Pub Date : 2025-02-13DOI: 10.1021/acs.macromol.4c02181
Joonhyeok Park, Ruth M. Muthoka, Yongjin Lee
We perform a systematic computational study for designing high-temperature resistant Oligo-polyimides (Oligo-PIs). Their properties can be significantly enhanced by substituting the diamine component. Oligo-PI Type A– end-capped with 4-Phenylethynyl anhydride (4-PEPA) groups and comprising of 11 repeat units of 1,3-Bis(4-aminophenoxy)benzene (TPE-R) and 10 repeat units of 3,4′-Biphthalic Anhydride (a-BPDA)) was chosen for modification. We selected 4-PEPA and a-BPDA due to their efficacy in forming thermally stable Oligo-PIs. Here, we developed a molecular modification approach to substitute the Oligo-PI Type A TPE-R segment with various commercially available polyimide (PI) monomers. This method, integrated with high-fidelity molecular dynamics simulations, allowed us to quantitatively predict the glass transition temperature (Tg) and identify 27 Oligo-PI candidates demonstrating structural integrity above 823 K, the conventional turbine inlet gas temperature. Posteriori structural analysis revealed important structural attributes such as side group, symmetry and configuration, chain–chain interactions, and molecular symmetry, which are crucial to their high Tg. This strategy demonstrates a promising method for the tailored design of high-temperature resistant materials, paving the way for advancements in gas turbine materials.
{"title":"Designing Thermally Resistant Polyimide Oligomers: Insights from Molecular Dynamics Simulations","authors":"Joonhyeok Park, Ruth M. Muthoka, Yongjin Lee","doi":"10.1021/acs.macromol.4c02181","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02181","url":null,"abstract":"We perform a systematic computational study for designing high-temperature resistant Oligo-polyimides (Oligo-PIs). Their properties can be significantly enhanced by substituting the diamine component. Oligo-PI Type A– end-capped with 4-Phenylethynyl anhydride (4-PEPA) groups and comprising of 11 repeat units of 1,3-Bis(4-aminophenoxy)benzene (TPE-R) and 10 repeat units of 3,4′-Biphthalic Anhydride (a-BPDA)) was chosen for modification. We selected 4-PEPA and a-BPDA due to their efficacy in forming thermally stable Oligo-PIs. Here, we developed a molecular modification approach to substitute the Oligo-PI Type A TPE-R segment with various commercially available polyimide (PI) monomers. This method, integrated with high-fidelity molecular dynamics simulations, allowed us to quantitatively predict the glass transition temperature (<i>T</i><sub>g</sub>) and identify 27 Oligo-PI candidates demonstrating structural integrity above 823 K, the conventional turbine inlet gas temperature. Posteriori structural analysis revealed important structural attributes such as side group, symmetry and configuration, chain–chain interactions, and molecular symmetry, which are crucial to their high <i>T</i><sub>g</sub>. This strategy demonstrates a promising method for the tailored design of high-temperature resistant materials, paving the way for advancements in gas turbine materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"63 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401348","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}
Pub Date : 2025-02-12DOI: 10.1021/acs.macromol.4c03034
Bin Zhao, Michael T. Kelly, Sachini H. Dayarathne, Shichen Yu, Kingsley O. Ojima, Christopher Y. Li
By utilizing the large size and the tunable amphiphilicity of shape-changing molecular bottlebrushes (MBBs), we show that MBBs with heterografted poly(ethylene oxide) (PEO) and poly(2-(N,N-diethylamino)ethyl methacrylate) (PDEAEMA) side chains (MBB-OE) are an efficient and pH-responsive emulsifier, producing highly stable emulsions that can be disrupted by external stimuli. MBB-OE was wormlike in acidic solution and collapsed into a globular shape with increasing pH due to the insolubility of PDEAEMA in basic water. Upon vortexing, water-in-oil (w/o) emulsions were formed from the mixtures of toluene and a pH 9.5 buffer with mass ratios ≥0.8:1.0, even using only 0.0068% MBB-OE. Vortexing caused the globular brushes to unfold and adsorb at the interface, reconfiguring into a Janus wormlike structure with PEO and PDEAEMA extending into the aqueous and toluene phase, respectively. This is supported by the observations of the partitioning of PEO and PDEAEMA between the two phases and the interfacial wrinkling of emulsion droplets during solvent evaporation. The emulsions were readily disrupted by changing the pH to 4.0 and reformed by vortexing after increasing the pH to 9.5; the emulsion formation and breaking can be repeated multiple times. Interestingly, oil-in-water (o/w) emulsions were formed at the toluene-to-water mass ratio ≤0.6:1.0 and remained stable after the pH was changed to 4.0 by HCl, likely because H+ was unable to cross the interface. However, bubbling with CO2 disrupted the emulsions. This work demonstrates the potential of shape-changing MBBs as stimuli-responsive emulsifiers, opening up opportunities for designing advanced emulsifiers by leveraging the large size, unique characteristics, and responsiveness of MBBs.
