Macromolecules最新文献

{"title":"Closer Look at the Substituent Effects on the Copolymerization of Thionolactones by Radical Ring-Opening Polymerization","authors":"Bastien Luzel, Lucas Raggio, Eytan Benharrous, Julien Monot, Didier Bourissou, Didier Siri, Didier Gigmes, Catherine Lefay, Blanca Martin-Vaca, Yohann Guillaneuf","doi":"10.1021/acs.macromol.5c00448","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00448","url":null,"abstract":"The negative impact of plastic waste on the environment is a serious issue for the future. Adding cleavable bonds to the polymer backbone can help to impart degradability properties. To this end, radical ring-opening polymerization (rROP) offers a very attractive way to achieve radical copolymerization with vinyl monomers. Thionolactones, one of the various cyclic monomers that can be used in rROP, are promising structures due to the efficiency of the C═S bond in acting as a radical acceptor. In this work, we used DFT calculations to better understand the effects of different substituents on the radical reactivity of thionolactones (dibenzo[<i>c</i>,<i>e</i>]oxepane-5-thione DOT derivatives) already described as more or less effective for copolymerization with vinyl monomers in order to adjust the reactivity of these thionolactones. To carry out these calculations, we focused on the value of the transfer constant <i>k</i>_tr and its relationship to the propagation constant <i>k</i>_p of the vinyl monomer. The calculations performed subsequently on 7-phenyloxepane-2-thione (POT) derivatives highlighted that electron-donating groups inserted in the para-position on the phenyl ring should improve the copolymerization efficiency with acrylate derivatives, and in contrast, electron-withdrawing groups should lead to more important compositional drift during styrene and acrylate copolymerization. Although POT derivatives bearing electro-donating groups could not be prepared, the preparation of those with CF₃ and NO₂ groups was successfully achieved. Experimental copolymerization of these two thionolactones with styrene and isobornyl acrylate is in good agreement with the calculations. This result confirmed the versatility and relevance of our calculation approach to account for the reactivity of thionolactones.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"35 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889854","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}

{"title":"Can a Simple Two-Letter Model Predict Complex Solution Phase Behavior of Block–Random Copolymers?","authors":"Amala Akkiraju, Lauren W. Taylor, Richard A. Register, Athanassios Z. Panagiotopoulos","doi":"10.1021/acs.macromol.5c00519","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00519","url":null,"abstract":"Control of synthetic polymer solution phase behavior is crucial for soft materials engineering. Recent experiments on styrene-isoprene block–random copolymers [<contrib-group><span>Taylor, L. W.</span></contrib-group> <cite><i>Macromolecules</i></cite> <span>2024</span>, <em>57</em>, 916–925] revealed various sequence-dependent phase behavior outcomes. This work aims to provide a quantitative description of those experimental findings using a simple two-letter lattice model with grand canonical Monte Carlo simulations. The results demonstrate that this can be achieved using a single solvent selectivity parameter and appropriate temperature scaling. Predictions of critical temperatures, phase diagrams, and certain micelle radii agree well with the corresponding experimental results. However, the model cannot reproduce large experimental crew-cut micelles, instead predicting large hollow-cored aggregates that disassemble into smaller micelles, raising questions about the equilibrium nature of the remarkably large experimental micelles. The model’s ability to quantitatively describe phase and aggregation behavior demonstrated in this work would be valuable for designing synthetic polymers with desirable properties.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"44 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889855","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}

{"title":"Self-Assembled Entanglements in Elastomers for Superior Toughness and Fatigue Resistance","authors":"Jingkai Wang, Jie Sun, Jie Chen, Biao Kang, Ai Lu, Ruolei Zhong, Hongtu He, Guocheng Li, Chengji Wen, Dengtao Yang, Ying Yin","doi":"10.1021/acs.macromol.5c00531","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00531","url":null,"abstract":"To address the long-standing trade-off between modulus, toughness, and fatigue resistance in elastomers, in this study, we propose an innovative strategy based on self-assembled chain entanglements. Unlike conventional strategies, the proposed entanglement-driven composite combines rigid, self-assembled entangled particles with a soft matrix enabled by strong interfacial adhesion. This system synergizes rigid entangled particles (with molecular segment entanglement topology) and the soft matrix to enable energy dissipation across molecular segments, polymer chains, and rigid entangled particles, ultimately achieving simultaneous enhancement of fracture toughness (∼0.043 MJ/m²), fatigue threshold (∼300 J/m²), and elastic modulus. Implemented via a one-step in situ self-assembly method, this strategy provides novel insights into designing high-performance elastomers.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"107 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889856","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}

