Pub Date : 2025-06-13DOI: 10.1021/acs.macromol.4c03172
Daniel J. Frazier, Daniel M. Knauss
Polymers with amine linkages composed of the halochromic phthalein moiety are prepared from n-octylamine, aniline, 4-hexylaniline, and p-anisidine with a dibromofunctionalized phthalein monomer via Buchwald–Hartwig polyaminations. Characterization with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed excellent thermal stability with onset degradation temperatures in air above 360 °C and high thermal transitions with Tgs up to 256 °C. Treating the polymers with a protic acid converts the nitrogen-linked phthalein structure into a conjugated form through the generation of ions in the backbone, which is supported by ultraviolet–visible (UV–vis) spectra that display evidence of carbocation species and reduced optical energy gaps, with the lowest energy gap observed at 1.45 eV. Cyclic voltammetry (CV) provides estimations of the energy levels for each polymer with deep highest occupied molecular orbital (HOMO) levels ranging from −5.37 to −5.47 eV. Additionally, electron paramagnetic resonance (EPR) spectroscopy detected air-stable unpaired electrons in the protic acid-treated polymers, which suggests resonance between a closed-shell ionic form and an open-shell radical form that is expected to yield intriguing electrical and magnetic properties.
{"title":"Conjugation of Nitrogen-Linked Phthalein Polymers by Forming Ions in the Backbone upon Protic Acid Addition","authors":"Daniel J. Frazier, Daniel M. Knauss","doi":"10.1021/acs.macromol.4c03172","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03172","url":null,"abstract":"Polymers with amine linkages composed of the halochromic phthalein moiety are prepared from <i>n</i>-octylamine, aniline, 4-hexylaniline, and <i>p</i>-anisidine with a dibromofunctionalized phthalein monomer via Buchwald–Hartwig polyaminations. Characterization with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed excellent thermal stability with onset degradation temperatures in air above 360 °C and high thermal transitions with <i>T</i><sub>g</sub>s up to 256 °C. Treating the polymers with a protic acid converts the nitrogen-linked phthalein structure into a conjugated form through the generation of ions in the backbone, which is supported by ultraviolet–visible (UV–vis) spectra that display evidence of carbocation species and reduced optical energy gaps, with the lowest energy gap observed at 1.45 eV. Cyclic voltammetry (CV) provides estimations of the energy levels for each polymer with deep highest occupied molecular orbital (HOMO) levels ranging from −5.37 to −5.47 eV. Additionally, electron paramagnetic resonance (EPR) spectroscopy detected air-stable unpaired electrons in the protic acid-treated polymers, which suggests resonance between a closed-shell ionic form and an open-shell radical form that is expected to yield intriguing electrical and magnetic properties.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"27 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144278629","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}
Creation of two-dimensional (2D) structures with low dispersity, controllable size, and spatially segmented compositions is of vital importance but still remains an enormous challenge. Living seeded heteroepitaxial growth of crystallizable block copolymers enables the formation of uniform 2D platelets with spatially defined and compositionally distinct cores. Therefore, revealing the general requirements such as lattice match criteria for the heteroepitaxial crystallization of one crystallizable polymer from the crystalline seeds of another polymer would lead to an expansion of the scope of the seeded heteroepitaxial growth. Herein, the melt polycondensation method has been utilized to synthesize a range of aliphatic polyesters that exhibit variable crystallographic data compared to a well-known polymer poly(ε-caprolactone) (PCL). The polyesters have been categorized into three groups that exhibit different lattice mismatches of d-spacing between two molecular stems for the contacted crystalline planes. Seeded growth experiments between two crystallizable polymers in different groups and crystallographic data analysis have confirmed that the distance between two neighboring stems of exposed crystal facets should be met for that of deposited crystals, which is due to a strong crystallographic interaction at the unit-cell level. Moreover, crystallization kinetics such as crystallization temperatures and polymer solubility are sufficient conditions for the occurrence of heteroepitaxial growth when the polymer pair meets the lattice match criteria. Therefore, detailed analysis of crystallographic data of the unit cell of each polymer would mostly predict the happening of heteroepitaxial crystallization of each crystallizable pair. On the basis of the result, we are able to predict the possibility of successful seeded heteroepitaxial growth between two polymers from the crystallographic data. This in-depth understanding of seeded heteroepitaxial growth from the crystallization perspective will further assist us in designing a wide range of 2D segmented polymer nanomaterials where the distinct core compositions and variable functionalities are spatially defined.
