title: Effect of acid on the aggregation of poly(ethylene xide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers.
abstract: The acid effect on the aggregation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers EO(20)PO(70)EO(20) has been investigated by transmission electron microscopy (TEM), particle size analyzer (PSA), Fourier transformed infrared, and fluorescence spectroscopy. The critical micellization temperature for Pluronic P123 in different HCl aqueous solutions increases with the increase of acid concentration. Additionally, the hydrolysis degradation of PEO blocks is observed in strong acid concentrations at higher temperatures. When the acid concentration is low, TEM and PSA show the increase of the micelle mean diameter and the decrease of the micelle polydispersity at room temperature, which demonstrate the extension of EO corona and tendency of uniform micelle size because of the charge repulsion. When under strong acid conditions, the aggregation of micelles through the protonated water bridges was observed.
authors.affiliation: Laboratory of Separation Science and Engineering, State Key Laboratory of Biochemical Engineering, Institution of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing 100080, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Chen
authors.initials: C
authors.lastname: Guo
authors.forename: Shu
authors.initials: S
authors.lastname: Chen
authors.forename: Junhe
authors.initials: J
authors.lastname: Ma
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Liang
authors.forename: Lily
authors.initials: L
authors.lastname: Zheng
authors.forename: Huizhou
authors.initials: H
authors.lastname: Liu
mesh_terms: D004852:Epoxy Compounds / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry* / Q000494:pharmacology; D006868:Hydrolysis; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D011060:Poloxalene / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011126:Polypropylenes / Q000737:chemistry*; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D004852:Epoxy Compounds; D008823:Micelles; D011108:Polymers; D011126:Polypropylenes; D014867:Water; C464484:pluronic block copolymer P123; D011092:Polyethylene Glycols; D011060:Poloxalene; D006851:Hydrochloric Acid; C009068:propylene oxide