Macromolecules最新文献

{"title":"Surface-Aligned Cholesteric Liquid Crystalline Elastomers with Tunable Mechanical Properties via Thiol–Ene Chemistry","authors":"Alexis T. Phillips, Judy C. Chen, David T. Kennedy, Timothy J. White","doi":"10.1021/acs.macromol.5c00861","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00861","url":null,"abstract":"Cholesteric liquid crystals (CLCs) exhibit Bragg reflection due to their spontaneous self-assembly into a one-dimensional photonic structure. Retaining this cholesteric order in a polymer network requires functionalizing liquid crystals with reactive end groups. However, conventional chemistries for synthesizing cholesteric liquid crystalline polymers often result in poor surface alignment and reduced optical quality. In this work, we investigate a thiol–ene step-growth polymerization approach to fabricate cholesteric liquid crystalline elastomers (CLCEs) with tunable mechanical properties and improved optical quality. By varying the cross-link density, we systematically study the effects on haze, cross-linking degree, and mechanical response. Compared to existing cholesteric liquid crystalline polymers, the thiol–ene-based CLCEs exhibit enhanced surface alignment, reduced haze, and greater mechanical tunability. These materials are further benchmarked against CLCEs synthesized via thiol–acrylate chain transfer polymerization, highlighting the advantages of the thiol–ene reaction for achieving precisely controlled properties in cholesteric polymer networks.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"184 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144104153","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":"Film Thickness Dependence of the Growth Rate Ratio of the β- to α-Crystal of Isotactic Polypropylene in Ultrathin Films","authors":"Ziyuan Zhou, Binghua Wang, Changyu Shen, Bin Zhang","doi":"10.1021/acs.macromol.5c00163","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00163","url":null,"abstract":"Previous research studies on isotactic polypropylene (iPP) have shown that the ratio of growth rate β to α phase (<i>G</i>_β/<i>G</i>_α) exceeds 1 when the crystallization temperature (<i>T</i>_c) is between the lower and upper critical temperature limits (<i>T</i>_c^** ∼ 100 °C and <i>T</i>_c^* ∼ 141 °C, respectively), due to the faster surface kinetics of β-iPP. However, in this work, we observed that when the film thickness (<i>d</i>) decreases from 24 to 9 nm, the temperature interval of <i>G</i>_β/<i>G</i>_α &gt; 1 narrows and even disappears, as <i>T</i>_c^* gradually shifts to lower temperatures while <i>T</i>_c^** remains constant. This is presumably because, as <i>d</i> decreases, the width (<i>w</i>_d) of the depletion zone of β-iPP expands more significantly than that of α-iPP, resulting in slower diffusion toward the growth front of β-iPP. Consequently, <i>G</i>_β decreases more than <i>G</i>_α as <i>d</i> diminishes, leading to a reduction in the value of <i>G</i>_β/<i>G</i>_α, especially at higher <i>T</i>_c, where <i>G</i>_β/<i>G</i>_α becomes less than 1. Moreover, we found that the diffusion activation energy (<i>E</i>_a^β) of β-iPP is consistently greater than that of α-iPP (<i>E</i>_a^α) at a given <i>d</i>, and the gap between <i>E</i>_a^α and <i>E</i>_a^β increases as <i>d</i> decreases. This further highlights that the slower diffusion process for β-iPP progressively becomes the main factor affecting the difference between <i>G</i>_α and <i>G</i>_β as <i>d</i> diminishes.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"38 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144122714","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":"Osmotic Pressure-Based Quantification of Network Inhomogeneity in Gels via Free Radical Polymerization","authors":"Ruka Ito, Naoyuki Sakumichi, Tsukuru Masuda, Takamasa Sakai","doi":"10.1021/acs.macromol.5c00554","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00554","url":null,"abstract":"Polymer gels synthesized via free radical polymerization inherently exhibit pronounced network inhomogeneity due to spatially nonuniform cross-linking distributions. While conventional light scattering techniques have been widely used to characterize these inhomogeneities, they lack quantitative reliability, particularly in turbid samples, where multiple scattering complicates analysis. Here, we present a novel macroscopic approach based on osmotic pressure measurements that enables the direct quantification of network inhomogeneity in polymer gels. By comparing the measured osmotic pressure of gels with that predicted for homogeneous semidilute polymer solutions, we quantify the fraction of insoluble polymer domains that contribute negligibly to the overall osmotic pressure. Using poly(<i>N,N</i>-dimethylacrylamide) (PDMAAm) hydrogels as a model system, we find a scaling law that predicts the fraction of insoluble polymer domains as a function of monomer and cross-linker concentrations. This scaling law provides a practical guideline for controlling network inhomogeneity. Our approach establishes a general framework for quantifying insoluble components in gels, overcoming the limitations of conventional semiquantitative characterization techniques.