{"title":"Fundamental Understanding of the Seeded Heteroepitaxial Growth of Crystallizable Polymers from Crystallographic Data","authors":"Liping Liu, Bowen Zheng, Deyu Ma, Shichang Chen, Zaizai Tong","doi":"10.1021/acs.macromol.5c00759","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00759","url":null,"abstract":"Creation of two-dimensional (2D) structures with low dispersity, controllable size, and spatially segmented compositions is of vital importance but still remains an enormous challenge. Living seeded heteroepitaxial growth of crystallizable block copolymers enables the formation of uniform 2D platelets with spatially defined and compositionally distinct cores. Therefore, revealing the general requirements such as lattice match criteria for the heteroepitaxial crystallization of one crystallizable polymer from the crystalline seeds of another polymer would lead to an expansion of the scope of the seeded heteroepitaxial growth. Herein, the melt polycondensation method has been utilized to synthesize a range of aliphatic polyesters that exhibit variable crystallographic data compared to a well-known polymer poly(ε-caprolactone) (PCL). The polyesters have been categorized into three groups that exhibit different lattice mismatches of d-spacing between two molecular stems for the contacted crystalline planes. Seeded growth experiments between two crystallizable polymers in different groups and crystallographic data analysis have confirmed that the distance between two neighboring stems of exposed crystal facets should be met for that of deposited crystals, which is due to a strong crystallographic interaction at the unit-cell level. Moreover, crystallization kinetics such as crystallization temperatures and polymer solubility are sufficient conditions for the occurrence of heteroepitaxial growth when the polymer pair meets the lattice match criteria. Therefore, detailed analysis of crystallographic data of the unit cell of each polymer would mostly predict the happening of heteroepitaxial crystallization of each crystallizable pair. On the basis of the result, we are able to predict the possibility of successful seeded heteroepitaxial growth between two polymers from the crystallographic data. This in-depth understanding of seeded heteroepitaxial growth from the crystallization perspective will further assist us in designing a wide range of 2D segmented polymer nanomaterials where the distinct core compositions and variable functionalities are spatially defined.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"223 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144278632","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 : 2025-06-12DOI: 10.1021/acs.macromol.5c00983
Ji-Yuan Xing, Sheng Li, Bo Liu, Hong Liu, You-Liang Zhu
Polymerization-induced self-assembly (PISA) offers a versatile platform for designing polymeric nanoparticles. Amphiphilic gradient copolymers, characterized by a gradual transition from hydrophilic to hydrophobic segments, exhibit reduced interfacial tension and enhanced stimulus responsiveness. However, the interplay between polymerization and self-assembly in PISA, influenced by the monomer feed ratio and reactivity, remains ambiguous. Herein, we employ coarse-grained simulations to investigate the role of the effective polymerization bias between monomers. Our results reveal that the relative monomer reactivity plays a key role in determining both the copolymer sequence and the vesicle formation pathway. At low reactivity differences, comparable monomer reactivities facilitate a cooperative polymerization-assembly process that produces numerous small spherical assemblies, which subsequently merge and reorganize into vesicles. In contrast, high reactivity asymmetry favors the formation of anisotropic worm-like micelles that progressively fuse, bend, and enclose into vesicular structures. Microstructural analysis further shows that gradient copolymer vesicles possess internal cavities larger than those formed from block copolymers. These insights provide guidance for tailoring vesicle formation pathways and fine-tuning microstructures for potential applications in drug delivery and materials science.
