Macromolecules最新文献

{"title":"Lipid Membrane Leaflets Unzip upon Hybridization with Polymer-Rich Nanodomains","authors":"James F. Tallman, Nurila Kambar, Cecília Leal, Antonia Statt","doi":"10.1021/acs.macromol.4c01874","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01874","url":null,"abstract":"There is a long-term interest in creating artificial biomimetic membranes where self-assembled phospholipid bilayers are selectively permeabilized by synthetic channel-like molecules. One example is the coassembly of amphiphilic block copolymers with phospholipids into a hybrid membrane. Hybrid phospholipid block copolymer bilayers display many properties, seen in biomembranes such as selective transport phenomena, synergistic elastic properties, and structural phase transformations. Just like in biomembranes, these fundamental properties of hybrid bilayers are often regulated by lateral phase separation. Understanding the molecular and physical cues that determine the formation of rafts or domains in hybrid membranes, their size, and morphology is paramount to elucidating and programming their function. Employing a combination of coarse-grained molecular dynamics simulations and high-resolution cryogenic electron microscopy, we discovered that phosphatidylcholine-cholesterol bilayers hybridized with poly(butadiene-<i>b</i>-ethylene oxide) develop two distinct phase-separated morphologies. At molar fractions of polymer above 10 mol % the expected molecular distribution into lipid-rich and polymer-rich domains is observed. However, at low polymer content, a new structure develops in which the bilayer leaflets unzip (but remain continuous) to incorporate nanodomains of hydrophobic butadiene globules. We conjecture that unzipping is energetically more favorable than sustaining the hydrophobic mismatch between butadiene blocks and phospholipid acyl chains. These findings offer new insights into the morphology of biomembranes upon the insertion of transmembrane proteins with bulky hydrophobic residues.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"10 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742777","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":"Impact of Ionic Modifications on Polyimide Properties for Gas Separation Applications","authors":"Sudhir Ravula, Fidel E. Rodríguez-González, Pravin S. Shinde, Ana L. Montero-Alejo, Claudio A. Terraza, Sree Laxmi, Sergey Vasenkov, Kathryn E. O’Harra, Alain Tundidor-Camba, Jason E. Bara","doi":"10.1021/acs.macromol.4c02315","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02315","url":null,"abstract":"In this study, we report the synthesis and investigate the structural and gas transport characteristics of polyimides containing an imidazole ring in the main chain. First, a neutral polyimide (<b>PI-Im-6FDA)</b> was synthesized through polycondensation, followed by quaternation of the imidazole rings, producing an ionic-polyimide (<b>PI-Im(Me)-6FDA)</b>. Interestingly, although the neutral form of the polyimide was able to form free-standing films, the ionic-polyimide was not able to form a self-standing film by itself. However, when free ionic liquid (IL) was added, good quality self-standing films were readily achieved (<b>PI-Im(Me)-6FDA</b> + IL). These three materials exhibited significant thermal stability, with a 10% weight loss occurring only when <i>T</i> &gt; 400 °C. The solubility profiles of the polymers in various solvents demonstrated that the ionic modification enhances solubility in common organic solvents like acetone. The molecular weights were determined to be 91 kDa for <b>PI-Im-6FDA</b> and 84 kDa for <b>PI-Im(Me)-6FDA</b>, indicating substantial polymeric chain lengths. Additionally, computational simulations indicate an increase in density and a decrease in free volume fraction with ionic content, suggesting a more compact polymer structure, as evidenced by reduced <i>d</i>-spacing values. Further, macroscopic gas transport measurements show that <b>PI-Im-6FDA</b> exhibited superior overall permselectivity performance, while <b>PI-Im(Me)-6FDA</b> + <b>IL</b> enhances the permeability of larger gases like CH₄ and N₂, making it a promising material for specific gas separation applications. Microscopic self-diffusion measurements performed by pulsed field gradient nuclear magnetic resonance (PFG NMR) techniques reveal a significant increase in the gas self-diffusivity upon IL addition. This result is in qualitative agreement with the transport diffusivity data from the macroscopic transport measurements. PFG NMR data also show that all materials have uniform transport properties on the length scales exceeding the smallest values of the root mean square displacements (1−2 μm) used in the measurements.