{"title":"pH-Responsive Shape-Changing Molecular Bottlebrush Emulsifier","authors":"Bin Zhao, Michael T. Kelly, Sachini H. Dayarathne, Shichen Yu, Kingsley O. Ojima, Christopher Y. Li","doi":"10.1021/acs.macromol.4c03034","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03034","url":null,"abstract":"By utilizing the large size and the tunable amphiphilicity of shape-changing molecular bottlebrushes (MBBs), we show that MBBs with heterografted poly(ethylene oxide) (PEO) and poly(2-(<i>N</i>,<i>N</i>-diethylamino)ethyl methacrylate) (PDEAEMA) side chains (MBB-OE) are an efficient and pH-responsive emulsifier, producing highly stable emulsions that can be disrupted by external stimuli. MBB-OE was wormlike in acidic solution and collapsed into a globular shape with increasing pH due to the insolubility of PDEAEMA in basic water. Upon vortexing, water-in-oil (w/o) emulsions were formed from the mixtures of toluene and a pH 9.5 buffer with mass ratios ≥0.8:1.0, even using only 0.0068% MBB-OE. Vortexing caused the globular brushes to unfold and adsorb at the interface, reconfiguring into a Janus wormlike structure with PEO and PDEAEMA extending into the aqueous and toluene phase, respectively. This is supported by the observations of the partitioning of PEO and PDEAEMA between the two phases and the interfacial wrinkling of emulsion droplets during solvent evaporation. The emulsions were readily disrupted by changing the pH to 4.0 and reformed by vortexing after increasing the pH to 9.5; the emulsion formation and breaking can be repeated multiple times. Interestingly, oil-in-water (o/w) emulsions were formed at the toluene-to-water mass ratio ≤0.6:1.0 and remained stable after the pH was changed to 4.0 by HCl, likely because H<sup>+</sup> was unable to cross the interface. However, bubbling with CO<sub>2</sub> disrupted the emulsions. This work demonstrates the potential of shape-changing MBBs as stimuli-responsive emulsifiers, opening up opportunities for designing advanced emulsifiers by leveraging the large size, unique characteristics, and responsiveness of MBBs.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"29 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393539","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}
Pub Date : 2025-02-12DOI: 10.1021/acs.macromol.4c01738
Chuanfa Li, Kun Zhang, Jiaxin Li, Qian Ye, Kailin Zhang, Bingjie Wang, Huisheng Peng
Fiber batteries have garnered significant attention due to their advantages, such as miniaturization, weavability, permeability, and integrability, making them ideal for wearable electronics. Polymer materials, by virtue of their high designability, light weight, low cost, high stability, and mechanical flexibility, have been widely introduced to achieve not only high flexibility and wearable compatibility, but also superior electrochemical performance and safety of fiber batteries. In this Perspective, we systematically discuss the applications of polymer materials in electrodes, electrolytes, separators, and packaging tubes for fiber batteries with an emphasis on material design and device performance. Finally, we summarize the remaining challenges and future directions for polymer-based fiber batteries.
