EFFECT OF INCORPORATING A TRACE AMOUNT OF FLUOROCARBON INTO POLY(N-ISOPROPYLACRYLAMIDE) ON ITS ASSOCIATION IN WATER

A combination of laser light scattering (LLS), viscometry, and fluores cence spectroscopy was used to study the association of a series of fl uorocarbon-modified poly(N-isopropylacrylamide) (PNIPAM) copolymers in aqueous solution. The interchain association increases as both the fl uorocarbon content and polymer concentration increase, evidenced by th e changes of the apparent molar mass, intrinsic viscosity, Huggins con stant, and fluorescence excimer-to-monomer intensity ratio. The LLS re sults are well-represented by the open association model. Our results also revealed that the intrachain association starts when each polymer chain, on average, has more than two fluorocarbon monomers.