ACS Macro Letters最新文献

{"title":"Versatile and Controlled Synthesis of Degradable, Water-Soluble Bottlebrush Polymers with Poly(disulfide) Backbones Derived from α-Lipoic Acid","authors":"Ivan O. Levkovsky,&nbsp;Lucca Trachsel,&nbsp;Hironobu Murata and Krzysztof Matyjaszewski*,&nbsp;","doi":"10.1021/acsmacrolett.4c0083910.1021/acsmacrolett.4c00839","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00839https://doi.org/10.1021/acsmacrolett.4c00839","url":null,"abstract":"<p >Bottlebrush (BB) polymers, with their densely grafted side chains and unique architecture, are highly advantageous for drug delivery due to their high functional group density for drug conjugation, unimolecular nature, and enhanced biodistribution properties. These attributes enable extended blood circulation half-life, improved tumor tissue penetration, and high tumoral drug accumulation. However, the typically nondegradable, all-carbon backbones of most BB polymers limit their suitability for applications requiring controlled clearance and biodegradability. To address this, we developed degradable BB polymers with poly(disulfide) backbones synthesized via reversible addition–fragmentation chain transfer (RAFT) copolymerization of α-lipoic acid (LA), a renewable and readily available compound, with acrylate-based inimers. These copolymers feature degradable backbones and initiating sites for subsequent BB synthesis. Using an atom transfer radical polymerization (ATRP) <i>grafting-from</i> methodology, we synthesized BB polymers with relatively low dispersities (<i>Đ</i> = 1.30–1.53), high backbone degrees of polymerization (<i>DP</i>_bb), and high molar masses (<i>M</i>_n,MALS = 650–2700 kg/mol). The easily cleavable disulfide bonds enabled backbone degradation under mild reducing conditions. Beyond hydrophilic BB with tri(ethylene glycol) methyl ether acrylate (TEGA) side chains, we synthesized BB with cationic, anionic, and zwitterionic side chains, demonstrating broad monomer compatibility. This scalable approach produces water-soluble, degradable BB polymers with tunable architectures and predictable molecular weights. By addressing the need for degradability in BB polymers, this work advances their potential for drug delivery, offering enhanced functionality, biocompatibility, and sustainability.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"14 2","pages":"207–213 207–213"},"PeriodicalIF":5.1,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsmacrolett.4c00839","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineering of Polyisoprene Networks Enabled by Host–Guest Thiol–Ene Reaction","authors":"Takashi Kitao,&nbsp;Ikki Matsuda and Takashi Uemura*,&nbsp;","doi":"10.1021/acsmacrolett.4c0078610.1021/acsmacrolett.4c00786","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00786https://doi.org/10.1021/acsmacrolett.4c00786","url":null,"abstract":"<p >Regulating cross-linking of polymers is critical for optimizing the physical properties of polymer networks. Herein, we present a strategic approach for designing polymer networks using dithiol-functionalized metal–organic frameworks (MOFs) with both one- and three-dimensional pore architectures. Upon thermal treatment, thiyl radicals were generated from the MOFs through the dissociation of S–H bonds, as confirmed by electron spin resonance measurements. Unlike in solution and bulk phases, the confinement of these radicals within the MOFs effectively suppressed homocoupling reactions, thus enabling their function as densely packed cross-linkers. The thiol–ene reaction between the MOFs and <i>cis</i>-1,4-polyisoprene (PI) chains, followed by the selective removal of MOF hosts, resulted in PI networks that retained the original structural features. The ordered alignment of the PI chains enhanced their thermal stability compared with the randomly cross-linked PI network.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"14 2","pages":"195–200 195–200"},"PeriodicalIF":5.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineering of Polyisoprene Networks Enabled by Host–Guest Thiol–Ene Reaction","authors":"Takashi Kitao, Ikki Matsuda, Takashi Uemura","doi":"10.1021/acsmacrolett.4c00786","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00786","url":null,"abstract":"Regulating cross-linking of polymers is critical for optimizing the physical properties of polymer networks. Herein, we present a strategic approach for designing polymer networks using dithiol-functionalized metal–organic frameworks (MOFs) with both one- and three-dimensional pore architectures. Upon thermal treatment, thiyl radicals were generated from the MOFs through the dissociation of S–H bonds, as confirmed by electron spin resonance measurements. Unlike in solution and bulk phases, the confinement of these radicals within the MOFs effectively suppressed homocoupling reactions, thus enabling their function as densely packed cross-linkers. The thiol–ene reaction between the MOFs and <i>cis</i>-1,4-polyisoprene (PI) chains, followed by the selective removal of MOF hosts, resulted in PI networks that retained the original structural features. The ordered alignment of the PI chains enhanced their thermal stability compared with the randomly cross-linked PI network.