Functionalized polyolefins hold great promise as a material group for a future society. The hierarchical structure formation process during crystallization and melting of such polymers is greatly influenced by the inter- and intrachain interactions induced by functional groups. Herein, we report the comprehensive structural analysis of strictly linear poly(ethylene-ran-acrylic acid), i.e., polyethylene bearing pendant carboxyl (−COOH) groups randomly along the chain (PE-COOH), during the crystallization and melting processes. Additional use of the corresponding methyl ester (PE-COOMe) and polyethylene (PE) enabled us to separate the effects of hydrogen bonds (H-bonds) among the −COOH groups from those caused by the random insertion of pendant groups. The crystallizable methylene sequences were divided by the randomly inserted pendant groups, giving rise to the sequence-length selective crystallization. That is, longer sequences crystallized at higher temperatures and vice versa. This significantly hindered the crystallization rate, crystal thickness, and crystallinity and led to a strong melt memory effect. The H-bonding between −COOH groups acted as physical cross-linking for the PE chains and hindered the chain motion. This further slowed the crystallization and reinforced the melt memory effect. On the other hand, the H-bonds contributed to increased crystallinity and melting point of PE-COOH crystallized at high temperatures, compared to those of PE-COOMe. Thus, it was found that the H-bonding of −COOH groups stabilized the crystals formed at high temperatures. This work presents a unified view of the crystallization and melting behavior of strictly linear PE with interacting pendant groups, providing the possibility to precisely control the crystalline morphology in scales of both lamella and spherulite by altering the thermal history.
{"title":"Crystallization of Strictly Linear Poly(ethylene-ran-acrylic acid) Copolymer: Impacts of Pendant Group Insertion and Hydrogen Bonding","authors":"Jian Zhou, Kohei Takahashi, Kyoko Nozaki, Yuta Yamamoto, Takuya Katashima, Naoko Yoshie, Shintaro Nakagawa","doi":"10.1021/acs.macromol.4c01250","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01250","url":null,"abstract":"Functionalized polyolefins hold great promise as a material group for a future society. The hierarchical structure formation process during crystallization and melting of such polymers is greatly influenced by the inter- and intrachain interactions induced by functional groups. Herein, we report the comprehensive structural analysis of strictly linear poly(ethylene-<i>ran</i>-acrylic acid), i.e., polyethylene bearing pendant carboxyl (−COOH) groups randomly along the chain (PE-COOH), during the crystallization and melting processes. Additional use of the corresponding methyl ester (PE-COOMe) and polyethylene (PE) enabled us to separate the effects of hydrogen bonds (H-bonds) among the −COOH groups from those caused by the random insertion of pendant groups. The crystallizable methylene sequences were divided by the randomly inserted pendant groups, giving rise to the sequence-length selective crystallization. That is, longer sequences crystallized at higher temperatures and vice versa. This significantly hindered the crystallization rate, crystal thickness, and crystallinity and led to a strong melt memory effect. The H-bonding between −COOH groups acted as physical cross-linking for the PE chains and hindered the chain motion. This further slowed the crystallization and reinforced the melt memory effect. On the other hand, the H-bonds contributed to increased crystallinity and melting point of PE-COOH crystallized at high temperatures, compared to those of PE-COOMe. Thus, it was found that the H-bonding of −COOH groups stabilized the crystals formed at high temperatures. This work presents a unified view of the crystallization and melting behavior of strictly linear PE with interacting pendant groups, providing the possibility to precisely control the crystalline morphology in scales of both lamella and spherulite by altering the thermal history.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1021/acs.macromol.4c02290
Hee Jeung Oh, William A. Phillip
This article references 43 other publications. This article has not yet been cited by other publications.
本文引用了 43 篇其他出版物。本文尚未被其他出版物引用。
{"title":"Polymer Physics of Separation Membranes","authors":"Hee Jeung Oh, William A. Phillip","doi":"10.1021/acs.macromol.4c02290","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02290","url":null,"abstract":"This article references 43 other publications. This article has not yet been cited by other publications.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate the ring-linear polymer blends under Poiseuille flow across a range of flow intensities. As rings are flexible (Kbr = 0), the threading probability gradually increases with an increase in flow field strength. However, as rings are semiflexible (Kbr > 0), the threading probability significantly decreases and then significantly increases as the flow field strength increases. Additionally, for different ring rigidity parameters, the critical flow field strength corresponding to the rapid increase in the threading probability is almost the same. When the flow field strength exceeds this critical value, ring-linear polymer blends will aggregate into a cluster due to the combination of entanglement between polymers and the large differences in the velocities of the polymers. The cluster moves along the direction of the flow field and can be bisected by the flow channel’s centerplane into two parts, and each part performs the tank-treading motion in opposite directions: one moving counterclockwise and the other moving clockwise. The dynamic movement of the cluster significantly promotes an increase in threading probability. Furthermore, the nonlinear relationship between the characteristic time of tank-treading motion and flow field strength suggests that the structure of the cluster exhibits similar dynamic and structural behaviors over a certain range of flow field strengths. The results could enhance our understanding of the intricate threading properties observed in ring-linear polymer blends upon exposure to external force fields.