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"34 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144088190","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":"Simultaneous Click Coupling Reaction and Declick Cyclization Reaction in the Synthesis of Degradable Polymers","authors":"Peiqiong Zhao, Li Liu, Hanying Zhao","doi":"10.1021/acs.macromol.5c00047","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00047","url":null,"abstract":"The development of degradable polymers with desirable functionalities and chemical structures is a challenging goal in the field of polymer chemistry. Central to the challenge are the applications of new chemical reactions in the polymerization and degradation processes. In this research, a method based on a simultaneous click coupling reaction and declick cyclization reaction is applied in the synthesis of degradable polymers. Base-catalyzed thiol-phenylsulfone click reactions among small monomer molecules containing a phenylsulfonyl group and a thiol group on each structure lead to the growth of polymer chains. Meanwhile, thiolate anions generated at the ends of polymer chains have a nucleophilic substitution reaction with heteroaromatic thioethers in the backbones, leading to the degradation of the formed polymer chains and the generation of a cyclic compound. The chain growth and degradation processes can be tuned by controlling the concentrations of monomer and polymer chains. The click polymerization is dominant in the initial stage, and with an increase in polymer concentration, the declick reaction is dominant. The declick reaction and degradation of polymer chains are inhibited at a low temperature. Both click and declick reactions can be terminated by adding acids, and stable polymers are synthesized. Through a coupling reaction between the degradable homopolymer and pyridyl disulfide terminated poly(ethylene glycol) monomethyl ether, a degradable triblock copolymer is synthesized. Degradable diblock copolymers are synthesized by reversible addition–fragmentation chain transfer polymerizations using a degradable macro chain transfer agent.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"103 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144104145","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":"Comprehensive Screening of Conditions for Block Copolymer Nanoaggregate Formation via Automated DLS","authors":"Lakshani J. Weerarathna, Oliver Weismantel, Tanja Junkers","doi":"10.1021/acs.macromol.4c03171","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03171","url":null,"abstract":"A fully automated robotic synthesizer for the screening of amphiphilic block copolymer (BCP) nanoparticle synthesis is presented. To reach this aim, BCP solutions are mixed in continuous flow with water, allowing for the automated variation of overall polymer concentration, mixing ratio of the water and organic solvent phase, and the overall flow rate of the system. Particle sizes are monitored online via a commercial dynamic light scattering instrument, and the obtained data are automatically analyzed. While the machine generally allows us to produce particles with a 10% standard deviation, the control software performs automatic outlier detection based on measurement of data in triplicates and repeats experiments until a statistically robust result is obtained. The synthesis platform was tested on 5 individual block copolymers, namely, poly(ethyl methacrylate)-<i>block</i>-poly(2-(dimethylamino)ethyl acrylate) (PEMA₇₅-<i>b</i>-PDMAEA₅₀), polystyrene-<i>block</i>-poly(2-(dimethylamino)ethyl acrylate) (PS₅₀-<i>b</i>-PDMAEA₂₅), polystyrene-<i>block</i>-poly(poly(ethylene glycol) methyl ether acrylate) (PS₄₀-<i>b</i>-PPEGMEA₃₅, PS₉₀-<i>b</i>-PPEGMEA₂₃), and polystyrene-<i>block</i>-poly(2-hydroxy ethyl acrylate) (PS₉₀-<i>b</i>-PHEA₁₄), which were obtained from reversible addition-fragmentation chain transfer polymerization. The screening revealed complex interdependencies of the synthesis parameters on the obtainable particle sizes. Generally, smaller particles were obtained at high water contents, high flow rates, and low polymer concentrations.