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}
Pub Date : 2026-03-11DOI: 10.1021/acs.macromol.6c00188
Kam C. Poon, Thomas M. McGuire, Chang Gao, Gregory S. Sulley, Charlotte K. Williams
Designing polymers that combine performance with sustainability remains a critical challenge. Here, we report high-performance elastomers derived from CO2 and biobased monomers that integrate both mechanical toughness and closed-loop chemical recyclability through a single material feature: dynamic metal–ionomer cross-links. These ABA block polymers, synthesized from ε-decalactone, δ-jasmolactone, CO2, and bicyclic epoxides, incorporate abundant and inexpensive metal carboxylates (Na(I), Zn(II), and Al(III)) into the midblock, forming reversible networks that enhance tensile strength by 150% while maintaining high strain at break (>1500%) and elastic recovery (>85%). The same cross-links act as built-in catalysts, enabling energy-efficient depolymerization of both polyester and polycarbonate domains at 200 °C, recovering the original monomers. This dual-function approach advances circular polymer design by combining enhanced performance with efficient, low-energy, closed-loop recycling.
{"title":"Function Meets Circularity: Metal–Ionomer Cross-Links Toughen and Recycle CO2-Derived Polymers","authors":"Kam C. Poon, Thomas M. McGuire, Chang Gao, Gregory S. Sulley, Charlotte K. Williams","doi":"10.1021/acs.macromol.6c00188","DOIUrl":"https://doi.org/10.1021/acs.macromol.6c00188","url":null,"abstract":"Designing polymers that combine performance with sustainability remains a critical challenge. Here, we report high-performance elastomers derived from CO<sub>2</sub> and biobased monomers that integrate both mechanical toughness and closed-loop chemical recyclability through a single material feature: dynamic metal–ionomer cross-links. These ABA block polymers, synthesized from ε-decalactone, δ-jasmolactone, CO<sub>2</sub>, and bicyclic epoxides, incorporate abundant and inexpensive metal carboxylates (Na(I), Zn(II), and Al(III)) into the midblock, forming reversible networks that enhance tensile strength by 150% while maintaining high strain at break (>1500%) and elastic recovery (>85%). The same cross-links act as built-in catalysts, enabling energy-efficient depolymerization of both polyester and polycarbonate domains at 200 °C, recovering the original monomers. This dual-function approach advances circular polymer design by combining enhanced performance with efficient, low-energy, closed-loop recycling.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"127 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147439755","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 : 2026-03-10DOI: 10.1021/acs.macromol.5c03543
Wen-Juan Qu,Wentao Hu,Ke Wang,Wenjing Shi,Xuzhao Li,Tai-Bao Wei,Qi Lin,Bingbing Shi
Controllable self-assembly provides an effective strategy for constructing ordered molecular architectures with tunable structures and functions. However, realizing precise control over the topological evolution of supramolecular systems in the solid state remains a considerable challenge. Here, we report a clamparene-based (CLP) donor–acceptor cocrystallization system with tetracyanobenzene (TCNB) that enables molecular-level regulation of supramolecular topology and photothermal behavior. The π-electron-rich CLP and electron-deficient TCNB form charge-transfer (CT) complexes through exo-wall π···π interactions. By tuning the donor-to-acceptor ratio, two distinct crystalline supramolecular polymers were obtained: a linear topology (TCNB@CLPα-1) and a zigzag topology (TCNB@CLPα-2). Single-crystal X-ray diffraction, spectroscopic analyses, and DFT calculations reveal that the CT interactions between CLP and TCNB narrow the HOMO–LUMO gap and facilitate nonradiative relaxation processes. Benefiting from these interactions, the crystalline supramolecular polymers exhibit efficient photothermal conversion under simulated sunlight, with TCNB@CLPα-1 showing superior performance due to a greater number of repeating CT units. This work demonstrates that structural modulation at the molecular scale provides a viable route to achieving controllable topologies and tunable macroscopic functions in crystalline supramolecular materials.
