Pub Date : 2026-03-13DOI: 10.1021/acs.macromol.5c03206
Maoyan Jie, Yali Zhang, Ruijuan Liu, Xiaogang Zhang, Zhongmin Jin
This study investigated the molecular modulation mechanisms underlying the high strength–toughness performance in long-chain branched polyethylene (LCBPE). Molecular dynamics simulations were employed to construct LCBPE systems with branch lengths ranging from one to four times the critical entanglement molecular weight (Me). The microstructural evolution of these systems during melt equilibration, crystallization, and tensile deformation was tracked to elucidate the structural foundations and molecular-level modulation mechanisms governing the strength–toughness performance. The results indicated that branch length in LCBPE exerted a nonmonotonic influence on the material’s strength–toughness performance. Within the tested parameter range, the material exhibited optimal mechanical performance when the chain length of the long-chain branch (LCB) was approximately twice the system’s critical Me. When the LCB length was below this threshold, although chain entanglement and tie-chain content increased compared to linear chains, they were insufficient to offset the negative impact of reduced crystallinity, manifesting as enhanced toughness and a reduction in peak stress. When the LCB length exceeded this threshold, the pronounced extensibility of the branches resulted in a less compact semicrystalline structure, which became more susceptible to interchain disentanglement under external loading. This structural change weakened the strain-hardening process and hindered the material’s ability to fully realize its strength–toughness potential.
{"title":"Molecular Modulation Mechanisms of Strength–Toughness Performance in Long-Chain Branched Polyethylene","authors":"Maoyan Jie, Yali Zhang, Ruijuan Liu, Xiaogang Zhang, Zhongmin Jin","doi":"10.1021/acs.macromol.5c03206","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03206","url":null,"abstract":"This study investigated the molecular modulation mechanisms underlying the high strength–toughness performance in long-chain branched polyethylene (LCBPE). Molecular dynamics simulations were employed to construct LCBPE systems with branch lengths ranging from one to four times the critical entanglement molecular weight (<i>M</i><sub>e</sub>). The microstructural evolution of these systems during melt equilibration, crystallization, and tensile deformation was tracked to elucidate the structural foundations and molecular-level modulation mechanisms governing the strength–toughness performance. The results indicated that branch length in LCBPE exerted a nonmonotonic influence on the material’s strength–toughness performance. Within the tested parameter range, the material exhibited optimal mechanical performance when the chain length of the long-chain branch (LCB) was approximately twice the system’s critical <i>M</i><sub>e</sub>. When the LCB length was below this threshold, although chain entanglement and tie-chain content increased compared to linear chains, they were insufficient to offset the negative impact of reduced crystallinity, manifesting as enhanced toughness and a reduction in peak stress. When the LCB length exceeded this threshold, the pronounced extensibility of the branches resulted in a less compact semicrystalline structure, which became more susceptible to interchain disentanglement under external loading. This structural change weakened the strain-hardening process and hindered the material’s ability to fully realize its strength–toughness potential.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"10 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147454654","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 : 2026-03-13DOI: 10.1021/acs.macromol.6c00024
Zheqi Li, Qingliang Song, Shichao You, Chenfei Xu, Lixin Liu, Weihua Li, Jianzhong Du, Zhijia Liu, Yi Shi, Yongming Chen
Altering the properties of polymer chains under confinement represents fundamental challenges in polymer science. Molecular bottlebrushes (MBs), with their densely grafted architecture, create a unique constrained environment that serves as an ideal model system for exploring the structure–property relationships of confined molecular chains. In this work, we employed a Me6TREN/CuBr-catalyzed CuAAC click chemistry to synthesize precisely defined MBs with ultrahigh grafting densities (up to 6.2 side chains (SCs) per C–C repeating unit) via a reaction-enhanced reactivity of intermediates (RERI)-driven grafting-onto strategy. Using this approach, we prepared 65 MBs bearing tetraphenylethylene (TPE) units, a fluorescent moiety sensitive to mechanical strain, at tailored positions along poly(ethylene glycol) (PEG) SCs, including the interior segment, middle portion, and terminal end of the side chains. By systematically varying grafting density (Gdst), molecular weight, composition, and TPE location of SCs, as well as the backbone length, and correlating these with the luminescent behavior in both good and poor solvents, we elucidated the local segmental motion within the SCs. The results demonstrate that the mobility of the interior SC segments decreases initially in a linear manner with an increase of Gdst. Beyond a critical threshold, however, the decline in the mobility of segments follows a steeper linear trend. Moreover, the mobility of the SC segments away from the backbone increases significantly, even under dense grafting. This work not only clarifies how molecular parameters influence side-chain dynamics but also provides a theoretical basis for the design of advanced functional materials based on MBs.
