Macromolecules最新文献

{"title":"Room-Temperature Ferromagnetism and Near-Infrared Luminescence Enabled by Interchain-Aggregation Control of Open-Shell Donor–Acceptor Alternating Copolymers","authors":"Feng Jiang,&nbsp; and ,&nbsp;Mingfeng Wang*,&nbsp;","doi":"10.1021/acs.macromol.4c0278710.1021/acs.macromol.4c02787","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02787https://doi.org/10.1021/acs.macromol.4c02787","url":null,"abstract":"<p >Charge transfer in alternating donor–acceptor (D–A) conjugated polymers plays a crucial role in the development of organic electronics and spintronics. However, the contribution of intrachain charge transfer to the optoelectronic properties remains poorly understood due to the interference of interchain aggregation. Here, we report an approach to rational control of the interchain interaction of an open-shell D–A polymer through segregation of strongly interactive backbones, from which polymeric side chains are grafted so that the intrachain interaction between donors and acceptors becomes dominant. The grafted bottlebrush polymers are still open-shell, owing to the presence of unpaired conduction electrons along the π-conjugated backbones, resulting in asymmetric electron spin resonance. Meanwhile, the minimized interchain aggregation leads to near-infrared photoluminescence despite the narrow optical band gap. Surprisingly, the intrachain dominating D–A charge transfer and delocalization, together with the long-range structural ordering of these bottlebrush polymers in solid states, enables ferromagnetism both at and below room temperature. The effects of the chain length and the grafting density of the polymeric side chains on the optical and magnetic properties have been studied in detail.</p>","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"58 3","pages":"1409–1424 1409–1424"},"PeriodicalIF":5.1,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376394","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":"Polymerization-Induced Sulfone-Bond-Driven Self-Assembly","authors":"Junrui Zhang, Qili Li, Tanrong Yu, Yijian Ma, Zizhuo Zhao, Chengshuo Shen, Xunshan Liu, Meng Huo","doi":"10.1021/acs.macromol.4c02860","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02860","url":null,"abstract":"Sulfone bonding refers to dipole–dipole interactions between sulfone groups, which have been long overlooked. Herein, sulfone bonding was employed for the first time as the driving force for the self-assembly of block copolymers via a polymerization-induced sulfone-bond-driven self-assembly (PI-SDSA) strategy. The presence of sulfone bonding in a sulfone-functionalized monomer was first confirmed by scanning tunneling microscopy break junction measurements at the single-molecule level. Successful PI-SDSA was achieved in toluene, and the polymerization kinetics confirmed the polymerization-enhanced sulfone bonding as the driving force. The PI-SDSA was demonstrated to possess a peculiar monomer/solvent library by the successful PI-SDSA of a series of sulfone-containing monomers in solvents with varying dipole moments. The as-prepared sulfone-functionalized polymer assemblies manifested unique salt-responsiveness because of the competitive ion–dipole interactions between the ions and sulfone groups, enabling the salt-responsive payload release. The use of sulfone bonding as the driving force for self-assembly has provided a new perspective for both the polymerization-induced self-assembly and the self-assembly of block copolymers and will inspire the design of stimuli-responsive supramolecular materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"33 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071975","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":"Lamellar Domain Spacing of Copolymers with Nonlinear Block Architectures","authors":"Andrzej Grzyb, Jarosław S. Kłos, Aykut Erbaş, Michael Lang, Jarosław Paturej","doi":"10.1021/acs.macromol.4c03106","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03106","url":null,"abstract":"Topological modification of block copolymer (BCP) conformations offers a promising approach for developing self-assembled periodic nanostructured materials with smaller domain sizes, which are essential for a range of technological applications. Cyclic polymers, with their inherently more compact conformations, present an effective strategy for achieving this miniaturization. In this work, through a combination of analytical theory and coarse-grained molecular dynamics simulations, we establish a relationship between different nonlinear topologies and the corresponding domain size of lamella-forming BCPs. Our investigations includes BCP architectures with one or two cyclic segments such as tadpoles, diblock and triblock 8-shaped polymers, and diblock nonconcatenated and concatenated rings. We demonstrate that the primary reduction in lamellar domain size is driven by the more compact arrangement of monomers in the cyclic architectures, with an additional contribution from the nonconcatenation of cyclic segments. This is corroborated by theoretical predictions for both domain size reduction and BCP conformations across different architectures. Moreover, consistent with theoretical expectations, the nonconcatenation of rings reduces the interpenetration of opposing brushes, thereby lowering friction between lamellae.