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"9 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742783","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":"Amino-yne Reaction for the Synthesis of Degradable Hydrogels: Study of the Cleavage of β-Aminoacrylate Cross-Links","authors":"Sara Bescós-Ramo, Jesús del Barrio, Pilar Romero, Laura Florentino-Madiedo, Milagros Piñol, Luis Oriol","doi":"10.1021/acs.macromol.4c01403","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01403","url":null,"abstract":"This work addresses a study of PEG-derived hydrogels based on β-aminoacrylate cross-links and obtained by amino-yne click chemistry, using a β-aminoacrylate-based model molecule as reference. The pH-triggered cleavage of the β-aminoacrylate bonds was monitored confirming not only the release of the conjugated amine but also the formation of a mixture of chemical species that depends on the acidity of the medium. Moreover, overall hydrogel degradation rates were able to be adjusted by modifying pH, temperature, polymer concentration, or the amine selected as linker of PEG chains. In particular, the labile nature of the β-aminoacrylate bond was confirmed even under physiological conditions (pH 7.4, 37 °C), leading to long-term material degradation. The release and recovery of the conjugated amine after the cleavage of the β-aminoacrylate bonds was demonstrated at both acidic and physiological pH, mimicking the results acquired through model molecule studies.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"37 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742784","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":"Helical Network Polymers Serving as Chiral Templates for Asymmetric Photo-Cross-Link Polymerizations","authors":"Hiromasa Yamamoto, Takuya Inagaki, Ryo Kurusutani, Jinwoo Park, Kosuke Kaneko, Tomonori Hanasaki, Kazuo Akagi","doi":"10.1021/acs.macromol.4c01904","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01904","url":null,"abstract":"First-generation helical network polymer (HNP-1) films bearing phenylcyclohexyl (PCH) mesogen-based moieties were synthesized through the photo-cross-linking polymerization of acrylate derivatives in chiral nematic liquid crystals (N*-LCs) used as asymmetric polymerization solvents. The HNP-1 films were stable in organic solvents, and their helical structures were undestroyed; therefore, they gave rise to an N*-LC phase when N-LCs were added onto the surface of the HNP-1 films. Then, the HNP-1 films were used as chiral templates that enabled subsequent photocross polymerization processes in N*-LCs. Second-generation HNP (HNP-2) films were synthesized via the photo-cross-linking polymerization of functionalized acrylate derivatives bearing bis(1,1′-biphenyl)fluorene-based moieties. The HNP-2 films showed fingerprint morphologies resembling those of the HNP-1 films and exhibited circular dichroism in terms of absorption and circularly polarized luminescence with high dissymmetry factors on the order of 10^–2. The HNP-1 films serve as chiral templates for the synthesis of other types of HNP films through photocross polymerizations that are free from chiral dopants.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"19 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742778","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":"Source of Processable Vitrimer Viscosities: Swap Frequencies and Steric Factors","authors":"Shalini J. Rukmani, Sungjin Kim, Md Anisur Rahman, Xiao Zhao, Alexei P. Sokolov, Tomonori Saito, Loukas Petridis, Jan-Michael Carrillo, Aditya Savara","doi":"10.1021/acs.macromol.4c01943","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01943","url":null,"abstract":"Vitrimers exhibit high, processable viscosities, where other polymers do not, and are among the most promising polymers for closed-loop material circularity. We sought to investigate the underlying chemical kinetic factors that result in high viscosities for vitrimers, which are crucial to designing vitrimers with tunable viscosity. To interrogate these factors, we achieved the first simulated predictions of real vitrimer viscosities, using a novel kinetic Monte Carlo molecular dynamics method, overcoming the time and length scale gaps to predict experimental bulk viscosities. The vitrimer architecture investigated is based on poly(dimethylsiloxane) chains and vinylogous urethane bond swaps. We probed the effects of the extent of free swapping groups, <b>%</b><i><b>F</b></i>, the activation energy, <i><b>E</b></i>_<b>A</b>, and the steric factor, <b>ρ</b>. The steric factor is related to the intrinsic reaction probability for molecules with sufficient energy. All three factors were found to be significant, but the role of <b>ρ</b> was found to be the biggest and also the most underappreciated. The results show that the inclusion of accurate <b>ρ</b> is of critical importance for viscosity predictions, with the evidence suggesting that the typical assumption of <b>ρ</b> = 1 is not valid for vitrimers and that, indeed, very low steric