{"title":"Segmental Mobility of Polymer Chains under Molecular Confinement: Insights from Precision Molecular Bottlebrushes","authors":"Zheqi Li, Qingliang Song, Shichao You, Chenfei Xu, Lixin Liu, Weihua Li, Jianzhong Du, Zhijia Liu, Yi Shi, Yongming Chen","doi":"10.1021/acs.macromol.6c00024","DOIUrl":"https://doi.org/10.1021/acs.macromol.6c00024","url":null,"abstract":"Altering the properties of polymer chains under confinement represents fundamental challenges in polymer science. Molecular bottlebrushes (MBs), with their densely grafted architecture, create a unique constrained environment that serves as an ideal model system for exploring the structure–property relationships of confined molecular chains. In this work, we employed a Me<sub>6</sub>TREN/CuBr-catalyzed CuAAC click chemistry to synthesize precisely defined MBs with ultrahigh grafting densities (up to 6.2 side chains (SCs) per C–C repeating unit) via a reaction-enhanced reactivity of intermediates (RERI)-driven grafting-onto strategy. Using this approach, we prepared 65 MBs bearing tetraphenylethylene (TPE) units, a fluorescent moiety sensitive to mechanical strain, at tailored positions along poly(ethylene glycol) (PEG) SCs, including the interior segment, middle portion, and terminal end of the side chains. By systematically varying grafting density (<i>G</i><sub>dst</sub>), molecular weight, composition, and TPE location of SCs, as well as the backbone length, and correlating these with the luminescent behavior in both good and poor solvents, we elucidated the local segmental motion within the SCs. The results demonstrate that the mobility of the interior SC segments decreases initially in a linear manner with an increase of <i>G</i><sub>dst</sub>. Beyond a critical threshold, however, the decline in the mobility of segments follows a steeper linear trend. Moreover, the mobility of the SC segments away from the backbone increases significantly, even under dense grafting. This work not only clarifies how molecular parameters influence side-chain dynamics but also provides a theoretical basis for the design of advanced functional materials based on MBs.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"93 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147454655","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 : 2026-03-13DOI: 10.1021/acs.macromol.6c00033
Siyuan Zhang, Meijiao Liu, Luyang Li, Li Peng, Xianbo Huang, Weihua Li
Based on the formation mechanism of stable hierarchical network structures composed of binary A/C-spheres in close contact in the AB2C quadruple-arm star copolymer, we propose that the ABC star triblock copolymer could also self-assemble into this kind of unusual network structures under the condition of χAC > χAB ∼ χBC. Accordingly, we first construct the phase diagram of the ABC star copolymer with respect to fB and χACN for χABN = χBCN = χN = 40 and fA = fC. It is observed that the usual polygonal phases transfer to the hierarchical network phases in the region of relatively large fB when χACN is increased to be significantly higher than χN, including hierarchical single-diamond (hSD0) and single-gyroid (hSG0). Moreover, another stable single-diamond phase (hSD1) is also predicted, all nodes of which are formed by A- or C-blocks and are separated by a “strut” domain composed of C- or A-blocks. It is revealed that the polygonal phase has more favorable interaction energy than the corresponding hierarchical network phase but unfavorable entropic contribution. More critically, the disadvantage of the interaction energy of the hierarchical network phase diminishes as χACN increases, improving its stability relative to that of the polygonal phase. By considering a special ratio of χAC/χAB = χAC/χBC to mimic an experimentally accessible ABC star copolymer, PI-b-PS-b-PEO (ISO), we confirm that these hierarchical single-network phases remain considerably stable in parameter regions. Our work is expected to promote relevant experimental research for the fabrication of these astonishing hierarchical single-network structures.