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"47 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kinetically Controlled Approach for One-Pot Synthesis of Poly(peptide-b-peptoid) Exhibiting Well-Defined Secondary Structure and Thermal Stability","authors":"Prabir Maity,&nbsp;Arjun Singh Bisht,&nbsp; Deepak and Raj Kumar Roy*,&nbsp;","doi":"10.1021/acsmacrolett.4c0082310.1021/acsmacrolett.4c00823","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00823https://doi.org/10.1021/acsmacrolett.4c00823","url":null,"abstract":"<p >Sequence-controlled polymerization aims to bridge the gap between biopolymers and synthetic macromolecules. In a kinetically controlled approach, the inherent reactivity differences among monomers determine the primary structure or sequence of the monomers linked within the resulting copolymer chains. This report outlines a one-pot synthesis of polypeptide-<i>b</i>-polypeptoid by choosing a suitable pair of N-carboxy anhydride (NCA) monomers with significant reactivity differences. We have demonstrated the preparation of well-defined block copolymers, including polyproline-<i>b</i>-polysarcosine (PLP-<i>b</i>-PSar) and poly(propargyl proline)-<i>b</i>-polysarcosine (PLPP-<i>b</i>-PSar) in a single step. ¹H NMR kinetic studies confirmed the sequence-controlled primary structures of these block copolymers. The NMR analysis indicated a striking reactivity ratio difference (<i>r</i>_PLP = 925 and <i>r</i>_PSar = 0.0014; <i>r</i>_PLPP = 860 and <i>r</i>_PSar = 0.0015) between the selected monomer pairs, which was crucial for a one-pot block copolymer synthesis. Notably, these sequence-controlled copolymers’ secondary structures and stability were remarkably similar to those of block copolymers synthesized through conventional sequential addition methods. This further underscores the practicality of this kinetically controlled approach.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"14 2","pages":"188–194 188–194"},"PeriodicalIF":5.1,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydration Effects Driving Network Remodeling in Hydrogels during Cyclic Loading","authors":"Baptiste Le Roi, Joshua M. Grolman","doi":"10.1021/acsmacrolett.4c00653","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00653","url":null,"abstract":"In complex networks and fluids such as the extracellular matrix, the mechanical properties are substantially affected by the movement of polymers both part of and entrapped in the network. As many cells are sensitive to the mechanical remodeling of their surroundings, it is important to appreciate how entrapped polymers may inhibit or facilitate remodeling in the network. Here, we explore a molecular-level understanding of network remodeling in a complex hydrogel environment through successive compressive loading and the role that noninteracting polymers may play in a dynamic network. We find that this is a highly localized and time-dependent effect, with one of the major driving factors of hydrogel matrix remodeling the interaction and movement of water within the network in calcium-cross-linked alginate. Our results suggest a more general mechanistic understanding of hydrogel remodeling, with implications for tissue transformations in disease, biomaterials, and food science formulation.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"7 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143044389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding the Topology Freezing Temperature of Vitrimer-Like Materials through Complementary Structural and Rheological Analyses for Phase-Separated Network","authors":"Mikihiro Hayashi, Maho Suzuki, Takumi Kito","doi":"10.1021/acsmacrolett.4c00783","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00783","url":null,"abstract":"Vitrimers are sustainable cross-linked polymers characterized by an associative bond exchange mechanism within their network. A well-known feature of vitrimers is the Arrhenius dependence of the viscosity or relaxation time. Another