{"title":"Polymers for Fiber Batteries","authors":"Chuanfa Li, Kun Zhang, Jiaxin Li, Qian Ye, Kailin Zhang, Bingjie Wang, Huisheng Peng","doi":"10.1021/acs.macromol.4c01738","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c01738","url":null,"abstract":"Fiber batteries have garnered significant attention due to their advantages, such as miniaturization, weavability, permeability, and integrability, making them ideal for wearable electronics. Polymer materials, by virtue of their high designability, light weight, low cost, high stability, and mechanical flexibility, have been widely introduced to achieve not only high flexibility and wearable compatibility, but also superior electrochemical performance and safety of fiber batteries. In this Perspective, we systematically discuss the applications of polymer materials in electrodes, electrolytes, separators, and packaging tubes for fiber batteries with an emphasis on material design and device performance. Finally, we summarize the remaining challenges and future directions for polymer-based fiber batteries.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"6 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393713","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}
Pub Date : 2025-02-12DOI: 10.1021/acs.macromol.4c02963
Xue Kang, Mengyang Yu, Hanying Zhao, Li Liu
In this study, we synthesized a heteroaromatic thioether-containing polymer through the ring-opening of N-acetyl homocysteine thiolactone (NHTL) and thiol-heteroaromatic sulfone click polymerization in a one-pot approach. A dithiol monomer, produced in situ via NHTL ring-opening, was polymerized with a bis(phenylsulfone)-containing monomer through the click step-growth polymerization, resulting in the generation of a thermally stable polymer with pyridinyl thioether moieties in its main chain. The obtained polymer demonstrated clustering-triggered emission behavior due to electron-rich N, O, and S heteroatoms in the polymer structure. It was explored as a fluorescent polymeric probe to detect Cu2+ ions in the visible region. With H2O2/Na2WO4 as the oxidative reagent, thioether moieties in the polymer backbone were converted to sulfoxide/sulfone moieties. The resulting oxidized polymer underwent degradation through a declick reaction with a monothiol-containing compound. After the declick reaction of 2-mercaptoethanol and the oxidized polymer, a small molecule readily separated from the degradation product was recycled as a diol monomer to prepare polyurethane with a diisocyanate monomer. The pyridinyl thioether-containing polymer with clustering-triggered emission behavior exhibits potential as a new degradable material that can address environmental concerns and enhance sustainability in various applications.
{"title":"Pyridinyl Polythioether via a One-Pot Thiolactone Ring-Opening and Thiol-Phenylsulfone Click Polymerization: Synthesis, Fluorescence, and Degradation Behavior","authors":"Xue Kang, Mengyang Yu, Hanying Zhao, Li Liu","doi":"10.1021/acs.macromol.4c02963","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02963","url":null,"abstract":"In this study, we synthesized a heteroaromatic thioether-containing polymer through the ring-opening of <i>N</i>-acetyl homocysteine thiolactone (NHTL) and thiol-heteroaromatic sulfone click polymerization in a one-pot approach. A dithiol monomer, produced in situ via NHTL ring-opening, was polymerized with a bis(phenylsulfone)-containing monomer through the click step-growth polymerization, resulting in the generation of a thermally stable polymer with pyridinyl thioether moieties in its main chain. The obtained polymer demonstrated clustering-triggered emission behavior due to electron-rich N, O, and S heteroatoms in the polymer structure. It was explored as a fluorescent polymeric probe to detect Cu<sup>2+</sup> ions in the visible region. With H<sub>2</sub>O<sub>2</sub>/Na<sub>2</sub>WO<sub>4</sub> as the oxidative reagent, thioether moieties in the polymer backbone were converted to sulfoxide/sulfone moieties. The resulting oxidized polymer underwent degradation through a declick reaction with a monothiol-containing compound. After the declick reaction of 2-mercaptoethanol and the oxidized polymer, a small molecule readily separated from the degradation product was recycled as a diol monomer to prepare polyurethane with a diisocyanate monomer. The pyridinyl thioether-containing polymer with clustering-triggered emission behavior exhibits potential as a new degradable material that can address environmental concerns and enhance sustainability in various applications.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"61 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401349","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}
Pub Date : 2025-02-12DOI: 10.1021/acs.macromol.4c03060
Martin Orságh, Ondrej Sedlacek
In this work, we developed a novel electron-rich dithiobenzoate chain transfer agent (CTA) with excellent control for both cationic and radical photoelectron/energy transfer-reversible addition–fragmentation chain transfer (PET RAFT) polymerizations. The 2,4-dimethoxydithiobenzoate-based CTA enables the optimized stabilization of chain transfer intermediates, outperforming trithiocarbonates in the control of cationic RAFT polymerizations and dithiocarbamates in radical RAFT polymerizations of more active monomers. The excellent control of cationic PET RAFT polymerization offered by this novel CTA was demonstrated by the blue-light-mediated synthesis of poly(isobutyl vinyl ether) of various chain lengths with sub-1.2 dispersities. Furthermore, to highlight its benefit over previously reported dithiocarbamate and trithiocarbonate CTAs, this new CTA was employed for the one-pot synthesis of poly(isobutyl vinyl ether)-block-poly(methyl acrylate) diblock copolymers. The prepared CTA-terminated poly(isobutyl vinyl ether) was chain-extended by methyl acrylate via red-light-mediated radical RAFT polymerization, which afforded a diblock copolymer with a dispersity of 1.26, which significantly surpassed the dispersities achieved with analogous trithiocarbonates. The radical polymerization step uses a zinc tetraphenylporphyrin photocatalyst to achieve complete wavelength orthogonality, with a tris(4-methoxyphenyl)pyrylium photocatalyst used for the cationic polymerization step. The optimized electron-rich dithiobenzoate can then be used as a universal agent in the synthesis of advanced copolymers involving radical-cationic RAFT crossover polymerization steps.