{"title":"Emergence and Stability of Distinct Hierarchical Single-Network Structures in ABC Star Triblock Copolymers","authors":"Siyuan Zhang, Meijiao Liu, Luyang Li, Li Peng, Xianbo Huang, Weihua Li","doi":"10.1021/acs.macromol.6c00033","DOIUrl":"https://doi.org/10.1021/acs.macromol.6c00033","url":null,"abstract":"Based on the formation mechanism of stable hierarchical network structures composed of binary A/C-spheres in close contact in the AB<sub>2</sub>C quadruple-arm star copolymer, we propose that the ABC star triblock copolymer could also self-assemble into this kind of unusual network structures under the condition of χ<sub>AC</sub> > χ<sub>AB</sub> ∼ χ<sub>BC</sub>. Accordingly, we first construct the phase diagram of the ABC star copolymer with respect to <i>f</i><sub>B</sub> and χ<sub>AC</sub><i>N</i> for χ<sub>AB</sub><i>N</i> = χ<sub>BC</sub><i>N</i> = χ<i>N</i> = 40 and <i>f</i><sub>A</sub> = <i>f</i><sub>C</sub>. It is observed that the usual polygonal phases transfer to the hierarchical network phases in the region of relatively large <i>f</i><sub>B</sub> when χ<sub>AC</sub><i>N</i> is increased to be significantly higher than χ<i>N</i>, including hierarchical single-diamond (hSD<sub>0</sub>) and single-gyroid (hSG<sub>0</sub>). Moreover, another stable single-diamond phase (hSD<sub>1</sub>) is also predicted, all nodes of which are formed by A- or C-blocks and are separated by a “strut” domain composed of C- or A-blocks. It is revealed that the polygonal phase has more favorable interaction energy than the corresponding hierarchical network phase but unfavorable entropic contribution. More critically, the disadvantage of the interaction energy of the hierarchical network phase diminishes as χ<sub>AC</sub><i>N</i> increases, improving its stability relative to that of the polygonal phase. By considering a special ratio of χ<sub>AC</sub>/χ<sub>AB</sub> = χ<sub>AC</sub>/χ<sub>BC</sub> to mimic an experimentally accessible ABC star copolymer, PI-<i>b</i>-PS-<i>b</i>-PEO (ISO), we confirm that these hierarchical single-network phases remain considerably stable in parameter regions. Our work is expected to promote relevant experimental research for the fabrication of these astonishing hierarchical single-network structures.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"86 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147454656","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}
Although the difference in hydrogen bonding between thioamide and amide groups has been widely discussed, their mechanical comparison remains unexplored. We report a postpolymerization modification strategy involving main-chain atom insertion to prepare polyethylenes bearing in-chain thioamide groups (polyethylene-thioamides) and their amide analogs (polyethylene-amides) with identical molecular weights and incorporation ratios, enabling mechanical evaluation of the difference in hydrogen bonding. Starting from polyethylenes bearing in-chain carbonyl groups (polyethylene-ketones), oxime formation followed by a (diethylamino)sulfur trifluoride (DAST) promoted rearrangement enabled nitrogen atom insertion into the polymer main-chain, and subsequent one-pot nucleophilic substitution with sodium hydrogen sulfide (NaSH) afforded polyethylene-thioamides. Mechanical testing revealed that polyethylene-thioamide containing 0.8 mol % thioamide groups exhibited a tensile strength of 21.3 MPa, significantly lower than that of polyethylene-amide (41.9 MPa, 0.7 mol % amide). These results provide direct experimental insight into the weaker hydrogen bonding of thioamides compared with that of amides, representing the first macroscopic mechanical comparison between the two.