{"title":"Controlled Self-Assembly of Clamparene-Based Cocrystals for Tunable Supramolecular Architectures and Their Application in Photothermal Conversion","authors":"Wen-Juan Qu,Wentao Hu,Ke Wang,Wenjing Shi,Xuzhao Li,Tai-Bao Wei,Qi Lin,Bingbing Shi","doi":"10.1021/acs.macromol.5c03543","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03543","url":null,"abstract":"Controllable self-assembly provides an effective strategy for constructing ordered molecular architectures with tunable structures and functions. However, realizing precise control over the topological evolution of supramolecular systems in the solid state remains a considerable challenge. Here, we report a clamparene-based (CLP) donor–acceptor cocrystallization system with tetracyanobenzene (TCNB) that enables molecular-level regulation of supramolecular topology and photothermal behavior. The π-electron-rich CLP and electron-deficient TCNB form charge-transfer (CT) complexes through exo-wall π···π interactions. By tuning the donor-to-acceptor ratio, two distinct crystalline supramolecular polymers were obtained: a linear topology (TCNB@CLPα-1) and a zigzag topology (TCNB@CLPα-2). Single-crystal X-ray diffraction, spectroscopic analyses, and DFT calculations reveal that the CT interactions between CLP and TCNB narrow the HOMO–LUMO gap and facilitate nonradiative relaxation processes. Benefiting from these interactions, the crystalline supramolecular polymers exhibit efficient photothermal conversion under simulated sunlight, with TCNB@CLPα-1 showing superior performance due to a greater number of repeating CT units. This work demonstrates that structural modulation at the molecular scale provides a viable route to achieving controllable topologies and tunable macroscopic functions in crystalline supramolecular materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"19 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383806","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 : 2026-03-10DOI: 10.1021/acs.macromol.5c02999
Jun He,Yi Cui,Saiya Li,Yiping Cao,Cuixia Sun,Wei Lu,Xiaoyang Li,Yiguo Zhao,Yapeng Fang
Hydrogels are increasingly employed in applications involving tensile loading, such as wearable devices, soft robotics, and biomedical sensors. However, their long-term mechanical behavior in air-exposed environments remains underexplored. In this study, we derive a constitutive model to describe the stress relaxation of Ca-alginate hydrogels under long-term sustained uniaxial loading in air and validate it experimentally. The mechanical responses of the hydrogel encompass initial viscoelastic relaxation, followed by progressive stiffening, culminating in a sharp increase in final stress due to network shrinkage. In the proposed constitutive model, an empirical parameter Q, representing volume-changed energy, accurately captures the evolution of stress over time, effectively correlating dehydration kinetics and shrinkage during long-term loading with the structural changes in the hydrogel. Molecular simulations, LF-NMR, in situ Raman, SAXS, and SEM reveal the long-term tensile loading-dependent structural evolution, including promoting molecular aggregation, shifts in water mobility, and multiscale anisotropy in the hydrogel. These results provide mechanistic insights into the coupled dehydration-deformation processes in hydrogels and establish a predictive phenomenological framework for enhancing hydrogel performance and reliability in air-exposed applications.