{"title":"Threading Behavior and Dynamics of Ring-Linear Polymer Blends under Poiseuille Flow","authors":"Deyin Wang, Zekai Shi, Xiaohui Wen, Dong Zhang, Linxi Zhang","doi":"10.1021/acs.macromol.4c01004","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01004","url":null,"abstract":"We investigate the ring-linear polymer blends under Poiseuille flow across a range of flow intensities. As rings are flexible (<i>K</i><sub>br</sub> = 0), the threading probability gradually increases with an increase in flow field strength. However, as rings are semiflexible (<i>K</i><sub>br</sub> > 0), the threading probability significantly decreases and then significantly increases as the flow field strength increases. Additionally, for different ring rigidity parameters, the critical flow field strength corresponding to the rapid increase in the threading probability is almost the same. When the flow field strength exceeds this critical value, ring-linear polymer blends will aggregate into a cluster due to the combination of entanglement between polymers and the large differences in the velocities of the polymers. The cluster moves along the direction of the flow field and can be bisected by the flow channel’s centerplane into two parts, and each part performs the tank-treading motion in opposite directions: one moving counterclockwise and the other moving clockwise. The dynamic movement of the cluster significantly promotes an increase in threading probability. Furthermore, the nonlinear relationship between the characteristic time of tank-treading motion and flow field strength suggests that the structure of the cluster exhibits similar dynamic and structural behaviors over a certain range of flow field strengths. The results could enhance our understanding of the intricate threading properties observed in ring-linear polymer blends upon exposure to external force fields.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amphiphilic random terpolymers bearing hydrophilic poly(ethylene glycol) (PEG) chains, quaternary ammonium cations, and hydrophobic dodecyl groups form size-controlled micelles in water. The terpolymer micelles show a lower critical solution temperature (LCST)-type solubility in water in the presence of salts. Focusing on the features, we herein investigated the thermoresponsive properties of the concentrated aqueous solutions of the PEG/cation random terpolymer micelles containing NaCl to find unique gelation and phase transition dependent on the PEG/cation composition. Upon heating, the PEG/cation (2/1, 1/1, and 1/2) terpolymer micelle solutions exhibited a two-step phase transition through transient gelation to viscous and turbid solutions via LCST-type phase separation. In contrast, a cation-rich PEG/cation (1/3) terpolymer micelle and a cation copolymer micelle formed gels in water at room temperature, where the former changed to a viscous and transparent solution upon heating. The rheological properties of the gels can be tuned by the PEG/cation ratio and degree of polymerization of the terpolymers. Small-angle neutron scattering measurements revealed that the transient gelation of the terpolymer micelle solutions occurred via the formation of intermicellar networks.
{"title":"Thermoresponsive Gelation and Phase Transition of PEG/Cation Random Terpolymer Micelles in Water in the Presence of Salts","authors":"Rikuto Kanno, Motoki Shibata, Mikihito Takenaka, Shin-ichi Takata, Kosuke Hiroi, Makoto Ouchi, Takaya Terashima","doi":"10.1021/acs.macromol.4c01677","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01677","url":null,"abstract":"Amphiphilic random terpolymers bearing hydrophilic poly(ethylene glycol) (PEG) chains, quaternary ammonium cations, and hydrophobic dodecyl groups form size-controlled micelles in water. The terpolymer micelles show a lower critical solution temperature (LCST)-type solubility in water in the presence of salts. Focusing on the features, we herein investigated the thermoresponsive properties of the concentrated aqueous solutions of the PEG/cation random terpolymer micelles containing NaCl to find unique gelation and phase transition dependent on the PEG/cation composition. Upon heating, the PEG/cation (2/1, 1/1, and 1/2) terpolymer micelle solutions exhibited a two-step phase transition through transient gelation to viscous and turbid solutions via LCST-type phase separation. In contrast, a cation-rich PEG/cation (1/3) terpolymer micelle and a cation copolymer micelle formed gels in water at room temperature, where the former changed to a viscous and transparent solution upon heating. The rheological properties of the gels can be tuned by the PEG/cation ratio and degree of polymerization of the terpolymers. Small-angle neutron scattering measurements revealed that the transient gelation of the terpolymer micelle solutions occurred via the formation of intermicellar networks.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1021/acs.macromol.4c01496
Zhiqiang Cao, Zhaofan Li, Madison Mooney, Changwoo Do, Kunlun Hong, Simon Rondeau-Gagné, Wenjie Xia, Xiaodan Gu
The conjugated polymer’s backbone conformation dictates the delocalization of electrons, ultimately affecting its optoelectronic properties. Most conjugated polymers can be viewed as semirigid rods with their backbone embedded among long alkyl side chains. Thus, it is challenging to experimentally quantify the conformation of a conjugated backbone. Here, we performed contrast variation neutron scattering on rigid conjugated donor–acceptor (D–A) diketopyrrolopyrrole (DPP) polymers with selectively deuterated side chains to measure the conjugated backbone conformation. We first synthesized DPP-based polymers with deuterated side chains, confirmed by NMR and FTIR. Using contrast variation neutron scattering, we found that the DPP-based conjugated polymers are much more rigid than poly(3-alkylthiophenes), with persistence length (Lp) at 16–18 nm versus 2–3 nm. More importantly, in contrast to the relatively flexible poly(3-alkylthiophenes) whose backbone is more flexible than the whole polymer, we found that the backbone of DPP-based polymers has the same Lp value compared to the whole polymer chain. This indicates that side chain interference on backbone conformation is not present for the semirigid polymer, which is further confirmed by coarse-grained molecular dynamics (CG-MD) simulations. Our work provides a novel protocol to probe polymer’s backbone conformation and paradigm-shifting understanding of the backbone conformation of semirigid conjugated polymers.