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"60 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072845","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":"Room-Temperature Ferromagnetism and Near-Infrared Luminescence Enabled by Interchain-Aggregation Control of Open-Shell Donor–Acceptor Alternating Copolymers","authors":"Feng Jiang, Mingfeng Wang","doi":"10.1021/acs.macromol.4c02787","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02787","url":null,"abstract":"Charge transfer in alternating donor–acceptor (D–A) conjugated polymers plays a crucial role in the development of organic electronics and spintronics. However, the contribution of intrachain charge transfer to the optoelectronic properties remains poorly understood due to the interference of interchain aggregation. Here, we report an approach to rational control of the interchain interaction of an open-shell D–A polymer through segregation of strongly interactive backbones, from which polymeric side chains are grafted so that the intrachain interaction between donors and acceptors becomes dominant. The grafted bottlebrush polymers are still open-shell, owing to the presence of unpaired conduction electrons along the π-conjugated backbones, resulting in asymmetric electron spin resonance. Meanwhile, the minimized interchain aggregation leads to near-infrared photoluminescence despite the narrow optical band gap. Surprisingly, the intrachain dominating D–A charge transfer and delocalization, together with the long-range structural ordering of these bottlebrush polymers in solid states, enables ferromagnetism both at and below room temperature. The effects of the chain length and the grafting density of the polymeric side chains on the optical and magnetic properties have been studied in detail.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"79 1 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071973","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":"Imbibition and Adsorption of a Bottlebrush Polymer in Nanopores","authors":"Panagiotis Kardasis, Ioannis Tzourtzouklis, Yun Dong, Moritz Meier-Merziger, Hans-Jürgen Butt, Holger Frey, George Floudas","doi":"10.1021/acs.macromol.4c02952","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02952","url":null,"abstract":"We report on the imbibition kinetics of bottlebrush polymer <i>cis</i>-1,4-polyfarnesene (PF) during flow in nanopores. To follow the polymer flow <i>in situ</i>, we employ <i>in situ</i> nanodielectric spectroscopy. The technique provides simultaneous access to the kinetics of imbibition and to the molecular dynamics during flow on the segmental and chain length scales. The imbibition process follows the <i>t</i>^1/2 dependence as predicted by the Lucas–Washburn equation. However, bottlebrush polymers with a molecular size smaller than the pore diameter (2<i>R</i>_g &lt; <i>d</i>, <i>d</i> is the pore diameter) penetrate nanopores with a higher effective viscosity than in bulk. The adsorption time scales are much longer than any molecular process, being several orders of magnitude slower than the segmental and longest normal modes. Compared to linear polymers, bottlebrush polymers exhibit even slower adsorption with characteristic time scales having a weak molar mass (τ_ads ∼ <i>N</i>_bb^1.2±0.1, <i>N</i>_bb is the number of backbone repeat units), pore size (log(τ_ads) ∼ ξ/<i>d, ξ</i> = 20 nm), and temperature (<i>E</i>_act ∼ 16 ± 2 kJ/mol) dependence. These findings are discussed in terms of an increased number of contacts of the bottlebrush polymer with the surface. Lastly, we investigate the separation of a polymer blend with linear/bottlebrush topologies into its constituents by the difference in the imbibition kinetics.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"47 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071974","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":"Upgrade Traditional KOH Catalyzed Ring-Opening Polymerization of Cyclosiloxanes to More Efficient Process by Adding Catalytic Phosphazenium Salt as Cocatalyst","authors":"Xiaoyu Guo,&nbsp;Zhedong Li,&nbsp;Jinfeng Shi,&nbsp;Chuanli Ren,&nbsp;Na Zhao* and Zhibo Li*,&nbsp;","doi":"10.1021/acs.macromol.4c0238810.1021/acs.macromol.4c02388","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02388https://doi.org/10.1021/acs.macromol.4c02388","url":null,"abstract":"<p >The development of efficient catalyst to overcome the limitation of equilibrium ring-opening polymerization (ROP) of cyclosiloxanes represents the most appealing solution to resolve the back-biting side reaction and high energy consumption during the traditional polysiloxane production. In this