Pub Date : 2026-03-05DOI: 10.1021/acs.macromol.5c03356
Taofeek Tejuosho, Janani Sampath
This study employs nonequilibrium molecular dynamics (NEMD) simulations to investigate the elongational-flow behavior of model polymer melts with varying dispersity. We examine how chain-length heterogeneity influences the nonlinear response of polymer melts and establish connections among macroscopic stress, chain-conformation evolution, and entanglement dynamics. At low strain rates, strain hardening becomes stronger as dispersity increases. However, at high strain rates, this trend reverses: the initial strain hardening weakens with increasing dispersity, with monodisperse melts exhibiting a more pronounced steady-state stress, while disperse melts continue to build stress at large strains. To probe the molecular origins of these behaviors, we follow the flow response of chains of two lengths (N = 360 and 500) embedded in melts of different dispersities and compare them with the monodisperse counterparts up to a Hencky strain ε ≥ 6. Chain conformations reveal significant stretching under flow, while the progressive loss of entanglements reflects tube elongation and thinning. Dispersity modulates both stretching and disentanglement with pronounced effects for longer and tightly entangled test chains. We interpret these results using two theoretical frameworks: the Rolie-Double-Poly model and an entropic elasticity model that explicitly incorporates chain-specific entanglement evolution. The entropic model provides accurate predictions across all strain rates and dispersities studied. Overall, our findings demonstrate that dispersity plays a central role in dictating the far-from-equilibrium response of moderately entangled polymer melts, with the direction and magnitude of strain hardening determined by the interplay between deformation-driven chain stretching and the rate at which entanglements are lost under flow.
{"title":"Effect of Dispersity on the Behavior of Entangled Polymer Melts under Extensional Flow: Insights from Nonequilibrium Molecular Dynamics Simulations","authors":"Taofeek Tejuosho, Janani Sampath","doi":"10.1021/acs.macromol.5c03356","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03356","url":null,"abstract":"This study employs nonequilibrium molecular dynamics (NEMD) simulations to investigate the elongational-flow behavior of model polymer melts with varying dispersity. We examine how chain-length heterogeneity influences the nonlinear response of polymer melts and establish connections among macroscopic stress, chain-conformation evolution, and entanglement dynamics. At low strain rates, strain hardening becomes stronger as dispersity increases. However, at high strain rates, this trend reverses: the initial strain hardening weakens with increasing dispersity, with monodisperse melts exhibiting a more pronounced steady-state stress, while disperse melts continue to build stress at large strains. To probe the molecular origins of these behaviors, we follow the flow response of chains of two lengths (<i>N</i> = 360 and 500) embedded in melts of different dispersities and compare them with the monodisperse counterparts up to a Hencky strain ε ≥ 6. Chain conformations reveal significant stretching under flow, while the progressive loss of entanglements reflects tube elongation and thinning. Dispersity modulates both stretching and disentanglement with pronounced effects for longer and tightly entangled test chains. We interpret these results using two theoretical frameworks: the Rolie-Double-Poly model and an entropic elasticity model that explicitly incorporates chain-specific entanglement evolution. The entropic model provides accurate predictions across all strain rates and dispersities studied. Overall, our findings demonstrate that dispersity plays a central role in dictating the far-from-equilibrium response of moderately entangled polymer melts, with the direction and magnitude of strain hardening determined by the interplay between deformation-driven chain stretching and the rate at which entanglements are lost under flow.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"74 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147359968","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 : 2026-03-04DOI: 10.1021/acs.macromol.5c03322
Yucheng He,Yihang Wang,Shuxian Liu,Yang Wang,Hao Li,Zhenyang Luo,Ye Sha,Ye Liu,Shaochuan Luo
Primary crystal nucleation is pivotal in polymer crystallization, dictating the semicrystalline morphology. Yet, the impact of sequence irregularities in random copolymers on this initial step is not fully understood due to challenges in probing nanoscale, transient nucleation events. Utilizing fast-scanning calorimetry (FSC) and polarized optical microscopy (POM), we probed how sequence-length distribution affects the thermodynamic barrier to primary crystal nucleation kinetics and nucleation density in cocrystallizable poly[(S)-3-hydroxybutyrate-co-(S)-3-hydroxyvalerate] (PHBV) random copolymers with about 14–25 mol % 3HV counits. Thermal analysis reveals that 3HV counits partially incorporate as defects into the 3HB crystal lattice (average defect free energy ≈ 2.08 kJ·mol–1). Kinetic analysis further demonstrates that the nucleation rate at higher incorporation of 3HV counits is governed by the competition between this heightened thermodynamic penalty and reduced diffusion constraints from the low glass transition temperature. The switch in nucleation kinetics from short-range diffusion-dominated to thermodynamically controlled behavior with increasing temperature, leads to a notable reduction in the b-axis lattice parameter. Meanwhile, the increasing 3HV counit incorporation expands the crystal lattice, elevates the thermodynamic free energy barrier to nucleation (ΔG*), and enlarges the requisite critical nucleus size (r*). Consequently, temperature-dependent spherulite density observations confirm a sequence-length selection mechanism: only sequences exceeding the critical length can nucleate, with the population of such effective sequences directly determining the final nucleation density. These results connect molecular-scale sequence-length distribution with nanoscale early-stage nucleation, offering mechanistic insight into random copolymer crystallization.