{"title":"Uncovering Backbone Conformation for Rigid DPP-Based Donor–Acceptor Conjugated Polymer Using Deuterium Labeling and Neutron Scattering","authors":"Zhiqiang Cao, Zhaofan Li, Madison Mooney, Changwoo Do, Kunlun Hong, Simon Rondeau-Gagné, Wenjie Xia, Xiaodan Gu","doi":"10.1021/acs.macromol.4c01496","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01496","url":null,"abstract":"The conjugated polymer’s backbone conformation dictates the delocalization of electrons, ultimately affecting its optoelectronic properties. Most conjugated polymers can be viewed as semirigid rods with their backbone embedded among long alkyl side chains. Thus, it is challenging to experimentally quantify the conformation of a conjugated backbone. Here, we performed contrast variation neutron scattering on rigid conjugated donor–acceptor (D–A) diketopyrrolopyrrole (DPP) polymers with selectively deuterated side chains to measure the conjugated backbone conformation. We first synthesized DPP-based polymers with deuterated side chains, confirmed by NMR and FTIR. Using contrast variation neutron scattering, we found that the DPP-based conjugated polymers are much more rigid than poly(3-alkylthiophenes), with persistence length (<i>L</i><sub>p</sub>) at 16–18 nm versus 2–3 nm. More importantly, in contrast to the relatively flexible poly(3-alkylthiophenes) whose backbone is more flexible than the whole polymer, we found that the backbone of DPP-based polymers has the same <i>L</i><sub>p</sub> value compared to the whole polymer chain. This indicates that side chain interference on backbone conformation is not present for the semirigid polymer, which is further confirmed by coarse-grained molecular dynamics (CG-MD) simulations. Our work provides a novel protocol to probe polymer’s backbone conformation and paradigm-shifting understanding of the backbone conformation of semirigid conjugated polymers.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1021/acs.macromol.4c01598
Anwar Shafe, Pouria Nourian, Xiyuan Liu, Guoqiang Li, Collin D. Wick, Andrew J. Peters
An approach for designing thermoset shape memory polymers (TSMPs) with improved shape memory properties through the integration of molecular dynamics (MD) simulation, machine learning (ML), and chemical intuition is presented. We identified key molecular features correlated with desired shape memory properties, and used MD simulations to create an initial data set of TSMPs consisting of commercially available and manually designed monomers. Our prediction set was prepared by employing four different approaches for modifying existing monomers based on chemical intuition and insights gleaned from the literature. We trained our ML model on the initial data set, used it to identify the most promising candidates, evaluated their properties, and added them to our initial data set. To further speed up the process, we identified the most promising candidate after a few cycles and modified its structure to obtain a variant with better properties. Our approach, which capitalizes on the synergy between computational methodologies and human expertise to enable efficient exploration of vast chemical space, resulted in the design of a monomer exhibiting more than 60% increase in the desired recovery stress compared to the highest experimentally validated one.
