Polymer Journal最新文献_第2页

Rapid and highly efficient recombination of crosslinking points in hydrogels generated via the template polymerization of dynamic covalent three-dimensional nanoparticle crosslinkers

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-12-13 DOI: 10.1038/s41428-024-00996-5

Mahmoud H. Othman, Yoshihiro Ito, Jun Akimoto

{"title":"Rapid and highly efficient recombination of crosslinking points in hydrogels generated via the template polymerization of dynamic covalent three-dimensional nanoparticle crosslinkers","authors":"Mahmoud H. Othman, Yoshihiro Ito, Jun Akimoto","doi":"10.1038/s41428-024-00996-5","DOIUrl":"10.1038/s41428-024-00996-5","url":null,"abstract":"Dynamic covalent bonds (DCBs) can be used as crosslinking points to induce self-healing and thermoplastic properties in hydrogels because the bonding and dissociation between molecules can be controlled by external stimuli. However, once DCBs dissociate, molecules diffuse inside the gel, delaying DCB reformation. In this study, a hydrogel was prepared via template polymerization using phenylboronic acid-coated nanoparticles to control the mobility of the molecules and the density of the DCB crosslinking points. Interestingly, the loss modulus, but not the storage modulus, of the hydrogel changed with temperature according to the formation/dissociation of boronic ester bonds. Furthermore, compared with conventional hydrogels, the hydrogels prepared here exhibited very rapid changes in physicochemical properties in response to changes in temperature because the high density of three-dimensional DCB crosslinking points limits the diffusion of molecules inside the gel. As a result, the prepared hydrogel showed rapid self-healing and thermoplastic properties as the temperature changed. A novel hydrogel (TempGel(NP)) was synthesized through template polymerization of phenylboronic-acid-coated nanoparticles with tris(hydroxymethyl)methyl acrylamide (THMAAm). This process forms dynamic boronic ester crosslinks, creating a highly dense and uniform three-dimensional network. The innovative structure exhibits reversible thermal responsiveness, enabling rapid bond dissociation and reformation upon temperature changes. The dense packing around nanoparticles minimizes molecular diffusion, ensuring superior self-healing, high thermal hysteresis, and tunable viscoelastic properties. This innovative design provides a robust platform for advanced applications in smart materials, biomedical devices and responsive hydrogels.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 3","pages":"315-325"},"PeriodicalIF":2.3,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00996-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Improvement in the toughness and compatibility of poly(lactic acid)/starch acetoacetate through reactive melt-kneading with amine-modified silicone

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-12-13 DOI: 10.1038/s41428-024-00971-0

Kazuki Shibasaki, Yu-I Hsu, Hiroshi Uyama

{"title":"Improvement in the toughness and compatibility of poly(lactic acid)/starch acetoacetate through reactive melt-kneading with amine-modified silicone","authors":"Kazuki Shibasaki, Yu-I Hsu, Hiroshi Uyama","doi":"10.1038/s41428-024-00971-0","DOIUrl":"10.1038/s41428-024-00971-0","url":null,"abstract":"Nonbiodegradable plastic pollution has taken centerstage because of its negative impacts on ecosystems, and poly(lactic acid) (PLA)/starch blends, which are biodegradable plastics, have attracted increased attention as sustainable materials. However, the poor compatibility between hydrophobic PLA and hydrophilic starch causes their composites to become brittle. In this study, to improve the compatibility between PLA and starch, the hydroxyl groups of starch were modified with acetoacetate, and amine-modified silicone was used as the compatibilizer. The acetoacetyl group readily reacts with primary amines under mild conditions to form enamines and is expected to react rapidly during the melt-kneading process. The amino groups also react with the decomposed PLA end groups via condensation. Therefore, amine-modified silicone is considered a suitable compatibilizer for PLA and starch acetoacetate (SAA). PLA/SAA/amine-modified silicone blends were prepared via melt-kneading. The toughness of PLA/SAA was improved by approximately 15 times when 3 wt% amine-modified silicone was added. Furthermore, in the SEM observation of the tensile fracture surface, it was found that the dispersibility of SAA in PLA was improved such that SAA and PLA were indistinguishable. This approach can contribute to the widespread use of biodegradable plastics in packaging materials and single-use plastics. In this study, to improve the compatibility of PLA and starch, the hydroxyl groups of the starch were modified with acetoacetic acid, and amine-modified silicone was used as a compatibilizer. PLA/SAA/amine-modified silicone blends were prepared by melt-kneading. The toughness of PLA/SAA was improved by about 15 times by adding 3 wt% amine-modified silicone. This approach can contribute to the widespread use of biodegradable plastics in packaging materials and single-use plastics.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 3","pages":"303-314"},"PeriodicalIF":2.3,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00971-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Relationship between the heterogeneity in particle dynamics and network topology in transient networks via a microrheological study