{"title":"Polymerization-Induced Self-Assembly for Modulating Assembly Pathways and Microstructures of Amphiphilic Gradient Copolymer Nanoparticles","authors":"Ji-Yuan Xing, Sheng Li, Bo Liu, Hong Liu, You-Liang Zhu","doi":"10.1021/acs.macromol.5c00983","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00983","url":null,"abstract":"Polymerization-induced self-assembly (PISA) offers a versatile platform for designing polymeric nanoparticles. Amphiphilic gradient copolymers, characterized by a gradual transition from hydrophilic to hydrophobic segments, exhibit reduced interfacial tension and enhanced stimulus responsiveness. However, the interplay between polymerization and self-assembly in PISA, influenced by the monomer feed ratio and reactivity, remains ambiguous. Herein, we employ coarse-grained simulations to investigate the role of the effective polymerization bias between monomers. Our results reveal that the relative monomer reactivity plays a key role in determining both the copolymer sequence and the vesicle formation pathway. At low reactivity differences, comparable monomer reactivities facilitate a cooperative polymerization-assembly process that produces numerous small spherical assemblies, which subsequently merge and reorganize into vesicles. In contrast, high reactivity asymmetry favors the formation of anisotropic worm-like micelles that progressively fuse, bend, and enclose into vesicular structures. Microstructural analysis further shows that gradient copolymer vesicles possess internal cavities larger than those formed from block copolymers. These insights provide guidance for tailoring vesicle formation pathways and fine-tuning microstructures for potential applications in drug delivery and materials science.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"58 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144269436","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 : 2025-06-12DOI: 10.1021/acs.macromol.5c00323
Robert J. S. Ivancic, Chase B. Thompson, Devin A. Golla, Bintou Koroma, Jack F. Douglas, Sara V. Orski, Debra J. Audus
Branch density and length substantially impact the properties of comb-like polymers. Scientists often use the dilute solution properties of these materials to quantify their architecture. As branch spacing decreases and branch length increases at a fixed molecular mass, dilute solution properties such as the radius of gyration, intrinsic viscosity, and hydrodynamic radius typically decrease because the length of the backbone decreases. However, this decrease is only partially driven by this change in backbone length, even for relatively short branches. While many models focus on predicting the dilute solution properties of these materials with fixed branch spacing, most comb-like polymers exhibit statistical branch spacing which leads to nontrivial changes in excluded volume effects. Using molecular dynamics simulations and the ZENO code, we show how changing the distribution of branches from fixed to statistical and then to diblock affects the dilute solution properties of a coarse-grained linear low-density polyethylene (LLDPE), a canonical comb-like polymer, in 1,2,4-trichlorobenzene, a standard good solvent. This approach explicitly accounts for excluded volume interactions that were not included in prior theories. We extend our previous theoretical work to account for statistical branch spacing and test prior renormalization group estimates of diblocks in good solvent to show that it is consistent with our numerical results. Our approach provides a framework for a more quantitative understanding of chain architecture from dilute solution properties, yielding better structure–property relationships.
