Surfactant-assisted entanglement of interfacial polymer chains

The temperature-induced conformational transitions of neutral poly(N-isopropylacrylamide) chains at interfaces are studied in the presence of a surfactant, sodium dodecyl sulfate in an aqueous solution. The results obtained from the collapse-to-swelling transition show that the polymer dimension in good solvency is smaller after collapse transition than that before the transition. Such a dimension difference due to the conformational changes becomes significant with increasing the surfactant concentration and final collapse temperature. The polymer-surfactant complexes, the ion pair, and the multiplet structure are believed to play roles in inducing the entanglement of interfacial chains in the poor solvency domain.