent polymer acceptors in all-polymer solar cells (all-PSCs). However, these polymers tend to exhibit strong self-aggregation, which can cause excessive phase separation and hinder optimal donor–acceptor mixing in the bulk heterojunction blend. To address this issue, random terpolymerization was employed to modulate the aggregation of NDI-based polymer acceptors, aiming to enhance the corresponding device performance of all-PSCs. Four terpolymers (PNDI-T21, PNDI-T23, PNDI-T25, and PNDI-RT) were synthesized by incorporating 10 mol % thiophene derivatives into PNDI-T2, a reference polymer with a regular configuration. Increased thiophene content enhanced backbone planarity, leading to greater aggregation and crystallinity, while a highly randomized backbone reduced both. When used as polymer acceptors in all-PSCs, PNDI-T21, with the weakest aggregation, achieved the highest power conversion efficiency (5.3%), whereas PNDI-T25, with the strongest aggregation, showed the lowest efficiency (3.2%).","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"19 1","pages":"484-489"},"PeriodicalIF":5.8,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143713383","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}
引用次数: 0
Hydrodynamically Enhanced Brownian Motion in Flowing Polymer Solutions.
IF 5.1 Q1 POLYMER SCIENCE Pub Date : 2025-03-23 DOI: 10.1021/acsmacrolett.5c00016
Neha Tyagi, Dejuante W Walker, Charles D Young, Charles E Sing

Diffusion of a molecule in solution typically occurs via thermally driven Brownian motion, with solvent collisions leading to a random-walk trajectory for the solute. This physical principle guides our understanding of molecular transport in a wide variety of situations, ranging from protein diffusion in biological systems and mixing in solution processes to charge transport in polyelectrolyte solutions. Thermal diffusion represents a "speed limit" for molecular transport, which can typically only be surpassed by imposing a directional, external field. The other way particles expedite diffusion is via self-propulsion. This "active Brownian motion" is famously seen in some single-cell organisms and can also be shown in some colloidal systems, but because it requires self-propulsion, this is not seen at the molecular level. We show that it is possible to dramatically increase the diffusion of small molecules in a way that mimics active Brownian motion, instead driven by the disturbance flows of highly stretched polymers in strong flows to induce propulsion at a distance. We use molecular simulations that account for these hydrodynamic disturbances to demonstrate that it is possible to increase the effective diffusion constant by more than an order of magnitude, and we provide a mechanistic model for how the interplay of polymer concentration, flow-induced polymer stretching, and chain length gives rise to hydrodynamically enhanced Brownian motion. This effect has important implications for molecular transport, and we show that strong flows and a low concentration of stretched polymers can be used to promote rapid diffusion.

{"title":"Hydrodynamically Enhanced Brownian Motion in Flowing Polymer Solutions.","authors":"Neha Tyagi, Dejuante W Walker, Charles D Young, Charles E Sing","doi":"10.1021/acsmacrolett.5c00016","DOIUrl":"https://doi.org/10.1021/acsmacrolett.5c00016","url":null,"abstract":"<p><p>Diffusion of a molecule in solution typically occurs via thermally driven Brownian motion, with solvent collisions leading to a random-walk trajectory for the solute. This physical principle guides our understanding of molecular transport in a wide variety of situations, ranging from protein diffusion in biological systems and mixing in solution processes to charge transport in polyelectrolyte solutions. Thermal diffusion represents a \"speed limit\" for molecular transport, which can typically only be surpassed by imposing a directional, external field. The other way particles expedite diffusion is via self-propulsion. This \"active Brownian motion\" is famously seen in some single-cell organisms and can also be shown in some