{"title":"The Importance of Branch Placement on the Dilute Solution Properties of Comb-like Macromolecules","authors":"Robert J. S. Ivancic, Chase B. Thompson, Devin A. Golla, Bintou Koroma, Jack F. Douglas, Sara V. Orski, Debra J. Audus","doi":"10.1021/acs.macromol.5c00323","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00323","url":null,"abstract":"Branch density and length substantially impact the properties of comb-like polymers. Scientists often use the dilute solution properties of these materials to quantify their architecture. As branch spacing decreases and branch length increases at a fixed molecular mass, dilute solution properties such as the radius of gyration, intrinsic viscosity, and hydrodynamic radius typically decrease because the length of the backbone decreases. However, this decrease is only partially driven by this change in backbone length, even for relatively short branches. While many models focus on predicting the dilute solution properties of these materials with fixed branch spacing, most comb-like polymers exhibit statistical branch spacing which leads to nontrivial changes in excluded volume effects. Using molecular dynamics simulations and the ZENO code, we show how changing the distribution of branches from fixed to statistical and then to diblock affects the dilute solution properties of a coarse-grained linear low-density polyethylene (LLDPE), a canonical comb-like polymer, in 1,2,4-trichlorobenzene, a standard good solvent. This approach explicitly accounts for excluded volume interactions that were not included in prior theories. We extend our previous theoretical work to account for statistical branch spacing and test prior renormalization group estimates of diblocks in good solvent to show that it is consistent with our numerical results. Our approach provides a framework for a more quantitative understanding of chain architecture from dilute solution properties, yielding better structure–property relationships.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"12 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144278630","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 : 2025-06-11DOI: 10.1021/acs.macromol.5c00004
Tzu-Ling Ma, Wei-Ting Du, Yang-Chin Kao, Mohamed Gamal Mohamed, Shiao-Wei Kuo
The miscibility behavior of polymer blends has garnered significant interest; however, while most binary polymer blends are immiscible due to thermodynamic challenges, reaction-induced miscibility (RIM) presents a promising yet underexplored phenomenon for achieving homogeneous mixtures through specific intermolecular hydrogen bonding interactions. This study investigates the design and synthesis of novel styrene- and benzoxazine-based copolymers to achieve RIM behavior with a poly(vinylpyrrolidone) (PVP) homopolymer. Two benzoxazine monomers, HPMI-BZ and Ty-BZ, were synthesized via Mannich condensation, incorporating maleimide groups to enable free radical copolymerization with styrene monomer to form PS-alt-P(HPMI-BZ) and PS-alt-P(Ty-BZ) alternating copolymers, which were characterized using Fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The thermal and miscibility behaviors of the PS-alt-P(HPMI-BZ)/PVP and PS-alt-P(Ty-BZ)/PVP binary blends were analyzed, focusing on their intermolecular hydrogen bonding after thermal ring-opening polymerization (ROP). Results demonstrated that the incorporation of functional groups such as OH units from benzoxazine units through thermal ROP facilitated strong intermolecular interactions with the C═O units of PVP, enabling RIM in otherwise immiscible blends. This work highlights the interplay between molecular structure, thermal stability, and miscibility behavior, offering insights into the development of next-generation thermoset/thermoplastic materials with tailored properties.
{"title":"Reaction-Induced Miscibility in Styrene- and Benzoxazine-Based Copolymers with Poly(vinylpyrrolidone) Blends Through Strong Intermolecular Hydrogen-Bonding Interactions","authors":"Tzu-Ling Ma, Wei-Ting Du, Yang-Chin Kao, Mohamed Gamal Mohamed, Shiao-Wei Kuo","doi":"10.1021/acs.macromol.5c00004","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00004","url":null,"abstract":"The miscibility behavior of polymer blends has garnered significant interest; however, while most binary polymer blends are immiscible due to thermodynamic challenges, reaction-induced miscibility (RIM) presents a promising yet underexplored phenomenon for achieving homogeneous mixtures through specific intermolecular hydrogen bonding