title: Synthesis and self-assembly behavior of four-arm poly(ethylene oxide)-b-poly(2-(diethylamino)ethyl methacrylate) star block copolymer in salt solutions.
abstract: A well-defined block copolymer consisting of four-arm poly(ethylene oxide)-b-poly(2-(diethylamino)ethyl methacrylate) (four-arm PEO56-b-PDEAEMA74) was synthesized by atom transfer radical polymerization. The pH-responsive self-assembly behavior was examined by potentiometric titration, surface tensiometry, laser light scattering, and transmission electron microscopy over the course of dissociation by the addition of a base or acid. The apparent hydrodynamic radius (Rh) of the micelle increased from 21 to 56 nm when the degree of protonation of the amine groups was increased from 0 to 0.5 in 0.01 M NaCl solution. In higher concentration NaCl solution, the micelle shrank due to the electrostatic charge screening of the protonated DEAEMA groups. At low pH, the micelles dissociated into unimers.
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.
authors.forename: E
authors.initials: E
authors.lastname: He
authors.forename: P
authors.initials: P
authors.lastname: Ravi
authors.forename: K C
authors.initials: KC
authors.lastname: Tam
mesh_terms: D002627:Chemistry, Physical / Q000379:methods; D002850:Chromatography, Gel; D004563:Electrochemistry / Q000379:methods; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008689:Methacrylates / Q000737:chemistry*; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D008968:Molecular Conformation; D009757:Nylons / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011199:Potentiometry / Q000379:methods; D012492:Salts / Q000494:pharmacology; D012542:Scattering, Radiation; D013499:Surface Properties
chemical_list: D008689:Methacrylates; D008823:Micelles; D009757:Nylons; D011108:Polymers; D012492:Salts; C109846:poly(2-(diethylamino)ethyl methacrylate)