Pub Date : 2024-06-18DOI: 10.1021/acs.macromol.4c00770
Ryan J. Anderson, Rachel L. Fine, Rachel M. Rapagnani, Ian A. Tonks
Ring-opening random, gradient, and block copolymerizations of CO2-derived δ-valerolactone 3-ethyl-6-vinyltetrahydro-2H-pyran-2-one (EtVP) with ε-caprolactone (ε-CL) and l-lactide (LLA) are reported. By employing both concurrent and sequential addition strategies, we could access a variety of thermal and physical properties. Concurrent copolymerization of EtVP with ε-CL yielded gradient copolymers with low glass transition temperatures, while block copolymerizations via sequential addition led to semicrystalline materials regardless of monomer feed ratios. For LLA copolymerizations, glass transition temperatures increased with LLA incorporation regardless of the addition method, but higher Tg values were observed in block copolymerizations from sequential addition. Tensile testing of poly(EtVP-b-LLA) with a molar ratio of 40:60 EtVP:LLA resulted in σ = 0.8 MPa, E = 5.6 MPa, and 83% elongation at break. The chemical recyclability of EtVP-based copolymers was explored as an end-of-life option. Both ε-CL and LLA copolymers could be recycled, with block copolymers giving higher yields of recycled monomers than random copolymers.
{"title":"Ring-Opening Copolymerizations of a CO2-Derived δ-Valerolactone with ε-Caprolactone and l-Lactide","authors":"Ryan J. Anderson, Rachel L. Fine, Rachel M. Rapagnani, Ian A. Tonks","doi":"10.1021/acs.macromol.4c00770","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c00770","url":null,"abstract":"Ring-opening random, gradient, and block copolymerizations of CO<sub>2</sub>-derived δ-valerolactone 3-ethyl-6-vinyltetrahydro-2<i>H</i>-pyran-2-one (EtVP) with ε-caprolactone (ε-CL) and <span>l</span>-lactide (LLA) are reported. By employing both concurrent and sequential addition strategies, we could access a variety of thermal and physical properties. Concurrent copolymerization of EtVP with ε-CL yielded gradient copolymers with low glass transition temperatures, while block copolymerizations via sequential addition led to semicrystalline materials regardless of monomer feed ratios. For LLA copolymerizations, glass transition temperatures increased with LLA incorporation regardless of the addition method, but higher <i>T</i><sub>g</sub> values were observed in block copolymerizations from sequential addition. Tensile testing of <i>poly</i>(EtVP-<i>b</i>-LLA) with a molar ratio of 40:60 EtVP:LLA resulted in σ = 0.8 MPa, <i>E</i> = 5.6 MPa, and 83% elongation at break. The chemical recyclability of EtVP-based copolymers was explored as an end-of-life option. Both ε-CL and LLA copolymers could be recycled, with block copolymers giving higher yields of recycled monomers than random copolymers.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425244","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 : 2024-06-18DOI: 10.1021/acs.macromol.4c00774
Muhammad Asadullah Khan, Zhen Chen
In this work, the glassy dynamic features of poly(amidoamine) (PAMAM) dendrimers were determined explicitly through their dielectric segmental relaxation behaviors, and the structure–dynamic relationships were revealed via the decoupling behavior of ionic conductivity from segmental relaxation. By means of broadband dielectric spectroscopy, the relaxation behaviors of PAMAM dendrimers of generations 0 through 4 were investigated in a broad frequency and temperature range. Three secondary relaxations were observed in the glassy state, including a typical Johari–Goldstein β relaxation, which is considered a precursor of the α relaxation and also signifies the glass transition, a γ relaxation, and a δ relaxation in order of increasing frequency. Above the glass transition temperature, the segmental α relaxation and a slow mode are distinctly disclosed in dielectric spectra. The slow mode was found to arise from interfacial polarization connected with ionic conductivity. The glass transition temperature and fragility of the dendrimers were determined to be in line with the VFT behavior of the α relaxation time. The former is basically consistent with that determined in DSC measurement, and the latter suggests that PAMAM dendrimers are moderately fragile glass formers. Decoupling of ionic conductivity from segmental relaxation was identified for all generations, but the decoupling pattern of generations 0 and 1 was found to be obviously different from that in generations 2 through 4, evidencing a fundamental divergence in the microscopic structure of these two groups as a result of different interpenetration behavior. Furthermore, it is advised that the ionic conduction in PAMAM dendrimers is because glassy dynamics resisted proton hopping in a hydrogen-bonding network.
