Macromolecules最新文献

{"title":"Reversible Thermoresponsive Host–Guest Binding of Pillar[n]arenes with Guest End-Functionalized Poly(2-n-Propyl-2-Oxazoline)s","authors":"Xinran Guan, Somdeb Jana, Takuya Tomita, Tomoki Ogoshi, Patrice Woisel, Richard Hoogenboom","doi":"10.1021/acs.macromol.4c02456","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02456","url":null,"abstract":"Host–guest based thermoresponsive supramolecular polymer assemblies have found significant interest in recent years as they provide unique opportunities for the reversible release of the guest upon thermally controlled collapse of the polymer. However, the reported systems are mostly based on polyacrylamides and polyacrylates in combination with the positively charged cyclobis(paraquat-<i>p</i>-phenylene) host. To investigate whether such thermally induced guest release can be more generally developed, here we investigated the thermoreversible host–guest association of guest-functionalized poly(2-<i>n</i>-propyl-2-oxazoline) (<b>P</b>^{<b><i>n</i></b>}<b>PrOx</b>) with various pillar[<i>n</i>]arene hosts. Two types of thermoresponsive poly(2-<i>n</i>-propyl-2-oxazoline) (<b>P</b>^{<b><i>n</i></b>}<b>PrOx</b>) consisting of a hydrophilic 4,4′-bipyridinium unit (<b>P</b>^{<b><i>n</i></b>}<b>PrOx-MV</b>) or a 5-aminopentanenitrile unit (<b>P</b>^{<b><i>n</i></b>}<b>PrOx-CN</b>; introduced as novel guest for percarboxylato pillar[5/6]arenes) as the end-group were prepared. The complexation of these guest-functionalized <b>P</b>^{<b><i>n</i></b>}<b>PrOx</b> with water-soluble pillar[5/6]arenes containing anionic carboxylate groups (<b>WP5</b> and <b>WP6</b>) or nonionic methoxytriethylene glycol (<b>TP5</b> and <b>TP6</b>) solubilizing groups was investigated in water. The 1:1 host–guest complexes, i.e., <b>WP6–P</b>^{<b><i>n</i></b>}<b>PrOx-MV</b> and <b>WP5–P</b>^{<b><i>n</i></b>}<b>PrOx-CN</b>, were formed by electrostatic interactions at 283.15 K with the association constants of (3.84 ± 0.25) × 10⁵ M^–1 and (0.96 ± 0.04) × 10⁴ M^–1, respectively. In contrast, the nonionic <b>TP5</b> and <b>TP6</b> only showed weak binding with the polymers. When heated above its cloud-point temperature, <b>P</b>^{<b><i>n</i></b>}<b>PrOx</b> collapses and precipitates due to the effect of lower critical solution temperature (LCST), which is demonstrated to lead to host–guest dissociation, providing thermal control over the complexation and decomplexation of the <b>WP6–P</b>^{<b><i>n</i></b>}<b>PrOx-MV</b> and <b>WP5–P</b>^{<b><i>n</i></b>}<b>PrOx-CN</b> host–guest complexes. The reversible, temperature-controlled threading and dethreading process suggest potential applications in sustainable separation and recovery processes, as well as in the development of smart materials with temperature-responsive functionalities.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"34 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143044383","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":"Dynamic Viscoelastic Properties of Polystyrene Composites Reinforced with Cellulose Nanocrystals","authors":"Hiroaki NOBUOKA, Reina TANAKA, Osamu URAKAWA, Tadashi INOUE","doi":"10.1021/acs.macromol.4c03221","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03221","url":null,"abstract":"We investigated the reinforcement mechanisms of cellulose nanocrystals, CNCs, in polymer matrices by incorporating them into polystyrene, a widely used simple amorphous resin that lacks specific interactions, such as hydrogen bonding. Rheological measurements revealed that the addition of CNC induced significant reinforcement effects in the complex moduli, particularly in the rubbery state. These effects are best described using the modified Morse theory, which accounts for the molecular dynamics of semiflexible polymers in a viscoelastic medium, rather than the classical Halpin–Tsai theory traditionally applied to straight rods. Dynamic birefringence measurements, specifically the frequency dependence of the strain-induced birefringence under oscillatory deformation, provided detailed insights into the contributions of various components to viscoelastic relaxation in the composite materials. The analyses indicated that the reinforcement effects were primarily driven by the tension mode of CNCs, originating from their undulated structure caused by thermal motion.