本文介绍了一种通过整合分子动力学（MD）模拟、机器学习（ML）和化学直觉来设计具有更佳形状记忆特性的热固性形状记忆聚合物（TSMP）的方法。我们确定了与所需形状记忆特性相关的关键分子特征，并利用 MD 模拟创建了一个 TSMP 初始数据集，该数据集由市面上销售的单体和人工设计的单体组成。我们的预测集是根据化学直觉和从文献中获得的启示，采用四种不同的方法对现有单体进行修改而准备的。我们在初始数据集上训练了我们的 ML 模型，用它来识别最有前途的候选单体，评估它们的特性，并将它们添加到初始数据集中。为了进一步加快进程，我们在几个循环后确定了最有希望的候选者，并修改了其结构，以获得具有更好特性的变体。我们的方法充分利用了计算方法与人类专业知识之间的协同作用，从而能够高效地探索广阔的化学空间，最终设计出了一种单体，与实验验证的最高单体相比，该单体的理想恢复应力提高了 60% 以上。
{"title":"Identification and Design of Better Diamine-Hardened Epoxy-Based Thermoset Shape Memory Polymers: Simulation and Machine Learning","authors":"Anwar Shafe, Pouria Nourian, Xiyuan Liu, Guoqiang Li, Collin D. Wick, Andrew J. Peters","doi":"10.1021/acs.macromol.4c01598","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01598","url":null,"abstract":"An approach for designing thermoset shape memory polymers (TSMPs) with improved shape memory properties through the integration of molecular dynamics (MD) simulation, machine learning (ML), and chemical intuition is presented. We identified key molecular features correlated with desired shape memory properties, and used MD simulations to create an initial data set of TSMPs consisting of commercially available and manually designed monomers. Our prediction set was prepared by employing four different approaches for modifying existing monomers based on chemical intuition and insights gleaned from the literature. We trained our ML model on the initial data set, used it to identify the most promising candidates, evaluated their properties, and added them to our initial data set. To further speed up the process, we identified the most promising candidate after a few cycles and modified its structure to obtain a variant with better properties. Our approach, which capitalizes on the synergy between computational methodologies and human expertise to enable efficient exploration of vast chemical space, resulted in the design of a monomer exhibiting more than 60% increase in the desired recovery stress compared to the highest experimentally validated one.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1021/acs.macromol.4c01359
Sidonie Laviéville, Cédric Totée, Pascale Guiffrey, Sylvain Caillol, Camille Bakkali-Hassani, Vincent Ladmiral, Eric Leclerc
This work presents the synthesis and characterization of a highly transparent and colorless covalent adaptable network (CAN) exhibiting short relaxation times (30 s at 150 °C) and limited creep at 100 °C. Based on N,S-acetal functions, strongly stabilized by a trifluoromethyl group, this network, however, retains the ability to undergo fast thiol exchanges. The present article describes a detailed monitoring of the cross-linking via ATR-FTIR and 19F HRMAS NMR (high-resolution magic angle spinning NMR), the complete structural characterization of the material via 13C HRMAS NMR, and the comprehensive study of the rheological properties of this novel N,S-acetal network. This CAN shows hydrolytic stability and higher activation energies (>90 kJ mol–1) than its nonfluorinated counterparts. Its reprocessing occurs under relatively mild conditions without the need for a catalyst, and depolymerization can be achieved either with an amine (benzylamine), under acidic conditions (1 M HCl) at room temperature, or with a thiol (1-dodecanethiol) at 100 °C.
这项研究合成并表征了一种高度透明、无色的共价适应性网络（CAN），它的弛豫时间很短（150 °C时为30秒），在100 °C时蠕变有限。这种网络以 N,S-缩醛功能为基础，并由一个三氟甲基基团强力稳定，但仍能进行快速的硫醇交换。本文介绍了通过 ATR-FTIR 和 19F HRMAS NMR（高分辨率魔角旋转 NMR）对交联进行的详细监测、通过 13C HRMAS NMR 对材料进行的完整结构表征，以及对这种新型 N,S-缩醛网络的流变特性进行的全面研究。与不含氟的同类产品相比，这种 CAN 具有水解稳定性和更高的活化能（90 kJ mol-1）。它可以在相对温和的条件下进行再加工，无需催化剂，并且可以在室温下用胺（苄胺）、酸性条件（1 M HCl）或在 100 °C 下用硫醇（1-十二烷硫醇）实现解聚。
{"title":"Trifluoromethylated N,S-Acetal as a Chemical Platform for Covalent Adaptable Networks: Fast Thiol Exchange and Strong Hydrostability for a Highly Transparent Material","authors":"Sidonie Laviéville, Cédric Totée, Pascale Guiffrey, Sylvain Caillol, Camille Bakkali-Hassani, Vincent Ladmiral, Eric Leclerc","doi":"10.1021/acs.macromol.4c01359","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01359","url":null,"abstract":"This work presents the synthesis and characterization of a highly transparent and colorless covalent adaptable network (CAN) exhibiting short relaxation times (30 s at 150 °C) and limited creep at 100 °C. Based on <i>N,S</i>-acetal functions, strongly stabilized by a trifluoromethyl group, this network, however, retains the ability to undergo fast thiol exchanges. The present article describes a detailed monitoring of the cross-linking via ATR-FTIR and <sup>19</sup>F HRMAS NMR (high-resolution magic angle spinning NMR), the complete structural characterization of the material via <sup>13</sup>C HRMAS NMR, and the comprehensive study of the rheological properties of this novel <i>N,S</i>-acetal network. This CAN shows hydrolytic stability and higher activation energies (>90 kJ mol<sup>–1</sup>) than its nonfluorinated counterparts. Its reprocessing occurs under relatively mild conditions without the need for a catalyst, and depolymerization can be achieved either with an amine (benzylamine), under acidic conditions (1 M HCl) at room temperature, or with a thiol (1-dodecanethiol) at 100 °C.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1021/acs.macromol.4c01486