{"title":"Role of Sequence-Length Distribution in Primary Crystal Nucleation of Poly[(S)-3-hydroxybutyrate-co-(S)-3-hydroxyvalerate)] Random Copolymers","authors":"Yucheng He,Yihang Wang,Shuxian Liu,Yang Wang,Hao Li,Zhenyang Luo,Ye Sha,Ye Liu,Shaochuan Luo","doi":"10.1021/acs.macromol.5c03322","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03322","url":null,"abstract":"Primary crystal nucleation is pivotal in polymer crystallization, dictating the semicrystalline morphology. Yet, the impact of sequence irregularities in random copolymers on this initial step is not fully understood due to challenges in probing nanoscale, transient nucleation events. Utilizing fast-scanning calorimetry (FSC) and polarized optical microscopy (POM), we probed how sequence-length distribution affects the thermodynamic barrier to primary crystal nucleation kinetics and nucleation density in cocrystallizable poly[(S)-3-hydroxybutyrate-co-(S)-3-hydroxyvalerate] (PHBV) random copolymers with about 14–25 mol % 3HV counits. Thermal analysis reveals that 3HV counits partially incorporate as defects into the 3HB crystal lattice (average defect free energy ≈ 2.08 kJ·mol–1). Kinetic analysis further demonstrates that the nucleation rate at higher incorporation of 3HV counits is governed by the competition between this heightened thermodynamic penalty and reduced diffusion constraints from the low glass transition temperature. The switch in nucleation kinetics from short-range diffusion-dominated to thermodynamically controlled behavior with increasing temperature, leads to a notable reduction in the b-axis lattice parameter. Meanwhile, the increasing 3HV counit incorporation expands the crystal lattice, elevates the thermodynamic free energy barrier to nucleation (ΔG*), and enlarges the requisite critical nucleus size (r*). Consequently, temperature-dependent spherulite density observations confirm a sequence-length selection mechanism: only sequences exceeding the critical length can nucleate, with the population of such effective sequences directly determining the final nucleation density. These results connect molecular-scale sequence-length distribution with nanoscale early-stage nucleation, offering mechanistic insight into random copolymer crystallization.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"91 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147346706","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}
To address the challenge of simultaneously enhancing the mechanical properties of addition-type liquid silicone rubber (ALSR) while maintaining excellent optical transparency, we report the design and synthesis of a novel liquid vinyl-functionalized POSS (Vi-POSS) via the Piers-Rubinsztajn reaction between SiH-containing Q-type POSS (H-POSS) and a heterofunctional oligosiloxane. This strategy enables precise modulation of cross-linking networks while improving filler–matrix compatibility through covalent bonding. The molecular structure of Vi-POSS was confirmed by 1H/29Si NMR and FT-IR spectroscopy, revealing complete vinyl functionalization. A series of ALSRs were prepared using Vi-POSS as both reinforcing filler and cross-linker. Systematic investigations demonstrated that optimal incorporation of 4 wt % Vi-POSS yielded exceptional thermomechanical performance: a 641% increase in tensile strength (2.52 MPa) and 322% enhancement in elongation at break (243.15%) compared to pristine ALSR, while maintaining 90% UV–vis transmittance across the visible spectrum. Thermal stability analysis revealed that with the incorporation of 6 wt % Vi-POSS, compared with the pristine ALSR, the initial decomposition temperature (T10%) and maximum degradation temperature (Tmax) increased by 20 and 12 °C, respectively. Additionally, the char residue at 800 °C was enhanced. Microstructural characterization via SEM confirmed the homogeneous dispersion of Vi-POSS without microphase separation, indicating an excellent interfacial compatibility and superior dispersion of Vi-POSS in the ALSR matrix. This work presents a paradigm shift in the design of transparent high-performance ALSR by integrating molecular-level structure control with nanoscale dispersion optimization. The demonstrated balance of mechanical robustness, thermal stability, and optical clarity positions these materials as promising candidates for advanced applications in flexible optoelectronics, transparent electronics, and biomedical devices requiring simultaneous load-bearing and optical functionality.