interactions. This study investigates the design and synthesis of novel styrene- and benzoxazine-based copolymers to achieve RIM behavior with a poly(vinylpyrrolidone) (PVP) homopolymer. Two benzoxazine monomers, HPMI-BZ and Ty-BZ, were synthesized via Mannich condensation, incorporating maleimide groups to enable free radical copolymerization with styrene monomer to form PS-<i>alt</i>-P(HPMI-BZ) and PS-<i>alt</i>-P(Ty-BZ) alternating copolymers, which were characterized using Fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The thermal and miscibility behaviors of the PS-<i>alt</i>-P(HPMI-BZ)/PVP and PS-<i>alt</i>-P(Ty-BZ)/PVP binary blends were analyzed, focusing on their intermolecular hydrogen bonding after thermal ring-opening polymerization (ROP). Results demonstrated that the incorporation of functional groups such as OH units from benzoxazine units through thermal ROP facilitated strong intermolecular interactions with the C═O units of PVP, enabling RIM in otherwise immiscible blends. This work highlights the interplay between molecular structure, thermal stability, and miscibility behavior, offering insights into the development of next-generation thermoset/thermoplastic materials with tailored properties.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"150 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268794","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 : 2025-06-11DOI: 10.1021/acs.macromol.5c00952
Arman Moini Jazani, Kriti Kapil, Hironobu Murata, Mozhdeh Madadi, Julian Sobieski, Piotr Mocny, Khidong Kim, Roberto R. Gil, Krzysztof Matyjaszewski
Poly(methacrylic acid) (PMAA) and poly(acrylic acid) (PAA) are synthesized on a large scale by conventional free radical polymerization (FRP). The access to architectural diversity by FRP is limited but can be addressed by reversible deactivation radical polymerization (RDRP), including atom transfer radical polymerization (ATRP). ATRP of methacrylic acid (MAA) and acrylic acid (AA) is challenging due to lactonization via the displacement of halide (X) end groups by penultimate carboxylate anions (CO2–) and the loss of chain-end functionality. Despite the successful polymerization of MAA or AA ((M)AA) using various RDRP methods, the oxygen-tolerant photo-ATRP of (M)AA has not yet been investigated. Herein, photo-ATRP of (M)AA in open vials was enabled by adding sodium pyruvate (SP) or pyruvic acid (PA) to the polymerization mixture. Photoirradiation of SP/PA generated radicals and enhanced the rate of polymerization at ambient temperature, which diminished lactonization reactions. This method allowed the synthesis of PMAA or PAA (P(M)AA) at low pH (1 to 3.2) with relatively low dispersity (Đ = 1.10–1.38 under optimized conditions) and good agreement between the theoretical molecular weight (Mn,theo) and the absolute molecular weight (Mn,abs). Photo-ATRP allowed the synthesis of PMAA in ≤1 h and also the synthesis of branched PAA by copolymerization with α-haloacrylic acids. Additionally, successful grafting of MAA from poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-co-CTFE) was achieved in dispersed aqueous media.
{"title":"Open-Vessel and Scalable Synthesis of Linear and Branched Poly(meth)acrylic Acid via Light-Mediated Atom Transfer Radical Polymerization in Water","authors":"Arman Moini Jazani, Kriti Kapil, Hironobu Murata, Mozhdeh Madadi, Julian Sobieski, Piotr Mocny, Khidong Kim, Roberto R. Gil, Krzysztof Matyjaszewski","doi":"10.1021/acs.macromol.5c00952","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00952","url":null,"abstract":"Poly(methacrylic acid) (PMAA) and poly(acrylic acid) (PAA) are synthesized on a large scale by conventional free radical polymerization (FRP). The access to architectural diversity by FRP is limited but can be addressed by reversible deactivation radical polymerization (RDRP), including atom transfer radical polymerization (ATRP). ATRP of methacrylic acid (MAA) and acrylic acid (AA) is challenging due to lactonization via the displacement of halide (<i>X</i>) end groups by penultimate carboxylate anions (CO<sub>2</sub><sup>–</sup>) and the loss of chain-end functionality. Despite the successful polymerization of MAA or AA ((M)AA) using various RDRP methods, the oxygen-tolerant photo-ATRP of (M)AA has not yet been investigated. Herein, photo-ATRP of (M)AA in open vials was enabled by adding sodium pyruvate (SP) or pyruvic acid (PA) to the polymerization mixture. Photoirradiation of SP/PA generated radicals and enhanced the rate of polymerization at ambient temperature, which diminished lactonization reactions. This method allowed the synthesis of PMAA or PAA (P(M)AA) at low pH (1 to 3.2) with relatively low dispersity (<i>Đ</i> = 1.10–1.38 under optimized conditions) and good agreement between the theoretical molecular weight (<i>M</i><sub>n,theo</sub>) and the absolute molecular weight (<i>M</i><sub>n,abs</sub>). Photo-ATRP allowed the synthesis of PMAA in ≤1 h and also the synthesis of branched PAA by copolymerization with α-haloacrylic acids. Additionally, successful grafting of MAA from poly(vinylidene fluoride-<i>co</i>-chlorotrifluoroethylene) (PVDF-<i>co</i>-CTFE) was achieved in dispersed aqueous media.