{"title":"Relaxation Behavior and Structural Evolution of Hydrogels under Long-Term Tensile Loading in Air","authors":"Jun He,Yi Cui,Saiya Li,Yiping Cao,Cuixia Sun,Wei Lu,Xiaoyang Li,Yiguo Zhao,Yapeng Fang","doi":"10.1021/acs.macromol.5c02999","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c02999","url":null,"abstract":"Hydrogels are increasingly employed in applications involving tensile loading, such as wearable devices, soft robotics, and biomedical sensors. However, their long-term mechanical behavior in air-exposed environments remains underexplored. In this study, we derive a constitutive model to describe the stress relaxation of Ca-alginate hydrogels under long-term sustained uniaxial loading in air and validate it experimentally. The mechanical responses of the hydrogel encompass initial viscoelastic relaxation, followed by progressive stiffening, culminating in a sharp increase in final stress due to network shrinkage. In the proposed constitutive model, an empirical parameter Q, representing volume-changed energy, accurately captures the evolution of stress over time, effectively correlating dehydration kinetics and shrinkage during long-term loading with the structural changes in the hydrogel. Molecular simulations, LF-NMR, in situ Raman, SAXS, and SEM reveal the long-term tensile loading-dependent structural evolution, including promoting molecular aggregation, shifts in water mobility, and multiscale anisotropy in the hydrogel. These results provide mechanistic insights into the coupled dehydration-deformation processes in hydrogels and establish a predictive phenomenological framework for enhancing hydrogel performance and reliability in air-exposed applications.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"4 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383808","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 : 2026-03-10DOI: 10.1021/acs.macromol.6c00112
Sudharshan Kannapadi,Rithwik Ghanta,Jared J. Rivera-Otero,Autumn S. Cook,Elena F. Granzeier,Fiona Scanu,James J. Griebler,Simon A. Rogers,Alexa S. Kuenstler
Associative dynamic covalent networks combine the elastic properties of cross-linked thermosets with the viscous flow of thermoplastics, thus enabling reprocessability while maintaining network connectivity. In this work, we investigate the effect of catalyst mobility and concentration on the linear viscoelasticity of associative thiol-thioester dynamic covalent networks. We present a simple method to covalently tether nucleophiles capable of catalyzing thiol-thioester exchange reactions to polymer networks and compare their viscoelastic behavior to their analogous untethered catalyst. We first show that the cross-linking density and bond dynamics can be independently tuned using precise stoichiometric adjustments for both catalyst systems. Notably, we find that the mobility of the catalysts does not affect the bond dynamics, as validated by similar relaxation times between the tethered and untethered catalysts for a given temperature and catalyst loading. Creep experiments show that the dynamic bonds are continuously exchanging in the polymer networks and can be well described by a single-mode Maxwell model. We find that a single set of horizontal and vertical shift factors was sufficient to construct time–temperature superposition (TTS) master curves and was directly related to the relaxation time and the cross-linking density, respectively, further validating the structure–property relations. Activation energies calculated from the Arrhenius relationship with the flow viscosity are systematically higher for the tethered catalysts, which we hypothesize is due to steric effects in the polymer networks. Finally, we propose the use of time–temperature-catalyst superposition (TTCS) as a framework to probe the bond dynamics spanning substantially longer time scales than TTS as a function of temperature and catalyst loading.