{"title":"Molecular Engineering of Heterofunctional-Oligosiloxane-Modified Vi-POSS via Piers-Rubinsztajn Reaction for Reinforcement in Transparent Silicone Elastomers","authors":"Hui Li,Jianping Zhu,Yongmei Xia,Jing Dong,Fangrui Xie,Liang Xu,Yingqian Hu,Lianbin Wu","doi":"10.1021/acs.macromol.5c03158","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03158","url":null,"abstract":"To address the challenge of simultaneously enhancing the mechanical properties of addition-type liquid silicone rubber (ALSR) while maintaining excellent optical transparency, we report the design and synthesis of a novel liquid vinyl-functionalized POSS (Vi-POSS) via the Piers-Rubinsztajn reaction between SiH-containing Q-type POSS (H-POSS) and a heterofunctional oligosiloxane. This strategy enables precise modulation of cross-linking networks while improving filler–matrix compatibility through covalent bonding. The molecular structure of Vi-POSS was confirmed by 1H/29Si NMR and FT-IR spectroscopy, revealing complete vinyl functionalization. A series of ALSRs were prepared using Vi-POSS as both reinforcing filler and cross-linker. Systematic investigations demonstrated that optimal incorporation of 4 wt % Vi-POSS yielded exceptional thermomechanical performance: a 641% increase in tensile strength (2.52 MPa) and 322% enhancement in elongation at break (243.15%) compared to pristine ALSR, while maintaining 90% UV–vis transmittance across the visible spectrum. Thermal stability analysis revealed that with the incorporation of 6 wt % Vi-POSS, compared with the pristine ALSR, the initial decomposition temperature (T10%) and maximum degradation temperature (Tmax) increased by 20 and 12 °C, respectively. Additionally, the char residue at 800 °C was enhanced. Microstructural characterization via SEM confirmed the homogeneous dispersion of Vi-POSS without microphase separation, indicating an excellent interfacial compatibility and superior dispersion of Vi-POSS in the ALSR matrix. This work presents a paradigm shift in the design of transparent high-performance ALSR by integrating molecular-level structure control with nanoscale dispersion optimization. The demonstrated balance of mechanical robustness, thermal stability, and optical clarity positions these materials as promising candidates for advanced applications in flexible optoelectronics, transparent electronics, and biomedical devices requiring simultaneous load-bearing and optical functionality.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"28 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147346731","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 : 2026-03-03DOI: 10.1021/acs.macromol.5c01799
Michael Cole,Jordan Fitch,Tara Y. Meyer
We report a strategy for analyzing and distinguishing the sequence distributions of random and semirandom poly(lactic-co-glycolic acid) (PLGA) analogs using selective digestion at cleavable olefin-containing monomer units. Semirandom copolymers were synthesized via a parallel-successive (P-S) approach that enables coarse-grained sequence control by coupling telechelic oligomers of varied composition and length. Following cross-metathesis digestion, the resulting fragment distributions were fractionated and analyzed via NMR, SEC, and MALDI-MS. These postdigestion data directly reflect the microstructural arrangement of the cleavable units in the predigestion copolymers. Monte Carlo simulations were employed to model both random and P-S copolymerizations, offering in silico digestion data that elucidate the influence of oligomer feed ratios and dispersity on the resulting block-length distributions. Experimental and simulated results demonstrate that P-S copolymers exhibit broader and sometimes bimodal fragment distributions compared to their random analogs, validating the method’s capacity to encode and detect distinct microstructural features. This approach provides a scalable, analytically tractable platform for tuning and characterizing sequence distributions in degradable polyesters and potentially other polymer systems where sequence plays a critical role in material properties.