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"587 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268850","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}
We directly observe surface freezing in 90–95% regioregular poly(3-alkylthiophene)s (P3ATs) of different molecular weights and side-chain lengths, i.e., a free surface-induced crystallization event occurs at temperatures 25–50 °C above bulk crystallization. For all studied P3ATs, surface freezing involves the development of highly edge-on oriented crystallites within 20 nm of the air–polymer interface; however, nucleation and growth of 2D spherulites (“circulites”) during surface freezing can be optically resolved only in P3ATs with relatively low circulite nucleation densities. For poly(3-hexylthiophene) (P3HT), molecular weight and regioregularity impact circulite nucleation density as well as surface and bulk crystallization kinetics. Both free surface and bulk crystallization temperatures are nearly insensitive to molecular weight for 95% regioregular P3HT but strongly decrease with increasing chain length for 90% regioregular P3HT. Overall, the results indicate that surface freezing and high edge-on orientation at the free surface are general phenomena in P3ATs, but circulites are not always observable.
{"title":"Generalization of Surface Freezing in P3AT Thin Films","authors":"Jesse Kuebler, Sunil Dhapola, Trygve Santelman, Lucia Fernandez-Ballester","doi":"10.1021/acs.macromol.5c00384","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00384","url":null,"abstract":"We directly observe surface freezing in 90–95% regioregular poly(3-alkylthiophene)s (P3ATs) of different molecular weights and side-chain lengths, i.e., a free surface-induced crystallization event occurs at temperatures 25–50 °C above bulk crystallization. For all studied P3ATs, surface freezing involves the development of highly edge-on oriented crystallites within 20 nm of the air–polymer interface; however, nucleation and growth of 2D spherulites (“circulites”) during surface freezing can be optically resolved only in P3ATs with relatively low circulite nucleation densities. For poly(3-hexylthiophene) (P3HT), molecular weight and regioregularity impact circulite nucleation density as well as surface and bulk crystallization kinetics. Both free surface and bulk crystallization temperatures are nearly insensitive to molecular weight for 95% regioregular P3HT but strongly decrease with increasing chain length for 90% regioregular P3HT. Overall, the results indicate that surface freezing and high edge-on orientation at the free surface are general phenomena in P3ATs, but circulites are not always observable.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"37 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144269410","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 : 2025-06-11DOI: 10.1021/acs.macromol.5c00723
Saquib Farooq, Miroslava Nedyalkova, Subhajit Pal, Aurelien Crochet, Marco Lattuada, Andreas F. M. Kilbinger
We present a next-generation helical polyamide synthesized from 5-amino-2,4-difluorobenzoic acid. Polymerization, driven by chloro-tritolylphosphonium iodide (PHOS3), achieved precise molecular weight control and narrow dispersity. Introducing (R) and (S) chiral initiators successfully induced well-defined helical structures, as confirmed by distinct Cotton effects with opposing signs. Molecular dynamics simulations provided deeper insight into the self-assembly process of two helices adopting opposite helicities (P and M). Notably, S–M helices formed compact, highly cohesive, noncovalent stacks, demonstrating packing efficiency over their S–P counterparts. These findings enhance our understanding of polymer chirality, molecular organization, and self-assembly, paving the way for the rational design of advanced helical materials with promising applications in materials science.