{"title":"The Role of Catalyst Mobility and Concentration on the Linear Viscoelasticity of Associative Dynamic Covalent Networks","authors":"Sudharshan Kannapadi,Rithwik Ghanta,Jared J. Rivera-Otero,Autumn S. Cook,Elena F. Granzeier,Fiona Scanu,James J. Griebler,Simon A. Rogers,Alexa S. Kuenstler","doi":"10.1021/acs.macromol.6c00112","DOIUrl":"https://doi.org/10.1021/acs.macromol.6c00112","url":null,"abstract":"Associative dynamic covalent networks combine the elastic properties of cross-linked thermosets with the viscous flow of thermoplastics, thus enabling reprocessability while maintaining network connectivity. In this work, we investigate the effect of catalyst mobility and concentration on the linear viscoelasticity of associative thiol-thioester dynamic covalent networks. We present a simple method to covalently tether nucleophiles capable of catalyzing thiol-thioester exchange reactions to polymer networks and compare their viscoelastic behavior to their analogous untethered catalyst. We first show that the cross-linking density and bond dynamics can be independently tuned using precise stoichiometric adjustments for both catalyst systems. Notably, we find that the mobility of the catalysts does not affect the bond dynamics, as validated by similar relaxation times between the tethered and untethered catalysts for a given temperature and catalyst loading. Creep experiments show that the dynamic bonds are continuously exchanging in the polymer networks and can be well described by a single-mode Maxwell model. We find that a single set of horizontal and vertical shift factors was sufficient to construct time–temperature superposition (TTS) master curves and was directly related to the relaxation time and the cross-linking density, respectively, further validating the structure–property relations. Activation energies calculated from the Arrhenius relationship with the flow viscosity are systematically higher for the tethered catalysts, which we hypothesize is due to steric effects in the polymer networks. Finally, we propose the use of time–temperature-catalyst superposition (TTCS) as a framework to probe the bond dynamics spanning substantially longer time scales than TTS as a function of temperature and catalyst loading.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"26 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383807","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}
Modified methylaluminoxanes (MMAOs) are widely used activators in olefin polymerization and selective oligomerization, yet quantitative structure-performance correlations are often obscured by compositional heterogeneity and residual trialkylaluminum (R3Al) that biases bulk measurements. We prepare MAO/IBAO/MMAO as dry powders and quantify residual R3Al using a THF-probe 1H NMR method that separates sharp R3Al signals from the broad aluminoxane background. By removing the R3Al contribution, we derive corrected number-average molecular weights (Mn,corr) and Gas/Al ratios that precisely reflect the intrinsic aluminoxane framework. Combined with the measured framework Me/iBu ratios, these constraints establish how TMA/TIBA, H2O/Al, and the synthetic sequence control framework composition and condensation. Low-temperature 1H NMR shows extensive alkyl exchange in TMA/TIBA premixes, generating mixed-alkyl aluminum species prior to hydrolysis. In Cr/PNP-catalyzed ethylene tetramerization, the optimized MMAO with Me/iBu of 2.45, a (Gas/Al)corr of 1.41, and Mn,corr of 806 g/mol achieves high activity with 80.8 wt % 1-octene selectivity and minimal polyethylene formation (0.95 wt %). DFT calculations support an Al10O8Me10(iBu)4 cage as a thermodynamically preferred MMAO motif consistent with experiment. These results provide a corrected and quantitative basis for defining aluminoxane identity and rationalizing MMAO effects in selective oligomerization.
{"title":"Composition, Molecular Weight, and Structure of Modified Methylaluminoxane (MMAO): Implications for Selective Ethylene Tetramerization with Cr/PNP Catalysts","authors":"Hengyu Zhong, Zhongyao Zhang, Yanjiao Xu, Haomiao Zhang, Jingdai Wang, Yongrong Yang","doi":"10.1021/acs.macromol.6c00577","DOIUrl":"https://doi.org/10.1021/acs.macromol.6c00577","url":null,"abstract":"Modified methylaluminoxanes (MMAOs) are widely used activators in olefin polymerization and selective oligomerization, yet quantitative structure-performance correlations are often obscured by compositional heterogeneity and residual trialkylaluminum (R<sub>3</sub>Al) that biases bulk measurements. We prepare MAO/IBAO/MMAO as dry powders and quantify residual R<sub>3</sub>Al using a THF-probe <sup>1</sup>H NMR method that separates sharp R<sub>3</sub>Al signals