{"title":"Cross-Sectional Effects on Nanorod Diffusion in Polymer Melts","authors":"Jia Zhang, Lijun Yang, Hai-Xing Wang, Jiuling Wang, Ruo-Yu Dong","doi":"10.1021/acs.macromol.5c00629","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00629","url":null,"abstract":"The diffusion of anisotropic nanoparticles, such as nanorods, in complex polymer environments is relevant to several scientific and industrial topics, including nanocomposites, and drug delivery. Despite recent advancements in understanding the dynamics of thin nanorods in polymer melts through scaling analyses and simulations, systematic investigations into the cross-sectional effects of nanorods on diffusion processes remain limited. In this study, coarse-grained molecular dynamics (CGMD) simulations were performed to explore the translational and rotational dynamics of a single nanorod in unentangled and entangled linear polymer melts. To introduce cross-sectional effects, we increased the nanorod diameter <i>d</i>, and analyzed the rotational diffusion for spinning <i>D</i>_RS, which is distinct from the rotational diffusion for end-overend tumbling <i>D</i>_RT. We conducted quantitative analyses to examine the scaling behavior of various diffusion coefficients with respect to the nanorod diameter, categorizing nanorods as either ‘thin’ (with diameters smaller than the tube diameter) or ‘thick’ (with diameters larger than the tube diameter). Our findings reveal a significant crossover in the scaling of the translational diffusion coefficient as <i>d</i> increases, while the scaling of the rotational diffusion coefficient remains almost constant. Hopping mechanisms contribute to nanorod dynamics in entangled melts, exhibiting different variations of translational and rotational dynamics with <i>d</i>. We finally unveiled that, the coupling between nanorod diffusion and polymer chain fluctuations enhances translational-rotational correlation at short time intervals but diminishes in the Fickian regime.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"114 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143893712","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}

{"title":"Manipulating the Mechanical Properties of Thermoplastic Polyurethane via Regulating Hard Segment Aggregation","authors":"Zehao Wang, Chending Wang, Xiaoli Zhao, Xiaoniu Yang","doi":"10.1021/acs.macromol.5c00142","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00142","url":null,"abstract":"Performance optimization of thermoplastic polyurethane (TPU) is hindered by the mysterious structure–property relationship due to intricate hard segment (HS) aggregation structures. Here, a typical MDI-BDO-based TPU was employed as a model to investigate the HS aggregation structures from multiscale morphology, and different annealing conditions were applied to transform them to effectively manipulate TPU’s mechanical properties. The pristine TPU has three HS aggregation structures. Structure I is hard domains with irregularly stacked hard blocks and disordered HS packing, while structures II and III are crystalline hard domains with loosely and compactly stacked hard blocks, respectively. Therefore, the reduced moduli (E_r) of structures II and III are 19 and 57% higher than that of structure I, respectively. Annealing at 170 °C enlarged structure I but decreased its number density, slightly lowering TPU’s modulus to 108.0 from 110.8 MPa. Annealing at 200 and 220 °C reorganized less ordered HSs into crystalline structures II and III, respectively, which significantly enhanced TPU’s modulus to 141.8 and 187.1 MPa, respectively. For viscoelasticity, TPU’s stress relaxation resistance decreased with annealing temperature because 170, 200, and 220 °C very slightly, partly, and completely broke the hard domain’s long-range connectivity, respectively. This work elucidated the evolution of HS aggregation structures during annealing, which provides guidelines for TPU’s performance optimization and design.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"43 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143893709","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}