{"title":"Synergizing Visible Light-Mediated Cationic and Radical PET RAFT Through Electron-Rich Dithiobenzoates","authors":"Martin Orságh, Ondrej Sedlacek","doi":"10.1021/acs.macromol.4c03060","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03060","url":null,"abstract":"In this work, we developed a novel electron-rich dithiobenzoate chain transfer agent (CTA) with excellent control for both cationic and radical photoelectron/energy transfer-reversible addition–fragmentation chain transfer (PET RAFT) polymerizations. The 2,4-dimethoxydithiobenzoate-based CTA enables the optimized stabilization of chain transfer intermediates, outperforming trithiocarbonates in the control of cationic RAFT polymerizations and dithiocarbamates in radical RAFT polymerizations of more active monomers. The excellent control of cationic PET RAFT polymerization offered by this novel CTA was demonstrated by the blue-light-mediated synthesis of poly(isobutyl vinyl ether) of various chain lengths with sub-1.2 dispersities. Furthermore, to highlight its benefit over previously reported dithiocarbamate and trithiocarbonate CTAs, this new CTA was employed for the one-pot synthesis of poly(isobutyl vinyl ether)-<i>block</i>-poly(methyl acrylate) diblock copolymers. The prepared CTA-terminated poly(isobutyl vinyl ether) was chain-extended by methyl acrylate via red-light-mediated radical RAFT polymerization, which afforded a diblock copolymer with a dispersity of 1.26, which significantly surpassed the dispersities achieved with analogous trithiocarbonates. The radical polymerization step uses a zinc tetraphenylporphyrin photocatalyst to achieve complete wavelength orthogonality, with a tris(4-methoxyphenyl)pyrylium photocatalyst used for the cationic polymerization step. The optimized electron-rich dithiobenzoate can then be used as a universal agent in the synthesis of advanced copolymers involving radical-cationic RAFT crossover polymerization steps.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"208 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393540","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}
Pub Date : 2025-02-12DOI: 10.1021/acs.macromol.4c02956
Mengru Ding, Lingling Ni, Ying Zheng, Bao Wang, Chengtao Yu, Guorong Shan, Yongzhong Bao, Junfeng Liu, Pengju Pan
Long-spaced aliphatic polyesters are typical sustainable polyethylene (PE)-like polymers. However, the presence of a low amount of ester groups can exert a profound effect on the crystalline structure of such PE-like polymers. Herein, we synthesized a series of long-spaced aliphatic polyesters bearing two proximate ester groups from ethylene glycol (EG) and n-methylene diacids (n = 9–18) and investigated their polymorphic crystallization and phase transitions. We find that the EG-based polyesters exhibit unique crystal polymorphism and phase transition behaviors. They can form a metastable hexagonal phase (form II) with nontilted, extended chain conformations at low temperatures or during rapid cooling but adopt the thermally stable orthorhombic phase (form I) with tilted chain packing at high temperatures or under slow cooling. Form I demonstrates a more densely packed chain structure and displays distinct mechanical properties compared to form II. The metastable hexagonal phase can transform into an orthorhombic phase during heating through a melt-recrystallization mechanism. This study advances the current understanding of the multiphase crystallization of PE-like long-spaced polyesters.