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-12-09 DOI: 10.1038/s41428-024-01000-w

Koshiro Nakamura, Shota Michida, Mitsuru Naito, Ung-il Chung, Takuya Katashima

{"title":"Relationship between the heterogeneity in particle dynamics and network topology in transient networks via a microrheological study","authors":"Koshiro Nakamura, Shota Michida, Mitsuru Naito, Ung-il Chung, Takuya Katashima","doi":"10.1038/s41428-024-01000-w","DOIUrl":"10.1038/s41428-024-01000-w","url":null,"abstract":"Soft materials encompass various hierarchical structures that determine their mechanical properties. However, the relationships between these hierarchical structures and mechanical properties remain unclear owing to a lack of studies on local information and the difficulty in controlling hierarchical structures. Herein, we demonstrate a multiple particle tracking method, which is a representative microrheological measurement method, within transient networks with a precisely controlled network topology. This is the most basic parameter of hierarchical structures. Our results reveal that the heterogeneity in particle dynamics is enhanced and reaches a maximum at the percolation threshold, which is a universal phenomenon in sol–gel transitions. Notably, this study is the first to report that the heterogeneity in particle dynamics within transient networks established via reversible bonds exhibits characteristics similar to those of percolation phenomena in hydrogels. These insights provide a basis for examining the relationships between the mechanical properties and hierarchical structures of soft materials. A multiple particle tracking method was used to track probe particles in Tetra-PEG slimes with various network connectivities, revealing that the deviation from the Gaussian distribution of the particle dynamics is greater than the percolation threshold (network connectivity = 0.34). This study is the first to report that the heterogeneity of particle dynamics in transient networks, formed through reversible bonds, exhibits characteristics similar to those observed during sol–gel transitions.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 4","pages":"427-434"},"PeriodicalIF":2.3,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-01000-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Synthesis and two-dimensional ordering of asymmetrically polymer–brush–decorated cellulose nanocrystals

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-12-05 DOI: 10.1038/s41428-024-00994-7

Yuji Kinose, Seitaro Fujimoto, Keita Sakakibara, Yoshinobu Tsujii

{"title":"Synthesis and two-dimensional ordering of asymmetrically polymer–brush–decorated cellulose nanocrystals","authors":"Yuji Kinose, Seitaro Fujimoto, Keita Sakakibara, Yoshinobu Tsujii","doi":"10.1038/s41428-024-00994-7","DOIUrl":"10.1038/s41428-024-00994-7","url":null,"abstract":"Rod-shaped cellulose nanocrystals (CNCs) are typically obtained by hydrolyzing cellulose nanofibers bearing an formyl group at their reducing end. In this study, we prepare CNCs bearing densely grafted polymer brushes of different molecular weights (asymmetrically polymer-brush–decorated CNCs; aPB-CNCs). aPB-CNCs exhibit good dispersion in organic solvents and form a monolayer at the air/water interface. The compression of this monolayer induces a phase transition of a long polymer brush at the reducing end and a change in the orientation of the CNC core due to repulsive interactions. A CNC is identified as a key intermediate, possessing dormant moieties for reversible addition–fragmentation polymerization and atom transfer radical polymerization at the reducing end and other surfaces, respectively (bifunctional dormant CNC). This functional CNC facilitates the polymerization of a wide range of monomers and enables the synthesis of aPB-CNCs with diverse chemical properties. The developed synthetic route not only provides a basis for exploring the ordered structure of nanoparticles but is also useful for modifying the reducing ends of CNCs. Cellulose nanocrystals (CNCs) bearing densely grafted polymer brushes of different molecular weights (asymmetrically polymer-brush–decorated CNCs; aPB-CNCs) were synthesized via a CNC intermediate possessing two types of dormant moieties for controlled radical polymerization at the reducing end and other surfaces, respectively. The aPB-CNCs exhibited good dispersion in organic solvents and form a monolayer at the air/water interface. The compression of this monolayer induced a phase transition of a long polymer brush at the reducing end and a change in the orientation of the CNC core due to repulsive interactions.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 3","pages":"269-277"},"PeriodicalIF":2.3,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00994-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Crosslink inhomogeneity in epoxy resins cured with a phenolic hardener under organophosphine catalysts revealed by small-angle X-ray scattering