{"title":"Fluorinated Aromatic Amide Helices: Synthesis and Modeling of Helical Handedness","authors":"Saquib Farooq, Miroslava Nedyalkova, Subhajit Pal, Aurelien Crochet, Marco Lattuada, Andreas F. M. Kilbinger","doi":"10.1021/acs.macromol.5c00723","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00723","url":null,"abstract":"We present a next-generation helical polyamide synthesized from 5-amino-2,4-difluorobenzoic acid. Polymerization, driven by chloro-tritolylphosphonium iodide (PHOS3), achieved precise molecular weight control and narrow dispersity. Introducing (R) and (S) chiral initiators successfully induced well-defined helical structures, as confirmed by distinct Cotton effects with opposing signs. Molecular dynamics simulations provided deeper insight into the self-assembly process of two helices adopting opposite helicities (P and M). Notably, S–M helices formed compact, highly cohesive, noncovalent stacks, demonstrating packing efficiency over their S–P counterparts. These findings enhance our understanding of polymer chirality, molecular organization, and self-assembly, paving the way for the rational design of advanced helical materials with promising applications in materials science.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"26 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268849","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 : 2025-06-10DOI: 10.1021/acs.macromol.5c00716
Jiayao Yang, Jialin Zhao, Na Li, Shiyao Sun, Yijia Lei, Jingyi Wu, Xihao Lin, Zhe Wang
The practical application of anion exchange membranes (AEMs) in alkaline fuel cells is often constrained by a trade-off between dimensional stability and ionic conductivity. To address this challenge, we drew inspiration from the nutrient transport system of Victoria lily and mimicked its hierarchical transport architecture. By introducing a microphase-separated morphology into the membrane, we established an efficient ion transport network that facilitates rapid hydroxide (OH–) conduction. A novel hydrophilic–hydrophobic block copolymer incorporating the branched monomer 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) was synthesized to fabricate advanced AEMs. The integration of robust CBP units not only enhanced the membrane’s dimensional stability but also altered polymer chain packing, thereby enlarging the ion-conducting channels. As a result, the membrane exhibited a high ionic conductivity (up to 179.9 mS cm–1 at 80 °C) and excellent dimensional stability (swelling ratio of 24.4%). Furthermore, it demonstrated outstanding chemical stability, retaining over 90% of its conductivity after 1500 h in 5 M NaOH at 80 °C. To demonstrate practical applicability, the AEM was integrated into membrane-electrode assemblies (MEAs), and fuel cell performance was evaluated. The results showed excellent and stable output, achieving a peak power density of 947 mW cm–2.
阴离子交换膜（AEMs）在碱性燃料电池中的实际应用经常受到尺寸稳定性和离子电导率之间权衡的限制。为了应对这一挑战，我们从百合的营养运输系统中汲取灵感，并模仿其分层运输结构。通过在膜中引入微相分离的形态，我们建立了一个高效的离子传输网络，促进了氢氧化物（OH -）的快速传导。采用支链单体4,4′-双（n -咔唑基）-1,1′-联苯（CBP）合成了一种新型亲疏水嵌段共聚物，用于制备先进的AEMs。强大的CBP单元的集成不仅提高了膜的尺寸稳定性，而且改变了聚合物链的填料，从而扩大了离子传导通道。结果表明，该膜具有较高的离子电导率（80℃时可达179.9 mS cm-1）和优良的尺寸稳定性（溶胀率为24.4%）。此外，它还表现出了出色的化学稳定性，在80°C的5 M NaOH中浸泡1500 h后，其导电性仍保持在90%以上。为了证明AEM的实用性，我们将其集成到膜电极组件（MEAs）中，并对燃料电池的性能进行了评估。结果表明，输出性能优异，稳定，峰值功率密度为947 mW cm-2。
{"title":"Branched Poly(aryl piperidinium) Anion Exchange Membranes with Microphase Separation for Fuel Cells","authors":"Jiayao Yang, Jialin Zhao, Na Li, Shiyao Sun, Yijia Lei, Jingyi Wu, Xihao Lin, Zhe Wang","doi":"10.1021/acs.macromol.5c00716","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00716","url":null,"abstract":"The practical application of anion exchange membranes (AEMs) in alkaline fuel cells is often constrained by a trade-off between dimensional stability and ionic conductivity. To address this challenge, we drew inspiration from the nutrient transport system of Victoria lily and mimicked its hierarchical transport architecture. By introducing a microphase-separated morphology into the membrane, we established an efficient ion transport