{"title":"Long-Chain Polythioamides: Synthesis and Mechanical Evaluation of Their Hydrogen Bonding Properties","authors":"Yipu Lu, Kohei Takahashi, Nontarin Roopsung, Shintaro Nakagawa, Naoko Yoshie, Kyoko Nozaki","doi":"10.1021/acs.macromol.5c03179","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03179","url":null,"abstract":"Although the difference in hydrogen bonding between thioamide and amide groups has been widely discussed, their mechanical comparison remains unexplored. We report a postpolymerization modification strategy involving main-chain atom insertion to prepare polyethylenes bearing in-chain thioamide groups (polyethylene-thioamides) and their amide analogs (polyethylene-amides) with identical molecular weights and incorporation ratios, enabling mechanical evaluation of the difference in hydrogen bonding. Starting from polyethylenes bearing in-chain carbonyl groups (polyethylene-ketones), oxime formation followed by a (diethylamino)sulfur trifluoride (DAST) promoted rearrangement enabled nitrogen atom insertion into the polymer main-chain, and subsequent one-pot nucleophilic substitution with sodium hydrogen sulfide (NaSH) afforded polyethylene-thioamides. Mechanical testing revealed that polyethylene-thioamide containing 0.8 mol % thioamide groups exhibited a tensile strength of 21.3 MPa, significantly lower than that of polyethylene-amide (41.9 MPa, 0.7 mol % amide). These results provide direct experimental insight into the weaker hydrogen bonding of thioamides compared with that of amides, representing the first macroscopic mechanical comparison between the two.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"5 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147454666","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 : 2026-03-12DOI: 10.1021/acs.macromol.5c03257
Subhojit Nayak, Subhendu Biswas, Anindita Das
In light of growing interest in developing strategies for new classes of degradable polymers, polythioesters (PTEs) remain relatively underexplored and are predominantly prepared via the ring-opening polymerization (ROP) of cyclic monomers. We report here a versatile, controllable step-growth methodology for the synthesis of telechelic PTEs directly from simple dithiols, exploring activated-ester-mediated thioesterification chemistry. Polycondensation reaction between a pentafluorophenyl (PFP)-based diester of adipic acid with two structurally different dithiols, viz., linear 1,6-hexanedithiol and the polar 3,6-dioxa-1,8-octanedithiol, afforded well-defined telechelic polythioesters with near-quantified monomer conversion under mild conditions (∼75 °C) using 4-dimethylaminopyridine (DMAP) as an organocatalyst in DMF as the solvent. The highly reactive nature of the PFP-ester facilitated efficient polymerization without the need to remove the released byproduct (pentafluorophenol), which is otherwise essential in traditional polycondensation reactions to prevent backward reactions and drive the equilibrium forward toward high-yield polymers. Detailed kinetic analysis demonstrated the efficacy of this methodology, which was accelerated by DMAP acting as a nucleophilic catalyst. Moreover, this strategy enables tuning of the degree of polymerization by varying the stoichiometric ratio between the activated diester and the dithiol. A stoichiometric excess of either the dithiol or the diester enabled the synthesis of thiol-terminated or PFP-ester-terminated telechelic PTEs, which were subjected to site-selective postpolymerization end-group modification via a thiol–ene click reaction or transesterification, respectively. The versatility of the approach was further demonstrated through a one-pot synthesis of a pyrene end-capped PTE using pyrene methanol as a “monofunctional impurity” during the polymerization reaction between the diester and the dithiol. Thermogravimetric analysis revealed that the resultant PTEs are highly stable but can be degraded by aminolysis under mild phosphate-buffered conditions. Comparing the thermal properties of a PTE with those of a structurally analogous polyester of comparable molecular weight indicated higher crystallization and melting temperatures for the polythioester analogue. Overall, this step-growth approach offers a straightforward route to PTEs by bypassing the need to synthesize sulfur-containing cyclic monomers essential for ROP, thereby offering the clear advantages of synthetic simplicity, structural tunability, and end-group functionalization.