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"432 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144104155","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":"Collective Short-Time Dynamics in Polymer Melts: Two-Step Quenches and Spinodal Decomposition","authors":"David Steffen, Jörg Rottler, Marcus Müller","doi":"10.1021/acs.macromol.5c00498","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00498","url":null,"abstract":"In polymer melts, the segmental density does not simply relax diffusively due to intramolecular dynamics on short time scales. Using particle-based simulations of a highly coarse-grained polymer model, we explore the collective short-time dynamics under two distinct scenarios: (i) noninteracting polymer chains subject to a two-step change of an external field and (ii) phase separation due to attractive interactions. In the case of the two-step external field, we observe a nonmonotonic relaxation behavior of a collective density modulation, while for the case of the spontaneous growth of density modulations in response to the introduction of attractive interactions (spinodal decomposition), we observe an initial nonexponential growth on very short time scales, followed by a transition to exponential growth. We show that these effects can be captured by linear response theory, in contrast to dynamic self-consistent field theory (D-SCFT) that always predicts a slow exponential relaxation of segmental density modes. The short-time deviations from D-SCFT stem from two key characteristics: (i) the molecular configurations are not in equilibrium with the instantaneous density field, and (ii) the segmental dynamics display subdiffusive behavior.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"38 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144104148","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":"Low-Voltage Organic Field-Effect Transistors Using a Phosphocholine-Based Polyampholyte Dielectric","authors":"Jinkang Hu, Muqiu Sun, Tangli Wei, Chi Chen, Xiaobo Wan, Youbing Mu","doi":"10.1021/acs.macromol.5c00219","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00219","url":null,"abstract":"Low-voltage organic field-effect transistors (OFETs) are of great significance for realizing low power-consumption electronics, where increasing the dielectric constant of gate dielectrics is an effective strategy to achieve low-voltage operation. Herein, a series of polyampholyte dielectrics with pendant phosphocholine zwitterionic groups are synthesized, and their applications in OFET devices are systematically studied. The dielectric constant of phosphocholine-based polyampholyte (<b>P-PA</b>) can reach 6.0, and the OFET performances based on <b>P-PA</b> dielectrics are greatly improved. Specifically, devices using <b>P-PA-20</b> that contains 20 mol % zwitterionic groups as the dielectric layer, show the best performance, boosting a three-orders-of-magnitude increase in mobility and decreasing the threshold voltage (<i>V</i>_th) to a value as low as 0.07 V compared with devices using the control dielectric without zwitterionic groups. In addition, the corresponding <b>P-PA</b>s exhibit excellent flexibility, with both high tensile strength exceeding 20 MPa and high elongation at break exceeding 400%. This study provides a novel method to construct polymeric dielectrics with a high dielectric constant, which may be further exploited to improve OFET device performance and be instructive for the design of new materials for future use in flexible/stretchable and wearable electronic devices.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"56 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144104146","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":"Novel All-Polymer Nanocomposites Enable Manipulation of Mechanical Properties via Self-Assembly","authors":"Jiajun Qu, Tongkui Yue, Hengheng Zhao, Yulong Chen, Liqun Zhang, Jun Liu","doi":"10.1021/acs.macromol.4c02696","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02696","url":null,"abstract":"Approaches to tailor the mechanical properties of polymer nanocomposites (PNCs) with various microstructures still remain limited. Herein, using coarse-grained molecular dynamics simulations, a new molecular design strategy is put forward to build a novel all-polymer nanocomposite (S_n-PNC) by grafting single-chain nanoparticles (SCNPs) as a block at both ends of a linear polymer chain. We investigated the effect of different volume fractions of SCNP (<i>f</i>_SCNP) and interfacial interaction strength (ε_AB) between SCNPs and the matrix on the phase separation behavior of the S_n-PNC. The results demonstrated that the morphology and degree of phase separation were predominantly dependent on <i>f</i>_SCNP and ε_AB, respectively. The dynamics of SCNPs in the typical phase separation morphologies, namely, lamellae, cylinder, and sphere, were similar at short time intervals, while at long time intervals, they exhibited a transition from ⟨Δ<i>r</i>²⟩ ∼ <i>t</i>^0.47 to ⟨Δ<i>r</i>²⟩ ∼ <i>t</i>^0.31. The mechanical response mechanisms of SCNPs and linear matrix chains under uniaxial tension were examined by