{"title":"Characterization of Sequence Distributions in Random and Semi-Random Copolymers","authors":"Michael Cole,Jordan Fitch,Tara Y. Meyer","doi":"10.1021/acs.macromol.5c01799","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c01799","url":null,"abstract":"We report a strategy for analyzing and distinguishing the sequence distributions of random and semirandom poly(lactic-co-glycolic acid) (PLGA) analogs using selective digestion at cleavable olefin-containing monomer units. Semirandom copolymers were synthesized via a parallel-successive (P-S) approach that enables coarse-grained sequence control by coupling telechelic oligomers of varied composition and length. Following cross-metathesis digestion, the resulting fragment distributions were fractionated and analyzed via NMR, SEC, and MALDI-MS. These postdigestion data directly reflect the microstructural arrangement of the cleavable units in the predigestion copolymers. Monte Carlo simulations were employed to model both random and P-S copolymerizations, offering in silico digestion data that elucidate the influence of oligomer feed ratios and dispersity on the resulting block-length distributions. Experimental and simulated results demonstrate that P-S copolymers exhibit broader and sometimes bimodal fragment distributions compared to their random analogs, validating the method’s capacity to encode and detect distinct microstructural features. This approach provides a scalable, analytically tractable platform for tuning and characterizing sequence distributions in degradable polyesters and potentially other polymer systems where sequence plays a critical role in material properties.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"3 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147346740","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 : 2026-03-03DOI: 10.1021/acs.macromol.6c00138
Abhishek S. Chankapure, Rahul Karmakar, Srikanth Sastry, Sanat K. Kumar, Tarak K. Patra
Reversible cross-links introduce structural reorganization in a polymer matrix. Two key features that are particularly relevant when reversible cross-links are used to compatibilize polymer interfaces are how they affect the (i) bulk polymer density and (ii) interfacial activity of the cross-link groups. To probe these issues, we model both a bulk polymer melt and a thin film of a polymer melt, both with explicit small molecular cross-linkers, in the associative limit, i.e., when the number of cross-links is fixed over time. We show that the bulk density and the distribution of stickers within a polymer matrix are strongly influenced by their size and interactions with the base polymer. Specifically, when the cross-linkers are chemically compatible with the base polymer, the overall packing fraction increases, regardless of cross-linker size, while it decreases when cross-linkers are incompatible with the polymers. Similarly, the cross-linkers segregate preferentially to the polymer–air interface when they are incompatible with the polymer chains, leading to a reduction in interfacial tension. These results demonstrate the key role of cross-linker-polymer interactions and cross-linker size on the structural and interfacial properties of polymer melts with reversible cross-links. We draw parallels between nanoparticle-filled polymer systems and polymers cross-linked by molecular-scale cross-linkers, as both introduce localized constraints that modify chain packing, dynamics, and interfacial properties.