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"41 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050482","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":"Backbone Stitching in Bottlebrush Copolymer Mesodomains and the Impact of Side Chain Crystallization","authors":"Mingqiu Hu, Hong-Gyu Seong, Michael S. Dimitriyev, Weiguo Hu, Zhan Chen, Xuchen Gan, Gregory M. Grason, Todd Emrick, Thomas P. Russell","doi":"10.1021/acs.macromol.4c02589","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02589","url":null,"abstract":"We synthesized bottlebrush statistical copolymers (BSCPs) having poly(ethylene oxide) (PEO) and poly(dimethylsiloxane) (PDMS) side chains attached to a polynorbornene backbone. Small-angle X-ray scattering analysis showed that for densely grafted BSCPs, the scattering length density gradually transitions between the PEO and PDMS domains. For loosely grafted BSCPs, the polymer backbone formed a distinct mesodomain, with a lower electron and mass density than both the PEO and PDMS domains. The bottlebrush backbone essentially “stitches” the PEO and PDMS side chains, looping back and forth from the PEO to PDMS domains with the backbone segments oriented normal to the domain interfaces. Self-consistent field theory (SCFT) calculations validated the stitching of the backbone driven by the microphase separation of PEO and PDMS, along with a strong segmental order of the side chains in the melt. The reduced birefringence upon PEO crystallization suggests the disruption of the strong segmental order by the crystallization. Both the static intrinsic and the form birefringences of the BSCPs decreased upon PEO crystallization. Solid-state NMR confirmed the rigidity of PEO crystallites and the bottlebrush backbone. Self-assembly of BSCPs containing polyhedral oligomeric silsesquioxane (POSS) pendent groups was also evaluated by X-ray scattering, showing the formation of lamellar microdomains that inhibited POSS crystallization.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"97 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143044384","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":"Precision Organocatalytic Synthesis of Fluoropolyesters with Enhanced Degradability and Ionic Conductivity","authors":"Chenke Zhao, Guanchen He, Tingwei Chen, Heng Li, Junpeng Zhao","doi":"10.1021/acs.macromol.4c03117","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03117","url":null,"abstract":"Extensively as fluoropolymers are studied and utilized, the impacts of fluorinated contents on polyesters are highly under-investigated. In this study, 3,3,3-trifluoropropylene oxide (TFPO) shows significantly higher activity than non-fluorinated epoxides in organocatalytic alternating copolymerization with cyclic anhydrides, which allows synthesis of well-defined fluoropolyesters under mild conditions and one-step construction of partly fluorinated tapered block copolyesters. Thermal stability of the fluoropolyesters rivals that of the non-fluorinated counterparts, while degradation by base-catalyzed methanolysis is remarkably accelerated and shown to occur selectively through cleavage of the CF₃-neighboring ester bond to form a single product. Besides, the fluoropolyesters constitute electrolytes with notably higher Li⁺ conductivity (up to 4.5 × 10^–5 S cm^–1 at 30 °C and 4.6 × 10^–4 S cm^–1 at 80 °C) as well as excellent oxidation stability at high voltage (&gt;4.5 V). Therefore, TFPO can be harnessed to set up a special toolkit for refining the synthesis and properties of polyesters.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"30 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050419","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":"Stepwise Grafting of Polymer Single Chains onto Nanoparticles","authors":"Yajing Yang, Jiye Yang, Fenglin Li, Dayin Sun, Jintao Zhu, Zhihong Nie, Zhenzhong Yang","doi":"10.1021/acs.macromol.4c03032","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03032","url":null,"abstract":"It is important to design hierarchically structured functional polymer/inorganic composite nanoparticles (NPs) and self-organize them toward programmable superstructures thereby. We propose the synthetic approach of stepwise grafting anionic polymer single chains onto functional nanoparticles via termination, which is ensured by the strong steric hindrance effect of the grafted chains to the target chains with a comparable size. The concept is demonstrated by the precision synthesis of NP-inserted diblock copolymer analogies of PVSt-<i>b</i>-PmSt-[Fe₃O₄@SiO₂]-PMMA-<i>b</i>-P<i>t</i>BA with two different polymer single chains at the opposite sides (PVSt-<i>b</i>-PmSt: poly(4-vinylphenyl-1-butene)-<i>block</i>-poly(4-methylstyrene), PMMA-<i>b</i>-P<i>t</i>BA: poly(methylmethacrylate)-<i>block</i>-poly(<i>tert</i>-butyl acrylate)). Both end segments of PVSt and P<i>t</i>BA are reactive to derive functional groups such as amino and carboxylic acids by the orthogonal clicking reaction and hydrolysis. The functional groups allow visualization of the composite NPs by stimulated emission depletion (STED) microscopy upon selective fluorescence dyeing and the self-organization by specific interactions toward superstructures at varied pHs. The approach is valid for the stepwise grafting of six single chains of varied compositions along the three-dimensional coordinate. The composite NPs with defined numbers and types of functional groups, and thus interaction directions, provide a huge platform for diversifying superstructures, especially under external fields.