contribution, equilibrium polymerization of octamethylcyclotetrasiloxane (D₄) catalyzed by KOH at high temperature was shifted to more efficient polymerization at ambient conditions via fast kinetics and back-biting suppressing by adding a catalytic amount of phosphazenium salt as cocatalyst. Polydimethylsiloxanes (PDMSs) were synthesized in high conversion (≥90%) by bulky phosphazenium salt P₅Cl/KOH catalyzed ROP of D₄ at room temperature in THF solution. The ratio of P₅Cl could be lowered to 0.001 mol % of D₄, and the back-biting reactions were negligible as evaluated by <i>in situ</i> ¹H NMR characterization of the polymerization system. Kinetics investigations suggested that the fast and controlled manner of the ROP was promoted by the P₅Cl/KOH combination. Furthermore, bulk ROP of D₄ and octaphenylcyclotetrasiloxane (P₄) catalyzed by activated phosphazenium salt P₅OMe conveniently afforded PDMSs with different molecular weights (up to 1616 kg mol^–1) and poly(dimethylsiloxane-<i>co</i>-diphenylsiloxane) (PMPS) copolymers with different diphenylsiloxane contents (8.4–63.8 mol %) at 100 °C. The good random characteristic of PMPS copolymers were thoroughly verified by ¹H/²⁹Si NMR and thermodynamic measurements.</p>","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"58 3","pages":"1652–1661 1652–1661"},"PeriodicalIF":5.1,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376013","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":"Side-Chain Architecture-Dependent Thermoresponsive Behaviors of Graft Polymers with Poly(N-isopropylacrylamide) Pendants","authors":"Fujin Duan, Gege Liu, Jinqian Zhang, Xin Zhao, Qingqing Wang, Youliang Zhao","doi":"10.1021/acs.macromol.4c02611","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02611","url":null,"abstract":"The variations of side-chain architecture can significantly affect the thermoresponsive behaviors of graft polymers. This study is aimed at designing linear graft polymers with linear or cyclic pendants (LGPLs/LGPCs) to elucidate the distinct thermostability of polymer solutions. Three pairs of poly(<i>N</i>-isopropylacrylamide) (PNIPAM)-bearing graft polymers with a weight-average graft number (<i>N</i>_g) up to 16 are synthesized by the combination of the ring-first method, fractionation, and topology transformation. The chain architecture and graft number can affect the thermostability and thermosensitivity of polymer aqueous solutions, in which thermo-induced maximal variations of transmittance, light scattering intensity, and fluorescence intensity ratio related to amide–water hydrogen bonding drastically decrease with the incorporation of cyclic pendants and an increase of <i>N</i>_g. LGPLs with pronounced chain entanglement can self-assemble into thermostable lamellae, while other polymer assemblies are subjected to thermo-induced sphere-to-vesicle or vesicle-to-lamella transitions. This research affords a promising method to construct graft polymers with variable architectural parameters to achieve topology-dependent thermoresponsive behaviors.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"234 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143056865","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":"Polyethylene-poly(methyl acrylate) Block Copolymers from PACE-SARA ATRP: Utilizing Polyolefin Active Ester Exchange-Based Macroinitiators in Atom Transfer Radical Polymerization","authors":"Khidong Kim, Jacobo Strong, Stephen Don Sarkar, Dung Nguyen, Huong Dau, D.A. Anwar Al-Aman, Sajjad Dadashi-Silab, Eva Harth, Krzysztof Matyjaszewski","doi":"10.1021/acs.macromol.4c02684","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02684","url":null,"abstract":"Accessing a facile pathway to prepare polyolefin-polar block copolymers with low dispersity and high control remains a challenge due to the distinct polymerization pathways of the composing blocks. This study utilized the polyolefin active ester exchange, the PACE approach, as a viable solution. The PACE approach, using palladium-catalyst-based coordination-insertion polymerization, was combined with SARA ATRP (supplemental activator/reducing agent atom transfer radical polymerization). A single-chain-end active ester functionalized polyethylene (PE) was produced from an α-diimine Pd(II) hexafluoroisopropyl ester chelate complex, which facilitated a living polymerization of ethylene. Transesterification with 2-hydroxyethyl α-bromoisobutyrate (HOBIB) or 2-hydroxyethyl α-bromoisobutyramide (HOBIBA) formed α-bromoisobutyrate or α-bromoisobutyramide chain-end-functionalized polyethylene. The approach resulted in controlled synthesis of polymers with low dispersity (<i>Đ</i>), high initiation efficiency, and high reproducibility. Both the amide-linked and ester-linked macroinitiators showed &gt;90% initiation efficiency and <i>Đ</i> values of block copolymers as low as 1.05. This work demonstrated a successful combination of two living polymerization techniques, an insertion and controlled radical polymerization, unified in PACE-SARA ATRP, offering access to polyolefin-containing block copolymers with chemically distinct structures.