Tongkui Yue, Xin Zou, Hengheng Zhao, Yulong Chen, Liqun Zhang, Jun Liu
Service performance can be significantly improved by adding nanofillers into polymers. However, entropy effects and enthalpic interactions between traditional inorganic fillers and polymers impede the simultaneous attainment of high strength and strong toughness. Polymer-based soft nanoparticles (SNPs) have emerged as promising candidates for achieving a balance between strength and toughness. To fully harness the deformability potential of SNPs and achieve superior mechanical performance, the pearl necklace structure was designed by employing molecular dynamics simulation. Compared to traditional all-polymer nanocomposite system (S<sub>T</sub>) composed of directly mixing polymer and SNPs, the SNPs in our novel system (S<sub>N</sub>) exhibit better dispersion and compatibility. Primitive path analysis revealed that the pearl necklace chains endow a greater degree of penetration between SNPs and polymer. The confinement effects of cross-linking networks alter the diffusion dynamics of SNPs embedded within polymer chains. The restricted displacement fluctuation distance <i></i><span style="color: inherit;"></span><span data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mrow><mi>d</mi></mrow><mrow><mrow><mi>fluct</mi></mrow></mrow><mrow><mrow><mi>SNP</mi></mrow></mrow></msubsup></math>' role="presentation" style="position: relative;" tabindex="0"><nobr aria-hidden="true"><span style="width: 2.513em; display: inline-block;"><span style="display: inline-block; position: relative; width: 2.052em; height: 0px; font-size: 122%;"><span style="position: absolute; clip: rect(1.13em, 1002.05em, 2.615em, -999.997em); top: -2.2em; left: 0em;"><span><span><span style="display: inline-block; position: relative; width: 2.052em; height: 0px;"><span style="position: absolute; clip: rect(3.128em, 1000.51em, 4.152em, -999.997em); top: -3.993em; left: 0em;"><span><span style="font-family: MathJax_Math-italic;">d<span style="display: inline-block; overflow: hidden; height: 1px; width: 0.003em;"></span></span></span><span style="display: inline-block; width: 0px; height: 3.998em;"></span></span><span style="position: absolute; clip: rect(3.332em, 1001.49em, 4.152em, -999.997em); top: -4.403em; left: 0.566em;"><span><span><span style="font-size: 70.7%; font-family: MathJax_Main;">SNP</span></span></span><span style="display: inline-block; width: 0px; height: 3.998em;"></span></span><span style="position: absolute; clip: rect(3.332em, 1001.49em, 4.152em, -999.997em); top: -3.737em; left: 0.515em;"><span><span><span style="font-size: 70.7%; font-family: MathJax_Main;">fluct</span></span></span><span style="display: inline-block; width: 0px; height: 3.998em;"></span></span></span></span></span><span style="display: inline-block; width: 0px; height: 2.205em;"></span></span></span><span style="display: inline-block; ove
通过在聚合物中添加纳米填料，可大大提高其使用性能。然而，传统无机填料与聚合物之间的熵效应和焓相互作用阻碍了高强度和强韧性的同时实现。基于聚合物的软纳米粒子（SNPs）已成为实现强度和韧性平衡的理想候选材料。为了充分利用 SNP 的变形潜力并实现优异的机械性能，我们通过分子动力学模拟设计了珍珠项链结构。与传统的聚合物与 SNP 直接混合的全聚合物纳米复合材料体系（ST）相比，我们的新型体系（SN）中的 SNP 具有更好的分散性和相容性。原始路径分析显示，珍珠项链使 SNP 与聚合物之间的渗透程度更高。交联网络的限制效应改变了嵌入聚合物链中的 SNP 的扩散动力学。SN 中 SNP 的限制位移波动距离 dSNPfluctdfluctSNPdfluctSNP 是由 van Hove 函数 Gs(r, Δt)求得的，dSNPfluctdfluctSNPdfluctSNP 与聚合物基体交联网络的网格尺寸⟨Lc⟩呈典型的线性相关。SN的独特结构和动态行为在宏观力学性能中得到了显著反映。应力分解分析表明，SNPs 在低应变时主要承受应力，而在高应变时则以聚合物为主，这与在水凝胶的双聚合物网络中观察到的增强机制类似。此外，与 ST 相比，SN 内的 SNP 表现出更大的变形和更慢的恢复速度，从而使滞后损失减少了 21.3%。通过三轴拉伸评估了复合材料的韧性。与 ST 相比，SN 沿着拉伸方向显示出更均匀的纤维分布，从而提高了抗裂性并增加了约 50% 的耗散功。总之，这种新型珍珠项链结构为平衡聚合物纳米复合材料的强度-韧性-滞后性开辟了一条新途径。
{"title":"Designing Novel All-Polymer Nanocomposites with Pearl Necklace Chain Structure with High Strength, High Toughness, and Low Hysteresis","authors":"Tongkui Yue, Xin Zou, Hengheng Zhao, Yulong Chen, Liqun Zhang, Jun Liu","doi":"10.1021/acs.macromol.4c01486","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01486","url":null,"abstract":"Service performance can be significantly improved by adding nanofillers into polymers. However, entropy effects and enthalpic interactions between traditional inorganic fillers and polymers impede the simultaneous attainment of high strength and strong toughness. Polymer-based soft nanoparticles (SNPs) have emerged as promising candidates for achieving a balance between strength and toughness. To fully harness the deformability potential of SNPs and achieve superior mechanical performance, the pearl necklace structure was designed by employing molecular dynamics simulation. Compared to traditional