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"48 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143044392","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":"Microstructure and Viscoelasticity of Oppositely Charged Ionomer Blend Melts","authors":"Chia-Chi Tsai, Jie Xu, Cassie Duclos, Shuyi Xie","doi":"10.1021/acs.macromol.4c02781","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02781","url":null,"abstract":"The electrostatic bonding between oppositely charged polymers results in polyelectrolyte complexes (PECs) with permanent shapes. However, the nearly complete suppression of chain diffusion renders PECs brittle and difficult to process without hydration and plasticization. This study investigates the viscoelastic behavior of ionomers (charge density ≤20 mol %) and the binary blends with oppositely charged counterparts. Unlike dried PECs, ionomer blends demonstrate inherent thermal reprocessability without the need for plasticizers. By varying the identity of the charged group, the charge density, and the ion distribution along the polymer chain, we achieve tunable linear viscoelastic (LVE) responses across a broad frequency range. The LVE behavior fits a sticky Rouse model, where strong net ionic interactions in the ionomers result in an extended elementary Rouse segment relaxation time τ₀ and ionic association lifetime τ_s. Notably, anionic ionomers with potassium sulfonate groups display more pronounced relaxation delays. Interestingly, after glass transition normalization, the viscosity of the blend aligns with that of the cationic parent ionomer, but is significantly lower than that of the anionic counterpart. This demonstrates a distinct outcome from the PEC system, as in most cases, higher viscosity is observed from blending oppositely charged polyelectrolytes (PEs). X-ray scattering analysis attributes the high viscosity of the anionic ionomer to potassium sulfonate ion clusters (approximately 1–2 nm in diameter) acting as transient physical cross-links, which are disrupted upon blending due to salt metathesis. Furthermore, placing charged monomers at the chain end results in ion-induced microphase separation, enhancing thermoplastic elasticity. This study offers fundamental insights into the structure–property relationships of ionomers and their blends, highlighting a big design space and their potential as reprocessable structural materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"58 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143030754","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":"High-Strength and Excellent Self-Healing Polyurethane Elastomer Based on Rigid Chain Segment Reinforcement","authors":"Li-Quan Huang, Hua-Xin Huang, Ning Yu, Chang-Zhou Chen, Yang Liu, Guo-Hua Hu, Jun Du, Hui Zhao","doi":"10.1021/acs.macromol.5c00013","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00013","url":null,"abstract":"Owing to their extensive application scope, elastomers that combine high strength and excellent self-healing efficiency have always attracted significant attention and are still a contradiction. In this study, a novel PU elastomer was prepared by combining rigid poly(amic acid) (PAA) chain segments and 3,3-dithiodipropionic dihydrazide (DPH) containing sextuple hydrogen-bonding units and disulfide bonds. The prepared elastomer exhibited a high tensile strength of 50.1 MPa and a high toughness of 144.2 MJ/m³. The rigid PAA chain segments serve as a rigid framework, significantly enhancing the mechanical strength of the elastomer. Meanwhile, DPH with sextuple hydrogen-bonding units and disulfide bonds enabled the elastomer to exhibit an excellent self-healing efficiency of 96.1% after 12 h at 80 °C. Additionally, the strong and reversible cross-linking of the hydrogen-bonding arrays in the elastomer endows it with excellent mechanical strength, self-healing ability, and recyclability, allowing it to be recycled after hot pressing and dissolution.