RAFTPolymerizationofN-VinylimidazoliumSaltsandSynthesisofThermoresponsiveIonicLiquidBlockCopolymers

摘要

ThepolymerizationsofN-vinylimidazoliumsalts,1-(3-phenylpropyl)-3-vinylimidazoliumbro-mide(PVI-Br),1-(6-ethoxycarbonylhexyl)-3-vinylimidazoliumbromide(EHVI-Br),and1-(2-ethoxyethyl)-3-vinylimidazoliumbromide(EtOEVI-Br),wereperformedbyreversibleaddition-fragmentationchaintransfer(RAFT)/macromoleculardesignviainterchangeofxanthate(MADIX)process.Twoxanthate-typechaintransferagents(CTAs),O-ethyl-S-(1-phenylethyl)dithiocarbonate(CTA1)andO-ethyl-S-(1-ethoxycarbonyl)ethyldithiocarbonate(CTA2),provedefficientforobtainingpoly(PVI-Br)sand(EHVI-Br)swithrelativelylowpolydispersities(Mw/Mn<1.4).Poly(EtOEVI-Br)swithmoderatemolecularweightdistributions(Mw/Mn=1.5-1.6)werealsoobtainedunderthesameconditions.ControlledcharacterofthepolymerizationofPVI-Brwasconfirmedbythemolecularweightcontrolledbythemonomer/CTAmolarratio,alinearincreaseinthenumber-averagemolecularweight(Mn)withconversion,andtheabilitytoextendthechainbyasecondadditionofmonomer.PolymerizationsoftheN-vinylimidazoliumsaltsusingthedithiocarbonate-terminatedpoly(N-isopropylacrylamide)asamacro-chain-transferagentprovidedwell-definedthermoresponsiveionicliquidblockcopolymers.Thermallyinducedphaseseparationbehaviorandassembledstructuresoftheblockcopolymerswerealsostudiedinaqueoussolution.