important aspect is the existence of a topology-freezing temperature (<i>T</i>_v), which represents a transition between the viscoelastic solid state and the malleable viscoelastic liquid state. Various methods, including viscosity-temperature plots and temperature-ramp creep (or dilatometry), have been proposed for determining the <i>T</i>_v. In this study, we complementarily employ X-ray scattering-based structural analysis and rheological analysis to assign <i>T</i>_v in phase-separated vitrimer-like materials undergoing trans-<i>N</i>-alkylation bond exchange. Note that the <i>trans</i>-<i>N</i>-alkylation progresses via the dissociative bond exchange pathway, whereas our previous studies demonstrated that the temperature-dependence of relaxation time followed the Arrhenius dependence, which was the reason for the classification as a vitrimer-like material. Specifically, we identify <i>T</i>_v as the temperature at which an anomalous increase in domain distance occurs during the rubbery state in the structural analysis. In the rheological analysis, <i>T</i>_v corresponds to the transition temperature marking the shift from the Williams–Landel–Ferry dependence to the Arrhenius dependence in the shift factors used to create master curves for frequency sweep rheology data. Importantly, both methods yield nearly the same <i>T</i>_v, validating the accuracy of the proposed assignment and, thus, providing valuable insights into the specific properties of vitrimers.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"39 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding the Topology Freezing Temperature of Vitrimer-Like Materials through Complementary Structural and Rheological Analyses for Phase-Separated Network","authors":"Mikihiro Hayashi*,&nbsp;Maho Suzuki and Takumi Kito,&nbsp;","doi":"10.1021/acsmacrolett.4c0078310.1021/acsmacrolett.4c00783","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00783https://doi.org/10.1021/acsmacrolett.4c00783","url":null,"abstract":"<p >Vitrimers are sustainable cross-linked polymers characterized by an associative bond exchange mechanism within their network. A well-known feature of vitrimers is the Arrhenius dependence of the viscosity or relaxation time. Another important aspect is the existence of a topology-freezing temperature (<i>T</i>_v), which represents a transition between the viscoelastic solid state and the malleable viscoelastic liquid state. Various methods, including viscosity-temperature plots and temperature-ramp creep (or dilatometry), have been proposed for determining the <i>T</i>_v. In this study, we complementarily employ X-ray scattering-based structural analysis and rheological analysis to assign <i>T</i>_v in phase-separated vitrimer-like materials undergoing trans-<i>N</i>-alkylation bond exchange. Note that the <i>trans</i>-<i>N</i>-alkylation progresses via the dissociative bond exchange pathway, whereas our previous studies demonstrated that the temperature-dependence of relaxation time followed the Arrhenius dependence, which was the reason for the classification as a vitrimer-like material. Specifically, we identify <i>T</i>_v as the temperature at which an anomalous increase in domain distance occurs during the rubbery state in the structural analysis. In the rheological analysis, <i>T</i>_v corresponds to the transition temperature marking the shift from the Williams–Landel–Ferry dependence to the Arrhenius dependence in the shift factors used to create master curves for frequency sweep rheology data. Importantly, both methods yield nearly the same <i>T</i>_v, validating the accuracy of the proposed assignment and, thus, providing valuable insights into the specific properties of vitrimers.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"14 2","pages":"182–187 182–187"},"PeriodicalIF":5.1,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydration Effects Driving Network Remodeling in Hydrogels during Cyclic Loading","authors":"Baptiste Le Roi,&nbsp; and ,&nbsp;Joshua M. Grolman*,&nbsp;","doi":"10.1021/acsmacrolett.4c0065310.1021/acsmacrolett.4c00653","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00653https://doi.org/10.1021/acsmacrolett.4c00653","url":null,"abstract":"<p >In complex networks and fluids such as the extracellular matrix, the mechanical properties are substantially affected by the movement of polymers both part of and entrapped in the network. As many cells are sensitive to the mechanical remodeling of their surroundings, it is important to appreciate how entrapped polymers may inhibit or facilitate remodeling in the network. Here, we explore a molecular-level understanding of network remodeling in a complex hydrogel environment through successive compressive loading and the role that noninteracting polymers may play in a dynamic network. We find that this is a highly localized and time-dependent effect, with one of the major driving factors of hydrogel matrix remodeling the interaction and movement of water within the network in calcium-cross-linked alginate. Our results suggest a more general mechanistic understanding of hydrogel remodeling, with implications for tissue transformations in disease, biomaterials, and food science formulation.