from the broad aluminoxane background. By removing the R<sub>3</sub>Al contribution, we derive corrected number-average molecular weights (<i>M</i><sub>n,corr</sub>) and Gas/Al ratios that precisely reflect the intrinsic aluminoxane framework. Combined with the measured framework Me/iBu ratios, these constraints establish how TMA/TIBA, H<sub>2</sub>O/Al, and the synthetic sequence control framework composition and condensation. Low-temperature <sup>1</sup>H NMR shows extensive alkyl exchange in TMA/TIBA premixes, generating mixed-alkyl aluminum species prior to hydrolysis. In Cr/PNP-catalyzed ethylene tetramerization, the optimized MMAO with Me/iBu of 2.45, a (<i>Gas</i>/<i>Al</i>)<sub>corr</sub> of 1.41, and <i>M</i><sub>n,corr</sub> of 806 g/mol achieves high activity with 80.8 wt % 1-octene selectivity and minimal polyethylene formation (0.95 wt %). DFT calculations support an Al<sub>10</sub>O<sub>8</sub>Me<sub>10</sub>(iBu)<sub>4</sub> cage as a thermodynamically preferred MMAO motif consistent with experiment. These results provide a corrected and quantitative basis for defining aluminoxane identity and rationalizing MMAO effects in selective oligomerization.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"53 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147381075","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 : 2026-03-09DOI: 10.1021/acs.macromol.5c03127
Yi Wu, Denghui Liu, Luo Yang, Xiaoyu Yin, Kunlun Wang, Yingliang Liu, Ergang Wang, Shaokui Cao, Shi-Jian Su, Shengang Xu
Generally, single-molecule white-emitting polymers (SMWEPs) are synthesized by the direct polymerization of functional monomers. Herein, we designed conjugated polymers PCFTN-X (X = 0.5, 1, 3, 5, or 10) by grafting red/green TADF units onto the backbone via alkyl linkers. This structural design balances the charge transport of the conjugated backbone with the independent photophysical properties of the TADF units on the side chains. PCFTN-X was synthesized via Suzuki polymerization and post-Click reaction, ensuring good reproducibility and tunable red/green ratios. The nondoped device based on PCFTN-3 achieved stable white emission with CIE coordinates of (0.34, 0.38), a low turn-on voltage (Von) of 3.4 V, a maximum external quantum efficiency (EQEmax) of 10.23%, and a maximum luminance (Lmax) of 3264 cd m–2. This design and synthesis strategy can be extended to other optoelectronic polymers.
一般来说，单分子发光聚合物（SMWEPs）是由功能单体直接聚合而成的。在此，我们设计了共轭聚合物PCFTN-X (X = 0.5, 1,3,5或10)，通过烷基连接剂将红/绿TADF单元接枝到主链上。这种结构设计平衡了共轭主链的电荷输运和侧链上TADF单元的独立光物理性质。PCFTN-X通过Suzuki聚合和post-Click反应合成，具有良好的重现性和可调的红绿比。基于PCFTN-3的非掺杂器件实现了稳定的白光发射，CIE坐标为（0.34,0.38），低导通电压（Von）为3.4 V，最大外量子效率（EQEmax）为10.23%，最大亮度（Lmax）为3264 cd m-2。这种设计和合成策略可以扩展到其他光电聚合物。
{"title":"Precise Synthesis of Conjugated Polymers Grafted with Red/Green TADF Units via Postfunctionalization for Single-Molecule White Electroluminescence","authors":"Yi Wu, Denghui Liu, Luo Yang, Xiaoyu Yin, Kunlun Wang, Yingliang Liu, Ergang Wang, Shaokui Cao, Shi-Jian Su, Shengang Xu","doi":"10.1021/acs.macromol.5c03127","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c03127","url":null,"abstract":"Generally, single-molecule white-emitting polymers (SMWEPs) are synthesized by the direct polymerization of functional monomers. Herein, we designed conjugated polymers PCFTN-<i>X</i> (<i>X</i> = 0.5, 1, 3, 5, or 10) by grafting red/green TADF units onto the backbone via alkyl linkers. This structural design balances the charge transport of the conjugated backbone with the independent photophysical properties of the TADF units on the side chains. PCFTN-<i>X</i> was synthesized via Suzuki polymerization and post-Click reaction, ensuring good reproducibility and tunable red/green ratios. The nondoped device based on PCFTN-3 achieved stable white emission with CIE coordinates of (0.34, 0.38), a low turn-on voltage (<i>V</i><sub>on</sub>) of 3.4 V, a maximum external quantum efficiency (EQE<sub>max</sub>) of 10.23%, and a maximum luminance (<i>L</i><sub>max</sub>) of 3264 cd m<sup>–2</sup>. This design and synthesis strategy can be extended to other optoelectronic polymers.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"31 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147381064","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 : 2026-03-08DOI: 10.1021/acs.macromol.6c00068