factors are present in bond-swap vitrimers such that values of <b>ρ</b> &lt; 10^–10 may be typical. This greatly influences the bond exchange rates and, ultimately, the viscosities. Recognition of this result is necessary for the prediction of vitrimer viscosities from molecular simulations and to make vitrimers by design from molecular dynamics. We also investigated the effects that <i><b>E</b></i>_<b>A</b>, <b>ρ</b>, and the number of free swapping groups have upon vitreous range temperatures, <i><b>T</b></i>_<b>V</b>, with respect to achieving a specific viscosity (<b>η</b>_<b>V</b> = 1 × 10⁸ Pa·s), as well as for a commonly reported higher viscosity extrapolation (<b>η</b>_<b>V</b> = 1 × 10¹² Pa·s). The evidence suggests that vitrimers may follow universal curves for <i><b>E</b></i>_<b>A</b> vs <i><b>T</b></i>_<b>V</b>, as a function of <b>ρ</b>. This study achieves the first of these comparisons of molecular simulations to experiments and reveals critical insights toward creating vitrimers by design, while providing a route for the prediction of <i><b>T</b></i><b>_V</b> from kinetic Monte Carlo molecular dynamics simulations.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"70 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142742790","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":"Designing a Self-Healing Shape Memory Polymer with High Stiffness and Toughness: The Role of Nonuniform Chain Networks","authors":"Jiaxin Shi, Tianze Zheng, Jing Yuan, Chong Qiu, Yuxuan Ha, Hao Zhang, Baohua Guo, Jun Xu","doi":"10.1021/acs.macromol.4c02201","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02201","url":null,"abstract":"It has long been believed that uniformly cross-linked networks are beneficial to enhancing the toughness of elastomers and hydrogels by reducing stress concentration. However, in cross-linked semicrystalline polymers, it is not clear yet whether the uniformly cross-linked network is beneficial or worse for mechanical properties, since the crystallinity associated with the cross-linking network is also a key factor influencing mechanical properties. In this work, we designed chemically cross-linked polyurethane with crystalline segments either of nonuniform length or of uniform length. The nonuniform cross-linked networks are easier to crystallize and demonstrate higher strength and ductility than the uniform networks. The enhanced crystallinity caused by nonuniform cross-linking leads to stronger mechanical properties, resulting in a balance between stiffness and toughness. The obtained crystalline polyurethane plastic with nonuniform networks is biodegradable, with a strength of 68 MPa, Young’s modulus of 178 MPa, and a toughness of 365 MJ/m³. Additionally, the obtained polyurethane exhibits shape memory-assisted self-healing of cracks with a width of millimeter scale, which is conducive to expanding its functionality and extending its lifespan. As a result, the molecular design strategy utilizing nonuniform long chain networks to promote crystallization in chemically cross-linked polymers is established, which provides a new method for the design of high-performance polymers.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"194 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718442","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":"Inducing Chiral Response in Conjugated Polymers Composed of Achiral Monomers Using Chiral End Groups","authors":"Siebe Detavernier, Trijntje Paredis, Silvia Pratesi, Julien De Winter, Elisabetta Salatelli, Pascal Gerbaux, Guy Koeckelberghs","doi":"10.1021/acs.macromol.4c02054","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02054","url":null,"abstract":"Chiral expression in conjugated polymers is commonly achieved through the incorporation of stereogenic carbon atoms into the side chains of the polymer backbone. In this study, we explore the potential of inducing chiral expression in conjugated polymers by introducing chiral end groups via isolated external chiral initiators despite the presence of achiral side chains in the poly(3-octylthiophene) backbone. Two classes of chiral end groups are investigated: stilbene derivatives containing stereogenic carbon atoms in their side chains and (<i>S</i>)-(−)-1,1′-bi(2-naphthol) derivatives that exhibit axial chirality. Through solvatochromism experiments combined with UV–vis and circular dichroism (CD) spectroscopies, we identified the conditions necessary to induce chiral expression during supramolecular polymer aggregation.