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"14 2","pages":"176–181 176–181"},"PeriodicalIF":5.1,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsmacrolett.4c00653","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Light-Induced Transformation from Covalent to Supramolecular Polymer Networks","authors":"Chuan Yue,&nbsp;Jingxi Deng,&nbsp;Bo Pang,&nbsp;Guoquan Liu,&nbsp;Yuanhao Wang,&nbsp;Haonan Xu,&nbsp;Shaolei Qu,&nbsp;Yuhang Liu,&nbsp;Yanxi Liu,&nbsp;Zhaoming Zhang*,&nbsp;Hui Zhou* and Xuzhou Yan*,&nbsp;","doi":"10.1021/acsmacrolett.4c0074410.1021/acsmacrolett.4c00744","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00744https://doi.org/10.1021/acsmacrolett.4c00744","url":null,"abstract":"<p >Stimuli-responsive polymers have demonstrated significant potential in the development of smart materials due to their capacity to undergo targeted property changes in response to external physical or chemical stimuli. However, the scales of response in most existing stimuli-responsive polymer systems are mainly focused on three levels: functional units, chain conformations, or polymer topologies. Herein, we have developed a covalent polymer network (CPN) capable of converting into a supramolecular polymer network (SPN) within bulk materials directly at the scale of polymer network types. This transformation is enabled by specifically designed covalent moieties that upon UV exposure reveal quadruple hydrogen bonding sites, allowing the formation of a supramolecular network. This network-type transition from CPN to SPN induces pronounced intrinsic changes in material properties, including a substantially increased breaking elongation, lower Young’s modulus, reduced fracture strength, and decreased creep resistance, marking a shift from a stable, rigid structure to a dynamic, adaptable one. These findings provide new insights into the design of advanced stimuli-responsive polymer materials through network-type transformations, opening new avenues for applications in smart and multifunctional materials.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"14 2","pages":"169–175 169–175"},"PeriodicalIF":5.1,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Light-Induced Transformation from Covalent to Supramolecular Polymer Networks","authors":"Chuan Yue, Jingxi Deng, Bo Pang, Guoquan Liu, Yuanhao Wang, Haonan Xu, Shaolei Qu, Yuhang Liu, Yanxi Liu, Zhaoming Zhang, Hui Zhou, Xuzhou Yan","doi":"10.1021/acsmacrolett.4c00744","DOIUrl":"https://doi.org/10.1021/acsmacrolett.4c00744","url":null,"abstract":"Stimuli-responsive polymers have demonstrated significant potential in the development of smart materials due to their capacity to undergo targeted property changes in response to external physical or chemical stimuli. However, the scales of response in most existing stimuli-responsive polymer systems are mainly focused on three levels: functional units, chain conformations, or polymer topologies. Herein, we have developed a covalent polymer network (CPN) capable of converting into a supramolecular polymer network (SPN) within bulk materials directly at the scale of polymer network types. This transformation is enabled by specifically designed covalent moieties that upon UV exposure reveal quadruple hydrogen bonding sites, allowing the formation of a supramolecular network. This network-type transition from CPN to SPN induces pronounced intrinsic changes in material properties, including a substantially increased breaking elongation, lower Young’s modulus, reduced fracture strength, and decreased creep resistance, marking a shift from a stable, rigid structure to a dynamic, adaptable one. These findings provide new insights into the design of advanced stimuli-responsive polymer materials through network-type transformations, opening new avenues for applications in smart and multifunctional materials.","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"4 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143044388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}