{"title":"Packing, Phase Separation, and Interface Compatibility of Polymers with Reversible Cross-Links","authors":"Abhishek S. Chankapure, Rahul Karmakar, Srikanth Sastry, Sanat K. Kumar, Tarak K. Patra","doi":"10.1021/acs.macromol.6c00138","DOIUrl":"https://doi.org/10.1021/acs.macromol.6c00138","url":null,"abstract":"Reversible cross-links introduce structural reorganization in a polymer matrix. Two key features that are particularly relevant when reversible cross-links are used to compatibilize polymer interfaces are how they affect the (i) bulk polymer density and (ii) interfacial activity of the cross-link groups. To probe these issues, we model both a bulk polymer melt and a thin film of a polymer melt, both with explicit small molecular cross-linkers, in the associative limit, i.e., when the number of cross-links is fixed over time. We show that the bulk density and the distribution of stickers within a polymer matrix are strongly influenced by their size and interactions with the base polymer. Specifically, when the cross-linkers are chemically compatible with the base polymer, the overall packing fraction increases, regardless of cross-linker size, while it decreases when cross-linkers are incompatible with the polymers. Similarly, the cross-linkers segregate preferentially to the polymer–air interface when they are incompatible with the polymer chains, leading to a reduction in interfacial tension. These results demonstrate the key role of cross-linker-polymer interactions and cross-linker size on the structural and interfacial properties of polymer melts with reversible cross-links. We draw parallels between nanoparticle-filled polymer systems and polymers cross-linked by molecular-scale cross-linkers, as both introduce localized constraints that modify chain packing, dynamics, and interfacial properties.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"99 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329947","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 : 2026-03-03DOI: 10.1021/acs.macromol.5c02873
Winnie H. Shi,Amanda B. Marciel
We investigate the effect of the charge block length on the chain conformation and phase behavior of atactic peptide polyampholytes (PAs) with equal numbers of cationic and anionic ionizable monomers. Atactic peptide PAs were produced by using solid-phase peptide synthesis (SPPS), which enables precise control of the molecular weight, monomer sequence, and chain tacticity. Using circular dichroism (CD) and Fourier-transform infrared (FTIR) spectroscopy, we observe that the atactic peptide PAs show no evidence of secondary structure formation, regardless of block length. Turbidity measurements show that the atactic peptide PAs remain in solution over a wide-range of salt concentrations. Small-angle X-ray scattering (SAXS) measurements reveal that the chain conformation of atactic peptide PAs is compressed compared to expectations for neutral systems. Interestingly, we find that the atactic peptide PAs form block length dependent multichain clusters in solution. These results are consistent with a recent theory predicting that PAs have a block length and concentration dependent threshold for phase separation.
{"title":"Influence of Charge Block Length on Conformation and Cluster Formation of Atactic Peptide Polyampholytes","authors":"Winnie H. Shi,Amanda B. Marciel","doi":"10.1021/acs.macromol.5c02873","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c02873","url":null,"abstract":"We investigate the effect of the charge block length on the chain conformation and phase behavior of atactic peptide polyampholytes (PAs) with equal numbers of cationic and anionic ionizable monomers. Atactic peptide PAs were produced by using solid-phase peptide synthesis (SPPS), which enables precise control of the molecular weight, monomer sequence, and chain tacticity. Using circular dichroism (CD) and Fourier-transform infrared (FTIR) spectroscopy, we observe that the atactic peptide PAs show no evidence of secondary structure formation, regardless of block length. Turbidity measurements show that the atactic peptide PAs remain in solution over a wide-range of salt concentrations. Small-angle X-ray scattering (SAXS) measurements reveal that the chain conformation of atactic peptide PAs is compressed compared to expectations for neutral systems. Interestingly, we find that the atactic peptide PAs form block length dependent multichain clusters in solution. These results are consistent with a recent theory predicting that PAs have a block length and concentration dependent threshold for phase separation.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"48 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147346736","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 : 2026-03-03DOI: 10.1021/acs.macromol.5c02803
Ya-Sen Sun, Chia-Liang Liu, Belda Amelia Junisu
This study investigates PbBr2 complexation, inclusion crystallization, and block copolymer–directed self-assembly in tetrahydrofuran (THF), using polystyrene-block-poly(ethylene oxide) (PS-b-PEO) as a structure-directing or crystallization-modulating agent. Here, we demonstrate that THF, a neutral solvent, enables a distinct complexation pathway: at low PS-b-PEO concentrations, [PbBr3]− complexes dominate, whereas mononuclear [PbBr4]2– and polynuclear [Pb4Br11]3– and [Pb2Br5]− complexes become more prominent at higher polymer loadings. This solvent environment gives rise to diverse mesoscale morphologies and molecular-scale polymorphs through competing driving forces of crystallization of the PEO-[PbxBry]2x−y complex blocks and the self-assembly tendency of the PS-b-(PEO-[PbxBry]2x−y complex) diblock molecules into micellar aggregates. At low PS-b-PEO concentrations, compact microplates primarily form via nucleation-limited aggregation, coexisting with small amounts of dense polygonal nanoplates and seaweed-like structures. The compact microplates are composed of large hexagonal complex crystals, while the dense polygonal nanoplates contain smaller hexagonal crystals. In contrast, the seaweed-like structures consist of orthorhombic complex crystals. As the PS-b-PEO concentration increases, the self-assembly tendency of the PS-b-(PEO–[PbxBry]2x−y complex) diblock molecules into cylindrical micellar aggregates becomes dominant over crystallization of the PEO–[PbxBry]2x−y complex blocks. Consequently, compact microplates evolve into cheese-like microplates that retain hexagonal symmetry, although their overall abundance significantly decreases. Instead, seaweeds, loose dendrites, and fibers─composed of orthorhombic complex crystals─emerge as the dominant morphologies. These findings shed light on the importance of solvent quality in tuning crystallization pathways and structural hierarchies, providing new insights into the design of inclusion crystallization and soft-matter self-assembly in neutral solvent systems.