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"79 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718843","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":"Stability of Frank–Kasper Phases in ABn Miktoarm Star Polymers with Dispersity in n: Simulations and Experiments","authors":"Kodai Watanabe, Duyu Chen, Yongsi Zhu, Devon Callan, Glenn H. Fredrickson, Christopher M. Bates","doi":"10.1021/acs.macromol.4c02202","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02202","url":null,"abstract":"Miktoarm star polymers with two or more blocks connected at a common junction are known to stabilize Frank–Kasper phases such as σ and A15 over wide regions of phase space due to arm-number asymmetry. To date, studies on AB_<i>n</i> miktoarm stars in this context have focused on well-defined materials with a precise number of A and B arms. Here, using a combination of self-consistent field theory simulations and experiments, we demonstrate that mixtures of AB_<i>n</i> miktoarm stars with dispersity in the number of B arms per molecule (<i>n</i>) similarly stabilize σ and A15. This insight highlights the utility of a synthetic technique known as μSTAR (miktoarm synthesis by termination after ring-opening metathesis polymerization) that simplifies the synthesis of miktoarm star polymers but inherently produces a mixture of AB_<i>n</i> molecules having a distribution in <i>n</i>.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"7 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718894","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":"Cyclodextrin-Grafted Poly(vanillin) Antimicrobial Bio-Nanohoops via “Graft From” RAFT and Supramolecular Host–Guest Chemistry","authors":"Jun Li, Yaping Zhang, Feng Zhang, Rongmin Wang, Yufeng He, Pengfei Song","doi":"10.1021/acs.macromol.4c01823","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01823","url":null,"abstract":"Microbial infections have been recognized as one of the most serious threats to healthcare and agriculture production, and it is still a great challenge to explore antimicrobial biomaterials with supramolecular self-assembling systems. To address this challenge, novel bionanohoops were fabricated via “graft from” reversible addition–fragmentation chain transfer (RAFT) and supramolecular host–guest chemistry. Admittedly, controllable grafting of vanillin-derived homopolymer (PVMA_<i>x</i>) from β-cyclodextrin (β-CD) to synthesize β-cyclodextrin-grafted poly(vanillin methacrylate) (β-CD-<i>g</i>-PVMA_<i>x</i>, <i>x</i> = 5, 35, 103) was calculated from ¹H NMR integral area, and 2D NOESY demonstrated that the primary structured linear homopolymer chains (β-CD-<i>g</i>-PVMA₅) were linked to each other by host–guest interactions. Additionally, GPC results illustrated that the secondary structured nanohoops ([β-CD-<i>g</i>-PVMA₅]_<i>y</i>, <i>y</i> = 38 or 364) were self-assembled in situ from β-CD-<i>g</i>-PVMA₅ through supramolecular host–guest chemistry. Compared with stacking nanorods, nanohoops not only exhibited excellent antibacterial and antifungal activities but also presented good biocompatibility and better paint adhesion. Overall, we provided a valuable strategy that constructs antimicrobial bionanohoops by combining “graft from” RAFT and supramolecular host–guest chemistry for addressing microbial infections.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"71 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718844","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":"Chemistry Agnostic and Facile Method for Programming the Molecular Weight Distribution of Polymers","authors":"Michael T. Taleff, Antonia Statt, Damien Guironnet","doi":"10.1021/acs.macromol.4c01973","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01973","url":null,"abstract":"Many of a polymer material’s bulk properties (e.g., tensile strength, viscosity, and self-assembly) are dependent upon its molecular weight distribution. Thus, optimizing the properties of polymers requires systematic tuning of their molecular weight distributions. We developed a simple protocol for the synthesis of polymers with precisely programmed molecular weight distributions, which is applicable across all polymerizations in which molecular weight increases with time. Experimentally, the solution from an active polymerization vessel is transferred to a quenching vessel over time, building a targeted molecular weight distribution. The transfer rate is calculated using a robust and versatile mathematical model. The model includes an interpolation method that predicts the molecular weight distribution at any time during polymerization from a limited set of kinetic data. This interpolation enables the predictive capabilities of our protocol. We demonstrate the method by synthesizing polymers with square or trapezoidal molecular weight distributions using the group transfer polymerization of methyl methacrylate, the ring-opening metathesis polymerization of exo-5-norbornene-2-methylbenzoate, the atom transfer radical polymerization of methyl methacrylate, and the ring-opening polymerization of butylene oxide.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"23 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718842","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}