all-polymer nanocomposite system (S<sub>T</sub>) composed of directly mixing polymer and SNPs, the SNPs in our novel system (S<sub>N</sub>) exhibit better dispersion and compatibility. Primitive path analysis revealed that the pearl necklace chains endow a greater degree of penetration between SNPs and polymer. The confinement effects of cross-linking networks alter the diffusion dynamics of SNPs embedded within polymer chains. The restricted displacement fluctuation distance <i></i><span style=\"color: inherit;\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><msubsup><mrow><mi>d</mi></mrow><mrow><mrow><mi>fluct</mi></mrow></mrow><mrow><mrow><mi>SNP</mi></mrow></mrow></msubsup></math>' role=\"presentation\" style=\"position: relative;\" tabindex=\"0\"><nobr aria-hidden=\"true\"><span style=\"width: 2.513em; display: inline-block;\"><span style=\"display: inline-block; position: relative; width: 2.052em; height: 0px; font-size: 122%;\"><span style=\"position: absolute; clip: rect(1.13em, 1002.05em, 2.615em, -999.997em); top: -2.2em; left: 0em;\"><span><span><span style=\"display: inline-block; position: relative; width: 2.052em; height: 0px;\"><span style=\"position: absolute; clip: rect(3.128em, 1000.51em, 4.152em, -999.997em); top: -3.993em; left: 0em;\"><span><span style=\"font-family: MathJax_Math-italic;\">d<span style=\"display: inline-block; overflow: hidden; height: 1px; width: 0.003em;\"></span></span></span><span style=\"display: inline-block; width: 0px; height: 3.998em;\"></span></span><span style=\"position: absolute; clip: rect(3.332em, 1001.49em, 4.152em, -999.997em); top: -4.403em; left: 0.566em;\"><span><span><span style=\"font-size: 70.7%; font-family: MathJax_Main;\">SNP</span></span></span><span style=\"display: inline-block; width: 0px; height: 3.998em;\"></span></span><span style=\"position: absolute; clip: rect(3.332em, 1001.49em, 4.152em, -999.997em); top: -3.737em; left: 0.515em;\"><span><span><span style=\"font-size: 70.7%; font-family: MathJax_Main;\">fluct</span></span></span><span style=\"display: inline-block; width: 0px; height: 3.998em;\"></span></span></span></span></span><span style=\"display: inline-block; width: 0px; height: 2.205em;\"></span></span></span><span style=\"display: inline-block; ove","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1021/acs.macromol.4c01716
Yilong Liao, Ricardo A. Pérez-Camargo, Tianyi Ma, Jon Maiz, Antxon Martínez de Ilarduya, Haritz Sardon, Guoming Liu, Dujin Wang, Alejandro J. Müller
In this work, we investigate the crystallization behavior of two series of novel aliphatic random copolycarbonates: poly(heptamethylene-ran-octamethylene carbonate) (PC7/PC8) and poly(octamethylene-ran-dodecamethylene carbonate) (PC12/PC8). Both copolymers display apparent isodimorphic behavior as they crystallize over the entire composition range, exhibiting pseudoeutectic points at 45 and 76 mol % of PC8 content for PC7/PC8 and PC12/PC8, respectively. However, the evolution in melting enthalpies (ΔHm) and crystallinities (Xc) deviate from the expected pseudoeutectic behavior, indicating mixed isodimorphic/isomorphic crystallization, a behavior reported for the first time recently by us in poly(hexamethylene-ran-octamethyelene carbonate) (PC6/PC8). Further understanding of this behavior was obtained through structural and conformational characterization employing in situ synchrotron radiation wide- and small-angle X-ray scattering (WAXS/SAXS) and Fourier-transform infrared spectroscopy (FT-IR). For PC7/PC8 copolymers, a new third crystalline phase, from now on named the γ phase, different from PC7- and PC8-type crystalline phases (or any of their polymorphs: δ, α, and β), emerged for intermediate compositions, i.e., 34–45 mol % PC8, in line with the atypical variations of ΔHm and Xc. For PC12/PC8 copolymers, a coexistence of the γ/PC8 type phase was found at PC8-rich contents. According to FT-IR results, the γ phase adopted a polyethylene-like conformation in all cases despite the presence of C═O groups. However, compared with those compositions where homopolymer-like phases dominate the crystallization, there is a stronger dipole–dipole interaction in the γ phase, evidenced by a shift of absorption band associated with C═O stretching. This evidence aligns with our previous work in PC6/PC8 copolymers, demonstrating that the mixed isodimorphic/isomorphic crystallization found in PC8-based random copolycarbonates is likely a general case. Additionally, as the number of methylene groups in the repeating unit of the second comonomer in the PC8-based copolymers increases, the composition range where the γ phase is observed narrows. At the same time, the position of the pseudoeutectic point shifts toward compositions rich in PC8, demonstrating how the chemical structure affects the exact location of the pseudoeutectic point in these random copolycarbonates.