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-12-04 DOI: 10.1038/s41428-024-00993-8

Takeshi Kakara, Atsushi Izumi, Yasuyuki Shudo, Atsuomi Shundo, Keiji Tanaka

{"title":"Crosslink inhomogeneity in epoxy resins cured with a phenolic hardener under organophosphine catalysts revealed by small-angle X-ray scattering","authors":"Takeshi Kakara, Atsushi Izumi, Yasuyuki Shudo, Atsuomi Shundo, Keiji Tanaka","doi":"10.1038/s41428-024-00993-8","DOIUrl":"10.1038/s41428-024-00993-8","url":null,"abstract":"In this study, the crosslink inhomogeneities in two types of epoxy resins cured with a phenolic hardener under organophosphine catalysts were successfully clarified by small-angle X-ray scattering (SAXS) using a solvent-swelling technique. Herein, triphenylphosphine (TPP) and tetraphenylphosphonium tetra-p-tolylborate (TPPTTB) were investigated as the curing catalysts. The SAXS profiles in a fully tetrahydrofuran (THF)-swollen state clearly revealed a difference between the two types of resins. The profiles at the early, middle, and late stages of gelation were effectively explained by a sum of structural functions representing the crosslinking inhomogeneity and concentration fluctuations of the polymer chains. Furthermore, the change in the profiles indicated that the characteristic size of inhomogeneity was associated with the size of the minor, low-crosslink density region. The correlation lengths of the mesh size decreased to 1 nm for both resins. These results confirmed the formation of a well-developed crosslinked network structure. Moreover, the correlation lengths of the crosslink inhomogeneity at the late stage of gelation were 1 and 5 nm for the TPP- and TPPTTB-cured resins, respectively. Thus, the phenolic-cured epoxy resins using an organophosphine catalyst system exhibited a THF-swellable, low crosslink density region due to inhomogeneity at the late stage of gelation. This rapid communication reports the first successful clarification of the difference in the crosslink inhomogeneity at the nanometer scale for two types of structurally identical epoxy resins cured with a phenolic hardener under organophosphine catalysts.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 4","pages":"377-383"},"PeriodicalIF":2.3,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00993-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Poisson’s ratio transition in strain crystallizing elastomer: from rubbery amorphous to semicrystalline 应变结晶弹性体的泊松比转变：从橡胶无定形到半结晶

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-12-04 DOI: 10.1038/s41428-024-00998-3

Takuho Naraoka, Ruito Tanaka, Hideaki Takagi, Katsuhiko Tsunoda, Thanh-Tam Mai, Shinichi Sakurai, Kenji Urayama

{"title":"Poisson’s ratio transition in strain crystallizing elastomer: from rubbery amorphous to semicrystalline","authors":"Takuho Naraoka, Ruito Tanaka, Hideaki Takagi, Katsuhiko Tsunoda, Thanh-Tam Mai, Shinichi Sakurai, Kenji Urayama","doi":"10.1038/s41428-024-00998-3","DOIUrl":"10.1038/s41428-024-00998-3","url":null,"abstract":"The Poisson’s ratio (μ) of natural rubber (NR) undergoing strain-induced crystallization (SIC) during uniaxial stretching was investigated as a function of the applied stretch ( $${lambda }_{{||}}$$ ) over a broad $${lambda }_{{||}}$$ range, encompassing the SIC onset stretch ( $${{lambda }_{{||}}}^{* }$$ ≈ 4.1). Below $${{lambda }_{{||}}}^{* }$$ , μ remains near 1/2, indicating the incompressible behavior of NR in its fully rubbery amorphous state. However, once $${lambda }_{{||}}$$ exceeds $${{lambda }_{{||}}}^{* }$$ , μ decreases as the degree of crystallinity (χc) increases. As $${lambda }_{{||}}$$ increases from $${{lambda }_{{||}}}^{* }$$ to fracture stretch ( $${lambda }_{{||}}$$ ≈ 7.1), χc increases to 18%, and μ gradually decreases to 0.33. This reduction in μ reflects the transformation of the NR matrix from a rubbery amorphous state to a semicrystalline state. In fact, the true stress (force per cross-sectional area in the deformed state) at the fracture point, obtained via actual lateral contraction, is approximately 85% of that estimated under the assumption μ = 1/2. These findings provide a critical foundation for accurately modeling the mechanical behavior of strain-crystallizing elastomers. The Poisson''s ratio (μ) of natural rubber undergoing strain-induced crystallization was studied across a broad stretch range. Below the crystallization onset stretch ( $${lambda }_{{||}}$$ * ≈ 4.1), μ remains near 0.5, indicating incompressibility. Beyond $${lambda }_{{||}}$$ *, μ decreases with increasing crystallinity, reaching 0.33 at fracture ( $${lambda }_{{||}}$$ ≈ 7.1), as the matrix transforms from amorphous to semicrystalline. The true stress at fracture, accounting for lateral contraction, is approximately 85% of the estimated value assuming μ = 0.5. These insights are vital for modeling the mechanical behavior of strain-crystallizing elastomers.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 4","pages":"477-482"},"PeriodicalIF":2.3,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00998-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Review of bioderived and biodegradable polymers/block-copolymers and their biomedical and electronic applications

