ACS Macro Letters最新文献

{"title":"Coordination-Engineered Zr Centers in Covalent Organic Frameworks: From O–Zr–O to N–Zr–N for Enhanced Ethylene Polymerization","authors":"Nian-Zu Shu,&nbsp;Hao-Tian Li,&nbsp;Yu-Qing Peng,&nbsp;Guo-Long He,&nbsp;Jie Gu,&nbsp;Yong-Qing Li,&nbsp;Yu-Cai Cao,&nbsp;Chuan-Lei Zhang","doi":"10.1021/acsmacrolett.6c00345","DOIUrl":"10.1021/acsmacrolett.6c00345","url":null,"abstract":"<p>The synthesis of ultrahigh-molecular-weight polyethylene(UHMWPE)is often hampered by the inherent compromise in traditional catalysts,such as Ziegler–Natta systems, which struggle to balance highactivity with precise control over molecular parameters. Covalentorganic frameworks (COFs) offer a promising alternative, allowingfor atomic-level design through their tunable pores and microenvironments.In this work, we address this challenge by designing a series of Zr@COFcatalysts─denoted as Zr@PQ-TFPB (O–Zr–O), Zr@PQSO-TFPB(N–Zr–O), and Zr@PQDO-TFPB (N–Zr–N)─tosystematically investigate the role of the coordination environment.Spectroscopic and catalytic studies reveal that the N–Zr–Nconfiguration in Zr@PQDO-TFPB optimally reduces the electron densityat the Zr center. This electronic modulation, characterized by reducedelectron density at the Zr center, facilitates ethylene adsorption/insertionwhile suppressing β-H elimination, leading to a superior polymerizationactivity of 3.87 × 10⁵ g·mol_Zr^–1·h^–1 at 3.0 MPa─66%and 38% higher than its O–Zr–O and N–Zr–Oanalogues, respectively. This catalyst produces UHMWPE with a highmolecular weight of 1.71 × 10⁶ g·mol^–1 and a relatively narrow dispersity (<em>Đ</em> = 2.2).Furthermore, the rigid nanochannels of the COF provide a confiningeffect that stabilizes the growing polyethylene chains. Our findingsunderscore a critical synergy between coordination-induced electroniceffects and spatial nanoconfinement, providing a novel design principlefor next-generation polyolefin catalysts.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1176–1184"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148462349","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":"“Dead” Layer Dynamics of Poly(ethyl methacrylate) in Nanotubes","authors":"Jianwei Zhang,&nbsp;Jiajia Zhou,&nbsp;Hans-Jürgen Butt,&nbsp;George Floudas","doi":"10.1021/acsmacrolett.6c00291","DOIUrl":"10.1021/acsmacrolett.6c00291","url":null,"abstract":"<p>We report the segmental dynamics of poly(<em>n</em>-ethylmethacrylate) melts forming nanotubes inside cylindrical alumina nanopores(AAOs). Long nanotubes were fabricated at the inner pore walls bythe polymer precursor film during the complete wetting transitionat high temperatures. Using differential scanning calorimetry anddielectric spectroscopy, we show that the segmental dynamics in thenanotubes are bimodal and slower than in bulk with a broad distributionof relaxation times. These features reflect the dynamic propertiesof the “dead layer” formed by the adsorbed polymer chainsat the pore walls.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1123–1128"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148546899","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":"Effects of Concentration, Cross-Linking, and Compression on Macromolecular Partitioning in Biological Hydrogels","authors":"Dan Wang,&nbsp;Juan Pablo Arango Velasquez,&nbsp;Matthew J. Gust,&nbsp;Rishi Dhayananth,&nbsp;Joseph Farroha,&nbsp;Daniel Lee,&nbsp;Nafi Bassoum,&nbsp;Caroline Calodney,&nbsp;Grace Castellano,&nbsp;John Castellano,&nbsp;Saran Diakite,&nbsp;Sena Gebreyesus,&nbsp;Lucas Klingele,&nbsp;Mauricio Lahera-Castillo,&nbsp;Patrick Megahan,&nbsp;Hafsa Musa,&nbsp;Katherine Neviaser,&nbsp;Maxi Ortiz,&nbsp;Priya Rangi,&nbsp;Richard S. Nho,&nbsp;Matthew A. Reilly,&nbsp;Nicholas Ferrell","doi":"10.1021/acsmacrolett.6c00249","DOIUrl":"10.1021/acsmacrolett.6c00249","url":null,"abstract":"<p>Transport of macromoleculesin biological hydrogels is importantfor understanding delivery, distribution, and movement of growth factors,cytokines, and peptide- or protein-based drugs within and betweenbiological tissues. This is primarily mediated by basement membranesand extracellular matrixes that separate tissue compartments and structurallysupport