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"13 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143026977","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":"Shortest Paths Govern Bond Rupture in Thermoset Networks","authors":"Zheng Yu, Nicholas E. Jackson","doi":"10.1021/acs.macromol.4c02438","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02438","url":null,"abstract":"Understanding bond rupture in polymer networks remains a fundamental challenge due to the interplay of network topology and condensed phase effects. In this work, we introduce a predictive approach for determining bond rupture in thermosets based on shortest paths (SPs) analysis of the network topology. This method enumerates SP sets in networks with periodic boundary conditions, with applications to both all-atom and coarse-grained simulations. We find that bond rupture is most likely to initiate on the first (shortest) SP in the thermoset network and the strain at which the first bond ruptures is linearly correlated with the topological path length. As a result, one can predict the first bond rupture by computing the first SP directly from the initial thermoset topology without resorting to MD simulations. Furthermore, the specific bond rupture location along the first SP follows a probability distribution associated with the SP-based betweenness centrality. Subsequent bond rupture events are dictated by the instantaneous SP of partially broken networks. Moreover, we quantify the length scale dependence of SP distributions, introducing a means of partially bridging the observed ductile rupture in molecular simulations and brittle rupture in experiments.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"27 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143026978","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":"Molecular Engineering of Surface-Aligned Supramolecular Liquid Crystalline Elastomers","authors":"Kristin L. Lewis, Jonathan D. Hoang, Sarah S. Aye, David T. Kennedy, Michael F. Toney, Timothy J. White","doi":"10.1021/acs.macromol.4c01944","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01944","url":null,"abstract":"The directional deformation of liquid crystalline elastomers (LCEs) is predicated on alignment, enforced by various processing techniques. Specifically, surface-aligned LCEs can exhibit higher temperature thermomechanical responses and weakened strain–temperature coupling in comparison to LCEs subjected to mechanical or rheological alignment. Recently, we reported enhanced stimuli response of mechanically aligned LCEs containing supramolecular liquid crystals. Here, we prepare supramolecular LCEs via surface-enforced alignment to study the impact of the supramolecular bond strength and intermolecular forces. This was evaluated using oxybenzoic acid (OBA) derivatives with and without pendant methyl groups as well as via oxybenzoic acid-pyridine complexes. Increased incorporation of supramolecular mesogens reduces the isotropic transition temperature and generally increases the strain–temperature coupling. The number of elastically active strands per unit volume, hydrogen bond conformations, and network morphology are affected by the supramolecular mesogens and influence the observed stimuli response. Overall, reduced intermolecular interactions correlate with more desirable actuation properties, demonstrating the influence of the supramolecular mesogen’s structure.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"51 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143026976","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":"Microstructure and Mechanical Properties of Jammed Dispersion of Nanogels","authors":"Chun Hsi, Bo-Sheng Lai, Heng-Kwong Tsao, Yu-Jane Sheng","doi":"10.1021/acs.macromol.4c02228","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02228","url":null,"abstract":"This study employs dissipative particle dynamics simulations to investigate the equilibrium microstructure and mechanical properties of jammed nanogel dispersions in a good solvent. The nanogels, composed of cross-linked linear polymers, exhibit impenetrability. Significant changes in size (radius of gyration) and shape (asphericity parameter) occur beyond a critical concentration (e.g., 15 wt %), resulting in densely packed configurations. The coordination number increases with rising concentration and stabilizes at a constant (approximately 13) for a jammed structure. For the jammed dispersion (25 wt %), rheological measurements reveal shear-thinning behavior and the presence of a static yield stress. Furthermore, oscillatory tests confirm the dominance of the storage modulus, indicating solid-like behavior. According to the compressive test, the Young’s modulus increases with the nanogel concentration due to denser packing. Free relaxation tests show an elastic response for small strains but a plastic response for large strains. This comprehensive analysis elucidates the relationship between the microstructure of nanogel dispersions and their solid-like characteristics.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"8 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143026966","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}