{"title":"Epitaxial Crystallization-Driven Self-Assembly of Block Copolymers with Asymmetric Stereoblock Polylactides into 3-D Triangular Prisms","authors":"Jae Hak Lee, Mo Beom Koo, Yongbeom Kwon, Kyoung Taek Kim","doi":"10.1021/acs.macromol.5c00758","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00758","url":null,"abstract":"The crystallization-driven self-assembly (CDSA) of block copolymers (BCPs) with crystallizable core-forming blocks typically produces low-dimensional nanostructures such as one-dimensional nanowires and two-dimensional platelets. This occurs because the solvent-soluble polymer blocks passivate a significant portion of the surface of the crystalline core. In this study, we report the formation of three-dimensional triangular prisms through the epitaxial CDSA of BCPs with asymmetric stereoblock polylactide, specifically [(<span>d</span>-lactide)₃₂-(<span>l</span>-lactide)₁₆]-<i>b</i>-PEG₄₅. The iterative exponential growth (IEG) of enantiopure lactides into stereochemically sequence-defined polylactides results in the formation of [DLA₃₂-LLA₁₆]. The programmed chain folding of the stereochemically sequence-defined [DLA₃₂-LLA₁₆] block via intramolecular stereocomplexation between size-matched enantiomeric oligo(lactide) domains allows the excess [DLA₁₆] domain to coexist with the stabilizing poly(ethylene glycol) (PEG) blocks on the top and bottom surfaces of the triangular core (approximately 9 nm in thickness) formed by the CDSA of this BCP. These surface-exposed homochiral [DLA₁₆] domains serve as nucleation sites for the epitaxial growth of the triangular cores into triangular prisms with thickness exceeding 600 nm. We determined that the concentration-dependent kinetics of chain folding and crystallization of the asymmetric stereoblock polylactide, steric passivation by surface-located PEG chains, and the enantiopurity of the protruding oligolactide domains are critical factors that enable epitaxial CDSA.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"47 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143893711","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}

{"title":"Nanoscale Morphology in Disodium Salt-Anchored Polyethylene Ionomers","authors":"Mengen Zhang, Ruijia Wang, Tinghao Jia, Congjing Ren, Jingdai Wang, Yongrong Yang, Yao Yang","doi":"10.1021/acs.macromol.5c00167","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00167","url":null,"abstract":"A molecular-level understanding of the ion cluster morphology is crucial to designing the structure and enhancing the properties of random polyethylene ionomer. Here, we report that the strategic addition of aliphatic disodium salt has a pronounced effect on the mechanical properties and nanoscale morphology. With the addition of various aliphatic disodium salts, both the tensile strength and Young’s modulus are significantly increased. By comparing the results of atomistic molecular dynamics simulations with experimental characterization data, the ionic cluster nanoscale morphology varies with different chain-length disodium salts, while maintaining the crystallization of the polyethylene matrix. The alkyl disodium salts with relatively short alkyl chains (&lt;C8) tend to anchor to the same cluster, forming encapsulation or loop structure. The alkyl disodium salts with relatively long alkyl chains (&gt;C12) bridge between clusters by anchoring to two different clusters, helping to redistribute the clusters within the polymer matrix and providing additional cross-link strength. The cluster morphological evolution during stretching was simulated, and its relation to mechanical properties is comprehensively discussed. This, in turn, unlocks the potential for structural regulation at the nanoscale by additive manufacturing to enhance the performance.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"114 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143893873","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}

{"title":"Expanding the Toolbox of DNA Supramolecular Polymerization for Hyperbranched Nanopolymers","authors":"Qianlin Cai, Tianyun Cai, Jiaping Lin, Liangshun Zhang","doi":"10.1021/acs.macromol.5c00606","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00606","url":null,"abstract":"With the unique combination of polymer-like functionality and biologically inspired dynamics, supramolecular DNA nanopolymers have become a highly promising platform for engineering next-generation smart soft materials. Realizing their full functional potential requires expanding the architectural diversity of DNA nanopolymers in a manner akin to that of classical polymers. In this contribution, we present a remarkable advancement in the introduction of trivalent DNA nanostars with carefully designed sequences of sticky ends. Through the coarse-grained molecular dynamics simulations, it is revealed that the trivalent DNA nanostars have the capability to yield the hyperbranched nanopolymers with a tunable branching degree under one-pot programmable self-assembly. Importantly, extending the classical model of polymerization kinetics enables the quantitative prediction of the growth kinetics and branching degree of hyperbranched DNA nanopolymers, which can be tailored through the designed elements of trivalent DNA nanostars. Furthermore, the terminations of hyperbranched DNA nanopolymers are used as active sites to ligate the DNA-functionalized nanoparticles and yield the hierarchical coassemblies of branched nanoarchitectures, a previously unreported topology. We envision that the polymerization-like self-assembly of DNA nanostars will serve as a versatile platform for diversifying the topological architectures of supramolecular nanostructures, thereby advancing the broad applicability of DNA-based functional materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"18 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143884953","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}