the extracellular microenvironment. Changes in the extracellularmatrix (ECM) architecture alter molecular transport and have implicationsfor delivery of biologically active agents in both normal and pathologicalsettings. Matrix density and cross-linking are altered in cancer,fibrotic diseases, and diabetes. Under physiological conditions, ECMsmay be compressed to varying degrees under normal or pathologicalstresses. Here we used multiple biological hydrogels including agarose,collagen I, and Matrigel to understand the relative effects of concentration,cross-linking, and compression on nanoscale molecular transport. Wehypothesized that increasing concentration, enzymatic cross-linking,and imparting gel compression would all result in reduced molecularpartitioning into hydrogels due to reductions in gel porosity. Wefound that concentration and compression had significant impacts onmolecular partitioning into hydrogels. Cross-linking with multipleenzymatic and chemical cross-linkers increased gel stiffness but hadminimal impact on diffusion-based molecular transport. These resultsindicate that changes in matrix architecture due to increased concentrationor reductions in porosity induced by mechanical compression, but notcross-linking, significantly alter macromolecular transport in biologicalhydrogels.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1093–1100"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148595838","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":"Rational Design of Functional Bottlebrush Polymers for Polylactide Blends with Improved Toughness and Antibacterial Performance","authors":"Jae Jun Kim,&nbsp;Hyojin Jung,&nbsp;Yejin Kim,&nbsp;So Youn Kim,&nbsp;Jong-Chan Lee","doi":"10.1021/acsmacrolett.6c00274","DOIUrl":"10.1021/acsmacrolett.6c00274","url":null,"abstract":"<p>A seriesof bottlebrush polymers was rationally synthesized usingnorbornene-functionalized polylactide (NB-PLA), polycaprolactone (NB-PCL),and quaternized poly(2-(dimethylamino)ethyl methacrylate (NB-QPDM)via ring-opening metathesis polymerization (ROMP). These polymericadditives enabled the simultaneous improvement of toughness and antibacterialactivity in PLA blends. Incorporating 10 wt % of P34, which consistsof NB-PLA, NB-PCL, and NB-QPDM with backbone degrees of polymerizationof 6, 34, and 4, respectively, led to a significant increase in tensiletoughness while maintaining the tensile strength and Young’smodulus comparable to neat PLA. This enhancement could be ascribedto the combined effects of a dispersed toughening phase and a weakphysical network structure. Furthermore, the PLA blend containingP34 exhibited outstanding antibacterial efficacy of 99.5% against <em>E. coli</em>, which originated from the presence of a quaternaryammonium group.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1110–1116"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148692134","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":"Beyond Stimuli Responsiveness: Toward Decision-Making Polymers","authors":"Navid Rabiee,&nbsp;Sidi A. Bencherif","doi":"10.1021/acsmacrolett.6c00272","DOIUrl":"10.1021/acsmacrolett.6c00272","url":null,"abstract":"<p>Stimuli-responsive polymers have transformed macromolecularscienceby enabling materials that dynamically alter their structure and functionin response to environmental cues. Despite these advances, however,most responsive polymers remain fundamentally reactive rather thaninterpretive, operating through direct stimulus–response couplingwithout contextual evaluation. In this viewpoint, we propose thatpolymer science is approaching a conceptual transition from stimuli-responsivematter to decision-making matter, where materials are engineered notonly to respond but also to integrate, discriminate, and selectivelyact upon complex, multivariate inputs. We define decision-making polymersas systems whose outputs emerge from multistimulus coupling, nonlinearresponse topology, internal state memory, and path-dependent dynamics.We further propose that such behavior can be understood through programmablefree-energy landscapes that enable context-dependent occupation ofcompeting metastable states. We discuss physicochemical strategiesfor encoding decision behavior, including coupled responsive motifs,sequence-defined architectures, spatial heterogeneity, and memory-bearingpolymer networks, and outline a framework for evaluating polymer performancebased on signal selectivity, conditional susceptibility, and adaptivestate evolution. Together, this work positions decision-making polymersas a promising new direction in macromolecular science for autonomousoperation in complex biological and technological environments. Here,decision-making refers to physicochemically encoded, context-selectivestate selection rather than cognition.