{"title":"Degradable Telechelic Polythioesters from Activated Diesters and Their Site-Selective End-Group Functionalization","authors":"Subhojit Nayak, Subhendu Biswas, Anindita Das","doi":"10.1021/acs.macromol.5c03257","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03257","url":null,"abstract":"In light of growing interest in developing strategies for new classes of degradable polymers, polythioesters (PTEs) remain relatively underexplored and are predominantly prepared via the ring-opening polymerization (ROP) of cyclic monomers. We report here a versatile, controllable step-growth methodology for the synthesis of telechelic PTEs directly from simple dithiols, exploring activated-ester-mediated thioesterification chemistry. Polycondensation reaction between a pentafluorophenyl (PFP)-based diester of adipic acid with two structurally different dithiols, viz., linear 1,6-hexanedithiol and the polar 3,6-dioxa-1,8-octanedithiol, afforded well-defined telechelic polythioesters with near-quantified monomer conversion under mild conditions (∼75 °C) using 4-dimethylaminopyridine (DMAP) as an organocatalyst in DMF as the solvent. The highly reactive nature of the PFP-ester facilitated efficient polymerization without the need to remove the released byproduct (pentafluorophenol), which is otherwise essential in traditional polycondensation reactions to prevent backward reactions and drive the equilibrium forward toward high-yield polymers. Detailed kinetic analysis demonstrated the efficacy of this methodology, which was accelerated by DMAP acting as a nucleophilic catalyst. Moreover, this strategy enables tuning of the degree of polymerization by varying the stoichiometric ratio between the activated diester and the dithiol. A stoichiometric excess of either the dithiol or the diester enabled the synthesis of thiol-terminated or PFP-ester-terminated telechelic PTEs, which were subjected to site-selective postpolymerization end-group modification via a thiol–ene click reaction or transesterification, respectively. The versatility of the approach was further demonstrated through a one-pot synthesis of a pyrene end-capped PTE using pyrene methanol as a “monofunctional impurity” during the polymerization reaction between the diester and the dithiol. Thermogravimetric analysis revealed that the resultant PTEs are highly stable but can be degraded by aminolysis under mild phosphate-buffered conditions. Comparing the thermal properties of a PTE with those of a structurally analogous polyester of comparable molecular weight indicated higher crystallization and melting temperatures for the polythioester analogue. Overall, this step-growth approach offers a straightforward route to PTEs by bypassing the need to synthesize sulfur-containing cyclic monomers essential for ROP, thereby offering the clear advantages of synthetic simplicity, structural tunability, and end-group functionalization.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"15 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147439753","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 : 2026-03-12DOI: 10.1021/acs.macromol.5c03590
Guan-Da Li, Hui Niu
Controlling the phase morphology of immiscible polyolefin blends, such as the isotactic polypropylene (iPP)/ethylene-propylene rubber (EPR) system, is fundamentally constrained by the trade-off between interfacial stability and melt processability, particularly under conditions of significant viscosity mismatch. Herein, we present a dynamic interfacial control strategy that reconciles these competing requirements via reversible aromatic associations. By introducing a small amount of 4-vinylbiphenyl onto both iPP and EPR chains through reactive extrusion, we establish dynamic π–π interactions across the phase interface. These interactions are sufficiently mobile to permit melt flow but strong enough to suppress coalescence, progressively refining the EPR domain size from 1.74 to 0.29 μm with increasing grafting content. Consequently, the room-temperature notched impact strength exhibits a 5-fold increase, accompanied by a pronounced brittle-to-ductile transition, while stiffness and melt rheology remain well-preserved. The toughening mechanism is attributed to the synergistic effects of refined rubber morphology and dynamically reinforced interfaces, which promote cavitation and extensive plastic deformation of the matrix. This work demonstrates that moderate, reversible supramolecular interactions offer a robust pathway for regulating the morphology and performance of nonpolar polymer systems without permanent cross-linking.