{"title":"Hexagonal and Orthorhombic Crystal Formations in Ethylene Glycol-Based Long-Spaced Aliphatic Polyesters Driven by Layer Packing of Proximate Ester Groups","authors":"Mengru Ding, Lingling Ni, Ying Zheng, Bao Wang, Chengtao Yu, Guorong Shan, Yongzhong Bao, Junfeng Liu, Pengju Pan","doi":"10.1021/acs.macromol.4c02956","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02956","url":null,"abstract":"Long-spaced aliphatic polyesters are typical sustainable polyethylene (PE)-like polymers. However, the presence of a low amount of ester groups can exert a profound effect on the crystalline structure of such PE-like polymers. Herein, we synthesized a series of long-spaced aliphatic polyesters bearing two proximate ester groups from ethylene glycol (EG) and <i>n</i>-methylene diacids (<i>n</i> = 9–18) and investigated their polymorphic crystallization and phase transitions. We find that the EG-based polyesters exhibit unique crystal polymorphism and phase transition behaviors. They can form a metastable hexagonal phase (form II) with nontilted, extended chain conformations at low temperatures or during rapid cooling but adopt the thermally stable orthorhombic phase (form I) with tilted chain packing at high temperatures or under slow cooling. Form I demonstrates a more densely packed chain structure and displays distinct mechanical properties compared to form II. The metastable hexagonal phase can transform into an orthorhombic phase during heating through a melt-recrystallization mechanism. This study advances the current understanding of the multiphase crystallization of PE-like long-spaced polyesters.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"129 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393723","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}
Pub Date : 2025-02-10DOI: 10.1021/acs.macromol.4c02670
Zhenjie Yang, Chenyang Hu, Xuan Pang, Liwen Zhang, Ruirui Qiao, Thomas P. Davis, Shunjie Liu, Xianhong Wang, Xuesi Chen
Degradable and self-healing polymers are considered next-generation materials since they can tackle both the end-of-life issues and the long-standing longevity of synthetic materials. Here, we design a series of aliphatic polyester-polycarbonate copolymers combining degradability and self-healability using commodity monomers comprising ε-caprolactone (ε-CL), cyclohexene oxide (CHO), and CO2. These copolymers are synthesized by random copolymerization catalyzed by a dinuclear salen-Mn catalyst under low CO2 pressure, affording randomly distributed carbonate units on a poly(ε-caprolactone) (PCL) chain. High molar mass copolymers with controllable components and microstructures are obtained by regulating the reaction conditions. Different from corresponding triblock copolymers, the random copolymers exhibit autonomous self-healing capability under ambient or even harsh conditions without any external intervention. The outperformance of random copolymers in self-healing is ascribed to the interchain diffusion and reconstruction of nanodomains. This sequence regulation method may serve as a general facile strategy for the design and synthesis of other self-healing copolymers.
