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Direct Controlled Polymerization of Ionic Monomers by Surface‐Initiated ATRP Using a Fluoroalcohol and Ionic Liquids
Author(s) -
Kobayashi Motoyasu,
Terada Masami,
Terayama Yuki,
Kikuchi Moriya,
Takahara Atsushi
Publication year - 2012
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.201100136
Subject(s) - polymerization , chemistry , polymer chemistry , monomer , polymer , atom transfer radical polymerization , dispersity , ionic liquid , methacrylate , organic chemistry , catalysis
Surface‐initiated atom transfer radical polymerization (ATRP) of (2‐methacryloyloxyethyl)trimethylammonium chloride (MTAC), 3‐( N ‐2‐methacryloyloxyethyl‐ N , N ‐dimethyl) ammonatopropanesulfonate) (MAPS), and 2‐methacryloyloxyethyl phosphorylcholine (MPC) was carried out in 2,2,2‐trifluoroethanol (TFE) containing a small amount of 1‐hexyl‐3‐methylimidazolium chloride at 60 °C to produce well‐defined ionic polymer brushes and the corresponding free polymers with predictable number‐average molecular weight ( M n , 1×10 4 −3×10 5 g mol −1 ) and narrow molecular weight dispersity ( M w / M n <1.2). A first‐order kinetic plot for ATRP of MTAC and MAPS revealed a linear relationship between the monomer conversion index (ln([M] 0 /[M])) and polymerization time. Reduction in polymerization rates was observed with an increase in ionic liquid concentration. The M n of both poly(MTAC) and poly(MAPS) increased in proportion to the conversion. The sequential polymerization of MAPS initiated with the chain ends of poly(MAPS) produced the postpolymer with quantitative efficiency. The thickness of the polymer brush was controllable from 5 to 100 nm based on the M n of the polymer. These results suggest the successful control of the polymerization of sulfobetaine‐type methacrylates owing to the TFE and ionic liquids. In particular, the high affinity of TFE for the sulfobetaine monomers and polymers yielded a homogeneous polymerization media to improve surface‐initiated polymerization generating the polymer brushes on the substrate surface as well as the free polymers formed in the solution. The effect on ATRP of the chemical structure of ionic liquids and ligands for copper catalyst was also investigated.