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1069–1079"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148692136","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":"Editorial for ACS Macro Letters Special Issue: Sustainable Innovations in Biobased Polymers","authors":"Eleftheria Roumeli,&nbsp;LaShanda T. J. Korley","doi":"10.1021/acsmacrolett.6c00331","DOIUrl":"10.1021/acsmacrolett.6c00331","url":null,"abstract":"","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1065–1068"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148756718","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":"Segmental Equilibration Governs the Adsorption of Confined Polymers","authors":"Panagiotis Kardasis,&nbsp;George Floudas","doi":"10.1021/acsmacrolett.6c00124","DOIUrl":"10.1021/acsmacrolett.6c00124","url":null,"abstract":"<p>Equilibration ofthe segmental dynamics following a thermalperturbationin the vicinity of <em>T</em>_g and chain adsorptionunder confinement are closely linked. Here we show that segmentalequilibration acts as a kinetic precursor to adsorption. The segmentalequilibration time, τ<span><span>^segm_eq</span></span>, involves dipole–dipole interactionsof polymer segments near the pore walls establishing orientationalorder. <em>In situ</em> nanodielectric spectroscopy is employedin linear, star-shaped, and bottlebrush polyisoprenes confined inself-ordered nanoporous alumina to determine the second characteristictime, τ_ads. In this mechanism, incoming chains replacethe already adsorbed chains by overcoming a low potential barrier <em>U</em>*. Both times exhibit an Arrhenius temperature dependencewith identical activation energies and share the same molar mass dependencebeing independent of the polymer architecture. A relation, τ_ads = exp[<em>E</em>_act/<em>U</em>*]τ<span><span>^segm_eq</span></span>, provides the link between adsorption and equilibration and canbe used to predict the slower time scale (adsorption) at lower temperatures,where the latter is practically inaccessible.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1080–1085"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147752645","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":"Side-Group Recognition Promoting Self-Switchable Ring-Opening Polymerization to Access High-Performance (AB)nCm Block Copolyesters","authors":"Jie Lin,&nbsp;Wenna Wang,&nbsp;Xin-Lei Li,&nbsp;Ji Xian,&nbsp;Xiongying Fan,&nbsp;Guangbei Nie,&nbsp;Dingyu Huang,&nbsp;Zhaowei Jia,&nbsp;Zhongxing Zhao,&nbsp;Zhenxia Zhao","doi":"10.1021/acsmacrolett.6c00385","DOIUrl":"10.1021/acsmacrolett.6c00385","url":null,"abstract":"<p>Thesynthesis of sequence-controlled block copolyesters from mixturesof both cyclic ester monomers remains challenging, as insufficientchemoselectivity leads to gradient or statistical copolymers ratherthan well-defined block structures. Herein we exploit CH−πinteractions between a zirconium alkoxide initiator and the aryl sidegroup of a lactone monomer to selectively enhance the coordinationof asymmetric 3-phenyl-1,4-dioxane-2,5-diketone (PDD) over that ofε-caprolactone (CL) in a self-switchable ring-opening polymerization(ROP). This monomer side-group recognition promoted preferential bindingmakes the ROP of PDD kinetically favored over that of CL, therebyendowing the system with high chemoselectivity. As a result, PDD isconsumed rapidly and nearly completely (98% conversion) before thepolymerization autonomously switches to the ROP of CL, affording well-defined(AB)_<em>n</em>C_<em>m</em>-typediblock copolyesters. By supplying additional monomer mixtures sequentiallyduring the