Water-Induced Formation of Reverse Micelles from Diblock Copolymer of Styrene and N-Isopropylacrylamide in 1,2-Dichloroethane

Abstract

Water-induced formation of reverse micelles from polystyrene-b-poly(N-isopropylacrylamide) (PS(x)–PN(y), where x and y were the degrees of polymerization of PS and PN blocks, respectively) in 1,2-dichloroethane (DCE) was investigated mainly by light scattering. Four PS(x)–PN(y) samples with different degrees of polymerization x and y were prepared by the reversible addition–fragmentation chain-transfer (RAFT) radical polymerization technique. While PS(x)–PN(y) was molecularly dispersed in DCE, the addition of water remarkably enhanced scattering light intensity from the DCE solutions of all the PS(x)–PN(y) samples, indicative of the formation of the reverse micelle having a water pool as the micellar core. Static light scattering (SLS) data for PS(x)–PN(y)/water/DCE ternary systems were analyzed using a model of spherical reverse micelle to estimate structural parameters, which were dependent on the hydrophilic–hydrophobic balance, i.e., y/x.