network that facilitates rapid hydroxide (OH<sup>–</sup>) conduction. A novel hydrophilic–hydrophobic block copolymer incorporating the branched monomer 4,4′-bis(<i>N</i>-carbazolyl)-1,1′-biphenyl (CBP) was synthesized to fabricate advanced AEMs. The integration of robust CBP units not only enhanced the membrane’s dimensional stability but also altered polymer chain packing, thereby enlarging the ion-conducting channels. As a result, the membrane exhibited a high ionic conductivity (up to 179.9 mS cm<sup>–1</sup> at 80 °C) and excellent dimensional stability (swelling ratio of 24.4%). Furthermore, it demonstrated outstanding chemical stability, retaining over 90% of its conductivity after 1500 h in 5 M NaOH at 80 °C. To demonstrate practical applicability, the AEM was integrated into membrane-electrode assemblies (MEAs), and fuel cell performance was evaluated. The results showed excellent and stable output, achieving a peak power density of 947 mW cm<sup>–2</sup>.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"23 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268798","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 : 2025-06-10DOI: 10.1021/acs.macromol.5c00475
Yuichi Masubuchi
This study investigated the fracture of star polymer networks made from pre-polymers with various arm molecular weights in the range, 2 ≤ Na ≤ 20, for node functionalities 3 ≤ f ≤ 8 and conversion ratios 0.6 ≤ φc ≤ 0.95 by phantom chain simulations. The networks were created via end-linking reactions of star polymers dispersed in a simulation box with a fixed monomer density ρ = 8. The resultant networks were alternatively subjected to energy minimization and uniaxial stretch until the break. The stretch at the break, λb, depended on the strand molecular weight Ns = 2Na + 1 with a power-law manner described as λb ∼ Ns0.67, consistent with the experiment. However, the strand length before stretch is proportional to Ns0.5, which does not explain the observed Ns-dependence of λb. The analysis based on the non-affine deformation theory does not interpret the phenomenon either. Instead, the increase of normalized pre-polymer concentration concerning the overlapping concentration with increasing Ns explains the result through a rise in the fraction of broken strands.
{"title":"Phantom Chain Simulations for the Fracture of Star Polymer Networks on the Effect of Arm Molecular Weight","authors":"Yuichi Masubuchi","doi":"10.1021/acs.macromol.5c00475","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00475","url":null,"abstract":"This study investigated the fracture of star polymer networks made from pre-polymers with various arm molecular weights in the range, 2 ≤ <i>N</i><sub><i>a</i></sub> ≤ 20, for node functionalities 3 ≤ <i>f</i> ≤ 8 and conversion ratios 0.6 ≤ φ<sub><i>c</i></sub> ≤ 0.95 by phantom chain simulations. The networks were created via end-linking reactions of star polymers dispersed in a simulation box with a fixed monomer density ρ = 8. The resultant networks were alternatively subjected to energy minimization and uniaxial stretch until the break. The stretch at the break, λ<sub><i>b</i></sub>, depended on the strand molecular weight <i>N</i><sub><i>s</i></sub> = 2<i>N</i><sub><i>a</i></sub> + 1 with a power-law manner described as λ<sub><i>b</i></sub> ∼ <i>N</i><sub><i>s</i></sub><sup>0.67</sup>, consistent with the experiment. However, the strand length before stretch is proportional to <i>N</i><sub><i>s</i></sub><sup>0.5</sup>, which does not explain the observed <i>N</i><sub><i>s</i></sub>-dependence of λ<sub><i>b</i></sub>. The analysis based on the non-affine deformation theory does not interpret the phenomenon either. Instead, the increase of normalized pre-polymer concentration concerning the overlapping concentration with increasing <i>N</i><sub><i>s</i></sub> explains the result through a rise in the fraction of broken strands.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"70 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268808","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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