defining the degree of asphericity and the degree of stretching, respectively. Primitive path analysis was further conducted to characterize the entanglement topology of spherical, cylindrical, and lamellar morphologies, exploring the influence of bridge and loop chains on the stress distribution. In addition, triaxial tension demonstrated that a spherical structure had the highest energy dissipation capacity, followed by a cylindrical one, and finally a lamellar structure. The volume fraction, number, and surface area of voids were quantified based on the Voronoi volume of beads. The nucleation of voids in the three self-assembled structures was primarily located in the polymer matrix. The tensile stress began to decrease when the small voids merged massively into large ones. The mechanical properties of the S_n-PNC designed in this work are better than those of the traditional composite systems. In general, this proposed new building block structure may open a door for the design and fabrication of novel PNCs with desirable mechanical properties.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"30 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083225","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 Dynamic Helical Polymers be Reduced to Linear Chains of Spins? Non-Local Effects from Polymer Self-Avoidance","authors":"Keerti Chauhan, Marcus Müller, Kostas Ch Daoulas","doi":"10.1021/acs.macromol.4c03197","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03197","url":null,"abstract":"Cooperative chiral order in dynamic helical polymers (DHPs) is commonly understood through their reduction to one-dimensional (1D) Ising-spin chains. In this framework, each spin, adopting the values σ = −1 and σ = 1, represents a left- and right-handed helical twist. Spins interact ferromagnetically, capturing the energetic cost of boundaries between domains of opposite chirality. All current spin models of DHPs assume that nearest-neighbor (NN) spin–spin interactions suffice to describe the system. We challenge this assumption using a minimal molecular model to investigate whether the self-avoidance of DHP chains, due to excluded volume, induces an effective, non-local coupling of spins. Our approach combines a 1D description of helicity, based on NN spin–spin interactions, with an explicit representation of DHPs as freely-jointed chains with flexible hinges. We generate both ideal and self-avoiding chain conformations through a Monte Carlo scheme. For ideal chains, the spin behavior agrees with the predictions of a NN 1D Ising model with coupling strength <i>J</i>. However, we find that chain self-avoidance does create effective long-range interactions, as demonstrated by spin–spin correlation functions and free-energy calculations. These interactions renormalize <i>J</i> and lead to finite-size effects that are inconsistent with the NN 1D Ising behavior.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"75 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083266","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":"Hydrogen Bonding Enhanced Polysaccharide-Based Gels with Ultrahigh Stretchability and Unprecedented Crack Propagation Strain","authors":"Jing Zhao, Dongmin Cheng, Ran Chen, Xinyi Yang, Yiluo Li, Yuejin Guo, Jingxia Zhang, Ruofei Hu, Junping Zheng","doi":"10.1021/acs.macromol.5c00537","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00537","url":null,"abstract":"The current strategies prove to be hard for the preparation of polysaccharide-based gels with excellent mechanical properties and high crack propagation resistance. Herein, ultrahigh stretchable polysaccharide-based polyacrylamide/carrageenan/phytic acid (PCP) gels are prepared by integrating strong and dense hydrogen bonds into the network. The phosphate ester bonds contained in phytic acid form strong and dense hydrogen bonds with polyacrylamide and carrageenan, which are 18.6 times higher than those in gel without phytic acid. A large number of hydrogen bonds endows PCP gels with ultrahigh stretchability (&gt;16,000%, without breakage), unprecedented crack propagation strain of 16,000%, high adhesion property (223 kPa), self-healing ability, low-temperature resistance, and moisturizing property. Furthermore, PCP gel can be obtained rapidly and facilely within minutes, integrated into clothes after a facile drawing method, and applied to monitor movement, breathing, and temperature states (e.g., contactless recognition for finger/palm, distinguishing between running phone/nonrunning phone). This study provides an essential strategy for designing or fabricating highly stretchable gel and its application in the wearable electronics field.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"18 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066009","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}