colloidal systems, but because it requires self-propulsion, this is not seen at the molecular level. We show that it is possible to dramatically increase the diffusion of small molecules in a way that mimics active Brownian motion, instead driven by the disturbance flows of highly stretched polymers in strong flows to induce propulsion at a distance. We use molecular simulations that account for these hydrodynamic disturbances to demonstrate that it is possible to increase the effective diffusion constant by more than an order of magnitude, and we provide a mechanistic model for how the interplay of polymer concentration, flow-induced polymer stretching, and chain length gives rise to hydrodynamically enhanced Brownian motion. This effect has important implications for molecular transport, and we show that strong flows and a low concentration of stretched polymers can be used to promote rapid diffusion.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":" ","pages":"464-471"},"PeriodicalIF":5.1,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143690464","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}
引用次数: 0
Reversible Switching and Recycling of Thermoresponsive 1,2,4-Triazolium-Based Poly(ionic liquid) Catalysts for Porous Organic Cage Synthesis in Organic Media
IF 5.8 Q1 POLYMER SCIENCE Pub Date : 2025-03-23 DOI: 10.1021/acsmacrolett.5c00072
Jiefeng Zhu, Feng Chen, Jie Zhang, Ruijie Hou, Jian-ke Sun, Xianjing Zhou, Jiayin Yuan, Xinping Wang
Homogeneous catalysts of high activity and selectivity often face challenges in the separation from feedstocks and products after reactions. In contrast, heterogeneous catalysts are easier to separate, usually at the cost of compromised catalytic performance. By designing catalysts capable of switching between homogeneous and heterogeneous states for catalysis and separation, the merits of both could be synergistically combined. In this study, a thermoresponsive 1,2,4-triazolium-based poly(ionic liquid) (PIL) was applied as a temperature-switchable organocatalyst for the controlled synthesis of porous organic cages in methanol. Variation of the reaction temperature induced a phase transition of the PIL, causing the polymer chains to dissolve or collapse in methanol, thereby exposing or shielding the catalytically active sites to proceed or retard the reaction, respectively. To note, at a sufficiently low temperature, the PIL as a catalyst precipitated out of its methanol solution and could be separated by centrifugation or filtration for reuse, similar to common heterogeneous catalysts. Such switchable and recyclable properties of polymeric catalysts will inspire the design of efficient and adaptable organic or hybrid nanoreactors in liquid media.
具有高活性和高选择性的均相催化剂在反应后与原料和产物分离时往往面临挑战。相比之下,异相催化剂更容易分离,但通常以降低催化性能为代价。通过设计能够在催化和分离的均相和异相状态之间切换的催化剂,可以将二者的优点协同结合起来。在本研究中,一种热致伸缩性 1,2,4-三唑鎓基聚(离子液体)(PIL)被用作温度可切换有机催化剂,用于在甲醇中受控合成多孔有机笼。反应温度的变化会引起 PIL 的相变,使聚合物链在甲醇中溶解或塌缩,从而暴露或屏蔽催化活性位点,分别促进或延缓反应的进行。值得注意的是,在足够低的温度下,作为催化剂的 PIL 会从甲醇溶液中析出,可以通过离心或过滤分离出来重新使用,这与普通的异相催化剂类似。聚合物催化剂的这种可转换和可回收特性将启发人们在液体介质中设计高效、适应性强的有机或混合纳米反应器。
{"title":"Reversible Switching and Recycling of Thermoresponsive 1,2,4-Triazolium-Based Poly(ionic liquid) Catalysts for Porous Organic Cage Synthesis in Organic Media","authors":"Jiefeng Zhu, Feng Chen, Jie Zhang, Ruijie Hou, Jian-ke Sun, Xianjing Zhou, Jiayin Yuan, Xinping Wang","doi":"10.1021/acsmacrolett.5c00072","DOIUrl":"https://doi.org/10.1021/acsmacrolett.5c00072","url":null,"abstract":"Homogeneous catalysts of high activity and selectivity often face challenges in the separation from feedstocks and products after reactions. In contrast, heterogeneous catalysts are easier to separate, usually at the cost of compromised catalytic performance. By designing catalysts capable of switching between homogeneous and heterogeneous states for catalysis and separation, the merits of both could be synergistically combined. In this study, a thermoresponsive 1,2,4-triazolium-based poly(ionic liquid) (PIL) was applied as a temperature-switchable organocatalyst for the controlled synthesis of porous