{"title":"Inclusion Crystallization Self-Assembly in Hybrids of Polystyrene-Block-Poly(Ethylene Oxide) and Lead(II) Bromide in Tetrahydrofuran","authors":"Ya-Sen Sun, Chia-Liang Liu, Belda Amelia Junisu","doi":"10.1021/acs.macromol.5c02803","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c02803","url":null,"abstract":"This study investigates PbBr<sub>2</sub> complexation, inclusion crystallization, and block copolymer–directed self-assembly in tetrahydrofuran (THF), using polystyrene-<i>block</i>-poly(ethylene oxide) (PS-<i>b</i>-PEO) as a structure-directing or crystallization-modulating agent. Here, we demonstrate that THF, a neutral solvent, enables a distinct complexation pathway: at low PS-<i>b</i>-PEO concentrations, [PbBr<sub>3</sub>]<sup>−</sup> complexes dominate, whereas mononuclear [PbBr<sub>4</sub>]<sup>2–</sup> and polynuclear [Pb<sub>4</sub>Br<sub>11</sub>]<sup>3–</sup> and [Pb<sub>2</sub>Br<sub>5</sub>]<sup>−</sup> complexes become more prominent at higher polymer loadings. This solvent environment gives rise to diverse mesoscale morphologies and molecular-scale polymorphs through competing driving forces of crystallization of the PEO-[Pb<sub><i>x</i></sub>Br<sub><i>y</i></sub>]<sup>2<i>x</i>−<i>y</i></sup> complex blocks and the self-assembly tendency of the PS-<i>b</i>-(PEO-[Pb<sub><i>x</i></sub>Br<sub><i>y</i></sub>]<sup>2<i>x</i>−<i>y</i></sup> complex) diblock molecules into micellar aggregates. At low PS-<i>b</i>-PEO concentrations, compact microplates primarily form via nucleation-limited aggregation, coexisting with small amounts of dense polygonal nanoplates and seaweed-like structures. The compact microplates are composed of large hexagonal complex crystals, while the dense polygonal nanoplates contain smaller hexagonal crystals. In contrast, the seaweed-like structures consist of orthorhombic complex crystals. As the PS-<i>b</i>-PEO concentration increases, the self-assembly tendency of the PS-<i>b</i>-(PEO–[Pb<sub><i>x</i></sub>Br<sub><i>y</i></sub>]<sup>2<i>x</i>−<i>y</i></sup> complex) diblock molecules into cylindrical micellar aggregates becomes dominant over crystallization of the PEO–[Pb<sub><i>x</i></sub>Br<sub><i>y</i></sub>]<sup>2<i>x</i>−<i>y</i></sup> complex blocks. Consequently, compact microplates evolve into cheese-like microplates that retain hexagonal symmetry, although their overall abundance significantly decreases. Instead, seaweeds, loose dendrites, and fibers─composed of orthorhombic complex crystals─emerge as the dominant morphologies. These findings shed light on the importance of solvent quality in tuning crystallization pathways and structural hierarchies, providing new insights into the design of inclusion crystallization and soft-matter self-assembly in neutral solvent systems.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"64 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329945","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 : 2026-03-03DOI: 10.1021/acs.macromol.6c00235
Jack E. Bowman, Abbey Piatkowski, Joshua G. Pemberton, Mark S. Workentin, Joe B. Gilroy
Click chemistry is an integral component of the modern polymer synthesis toolbox. It can be used to create functional materials with precise control over structure. Many click chemistries have been investigated, including azide–alkyne cycloadditions, thiol–ene chemistry, and Staudinger-Bertozzi ligations (SBL). However, traceless Staudinger–Bertozzi ligation, which yields materials free of potentially toxic and reactive phosphorus-containing residues, is virtually unexplored in the polymer materials arena. Herein, we prepare styrene-based polymers with pendant phosphines on each repeating unit capable of undergoing traceless SBL using reversible addition–fragmentation chain-transfer (RAFT) polymerization. These polymers undergo efficient traceless SBL with a variety of azides. Our proof-of-concept study includes the preparation of redox-active, water-solubilizing, and fluorescent polymers as well as styrene-functionalized polymers that cannot be accessed by direct polymerization. Our fluorescent polymers were effective as conjugates for the design of live-cell imaging probes, demonstrating the potential of this class of polymers as a platform for the straightforward synthesis of polymeric cell imaging agents. In conducting this study, we have made a valuable addition to the click chemistry toolbox for polymer synthesis.