polymerization, this approach can be further extended tosequence-controlled ((AB)_<em>n</em>C_<em>m</em>)_<em>z</em>-type multiblock copolyesters.The thermal and mechanical analyses reveal that both block lengthratios and chain architecture govern material performance. Remarkably,the diblock PPDD-<em>b</em>-PCL exhibited a tensile strengthof 47.2 ± 2.5 MPa and an elongation at break of 942.0 ±45.0%, making it a strong and ductile material comparable to commercialisotactic polypropylene. This work establishes a side-group recognitionapproach for self-switchable polymerization, establishing a powerfulplatform for the precision synthesis of sustainable plastics.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1191–1198"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148655829","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":"Veratraldehyde-Derived Poly(phenol imidazole) Nanosheets for Thermally Stable UV-Shielding Poly(vinyl alcohol) Composites","authors":"Di Wang,&nbsp;Jia Xin Yu,&nbsp;Ya Lin Cao,&nbsp;Yang You","doi":"10.1021/acsmacrolett.6c00353","DOIUrl":"10.1021/acsmacrolett.6c00353","url":null,"abstract":"<p>Developingnanomaterials from lignin and its derivatives representsan effective strategy for the high-value utilization of lignin; however,achieving template-free morphological control of lignin-based nanomaterialsremains a significant challenge. Herein, we propose a strategy combiningScholl and demethylation reactions for the preparation of lignin-derivednanosheets using veratraldehyde-derived triarylimidazoles as the precursor.Oligomerization is achieved through the Scholl reaction of aromaticring moieties, concurrent with the conversion of methoxy moietiesto phenolic hydroxyl groups via demethylation.This dual mechanismenables the monomers to assemble into poly(phenol imidazole) nanosheetswith a thickness of 5 nm, mediated by both covalent polymerizationand noncovalent interactions. By incorporating these nanosheets intoa poly(vinyl alcohol) matrix, the mechanical properties, thermal stability,and UV-shielding capabilities of the resulting composites are simultaneouslyenhanced. This work provides valuable insights into the high-valuevalorization of lignin and offers a novel template-free synthesisstrategy for low-dimensional organic nanomaterials.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1185–1190"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148692138","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":"Determining Preparation-Induced Differences in Local Forces Acting along Polymer Chains in Spin-Coated Films","authors":"Meirui Fu,&nbsp;Raphael Hertel,&nbsp;Bence Dajka,&nbsp;Michael Walter,&nbsp;Michael Sommer,&nbsp;Günter Reiter","doi":"10.1021/acsmacrolett.6c00311","DOIUrl":"10.1021/acsmacrolett.6c00311","url":null,"abstract":"<p>We employed photoluminescence (PL) from mechanochromophorescovalentlylinked into the backbone of a glassy polymer as optical force sensors(“optical springs”) to resolve forces acting along polymerchains in spin-coated thin films. From the shift of the peak positionof the PL spectrum, we deduced changes in the main force. Changesin the shape of the spectra were interpreted as alterations in populationsof polymer chains experiencing lower and higher forces than the mainforce. Depending on the conditions of spin coating, expressed througha preparation parameter <em>p</em>_ev, we observeddistinct changes in the corresponding PL spectra of the resultingpolymer films, reflecting characteristic variations in the distributionof forces acting along polymer chains as a function of <em>p</em>_ev. Our results allowed to link the forces acting alongindividual polymer chains in spin-coated polymer films with macroscopicallydetected residual stresses, with the latter reflecting the combinedand cooperative response of a large ensemble of polymer chains. Interestingly,residual stresses and the forces acting along individual polymer chainsdid not exhibit the same dependence on <em>p</em>_ev.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":"15 8","pages":"1157–1162"},"PeriodicalIF":4.9,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148589259","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}