{"title":"New Insights into the Dynamics of Poly(amidoamine) Dendrimers with Amino Surface Groups from Segmental Relaxation and Ionic Conductivity","authors":"Muhammad Asadullah Khan, Zhen Chen","doi":"10.1021/acs.macromol.4c00774","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c00774","url":null,"abstract":"In this work, the glassy dynamic features of poly(amidoamine) (PAMAM) dendrimers were determined explicitly through their dielectric segmental relaxation behaviors, and the structure–dynamic relationships were revealed via the decoupling behavior of ionic conductivity from segmental relaxation. By means of broadband dielectric spectroscopy, the relaxation behaviors of PAMAM dendrimers of generations 0 through 4 were investigated in a broad frequency and temperature range. Three secondary relaxations were observed in the glassy state, including a typical Johari–Goldstein β relaxation, which is considered a precursor of the α relaxation and also signifies the glass transition, a γ relaxation, and a δ relaxation in order of increasing frequency. Above the glass transition temperature, the segmental α relaxation and a slow mode are distinctly disclosed in dielectric spectra. The slow mode was found to arise from interfacial polarization connected with ionic conductivity. The glass transition temperature and fragility of the dendrimers were determined to be in line with the VFT behavior of the α relaxation time. The former is basically consistent with that determined in DSC measurement, and the latter suggests that PAMAM dendrimers are moderately fragile glass formers. Decoupling of ionic conductivity from segmental relaxation was identified for all generations, but the decoupling pattern of generations 0 and 1 was found to be obviously different from that in generations 2 through 4, evidencing a fundamental divergence in the microscopic structure of these two groups as a result of different interpenetration behavior. Furthermore, it is advised that the ionic conduction in PAMAM dendrimers is because glassy dynamics resisted proton hopping in a hydrogen-bonding network.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425342","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 : 2024-06-18DOI: 10.1021/acs.macromol.4c00937
Haicheng Wang, Haiyan Ma
No-end topology provides cyclic polyesters with potential abstracting applications, but more efficient and selective routes still need to be explored to access cyclic polyesters with high molecular weights and tacticity control. We report here that a series of aminophenolate zinc chlorides display hyperstability and hyper productivity toward the ring-opening polymerization of technical grade rac-lactide (rac-LA) in cyclohexene oxide, capable of converting up to 20,000 equiv of rac-LA (TONs up to 18,600) to cyclic polymers with high molecular weights and narrow to moderate distributions (Mn up to 58.0 kg/mol, D̵ = 1.19–1.60). At ambient temperature, highly isotactic cyclic poly(rac-LA)s could be obtained (e.g., complex 6, Pm = 0.87, Mn = 23.5 kg/mol, 25 °C; with Pm further improved to 0.93 at −45 °C), which show to possess stereoblocky microstructures. Selective end-to-end cyclization proved to be thoroughly involved in the polymerization, leading to cyclic polylactides with only even-numbered lactyl units.