{"title":"Traceless Staudinger–Bertozzi Ligation for Postpolymerization Modification","authors":"Jack E. Bowman, Abbey Piatkowski, Joshua G. Pemberton, Mark S. Workentin, Joe B. Gilroy","doi":"10.1021/acs.macromol.6c00235","DOIUrl":"https://doi.org/10.1021/acs.macromol.6c00235","url":null,"abstract":"Click chemistry is an integral component of the modern polymer synthesis toolbox. It can be used to create functional materials with precise control over structure. Many click chemistries have been investigated, including azide–alkyne cycloadditions, thiol–ene chemistry, and Staudinger-Bertozzi ligations (SBL). However, traceless Staudinger–Bertozzi ligation, which yields materials free of potentially toxic and reactive phosphorus-containing residues, is virtually unexplored in the polymer materials arena. Herein, we prepare styrene-based polymers with pendant phosphines on each repeating unit capable of undergoing traceless SBL using reversible addition–fragmentation chain-transfer (RAFT) polymerization. These polymers undergo efficient traceless SBL with a variety of azides. Our proof-of-concept study includes the preparation of redox-active, water-solubilizing, and fluorescent polymers as well as styrene-functionalized polymers that cannot be accessed by direct polymerization. Our fluorescent polymers were effective as conjugates for the design of live-cell imaging probes, demonstrating the potential of this class of polymers as a platform for the straightforward synthesis of polymeric cell imaging agents. In conducting this study, we have made a valuable addition to the click chemistry toolbox for polymer synthesis.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"45 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330004","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}
This study presents a comprehensive host–guest investigation of the p-sulfonatothiacalix[4]arene macrocycle and its application as a dopant in the fabrication of a self-doped polyaniline adsorbent for Zn(II) removal. Proton nuclear magnetic resonance (1H NMR) titration of p-sulfonatothiacalix[4]arene with Zn(II) ions revealed a strong binding affinity, quantified by an association constant (Ka) exceeding 104 M–1, indicative of robust encapsulation at the macrocyclic cavity. Due to the limited solubility of the polymer, solid-state NMR spectroscopy was employed to elucidate the complexation behavior of Zn(II) within the self-doped polyaniline, revealing marked heterogeneity and localized variations in charge density while preserving the intrinsic conductivity characteristics of the polymer matrix. Complementary density functional theory (DFT) calculations identified the sulfonate (−SO3–) rim of the thiacalix as the primary binding site for Zn(II), whereas in the self-doped polyaniline, the strongest adsorption resulted from cooperative interactions between the sulfonate groups and the polyaniline backbone. Quantum Theory of Atoms in Molecules (QTAIM) analysis further characterized the interactions, showing predominantly ionic binding with minor covalent contributions in thiacalix–Zn complexes and ionic/dative bonding with weak covalent character in the polymer-Zn system. The integrated NMR and computational insights provide a detailed understanding of the adsorption mechanisms and chelation sites, highlighting the efficacy of p-sulfonatothiacalix[4]arene as a functional dopant for advanced conductive polymer adsorbents targeting heavy metal ions.