{"title":"Sequence Design of Poly(ester-co-carbonate): A Unique Example of Degradable Self-Healing Copolymers","authors":"Zhenjie Yang, Chenyang Hu, Xuan Pang, Liwen Zhang, Ruirui Qiao, Thomas P. Davis, Shunjie Liu, Xianhong Wang, Xuesi Chen","doi":"10.1021/acs.macromol.4c02670","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02670","url":null,"abstract":"Degradable and self-healing polymers are considered next-generation materials since they can tackle both the end-of-life issues and the long-standing longevity of synthetic materials. Here, we design a series of aliphatic polyester-polycarbonate copolymers combining degradability and self-healability using commodity monomers comprising ε-caprolactone (ε-CL), cyclohexene oxide (CHO), and CO<sub>2</sub>. These copolymers are synthesized by random copolymerization catalyzed by a dinuclear salen-Mn catalyst under low CO<sub>2</sub> pressure, affording randomly distributed carbonate units on a poly(ε-caprolactone) (PCL) chain. High molar mass copolymers with controllable components and microstructures are obtained by regulating the reaction conditions. Different from corresponding triblock copolymers, the random copolymers exhibit autonomous self-healing capability under ambient or even harsh conditions without any external intervention. The outperformance of random copolymers in self-healing is ascribed to the interchain diffusion and reconstruction of nanodomains. This sequence regulation method may serve as a general facile strategy for the design and synthesis of other self-healing copolymers.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"25 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143385272","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}
Pub Date : 2025-02-10DOI: 10.1021/acs.macromol.4c03244
Xiaohua Wang, Lishuang Ma, Bo Dong, Chunyu Zhang, Xuequan Zhang, Heng Liu
Axial anagostic bond Mt···H–C can occupy the apical site of d8 square planar metal complexes, which is highly desired, yet never explored, for olefin polymerization because of its capability to suppress associative chain transfer to access high molecular weight polyolefin products. In this research, we present a method for how such axial anagostic interaction Ni···H–C can be constructed into α-diimine NiBr2 complexes, and more importantly, demonstrate its pivotal role in improving the overall ethylene polymerization performance, including (i) ultrahigh efficiency in suppressing associative chain transfer to afford UHMWPEs with Mw up to 724.2 × 104 g/mol, (ii) significantly impeded decomposition of the cationic active species that brings in better storage stability, and (iii) higher branched nature of the PE products that guarantee a well-controlled living fashion for the whole polymerization process even when Mw reaches ultrahigh levels. With the aid of DFT calculations, the nature of such an anagostic bond and its influence on each step of the polymerization process are also elucidated.
{"title":"Axial Anagostic Interaction in α-Diimine Nickel Catalysts: An Ultraefficient Occupation Strategy in Suppressing Associative Chain Transfers to Achieve UHMWPEs","authors":"Xiaohua Wang, Lishuang Ma, Bo Dong, Chunyu Zhang, Xuequan Zhang, Heng Liu","doi":"10.1021/acs.macromol.4c03244","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03244","url":null,"abstract":"Axial anagostic bond Mt···H–C can occupy the apical site of <i>d</i><sup>8</sup> square planar metal complexes, which is highly desired, yet never explored, for olefin polymerization because of its capability to suppress associative chain transfer to access high molecular weight polyolefin products. In this research, we present a method for how such axial anagostic interaction Ni···H–C can be constructed into α-diimine NiBr<sub>2</sub> complexes, and more importantly, demonstrate its pivotal role in improving the overall ethylene polymerization performance, including (i) ultrahigh efficiency in suppressing associative chain transfer to afford UHMWPEs with <i>M</i><sub>w</sub> up to 724.2 × 10<sup>4</sup> g/mol, (ii) significantly impeded decomposition of the cationic active species that brings in better storage stability, and (iii) higher branched nature of the PE products that guarantee a well-controlled living fashion for the whole polymerization process even when <i>M</i><sub>w</sub> reaches ultrahigh levels. With the aid of DFT calculations, the nature of such an anagostic bond and its influence on each step of the polymerization process are also elucidated.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"4 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375804","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}
Pub Date : 2025-02-10DOI: 10.1021/acs.macromol.4c02687
Bocheng Shang, Wei Yu
The transient strain hardening during extension is critical to the industrial processing of polymers. However, the molecular mechanism of strain hardening of linear polymers under fast extension is still controversial. Both extension-enhanced and extension-reduced monomeric frictions have been proposed to explain the experimental observations in different polymers. In this study, we systematically studied the extensional rheology of unentangled azobenzene polymers (Pazo) and their copolymers and revealed the possibility of synergetic contribution of the side-chain self-dilution and π–π stacking to the strain hardening. In the slow flow regime (Rouse Weissenberg number WiR < 0.5), the strain hardening during extension is dominated by extension-enhanced friction due to the side-chain π–π stacking. The importance of side-chain self-dilution grows as WiR increases, and there is a critical side-chain length for the solvation effect to play a role under fast extension (WiR > 0.5). The strain hardening under all extension conditions weakens as the molar fraction of the azobenzene monomer in the copolymer decreases. However, azobenzene content as low as 0.2 in the copolymer is sufficient to generate evident π–π stacking-induced friction enhancement. The in situ wide-angle X-ray scattering (WAXS) experiments reveal a distinct enhancement of π–π stacking in Pazo in the transverse direction of extension due to side-chain flexibility, in contrast to the enhancement in the stretching direction in polymers with short rigid side chains containing benzene rings.