Lu-Feng Deng, Zhi-Guang Guo, Zheng-Yuan Chen, Jie Zhang, Gan-Ji Zhong, Jun Lei, Zhong-Ming Li
Flow-induced crystallization of isotactic polypropylene with β-nucleating agent (iPP/β) is investigated using a homemade in situ characterization platform for injection molding, featuring millisecond-scale time-resolved synchrotron X-ray diffraction and scattering techniques (WAXD/SAXS). By combining ex situ microfocus WAXD and scanning electron microscopy (SEM) measurements, we have elucidated a full-path scenario of injection-molded iPP/β for the first time, encompassing the evolution of crystalline phases, the formation of shish and lamellae, and the “skin-core” morphology. Results indicate that the competitive growth of α-, β-, and γ-crystals occurs within every layer of injection-molded iPP/β samples, driven by the nucleation barriers of the three crystalline forms and the nucleation efficiency of the β-nucleating agent (β-NA), depending on specific processing fields. The crystallization kinetics of β-crystals in iPP/β is jointly influenced by shear intensity and duration. Shear intensity promotes the early growth of β-crystals by inducing oriented α-row nuclei, yet concurrently suppresses the nucleation activity of β-NA. Shear duration influences the relaxation of oriented structures and modulates the starting time and duration of β-NA-induced β-crystals. Furthermore, the β-NA exhibits a dual role in promoting the development of the meridional β-epitaxial kebabs and main equatorial kebabs. When β-crystals are dominant, the ductility of the samples is positively correlated with β-crystals content, accompanied by a unique secondary necking phenomenon. This work provides important insights for tailoring the crystalline composition and structural hierarchy of iPP products through processing, thereby facilitating the optimization of their end-use performance.
{"title":"A Full-Process Perspective of Hierarchical Structure Development for Injection-Molded Isotactic Polypropylene with β-Nucleating Agent","authors":"Lu-Feng Deng, Zhi-Guang Guo, Zheng-Yuan Chen, Jie Zhang, Gan-Ji Zhong, Jun Lei, Zhong-Ming Li","doi":"10.1021/acs.macromol.6c00068","DOIUrl":"https://doi.org/10.1021/acs.macromol.6c00068","url":null,"abstract":"Flow-induced crystallization of isotactic polypropylene with β-nucleating agent (iPP/β) is investigated using a homemade in situ characterization platform for injection molding, featuring millisecond-scale time-resolved synchrotron X-ray diffraction and scattering techniques (WAXD/SAXS). By combining ex situ microfocus WAXD and scanning electron microscopy (SEM) measurements, we have elucidated a full-path scenario of injection-molded iPP/β for the first time, encompassing the evolution of crystalline phases, the formation of shish and lamellae, and the “skin-core” morphology. Results indicate that the competitive growth of α-, β-, and γ-crystals occurs within every layer of injection-molded iPP/β samples, driven by the nucleation barriers of the three crystalline forms and the nucleation efficiency of the β-nucleating agent (β-NA), depending on specific processing fields. The crystallization kinetics of β-crystals in iPP/β is jointly influenced by shear intensity and duration. Shear intensity promotes the early growth of β-crystals by inducing oriented α-row nuclei, yet concurrently suppresses the nucleation activity of β-NA. Shear duration influences the relaxation of oriented structures and modulates the starting time and duration of β-NA-induced β-crystals. Furthermore, the β-NA exhibits a dual role in promoting the development of the meridional β-epitaxial kebabs and main equatorial kebabs. When β-crystals are dominant, the ductility of the samples is positively correlated with β-crystals content, accompanied by a unique secondary necking phenomenon. This work provides important insights for tailoring the crystalline composition and structural hierarchy of iPP products through processing, thereby facilitating the optimization of their end-use performance.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"15 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2026-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147381076","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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