{"title":"Mixed Isodimorphic/Isomorphic Crystallization in Aliphatic Random Copolycarbonates","authors":"Yilong Liao, Ricardo A. Pérez-Camargo, Tianyi Ma, Jon Maiz, Antxon Martínez de Ilarduya, Haritz Sardon, Guoming Liu, Dujin Wang, Alejandro J. Müller","doi":"10.1021/acs.macromol.4c01716","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01716","url":null,"abstract":"In this work, we investigate the crystallization behavior of two series of novel aliphatic random copolycarbonates: poly(heptamethylene-<i>ran</i>-octamethylene carbonate) (PC7/PC8) and poly(octamethylene-<i>ran</i>-dodecamethylene carbonate) (PC12/PC8). Both copolymers display apparent isodimorphic behavior as they crystallize over the entire composition range, exhibiting pseudoeutectic points at 45 and 76 mol % of PC8 content for PC7/PC8 and PC12/PC8, respectively. However, the evolution in melting enthalpies (Δ<i>H</i><sub>m</sub>) and crystallinities (<i>X</i><sub><i>c</i></sub>) deviate from the expected pseudoeutectic behavior, indicating mixed isodimorphic/isomorphic crystallization, a behavior reported for the first time recently by us in poly(hexamethylene-<i>ran</i>-octamethyelene carbonate) (PC6/PC8). Further understanding of this behavior was obtained through structural and conformational characterization employing in situ synchrotron radiation wide- and small-angle X-ray scattering (WAXS/SAXS) and Fourier-transform infrared spectroscopy (FT-IR). For PC7/PC8 copolymers, a new third crystalline phase, from now on named the γ phase, different from PC7- and PC8-type crystalline phases (or any of their polymorphs: δ, α, and β), emerged for intermediate compositions, i.e., 34–45 mol % PC8, in line with the atypical variations of Δ<i>H</i><sub>m</sub> and <i>X</i><sub>c</sub>. For PC12/PC8 copolymers, a coexistence of the γ/PC8 type phase was found at PC8-rich contents. According to FT-IR results, the γ phase adopted a polyethylene-like conformation in all cases despite the presence of C═O groups. However, compared with those compositions where homopolymer-like phases dominate the crystallization, there is a stronger dipole–dipole interaction in the γ phase, evidenced by a shift of absorption band associated with C═O stretching. This evidence aligns with our previous work in PC6/PC8 copolymers, demonstrating that the mixed isodimorphic/isomorphic crystallization found in PC8-based random copolycarbonates is likely a general case. Additionally, as the number of methylene groups in the repeating unit of the second comonomer in the PC8-based copolymers increases, the composition range where the γ phase is observed narrows. At the same time, the position of the pseudoeutectic point shifts toward compositions rich in PC8, demonstrating how the chemical structure affects the exact location of the pseudoeutectic point in these random copolycarbonates.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142448179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hydrogels prepared through free radical polymerization hold great promise for large-scale production and practical applications but face challenges due to oxygen inhibition during polymerization and poor mechanical properties. These issues often necessitate complex structural designs and time-consuming anaerobic processes. This work presents a novel approach using tetrahydroxydiboron (THDB) combined with potassium persulfate (KPS) to rapidly produce hydrogels with enhanced mechanical properties under aerobic conditions, overcoming traditional limitations. The THDB-KPS system facilitates the gelation of acrylamide (AM) precursors in just 2 min under ambient conditions, significantly outperforming existing systems. This method is versatile across various monomer types, including hydrophilic, electrolyte, macromolecular and zwitterionic monomers. This rapid gelation effect stems from the THDB’s ability to interact with dissolved oxygen to neutralize the inhibitory effects of oxygen, and to promote persulfate decomposition efficiently by homolytic cleavage to produce (HO)2B· radicals through the coordination of N or O in the vinyl monomers with the diboron structure. Meanwhile, boron-induced hydrogen bonding and coordination interactions, along with the fast rise in temperature and viscosity of the reaction system, contribute to the shortened gelation time as well. These factors also lead to the formation of multiple physical cross-links as well as a network of densely and loosely cross-linked regions. Consequently, the mechanical properties of the hydrogel are significantly enhanced through the progressive deformation of these densely and loosely cross-linked regions along with the breakage of physical cross-links. This rapid gelation and mechanical reinforcement effect remains effective even under challenging conditions, including acidic or alkaline environments, low temperatures and impurity-laden environments. Therefore, this breakthrough offers a scalable and efficient method for producing high-performance hydrogel under harsh conditions, promising substantial advancements in industrial applications and practical use in diverse fields.