{"title":"Dynamic Interfacial Compatibilization of Immiscible Polyolefin Blends via Reversible Aromatic Interactions","authors":"Guan-Da Li, Hui Niu","doi":"10.1021/acs.macromol.5c03590","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03590","url":null,"abstract":"Controlling the phase morphology of immiscible polyolefin blends, such as the isotactic polypropylene (iPP)/ethylene-propylene rubber (EPR) system, is fundamentally constrained by the trade-off between interfacial stability and melt processability, particularly under conditions of significant viscosity mismatch. Herein, we present a dynamic interfacial control strategy that reconciles these competing requirements via reversible aromatic associations. By introducing a small amount of 4-vinylbiphenyl onto both iPP and EPR chains through reactive extrusion, we establish dynamic π–π interactions across the phase interface. These interactions are sufficiently mobile to permit melt flow but strong enough to suppress coalescence, progressively refining the EPR domain size from 1.74 to 0.29 μm with increasing grafting content. Consequently, the room-temperature notched impact strength exhibits a 5-fold increase, accompanied by a pronounced brittle-to-ductile transition, while stiffness and melt rheology remain well-preserved. The toughening mechanism is attributed to the synergistic effects of refined rubber morphology and dynamically reinforced interfaces, which promote cavitation and extensive plastic deformation of the matrix. This work demonstrates that moderate, reversible supramolecular interactions offer a robust pathway for regulating the morphology and performance of nonpolar polymer systems without permanent cross-linking.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"43 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440269","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 : 2026-03-12DOI: 10.1021/acs.macromol.6c00201
Irene De Franceschi, Sareh Rezaei Hosseinabadi, Laurens A. J. Rutgeerts, Sutapa Roy Swarna, Zahra Bozorgmehr, Guy Koeckelberghs, Nezha Badi, Ivo F. J. Vankelecom, Filip E. Du Prez
Abiotic sequence-defined macromolecules (SDMs) offer unique opportunities for precision molecular design, yet their broader adoption and utilization remain limited by the lack of general and efficient workflows that unify iterative synthesis and purification across chemically diverse structures. Here we report a platform that combines soluble-support SDM growth with solvent-resistant nanofiltration (SRNF) and demonstrate its implementation within multiple synthesis protocols. The reaction and purification steps are performed in a single solvent and reactor, enabling high membrane flux and operational simplicity. All SDMs are synthesized on uniform soluble supports bearing cleavable linkers and long alkyl chains, ensuring efficient membrane retention and broad applicability. The platform is validated for thiolactone-, oligo(amide)-, and oligo(carbamate)-based SDMs, including hydrophilic, hydrophobic, and amphiphilic structures. In addition, a bidirectional growth strategy compatible with the same purification methodology reduces the number of reaction steps and accelerates the SDM preparation. Overall, this work establishes a robust, automation-compatible approach for integrated abiotic SDM synthesis and purification, enabling efficient access to chemically diverse sequence-defined macromolecular structures.
{"title":"Integrated Synthesis and Purification of Chemically Diverse Abiotic Sequence-Defined Macromolecules via Solvent-Resistant Nanofiltration","authors":"Irene De Franceschi, Sareh Rezaei Hosseinabadi, Laurens A. J. Rutgeerts, Sutapa Roy Swarna, Zahra Bozorgmehr, Guy Koeckelberghs, Nezha Badi, Ivo F. J. Vankelecom, Filip E. Du Prez","doi":"10.1021/acs.macromol.6c00201","DOIUrl":"https://doi.org/10.1021/acs.macromol.6c00201","url":null,"abstract":"Abiotic sequence-defined macromolecules (SDMs) offer unique opportunities for precision molecular design, yet their broader adoption and utilization remain limited by the lack of general and efficient workflows that unify iterative synthesis and purification across chemically diverse structures. Here we report a platform that combines soluble-support SDM growth with solvent-resistant nanofiltration (SRNF) and demonstrate its implementation within multiple synthesis protocols. The reaction and purification steps are performed in a single solvent and reactor, enabling high membrane flux and operational simplicity. All SDMs are synthesized on uniform soluble supports bearing cleavable linkers and long alkyl chains, ensuring efficient membrane retention and broad applicability. The platform is validated for thiolactone-, oligo(amide)-, and oligo(carbamate)-based SDMs, including hydrophilic, hydrophobic, and amphiphilic structures. In addition, a bidirectional growth strategy compatible with the same purification methodology reduces the number of reaction steps and accelerates the SDM preparation. Overall, this work establishes a robust, automation-compatible approach for integrated abiotic SDM synthesis and purification, enabling efficient access to chemically diverse sequence-defined macromolecular structures.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"9 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440354","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}
