{"title":"Thermoresponsive Gelation and Phase Transition of PEG/Cation Random Terpolymer Micelles in Water in the Presence of Salts","authors":"Rikuto Kanno, Motoki Shibata, Mikihito Takenaka, Shin-ichi Takata, Kosuke Hiroi, Makoto Ouchi, Takaya Terashima","doi":"10.1021/acs.macromol.4c01677","DOIUrl":null,"url":null,"abstract":"Amphiphilic random terpolymers bearing hydrophilic poly(ethylene glycol) (PEG) chains, quaternary ammonium cations, and hydrophobic dodecyl groups form size-controlled micelles in water. The terpolymer micelles show a lower critical solution temperature (LCST)-type solubility in water in the presence of salts. Focusing on the features, we herein investigated the thermoresponsive properties of the concentrated aqueous solutions of the PEG/cation random terpolymer micelles containing NaCl to find unique gelation and phase transition dependent on the PEG/cation composition. Upon heating, the PEG/cation (2/1, 1/1, and 1/2) terpolymer micelle solutions exhibited a two-step phase transition through transient gelation to viscous and turbid solutions via LCST-type phase separation. In contrast, a cation-rich PEG/cation (1/3) terpolymer micelle and a cation copolymer micelle formed gels in water at room temperature, where the former changed to a viscous and transparent solution upon heating. The rheological properties of the gels can be tuned by the PEG/cation ratio and degree of polymerization of the terpolymers. Small-angle neutron scattering measurements revealed that the transient gelation of the terpolymer micelle solutions occurred via the formation of intermicellar networks.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.1000,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Macromolecules","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.macromol.4c01677","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
Amphiphilic random terpolymers bearing hydrophilic poly(ethylene glycol) (PEG) chains, quaternary ammonium cations, and hydrophobic dodecyl groups form size-controlled micelles in water. The terpolymer micelles show a lower critical solution temperature (LCST)-type solubility in water in the presence of salts. Focusing on the features, we herein investigated the thermoresponsive properties of the concentrated aqueous solutions of the PEG/cation random terpolymer micelles containing NaCl to find unique gelation and phase transition dependent on the PEG/cation composition. Upon heating, the PEG/cation (2/1, 1/1, and 1/2) terpolymer micelle solutions exhibited a two-step phase transition through transient gelation to viscous and turbid solutions via LCST-type phase separation. In contrast, a cation-rich PEG/cation (1/3) terpolymer micelle and a cation copolymer micelle formed gels in water at room temperature, where the former changed to a viscous and transparent solution upon heating. The rheological properties of the gels can be tuned by the PEG/cation ratio and degree of polymerization of the terpolymers. Small-angle neutron scattering measurements revealed that the transient gelation of the terpolymer micelle solutions occurred via the formation of intermicellar networks.
期刊介绍:
Macromolecules publishes original, fundamental, and impactful research on all aspects of polymer science. Topics of interest include synthesis (e.g., controlled polymerizations, polymerization catalysis, post polymerization modification, new monomer structures and polymer architectures, and polymerization mechanisms/kinetics analysis); phase behavior, thermodynamics, dynamic, and ordering/disordering phenomena (e.g., self-assembly, gelation, crystallization, solution/melt/solid-state characteristics); structure and properties (e.g., mechanical and rheological properties, surface/interfacial characteristics, electronic and transport properties); new state of the art characterization (e.g., spectroscopy, scattering, microscopy, rheology), simulation (e.g., Monte Carlo, molecular dynamics, multi-scale/coarse-grained modeling), and theoretical methods. Renewable/sustainable polymers, polymer networks, responsive polymers, electro-, magneto- and opto-active macromolecules, inorganic polymers, charge-transporting polymers (ion-containing, semiconducting, and conducting), nanostructured polymers, and polymer composites are also of interest. Typical papers published in Macromolecules showcase important and innovative concepts, experimental methods/observations, and theoretical/computational approaches that demonstrate a fundamental advance in the understanding of polymers.