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"11 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071978","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 Dynamics Simulation and Theoretical Analysis of Structural Relaxation, Bond Exchange Dynamics, and Glass Transition in Vitrimers","authors":"Tsai-Wei Lin, Baicheng Mei, Sarit Dutta, Kenneth S. Schweizer, Charles E. Sing","doi":"10.1021/acs.macromol.4c02659","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02659","url":null,"abstract":"Vitrimers are a class of polymer networks featuring dynamic covalent cross-links that can undergo associative bond exchange. There has been recent interest in these materials due to their promise as recyclable thermosets or self-healing polymers because of the ability of vitrimer networks to rearrange at the molecular level and undergo macroscopic flow. However, the practical use of these materials often occurs in the supercooled regime or glassy state, where the implications of dynamic bonds are complicated by the interplay between slow activated segmental dynamics, cross-link (i.e., bond-exchange) kinetics, and ultimately material properties. In this paper, we combine coarse-grained molecular dynamics simulation and microscopic statistical mechanical theory to understand how cross-linking kinetics affect material dynamics and how this couples to segmental relaxation of the polymeric network strands across a spectrum of length and time scales, especially in the supercooled regime. We characterize the Kuhn segmental alpha relaxation time and bond exchange time for vitrimer systems across various cross-link densities, temperatures, and bond exchange rates. Simulation and theory both exhibit a bending-up behavior for bond exchange time upon cooling, suggesting a coupling between bond exchange dynamics and segmental relaxation that intensifies with faster bond exchange kinetics. We also found bond exchange dynamics have an impact on Kuhn segment alpha relaxation time, which is most significant at higher cross-link densities. Both these effects are most prominent when the bond exchange time is similar to the Kuhn segment alpha relaxation time, and the resulting coupling of these two relaxation processes is tied to both the probability of a free end to find a bonded pair and the time scale of the constraints imposed by the dynamic cross-links. This relationship is reflected by a cross-link dependence of a theoretical parameter which represents the quantitative degree of coupling between bond exchange and segmental dynamics. Overall, the combination of simulation and theory clarifies the intricate interaction between bond kinetics and segmental relaxation and demonstrates the ability to provide molecular-level insights into vitrimer dynamics over a wide temperature range.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"6 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071977","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":"Side-Chain Architecture-Dependent Thermoresponsive Behaviors of Graft Polymers with Poly(N-isopropylacrylamide) Pendants","authors":"Fujin Duan,&nbsp;Gege Liu,&nbsp;Jinqian Zhang,&nbsp;Xin Zhao,&nbsp;Qingqing Wang and Youliang Zhao*,&nbsp;","doi":"10.1021/acs.macromol.4c0261110.1021/acs.macromol.4c02611","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02611https://doi.org/10.1021/acs.macromol.4c02611","url":null,"abstract":"<p >The variations of side-chain architecture can significantly affect the thermoresponsive behaviors of graft polymers. This study is aimed at designing linear graft polymers with linear or cyclic pendants (LGPLs/LGPCs) to elucidate the distinct thermostability of polymer solutions. Three pairs of poly(<i>N</i>-isopropylacrylamide) (PNIPAM)-bearing graft polymers with a weight-average graft number (<i>N</i>_g) up to 16 are synthesized by the combination of the ring-first method, fractionation, and topology transformation. The chain architecture and graft number can affect the thermostability and thermosensitivity of polymer aqueous solutions, in which thermo-induced maximal variations of transmittance, light scattering intensity, and fluorescence intensity ratio related to amide–water hydrogen bonding drastically decrease with the incorporation of cyclic pendants and an increase of <i>N</i>_g. LGPLs with pronounced chain entanglement can self-assemble into thermostable lamellae, while other polymer assemblies are subjected to thermo-induced sphere-to-vesicle or vesicle-to-lamella transitions. This research affords a promising method to construct graft polymers with variable architectural parameters to achieve topology-dependent thermoresponsive behaviors.</p>","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"58 3","pages":"1594–1607 1594–1607"},"PeriodicalIF":5.1,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376055","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}