{"title":"Controlled Synthesis of High-Molecular-Weight and Isotactic Cyclic Polylactides from rac-Lactide Using Aminophenolate Zinc Chlorides","authors":"Haicheng Wang, Haiyan Ma","doi":"10.1021/acs.macromol.4c00937","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c00937","url":null,"abstract":"No-end topology provides cyclic polyesters with potential abstracting applications, but more efficient and selective routes still need to be explored to access cyclic polyesters with high molecular weights and tacticity control. We report here that a series of aminophenolate zinc chlorides display hyperstability and hyper productivity toward the ring-opening polymerization of technical grade <i>rac</i>-lactide (<i>rac</i>-LA) in cyclohexene oxide, capable of converting up to 20,000 equiv of <i>rac</i>-LA (TONs up to 18,600) to cyclic polymers with high molecular weights and narrow to moderate distributions (<i>M</i><sub>n</sub> up to 58.0 kg/mol, <i>D̵</i> = 1.19–1.60). At ambient temperature, highly isotactic cyclic poly(<i>rac</i>-LA)s could be obtained (e.g., complex <b>6</b>, <i>P</i><sub>m</sub> = 0.87, <i>M</i><sub>n</sub> = 23.5 kg/mol, 25 °C; with <i>P</i><sub>m</sub> further improved to 0.93 at −45 °C), which show to possess stereoblocky microstructures. Selective end-to-end cyclization proved to be thoroughly involved in the polymerization, leading to cyclic polylactides with only even-numbered lactyl units.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425305","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 : 2024-06-17DOI: 10.1021/acs.macromol.4c00064
Sweeta Akbari, Mart Kroon, Vijay Singh Parihar, Janne T. Koivisto, Markus Hannula, Minna Kellomäki, Jari Hyttinen
Polymerized high internal phase emulsions (polyHIPEs) were combined with gellan gum (GG) in an innovative approach. Four GG concentrations in polyHIPEs (P-GG 0%, P-GG 0.1%, P-GG 0.5%, and P-GG 1%) were explored for their impact on polyHIPE materials. The resulting macroporous polyHIPE-GG (P-GG) scaffolds exhibited up to 95% porosity and remarkable interconnectivity. Elevating GG concentration correlated with larger pore sizes, increased hydrophilicity, and degradability. Scanning electron microscopy (SEM) and X-ray microcomputed tomography provided insights into the structural influence of GG on polyHIPE materials. Pore sizes ranged from 32 to 1036 μm. In vitro Live/Dead assay confirmed the cytocompatibility of these scaffolds with human fibroblast cells, showcasing their potential for mimicking cartilage and bone tissue structures, promoting cell activities, nutrient exchange, supporting various cell lines, and facilitating vascularization.
{"title":"Synthesis and Characterization of PolyHIPE-Gellan Gum Material with Tunable Macroporosity for Tissue Engineering Applications","authors":"Sweeta Akbari, Mart Kroon, Vijay Singh Parihar, Janne T. Koivisto, Markus Hannula, Minna Kellomäki, Jari Hyttinen","doi":"10.1021/acs.macromol.4c00064","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c00064","url":null,"abstract":"Polymerized high internal phase emulsions (polyHIPEs) were combined with gellan gum (GG) in an innovative approach. Four GG concentrations in polyHIPEs (P-GG 0%, P-GG 0.1%, P-GG 0.5%, and P-GG 1%) were explored for their impact on polyHIPE materials. The resulting macroporous polyHIPE-GG (P-GG) scaffolds exhibited up to 95% porosity and remarkable interconnectivity. Elevating GG concentration correlated with larger pore sizes, increased hydrophilicity, and degradability. Scanning electron microscopy (SEM) and X-ray microcomputed tomography provided insights into the structural influence of GG on polyHIPE materials. Pore sizes ranged from 32 to 1036 μm. In vitro Live/Dead assay confirmed the cytocompatibility of these scaffolds with human fibroblast cells, showcasing their potential for mimicking cartilage and bone tissue structures, promoting cell activities, nutrient exchange, supporting various cell lines, and facilitating vascularization.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425295","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 : 2024-06-17DOI: 10.1021/acs.macromol.3c02262
Tamaned Chayrattanaroj, Siripon Anantawaraskul, João B. P. Soares
Olefin block copolymers (OBCs)─a new type of linear thermoplastic ethylene/1-olefin elastomer─are made via chain-shuttling polymerization using two catalysts with different reactivity ratios and a chain-shuttling agent. The microstructure of the OBCs has been analyzed using standard characterization techniques, but these methods cannot reveal the details of their molecular architectures, such as the distribution of the number of blocks in the polymer population; these finer microstructural features fall in the realm of mathematical models. In this article, we developed probability model equations to describe the microstructure of the OBCs and validated our solutions with Monte Carlo simulations. These new equations describe the distributions of molecular weight, chemical composition, number and length of blocks in OBCs made in a continuous stirred-tank reactor operated at steady-state conditions. We also developed a new method to predict the multimodality of the chemical composition distribution of OBCs (which can be experimentally measured) to assist in the design of new OBC materials.
