Water-Induced Formation of Reverse Micelles from Diblock Copolymer of Styrene and <i>N</i>‑Isopropylacrylamide in 1,2-Dichloroethane

Abstract

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