The ability to exquisitely tailor the crystal orientation in conjugated polymers is highly desirable for improving device performance and establishing structure–property relationships. However, investigations into modulating crystal orientation in conjugated donor–acceptor (D–A) block copolymers (BCPs) remain limited. Herein, we report the tailoring of the orientation modes (i.e., edge-on and face-on) in a family of P3AT-b-PDPP and P3BT-b-P3BrHT-b-PDPP BCPs via molecular engineering. Specifically, the crystal orientation induction between the P3AT block (i.e., which intrinsically exhibits an edge-on orientation) and the PDPP block (i.e., which intrinsically forms a face-on orientation) was effectively controlled by systematically adjusting the molecular weight (MW) and alkyl side chain of the P3AT block and the MW of the middle P3BrHT block. An increased MW and a shorter alkyl side chain of the P3AT block were found to induce a transition of the PDPP block from an initial face-on to an edge-on orientation in P3AT-b-PDPP BCPs. This induction effect of the P3AT block on the PDPP block was progressively weakened by separating the two blocks with a P3BrHT block of increasing MW in P3BT-b-P3BrHT-b-PDPP BCPs. This study demonstrates that crystal orientations in conjugated D–A BCPs can be tailored through robust molecular engineering, thereby strengthening the fundamental understanding of the interplay among the different components in conjugated BCPs.
{"title":"Tuning Edge-On/Face-On Crystal Orientation in Conjugated Donor–Acceptor Block Copolymers via Molecular Engineering","authors":"Hao Zhan,Hao Zheng,Bingjie Wu,Yanan Guo,Yongjie Dong,Qingqing Zhao,Xuebing Luo,Juan Peng","doi":"10.1021/acs.macromol.5c02912","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c02912","url":null,"abstract":"The ability to exquisitely tailor the crystal orientation in conjugated polymers is highly desirable for improving device performance and establishing structure–property relationships. However, investigations into modulating crystal orientation in conjugated donor–acceptor (D–A) block copolymers (BCPs) remain limited. Herein, we report the tailoring of the orientation modes (i.e., edge-on and face-on) in a family of P3AT-b-PDPP and P3BT-b-P3BrHT-b-PDPP BCPs via molecular engineering. Specifically, the crystal orientation induction between the P3AT block (i.e., which intrinsically exhibits an edge-on orientation) and the PDPP block (i.e., which intrinsically forms a face-on orientation) was effectively controlled by systematically adjusting the molecular weight (MW) and alkyl side chain of the P3AT block and the MW of the middle P3BrHT block. An increased MW and a shorter alkyl side chain of the P3AT block were found to induce a transition of the PDPP block from an initial face-on to an edge-on orientation in P3AT-b-PDPP BCPs. This induction effect of the P3AT block on the PDPP block was progressively weakened by separating the two blocks with a P3BrHT block of increasing MW in P3BT-b-P3BrHT-b-PDPP BCPs. This study demonstrates that crystal orientations in conjugated D–A BCPs can be tailored through robust molecular engineering, thereby strengthening the fundamental understanding of the interplay among the different components in conjugated BCPs.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"6 10 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383803","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}
High mechanical robustness and high photovoltaic performance are essential for the practical application of stretchable organic solar cells (SOSCs) in stretchable and wearable electronics. In this regard, we designed and synthesized a series of novel donor polymers by incorporating amide units with flexible alkyl segments of varying lengths as a third component into the conjugated backbone of the D18 polymer. Tuning the length of these alkyl segments effectively modulates the aggregation behavior and crystallinity of the donor polymers, leading to an optimal blend morphology with the polymer acceptor PY-IT and enhancing both the mechanical and photovoltaic properties of the resulting blend films. Specifically, the solar cell based on the D18-C6:PY-IT blend achieved a high power conversion efficiency of 14.67% and demonstrated excellent stretchability with a crack onset strain of 30%, marking a significant improvement over the reference D18:PY-IT blend. This study elucidates the influence of the alkyl segment length within amide units on polymer crystallinity, providing a strategic approach for the design of high-performance stretchable active layer materials.