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-12-03 DOI: 10.1038/s41428-024-00980-z

Ping-Jui Yu, Yan-Cheng Lin, Wen-Chang Chen

{"title":"Review of bioderived and biodegradable polymers/block-copolymers and their biomedical and electronic applications","authors":"Ping-Jui Yu, Yan-Cheng Lin, Wen-Chang Chen","doi":"10.1038/s41428-024-00980-z","DOIUrl":"10.1038/s41428-024-00980-z","url":null,"abstract":"The growing awareness of eco-friendly and high-value materials has attracted many researchers to green chemistry. With versatile advantages, biodegradability is the paramount property for waste disposal or recycling, and it can determine whether a product is environmentally sustainable. Moreover, bioderived materials are crucial because the reprocessed products are difficult to handle after recycling. Therefore, biodegradable and bioderived materials can address increasing environmental issues via recycling approaches and reprocessing products. Combining these sustainable concepts, block copolymers (BCPs) with self-assembling characteristics have been extensively investigated for use in biobased materials, green processing, and recyclable electronic applications. This mini-review introduces the design and syntheses of the starting biobased monomers, prepolymers, and block copolymers. Then, their degradability and recyclability are evaluated. Due to their significant potential, biobased and biodegradable BCPs hold great promise in biomedical and optoelectronic applications. Bioderived materials are value-added by recycling excessive residues to gain a new life for themselves. Biodegradable materials can address increasing environmental issues via recycling approaches and reprocessing products. Concerning these attractive advantages, in the first part of this review, commodity polymers from biosources and their recycling and biodegradable pathways are described. The second part summarizes the recent advances of bioderived and biodegradable block copolymers in biomedical and electronic applications, including drug carriers, field-effect transistors, and nonvolatile memory. This review sheds light on the bright perspective of bioderived and biodegradable polymers.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 3","pages":"233-247"},"PeriodicalIF":2.3,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Off-stoichiometry effect on the physical properties of epoxy resins 非化学计量对环氧树脂物理性质的影响

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-11-29 DOI: 10.1038/s41428-024-00983-w

Satoru Yamamoto, Nguyen Thao Phan, Kouki Kihara, Atsuomi Shundo, Keiji Tanaka

{"title":"Off-stoichiometry effect on the physical properties of epoxy resins","authors":"Satoru Yamamoto, Nguyen Thao Phan, Kouki Kihara, Atsuomi Shundo, Keiji Tanaka","doi":"10.1038/s41428-024-00983-w","DOIUrl":"10.1038/s41428-024-00983-w","url":null,"abstract":"Amines generally tend to segregate at the interface of the epoxy resins cured with amines. To gain better insight into the aggregation states and physical properties at the adhesive interface, we examined the cross-linking structure and physical properties of the cured epoxy resins with an off-stoichiometric ratio of epoxy and amine. As the excess amine increased, the amine not only remained as unreacted monomers or low-molecular-weight isolated chains within the cross-linking structure but also formed dangling chain ends, increasing heterogeneity in the cured epoxy resin. As a result, the cross-linking density and mass density decreased, along with a reduction in the glass transition temperature. On the other hand, Young’s modulus increased with the excess amount of amine. Wide-angle X-ray scattering experiments, in conjunction with molecular dynamics simulations, revealed that the excess amine suppressed the widening of the distance between phenyl groups during the curing reaction, suggesting that this could act as steric resistance during deformation. The cross-linking structure and physical properties of epoxy resins cured with amine under off-stoichiometric ratio conditions were examined. As the excess amine increased, some of the amine not only remained as unreacted monomers or low-molecular-weight isolated chains within the cross-linking structure, but also formed dangling chain ends. As a result, the cross-linking density and mass density decreased, as did the glass transition temperature. On the other hand, Young’s modulus increased with the excess amount of amine due to the suppression of the widening distance between phenyl groups.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 4","pages":"357-366"},"PeriodicalIF":2.3,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00983-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Salt concentration dependency of the hydrated swollen structure of cholinephosphate-type polyzwitterion brushes