{"title":"Host–Guest Interaction of p-Sulfonatothiacalix[4]arene with Zn(II) and Its Role in Structuring Self-Doped Polyaniline Adsorbents","authors":"Rafieh-Sadat Norouzian,Kaisa Helttunen,Fatemeh Fateminasab,Moslem Mansour Lakouraj,Elina Sievänen","doi":"10.1021/acs.macromol.5c03383","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03383","url":null,"abstract":"This study presents a comprehensive host–guest investigation of the p-sulfonatothiacalix[4]arene macrocycle and its application as a dopant in the fabrication of a self-doped polyaniline adsorbent for Zn(II) removal. Proton nuclear magnetic resonance (1H NMR) titration of p-sulfonatothiacalix[4]arene with Zn(II) ions revealed a strong binding affinity, quantified by an association constant (Ka) exceeding 104 M–1, indicative of robust encapsulation at the macrocyclic cavity. Due to the limited solubility of the polymer, solid-state NMR spectroscopy was employed to elucidate the complexation behavior of Zn(II) within the self-doped polyaniline, revealing marked heterogeneity and localized variations in charge density while preserving the intrinsic conductivity characteristics of the polymer matrix. Complementary density functional theory (DFT) calculations identified the sulfonate (−SO3–) rim of the thiacalix as the primary binding site for Zn(II), whereas in the self-doped polyaniline, the strongest adsorption resulted from cooperative interactions between the sulfonate groups and the polyaniline backbone. Quantum Theory of Atoms in Molecules (QTAIM) analysis further characterized the interactions, showing predominantly ionic binding with minor covalent contributions in thiacalix–Zn complexes and ionic/dative bonding with weak covalent character in the polymer-Zn system. The integrated NMR and computational insights provide a detailed understanding of the adsorption mechanisms and chelation sites, highlighting the efficacy of p-sulfonatothiacalix[4]arene as a functional dopant for advanced conductive polymer adsorbents targeting heavy metal ions.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"227 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147346732","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 : 2026-03-03DOI: 10.1021/acs.macromol.5c03301
Xin Ming Wei,Lin Lin Cheng,Hao Lin Han,Cui Lian Qiu,Guan Ben Du,Long Yang,Yan Mei Li
To address the challenge of achieving multisite functionalization of inert C═C bonds in plant oils while preserving the triglyceride scaffold to develop high-performance and recyclable thermosets, a universal strategy is proposed based on thiol–ene click chemistry and dynamic thiocarbamate networks. Pentaerythritol tetrakis(mercaptoacetate) is employed to introduce multiple thiol groups onto the double bonds without disrupting the triglyceride structure. Subsequent polymerization with isocyanate monomers yields tunable thermosets, with tensile strength ranging from ∼10 to 40 MPa and elongation at break from ∼5% to ∼1300%. The dynamic thiocarbamate bonds enable solid-state reprocessability (68%–101% recovery) and self-healing (75%–94% healing efficiency). A sunlight-driven synthesis is developed as a green alternative to UV initiation, producing resins with comparable performance. The retained triglyceride motifs also allow enzymatic degradation, with over 40% mass loss within 30 days. This work provides a versatile platform for upcycling plant oils into high-performance polymers with mechanical robustness, recyclability, and end-of-life degradability, enabling a closed-loop lifecycle.
{"title":"Research on the High-Value Transformation of Plant Oils: Toward High-Performance Recycled and Degradable Thermosetting Polymers","authors":"Xin Ming Wei,Lin Lin Cheng,Hao Lin Han,Cui Lian Qiu,Guan Ben Du,Long Yang,Yan Mei Li","doi":"10.1021/acs.macromol.5c03301","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03301","url":null,"abstract":"To address the challenge of achieving multisite functionalization of inert C═C bonds in plant oils while preserving the triglyceride scaffold to develop high-performance and recyclable thermosets, a universal strategy is proposed based on thiol–ene click chemistry and dynamic thiocarbamate networks. Pentaerythritol tetrakis(mercaptoacetate) is employed to introduce multiple thiol groups onto the double bonds without disrupting the triglyceride structure. Subsequent polymerization with isocyanate monomers yields tunable thermosets, with tensile strength ranging from ∼10 to 40 MPa and elongation at break from ∼5% to ∼1300%. The dynamic thiocarbamate bonds enable solid-state reprocessability (68%–101% recovery) and self-healing (75%–94% healing efficiency). A sunlight-driven synthesis is developed as a green alternative to UV initiation, producing resins with comparable performance. The retained triglyceride motifs also allow enzymatic degradation, with over 40% mass loss within 30 days. This work provides a versatile platform for upcycling plant oils into high-performance polymers with mechanical robustness, recyclability, and end-of-life degradability, enabling a closed-loop lifecycle.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"3 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147346733","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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