{"title":"Using Probability Models to Design the Microstructure of Linear Olefin Block Copolymers","authors":"Tamaned Chayrattanaroj, Siripon Anantawaraskul, João B. P. Soares","doi":"10.1021/acs.macromol.3c02262","DOIUrl":"https://doi.org/10.1021/acs.macromol.3c02262","url":null,"abstract":"Olefin block copolymers (OBCs)─a new type of linear thermoplastic ethylene/1-olefin elastomer─are made via chain-shuttling polymerization using two catalysts with different reactivity ratios and a chain-shuttling agent. The microstructure of the OBCs has been analyzed using standard characterization techniques, but these methods cannot reveal the details of their molecular architectures, such as the distribution of the number of blocks in the polymer population; these finer microstructural features fall in the realm of mathematical models. In this article, we developed probability model equations to describe the microstructure of the OBCs and validated our solutions with Monte Carlo simulations. These new equations describe the distributions of molecular weight, chemical composition, number and length of blocks in OBCs made in a continuous stirred-tank reactor operated at steady-state conditions. We also developed a new method to predict the multimodality of the chemical composition distribution of OBCs (which can be experimentally measured) to assist in the design of new OBC materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425224","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 : 2024-06-17DOI: 10.1021/acs.macromol.4c00656
Siteng Zhang, Zhiqiang Cao, Xiaodan Gu, Ting Ge
The ductility of polymer thin films is critical to many applications such as organic electronics and separation membranes. Large-scale molecular simulations are performed to reproduce the experimentally observed necking, a ductile deformation mode. The simulations show that the morphology of a necked film differs qualitatively from craze fibrils in brittle polymers. The micromechanics of thin film necking are revealed with details transcending the capability of experiments. The free boundary of a thin film promotes the plane stress condition and allows the onset of a neck via strain localization. The underlying entanglement network stabilizes the neck by preventing chain pullout. The strain hardening of entangled polymers in the neck region compensates for the reduction in thickness and supports stable neck propagation under a constant tensile force with no bond breaking. Despite the critical role of entanglements, the width of the neck is much larger than the entanglement spacing. The Considère construction predicts well the onset of necking but not the draw ratio of necked polymers, where voids break down the conservation of volume. Krupenkin and Fredrickson’s geometric argument based on the extension of entanglement network strands is able to predict the draw ratio, as verified by the topological analysis using the Z1+ package. The ductile thin film necking is consistently observed in the simulations with thicknesses larger than the unperturbed polymer chain size, temperatures below the glass transition, and deformation rates much higher than the limited monomer mobility.
{"title":"Polymer Thin Film Necking: Ductility from Entanglements and Plane Stress Condition","authors":"Siteng Zhang, Zhiqiang Cao, Xiaodan Gu, Ting Ge","doi":"10.1021/acs.macromol.4c00656","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c00656","url":null,"abstract":"The ductility of polymer thin films is critical to many applications such as organic electronics and separation membranes. Large-scale molecular simulations are performed to reproduce the experimentally observed necking, a ductile deformation mode. The simulations show that the morphology of a necked film differs qualitatively from craze fibrils in brittle polymers. The micromechanics of thin film necking are revealed with details transcending the capability of experiments. The free boundary of a thin film promotes the plane stress condition and allows the onset of a neck via strain localization. The underlying entanglement network stabilizes the neck by preventing chain pullout. The strain hardening of entangled polymers in the neck region compensates for the reduction in thickness and supports stable neck propagation under a constant tensile force with no bond breaking. Despite the critical role of entanglements, the width of the neck is much larger than the entanglement spacing. The Considère construction predicts well the onset of necking but not the draw ratio of necked polymers, where voids break down the conservation of volume. Krupenkin and Fredrickson’s geometric argument based on the extension of entanglement network strands is able to predict the draw ratio, as verified by the topological analysis using the Z1+ package. The ductile thin film necking is consistently observed in the simulations with thicknesses larger than the unperturbed polymer chain size, temperatures below the glass transition, and deformation rates much higher than the limited monomer mobility.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425308","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 : 2024-06-15DOI: 10.1021/acs.macromol.4c00308
Shu Wang, Chase M. Hartquist, Bolei Deng, Xuanhe Zhao
We present a loop-opening model that accounts for the molecular details of the intrinsic fracture energy for fracturing polymer networks. This model includes not only the energy released from the scission of bridging chains but also the subsequent energy released from the network continuum. Scission of a bridging chain releases the cross-links and opens the corresponding topological loop. The released cross-links will be caught by the opened loop to reach a new force-balanced state. The amount of energy released from the network continuum is limited by the stretchability of the opened loop. Based on this loop-opening process, we suggest that the intrinsic fracture energy per broken chain approximately scales with the product of the fracture force and the contour length of the opened loop. This model predicts an intrinsic fracture energy that aligns well with various experimental data on the fracture of polymer networks.