{"title":"Terahertz Birefringence and Anisotropic Absorption Characteristic of Ordered Polymer Structures for Simultaneous Orientation Measurement in Crystalline and Amorphous Regions","authors":"Haokun Xiao, Jianjian Huang, Xiaowen Bian, Mengmeng Wang, Xianrong Liang, Maoyuan Li, Gang Jin","doi":"10.1021/acs.macromol.5c00078","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00078","url":null,"abstract":"Strain-induced crystallization (SIC) is one of the most significant phenomena in semicrystalline polymers. During the stretching process, ordered structures occur in the crystalline and amorphous regions, accompanied by a complex evolution process. The ordered structure of the crystalline region is usually a perfect crystal, while that of the amorphous region mainly consists of locally ordered chain segments. The simultaneous characterization of ordered structures in both crystalline and amorphous regions faces significant challenges due to differences in the scale of the ordered structure. This research proposed a method for simultaneously measuring ordered structures of poly(ethylene terephthalate) (PET) in both crystalline and amorphous regions based on terahertz time-domain spectroscopy (THz-TDS) with extreme sensitivity to the long-range ordered structure. The models between orientation and birefringence and absorption anisotropy in the THz band were established. The evolution of the refractive index and absorption coefficient of samples at different draw ratios was investigated. The results showed that birefringence was proportional to the orientation of <i>trans</i> conformations, and the orientation–birefringence model was validated in the THz band. Then, two characteristic absorption bands, ranging within 1.3–2.3 and 2.3–3.0 THz, in the absorption spectra of stretched PET are closely related to the content and orientation of <i>trans</i> conformation in the amorphous and crystalline regions of PET. Finally, the mechanism of strain-induced anisotropy of the refractive index and absorption coefficient was elucidated, which originates from the orientation of the molecular chain during necking and undergoes rapid changes once necking occurs. These insights deepen the understanding of the refractive index and absorption in the THz frequency range and provide an effective method for simultaneously characterizing the ordered structures in the amorphous and crystalline regions.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"69 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889857","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}

{"title":"Characterizing the Mechanical Response of a Polycarbonate Coarse-Grained Model Developed with Energy Renormalization","authors":"Heather L. White, Müge Fermen-Coker, Wei Chen, Sinan Keten","doi":"10.1021/acs.macromol.5c00302","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00302","url":null,"abstract":"Polycarbonate (PC) possesses uniquely high toughness among polymers, making it well-suited for use as an impact-resistant barrier material. This propensity toward energy dissipation has been associated with characteristics such as backbone flexibility, high entanglement density, and homogeneity. While recent works have enhanced our understanding of how these nanoscale mechanisms contribute to toughness in PC, it remains unclear how they are affected by the deformation mode, rate, and molecular weight of the chains. To study these effects over spatiotemporal scales that extend beyond the reach of atomistic models, we utilized a coarse-grained molecular dynamics (CGMD) model of PC developed with the energy renormalization method. We establish that yield stress rate dependence follows the Cowper–Symonds model for flow stress, the fit for which asymptotically converges to values consistent with low-rate experimental data. As a demonstration of the model’s utility, we additionally explore the effects of PC chain length on fracture behavior and show that toughness is improved through the augmentation of extensive entanglement networks that enable increased stress levels in the material. For chains 50 monomers and longer, chain length has a minimal effect on yield stress and elastic modulus, suggesting that small-strain mechanical response is dominated by nonbonded interactions. This work enables an enhanced understanding of molecular contributions to the macroscopic mechanical behavior of PC and reflects the importance of the polycarbonate chain network in modulating energy dissipation. It additionally highlights the importance of bond breaking in MD models subjected to large strain. More broadly, it represents a critical step toward the CGMD modeling of PC-based nanocomposites.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"8 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143884952","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}