organic cages in methanol. Variation of the reaction temperature induced a phase transition of the PIL, causing the polymer chains to dissolve or collapse in methanol, thereby exposing or shielding the catalytically active sites to proceed or retard the reaction, respectively. To note, at a sufficiently low temperature, the PIL as a catalyst precipitated out of its methanol solution and could be separated by centrifugation or filtration for reuse, similar to common heterogeneous catalysts. Such switchable and recyclable properties of polymeric catalysts will inspire the design of efficient and adaptable organic or hybrid nanoreactors in liquid media.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"71 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678100","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}
引用次数: 0
Supramolecular Zwitterionic Network Enabling Environment-Tolerant, Transparent, Adhesive, and Biocompatible Organogel for Epidermal Electronics
IF 5.8 Q1 POLYMER SCIENCE Pub Date : 2025-03-20 DOI: 10.1021/acsmacrolett.5c00098
Min Gong, Xiaobo Wang, Heng An, You Wu, Liang Zhang, Xiang Lin, Fengxian Gao, Zhen Wu, Dongrui Wang
Ionic hydrogels are ideal for soft bioelectronics due to their softness, stretchability, and ion-mediated signal transduction. However, traditional hydrogels face dehydration and freezing issues. Inspired by natural skin, this study creates a supramolecular ionic organogel using silk fibroin, zwitterionic polymers, Ca2+, and ethylene glycol (EG). The organogel is conductive, highly stretchable, adhesive, environmentally stable, and biocompatible. Theoretical calculations reveal that interactions among Ca2+, zwitterionic groups, EG, and water are stronger than water–water interactions, converting “free” water into “locked” water. This mechanism allows the organogel to retain over 90% of its weight after 30 days at 25 °C and 60% relative humidity, while also resisting freezing by disrupting ice formation. Its conductivity, adhesion, and biocompatibility enable applications in on-skin strain sensors and electrodes for monitoring motion and recording electrophysiological signals. This work elucidates molecular interactions in organogel networks, provides a design framework for environmentally tolerant organogel, and advances ion-conductive bioelectronics.
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引用次数: 0
Helical Poly(quioxaline-2,3-diyl)-Based Poly(carboxylic acid)s as a Chiroptical Chemosensor for Detection and Quantification of Small Enantiomeric Imbalances of Chiral Amines in Water. 螺旋状聚(喹喔啉-2,3-二基)聚(羧酸)作为千光化学传感器,用于检测和定量水中手性胺的微小对映异构体失衡。
IF 5.1 Q1 POLYMER SCIENCE Pub Date : 2025-03-18 Epub Date: 2025-02-14 DOI: 10.1021/acsmacrolett.4c00814
Tomonori Yamawaki, Takuma Kuroda, Takeshi Yamamoto, Yuuya Nagata, Michinori Suginome

Achiral dynamic helical polymers, poly(quinoxaline-2,3-diyl)s (P1 and P2) bearing achiral carboxylic acid side chains, i.e., carboxymethoxymethyl (in P1) and carboxyethoxymethyl (in P2), with different polymerization degrees were synthesized. They exhibited induced circular dichroism (ICD) in the presence of chiral amines such as 1-phenylethylamine and nicotine, 1,2-amino alcohols such as valinol, leucinol, and prolinol, and the basic amino acid, arginine, in response to the induction of right- or left-handed helical conformation. The efficiency of helix induction depends on the compatibility of the structures of amines and polymers, with no clear structural correlation. The highly sensitive and formulated nature of ICD with the helical polymer-based poly(carboxylic acid)s allowed their use as CD-based sensors to detect and quantify minute imbalances of the enantiomeric excess of chiral molecules. We determined 0.2%-0.6% ee in the commercially available 1-phenylethylamine from three different suppliers, which have the label of "dl" or no indication of enantiopurity using P1 as a chemosensor.

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引用次数: 0
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ACS Macro Letters
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