通过自由基聚合制备的水凝胶在大规模生产和实际应用方面前景广阔，但由于聚合过程中的氧气抑制和机械性能较差，水凝胶的制备面临着挑战。这些问题往往需要复杂的结构设计和耗时的厌氧工艺。本研究提出了一种新方法，利用四羟基二硼（THDB）与过硫酸钾（KPS）相结合，在有氧条件下快速生产出机械性能更强的水凝胶，克服了传统的局限性。在环境条件下，THDB-KPS 系统只需 2 分钟就能使丙烯酰胺 (AM) 前体凝胶化，大大优于现有系统。这种方法适用于各种单体类型，包括亲水性、电解质、大分子和齐聚物单体。这种快速凝胶化效果源于 THDB 能够与溶解氧相互作用，中和氧气的抑制作用，并通过乙烯基单体中的 N 或 O 与二硼结构的配位，以均解裂解的方式促进过硫酸盐的有效分解，从而产生 (HO)2B- 自由基。同时，硼引起的氢键和配位相互作用，以及反应体系温度和粘度的快速上升，也有助于缩短凝胶化时间。这些因素还导致形成多种物理交联以及由密集交联区和松散交联区组成的网络。因此，随着物理交联的断裂，这些密集和松散交联区域逐渐变形，水凝胶的机械性能也随之显著增强。即使在酸性或碱性环境、低温和含有杂质的环境等具有挑战性的条件下，这种快速凝胶化和机械增强效果也能保持有效。因此，这一突破为在苛刻条件下生产高性能水凝胶提供了一种可扩展的高效方法，有望在工业应用和不同领域的实际使用方面取得重大进展。
{"title":"Fast Gelation and Mechanical Reinforcement of Tetrahydroxydiboron-Induced Free Radical Polymerized Hydrogels under Harsh Conditions","authors":"Yi Wang, Wanting Yuan, Qianqian Liang, Hongyi Lv, Xiaoting Liu, Lijuan Zhao, Jinrong Wu","doi":"10.1021/acs.macromol.4c01654","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01654","url":null,"abstract":"Hydrogels prepared through free radical polymerization hold great promise for large-scale production and practical applications but face challenges due to oxygen inhibition during polymerization and poor mechanical properties. These issues often necessitate complex structural designs and time-consuming anaerobic processes. This work presents a novel approach using tetrahydroxydiboron (THDB) combined with potassium persulfate (KPS) to rapidly produce hydrogels with enhanced mechanical properties under aerobic conditions, overcoming traditional limitations. The THDB-KPS system facilitates the gelation of acrylamide (AM) precursors in just 2 min under ambient conditions, significantly outperforming existing systems. This method is versatile across various monomer types, including hydrophilic, electrolyte, macromolecular and zwitterionic monomers. This rapid gelation effect stems from the THDB’s ability to interact with dissolved oxygen to neutralize the inhibitory effects of oxygen, and to promote persulfate decomposition efficiently by homolytic cleavage to produce (HO)<sub>2</sub>B· radicals through the coordination of N or O in the vinyl monomers with the diboron structure. Meanwhile, boron-induced hydrogen bonding and coordination interactions, along with the fast rise in temperature and viscosity of the reaction system, contribute to the shortened gelation time as well. These factors also lead to the formation of multiple physical cross-links as well as a network of densely and loosely cross-linked regions. Consequently, the mechanical properties of the hydrogel are significantly enhanced through the progressive deformation of these densely and loosely cross-linked regions along with the breakage of physical cross-links. This rapid gelation and mechanical reinforcement effect remains effective even under challenging conditions, including acidic or alkaline environments, low temperatures and impurity-laden environments. Therefore, this breakthrough offers a scalable and efficient method for producing high-performance hydrogel under harsh conditions, promising substantial advancements in industrial applications and practical use in diverse fields.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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