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-11-28 DOI: 10.1038/s41428-024-00991-w

Takumi Komiya, Norifumi L. Yamada, Motoyasu Kobayashi

{"title":"Salt concentration dependency of the hydrated swollen structure of cholinephosphate-type polyzwitterion brushes","authors":"Takumi Komiya, Norifumi L. Yamada, Motoyasu Kobayashi","doi":"10.1038/s41428-024-00991-w","DOIUrl":"10.1038/s41428-024-00991-w","url":null,"abstract":"The swollen thicknesses of zwitterionic polymer brushes with phosphorylcholine (PC), cholinephosphate (CP), sulfobetaine, and carboxybetaine groups were measured in aqueous sodium chloride (NaCl) or calcium chloride (CaCl2) solutions via force curve measurements by scanning probe microscopy (SPM) and neutron reflectivity measurements. PC and CP have different charge positions in betaine units consisting of ammonium and phosphate. The PC-type polymer brush did not distinctly reduce the swollen thickness in either the NaCl or CaCl2 solution, even at 1000 mM. However, the swollen thickness of the CP-type polymer brushes was clearly reduced in the aqueous CaCl2 solution. Unlike the phosphate of PC, which is located inside the betaine unit, the phosphate of CP tends to form insoluble calcium phosphate, resulting in the collapse of the brush structure. The effect of calcium ion on the swelling structure of polymer brushes bearing phosphorylcholine (PC) and cholinephosphate (CP) groups in aqueous solution were investigated by scanning probe microscopy and neutron reflectivity measurements. The CP-type polymer brushes formed collapsed structure in the aqueous CaCl2 solution because the phosphate of CP, which is located outside the betaine unit, strongly interacts with calcium ions to form insoluble calcium phosphate. In contrast, no significant change was observed in the swollen thickness of the PC-type polymer brush in the aqueous CaCl2 solution.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 3","pages":"291-301"},"PeriodicalIF":2.3,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Brownian simulations for fracture of star polymer phantom networks

IF 2.3 4区化学

Polymer Journal Pub Date : 2024-11-28 DOI: 10.1038/s41428-024-00992-9

Yuichi Masubuchi, Yusuke Koide, Takato Ishida, Takashi Uneyama

{"title":"Brownian simulations for fracture of star polymer phantom networks","authors":"Yuichi Masubuchi, Yusuke Koide, Takato Ishida, Takashi Uneyama","doi":"10.1038/s41428-024-00992-9","DOIUrl":"10.1038/s41428-024-00992-9","url":null,"abstract":"According to a recent simulation study [Masubuchi et al., Macromolecules, 56, 9359 (2023)], the cycle rank plays a significant role in determining the fracture characteristics of network polymers. However, the previous studies considered only energy-minimized networks without including the effects of thermal agitation. To address this gap, this study conducted Brownian dynamics simulations at various stretch rates. The results showed that even with Brownian motion, the strain and stress at break obtained for different node functionalities and conversion ratios exhibited master curves when plotted versus the cycle rank. These master curves depend on the strain rate, indicating that the strain and stress at break decrease with decreasing strain rate. The curves are qualitatively similar to those observed in energy-minimized simulations, even though the competition among Brownian motion, elongation, and bond scission affects the fracture process. This study examined the fracture of polymer networks via Brownian simulations with various strain rates. The networks were created from star polymers with different branching degrees and conversion ratios. The results showed that strain and stress at break, plotted against cycle rank, form master curves dependent on strain rate; the fracture characteristics decrease with decreasing strain rate. Despite the interplay of Brownian motion, elongation, and bond scission, the cycle rank dependence is qualitatively similar to that reported previously for energy-minimized networks.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 4","pages":"483-489"},"PeriodicalIF":2.3,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00992-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0