{"title":"Designing High-Performance Stretchable Light-Harvesting Polymers for Organic Solar Cells through Tailored Amide Units with Varied Alkyl Chain Lengths","authors":"Hongli Wang, Zhuang Chen, Hongming Kou, Jiye Pan, Xunchang Wang, Renqiang Yang, Deyu Liu","doi":"10.1021/acs.macromol.5c03260","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03260","url":null,"abstract":"High mechanical robustness and high photovoltaic performance are essential for the practical application of stretchable organic solar cells (SOSCs) in stretchable and wearable electronics. In this regard, we designed and synthesized a series of novel donor polymers by incorporating amide units with flexible alkyl segments of varying lengths as a third component into the conjugated backbone of the D18 polymer. Tuning the length of these alkyl segments effectively modulates the aggregation behavior and crystallinity of the donor polymers, leading to an optimal blend morphology with the polymer acceptor PY-IT and enhancing both the mechanical and photovoltaic properties of the resulting blend films. Specifically, the solar cell based on the D18-C6:PY-IT blend achieved a high power conversion efficiency of 14.67% and demonstrated excellent stretchability with a crack onset strain of 30%, marking a significant improvement over the reference D18:PY-IT blend. This study elucidates the influence of the alkyl segment length within amide units on polymer crystallinity, providing a strategic approach for the design of high-performance stretchable active layer materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"95 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147439754","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 : 2026-03-11DOI: 10.1021/acs.macromol.5c03108
Yuwenya Zhang,Liang Liu,Wenqi Kang,Hao Sun,Wei Xu,Jungen Chen,Hang Guo,Hongjun Zhang,Liangbin Li
With a high-counting-rate positron annihilation lifetime spectrometer, the current work achieves an in situ measurement of free volume in the amorphous layer of oriented polyethylene terephthalate (PET) film during tensile deformation. Tuning the amorphous structure with different annealing temperatures, we discovered that stretch in the linear deformation region enlarges the hole size for the samples annealed at low temperatures (25 and 150 °C), while it increases the number density of free volume for the samples annealed at high temperatures (190 and 230 °C). Interestingly, for all samples, the fraction of free volume increases linearly with stress with the same slopes in linear elastic and plastic deformation regions, respectively. The linear relation between stress and fraction of free volume stimulates us to propose a new concept of the free volume modulus Kf, which is about 0.77 and 0.25 GPa in linear elastic and plastic deformation regions, respectively. A quantitative mechanic model accounting for the contribution of free volume is established for the amorphous layer in a semicrystalline polymer.
{"title":"Quantitative Correlation between Mechanical Behaviors and Free Volume of Oriented Polyethylene Terephthalate: an In Situ PALS Study","authors":"Yuwenya Zhang,Liang Liu,Wenqi Kang,Hao Sun,Wei Xu,Jungen Chen,Hang Guo,Hongjun Zhang,Liangbin Li","doi":"10.1021/acs.macromol.5c03108","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03108","url":null,"abstract":"With a high-counting-rate positron annihilation lifetime spectrometer, the current work achieves an in situ measurement of free volume in the amorphous layer of oriented polyethylene terephthalate (PET) film during tensile deformation. Tuning the amorphous structure with different annealing temperatures, we discovered that stretch in the linear deformation region enlarges the hole size for the samples annealed at low temperatures (25 and 150 °C), while it increases the number density of free volume for the samples annealed at high temperatures (190 and 230 °C). Interestingly, for all samples, the fraction of free volume increases linearly with stress with the same slopes in linear elastic and plastic deformation regions, respectively. The linear relation between stress and fraction of free volume stimulates us to propose a new concept of the free volume modulus Kf, which is about 0.77 and 0.25 GPa in linear elastic and plastic deformation regions, respectively. A quantitative mechanic model accounting for the contribution of free volume is established for the amorphous layer in a semicrystalline polymer.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"54 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383805","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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