{"title":"Extensional Rheology of Unentangled Azobenzene Polymers: Synergetic Effect of π–π Interactions and Side-Chain Self-Dilution","authors":"Bocheng Shang, Wei Yu","doi":"10.1021/acs.macromol.4c02687","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02687","url":null,"abstract":"The transient strain hardening during extension is critical to the industrial processing of polymers. However, the molecular mechanism of strain hardening of linear polymers under fast extension is still controversial. Both extension-enhanced and extension-reduced monomeric frictions have been proposed to explain the experimental observations in different polymers. In this study, we systematically studied the extensional rheology of unentangled azobenzene polymers (Pazo) and their copolymers and revealed the possibility of synergetic contribution of the side-chain self-dilution and π–π stacking to the strain hardening. In the slow flow regime (Rouse Weissenberg number <i>Wi</i><sub>R</sub> < 0.5), the strain hardening during extension is dominated by extension-enhanced friction due to the side<i>-</i>chain π–π stacking. The importance of side-chain self-dilution grows as <i>Wi</i><sub>R</sub> increases, and there is a critical side-chain length for the solvation effect to play a role under fast extension (<i>Wi</i><sub>R</sub> > 0.5). The strain hardening under all extension conditions weakens as the molar fraction of the azobenzene monomer in the copolymer decreases. However, azobenzene content as low as 0.2 in the copolymer is sufficient to generate evident π–π stacking-induced friction enhancement. The in situ wide-angle X-ray scattering (WAXS) experiments reveal a distinct enhancement of π–π stacking in Pazo in the transverse direction of extension due to side-chain flexibility, in contrast to the enhancement in the stretching direction in polymers with short rigid side chains containing benzene rings.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"62 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375803","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}
Pub Date : 2025-02-09DOI: 10.1021/acs.macromol.4c02829
Bailee N. Barrett, Pedram AziziHariri, Vijay T. John, Donghui Zhang
The micellar aggregation of singly charged sequence-defined ionic peptoid block copolymers can be finely tuned by adjusting the position of the ionizable monomer along the chain and varying the solution pH. The pH-induced structural reorganization of these micelles was found to depend on the position of the ionizable monomer along the chain, influencing the balance of the hydrophobic interactions, excluded volume effect, and electrostatic forces (i.e., charge repulsion, solvation of the ionic monomers, counterion association) that govern the micellar structure. As the solution pH increases, positioning the ionizable monomer closer to the junction of the hydrophobic and hydrophilic blocks causes a larger reduction in the micellar size and aggregation number across two distinct regimes. In contrast, placing the ionizable monomer at the terminus of the hydrophilic block results in a smaller reduction in the micellar size and aggregation number over three regimes. This study provides new insights into leveraging the strategic positioning of ionizable monomers to design stimuli-responsive nanoassemblies capable of programmable structural reorganization.
{"title":"Modulating the Aqueous Micellar Reorganization of Sequence-Defined Ionic Peptoid Block Copolymers by Ionizable Monomer Position and Solution pH","authors":"Bailee N. Barrett, Pedram AziziHariri, Vijay T. John, Donghui Zhang","doi":"10.1021/acs.macromol.4c02829","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02829","url":null,"abstract":"The micellar aggregation of singly charged sequence-defined ionic peptoid block copolymers can be finely tuned by adjusting the position of the ionizable monomer along the chain and varying the solution pH. The pH-induced structural reorganization of these micelles was found to depend on the position of the ionizable monomer along the chain, influencing the balance of the hydrophobic interactions, excluded volume effect, and electrostatic forces (i.e., charge repulsion, solvation of the ionic monomers, counterion association) that govern the micellar structure. As the solution pH increases, positioning the ionizable monomer closer to the junction of the hydrophobic and hydrophilic blocks causes a larger reduction in the micellar size and aggregation number across two distinct regimes. In contrast, placing the ionizable monomer at the terminus of the hydrophilic block results in a smaller reduction in the micellar size and aggregation number over three regimes. This study provides new insights into leveraging the strategic positioning of ionizable monomers to design stimuli-responsive nanoassemblies capable of programmable structural reorganization.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"41 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375805","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}
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