{"title":"A Loop-Opening Model for the Intrinsic Fracture Energy of Polymer Networks","authors":"Shu Wang, Chase M. Hartquist, Bolei Deng, Xuanhe Zhao","doi":"10.1021/acs.macromol.4c00308","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c00308","url":null,"abstract":"We present a loop-opening model that accounts for the molecular details of the intrinsic fracture energy for fracturing polymer networks. This model includes not only the energy released from the scission of bridging chains but also the subsequent energy released from the network continuum. Scission of a bridging chain releases the cross-links and opens the corresponding topological loop. The released cross-links will be caught by the opened loop to reach a new force-balanced state. The amount of energy released from the network continuum is limited by the stretchability of the opened loop. Based on this loop-opening process, we suggest that the intrinsic fracture energy per broken chain approximately scales with the product of the fracture force and the contour length of the opened loop. This model predicts an intrinsic fracture energy that aligns well with various experimental data on the fracture of polymer networks.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141329513","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 : 2024-06-14DOI: 10.1021/acs.macromol.4c00528
Jean-Baptiste Masclef, Emmanuelle M. N. Acs, Jesko Koehnke, Joëlle Prunet, Bernhard V. K. J. Schmidt
Hydrophilic polymers have found ubiquitous use in drug delivery and novel polymer materials to advance drug delivery systems are highly sought after. Herein, an amylose mimic (PEGose) was combined with poly(lactic acid) (PLA) in an amphiphilic block copolymer to form PEG-free nanoparticles as an alternative to PEG-based nanomedicines. The block copolymer self-assembled into 150–200 nm particles with a narrow dispersity in aqueous environment. The formed nanoparticles were capable of encapsulation, the sustained release of both hydrophilic and hydrophobic dyes. Moreover, the nanoparticles were found to be remarkably stable and had a very low cytotoxicity and a high propensity to penetrate cells. These results highlight the potential of PEGose-b-PLA to be used in drug delivery with a new hydrophilic building block.
{"title":"PEGose Block Poly(lactic acid) Nanoparticles for Cargo Delivery","authors":"Jean-Baptiste Masclef, Emmanuelle M. N. Acs, Jesko Koehnke, Joëlle Prunet, Bernhard V. K. J. Schmidt","doi":"10.1021/acs.macromol.4c00528","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c00528","url":null,"abstract":"Hydrophilic polymers have found ubiquitous use in drug delivery and novel polymer materials to advance drug delivery systems are highly sought after. Herein, an amylose mimic (PEGose) was combined with poly(lactic acid) (PLA) in an amphiphilic block copolymer to form PEG-free nanoparticles as an alternative to PEG-based nanomedicines. The block copolymer self-assembled into 150–200 nm particles with a narrow dispersity in aqueous environment. The formed nanoparticles were capable of encapsulation, the sustained release of both hydrophilic and hydrophobic dyes. Moreover, the nanoparticles were found to be remarkably stable and had a very low cytotoxicity and a high propensity to penetrate cells. These results highlight the potential of PEGose-<i>b</i>-PLA to be used in drug delivery with a new hydrophilic building block.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141329472","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 : 2024-06-14DOI: 10.1021/acs.macromol.4c00544
Matthias Maier, Felix Brosge, Johannes S. Schneider, Jonas Bachmann, Sinah Schmidt, Carsten Bolm, Holger Helten
New sulfur-containing inorganic–organic hybrid polymers featuring B═N and B–O linkages are described. Sulfones, sulfoximines, and sulfoxides have been used as sulfur core units. An analogous sulfilimine proved unsuitable leading to an unprecedented side product. Aryl bromoboranes served as starting materials for the B═N and B–O linkages. For each polymer, the respective low-molecular-weight analogues were studied. Finally, degradation studies showed that the sulfur units can be regenerated by pH changes suggesting the new materials to be applicable in drug release programs.
{"title":"Sulfur-Based Building Blocks in BN- and BO-Doped Inorganic–Organic Hybrid Polymers","authors":"Matthias Maier, Felix Brosge, Johannes S. Schneider, Jonas Bachmann, Sinah Schmidt, Carsten Bolm, Holger Helten","doi":"10.1021/acs.macromol.4c00544","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c00544","url":null,"abstract":"New sulfur-containing inorganic–organic hybrid polymers featuring B═N and B–O linkages are described. Sulfones, sulfoximines, and sulfoxides have been used as sulfur core units. An analogous sulfilimine proved unsuitable leading to an unprecedented side product. Aryl bromoboranes served as starting materials for the B═N and B–O linkages. For each polymer, the respective low-molecular-weight analogues were studied. Finally, degradation studies showed that the sulfur units can be regenerated by pH changes suggesting the new materials to be applicable in drug release programs.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141329511","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 : 2024-06-14DOI: 10.1021/acs.macromol.4c01054
Xintong Zhao, Yihua Zhao, Zhongbao Jian, Ying Lu, Yongfeng Men
Deuterated isotactic polybutene-1 (dPB-1) (Mw: 349 kg/mol) and its hydrogeneous counterpart (hPB-1) (Mw: 346 kg/mol) have been synthesized using deuterated 1-butene and hydrogeneous 1-butene monomers, respectively. The dPB-1 shows similar crystallization habit as hPB-1, i.e., crystallizing into metastable form II, which then transforms into stable form I. This peculiar polymorphic transition in hPB-1 normally occurs after cooling to lower temperatures after the crystallization of form II crystals because an internal stress along the lamellar normal built-up during cooling helps to overcome the nucleation barrier of the transition. Surprisingly, a spontaneous form II to I transition at the isothermal crystallization temperature is observed in dPB-1. The crystallization kinetics of form II in dPB-1 is essentially similar to that of hPB-1. The kinetics of the II to I transition in dPB-1 at the isothermal crystallization temperature exhibits a two-step process with the first one with kinetics nearly the same as the crystallization and the second one much slower. The results indicate a very low overall free energy barrier for the II to I transition in dPB-1 suggesting a critical role of the amorphous phase. Indeed, unlike in hPB-1 the conformational energy of 3/1helix in form I is even slightly higher than the 11/3 helix in form II in dPB-1 meaning that the driving force for the II to I transition from inside the crystalline phase is at most similar in both hPB-1 and dPB-1. It turns out that the entropy in the amorphous phase of the dPB-1 is much lower than that of hPB-1 because the vibrational entropy of bonds in both systems is largely different. As such, a much smaller free energy barrier is obtained for the II to I transition in dPB-1 so that a spontaneous transition is observed.
我们分别使用氚代 1-丁烯和氢代 1-丁烯单体合成了氚代异方向聚丁烯-1（dPB-1）（Mw：349 kg/mol）及其氢代异方向聚丁烯-1（hPB-1）（Mw：346 kg/mol）。dPB-1 显示出与 hPB-1 相似的结晶习性，即结晶为可转移的形式 II，然后转变为稳定的形式 I。形式 II 晶体结晶后冷却到较低温度时，hPB-1 通常会发生这种奇特的多态转变，因为冷却过程中沿薄片法线形成的内应力有助于克服转变的成核障碍。令人惊讶的是，在 dPB-1 中观察到了在等温结晶温度下形式 II 向形式 I 的自发转变。dPB-1 中形式 II 的结晶动力学与 hPB-1 基本相似。在等温结晶温度下，dPB-1 中 II 型向 I 型转变的动力学过程分为两步，第一步的动力学过程与结晶过程几乎相同，而第二步则要慢得多。结果表明，dPB-1 中 II 到 I 转变的总自由能垒非常低，这表明非晶相起着关键作用。事实上，与 hPB-1 不同，dPB-1 中形态 I 的 3/1 螺旋的构象能甚至略高于形态 II 的 11/3 螺旋，这意味着在 hPB-1 和 dPB-1 中，从结晶相内部从 II 到 I 的转变的驱动力最多是相似的。事实证明，dPB-1 非晶相中的熵要比 hPB-1 低得多，因为这两种体系中键的振动熵有很大不同。因此，dPB-1 中 II 到 I 转变的自由能障要小得多，从而可以观察到自发转变。
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