SOLUTION PROPERTIES OF POLY(N-ISOPROPYLACRYLAMIDE) IN WATER

Various molecular parameters characterizing the solution properties of poly(N-isopropylacrylamide) (in the range of molecular weight from 13.8 to 910×104) in water at 20°C and the temperature dependence of them in the range of 20°C to 30.6°C were determined with static and dynamic light scattering technique. (Modified) Flory’s fifth power law of excluded volume effect predicts well the temperature dependence of the chain dimension. It is shown that this polymer molecule behaves as a flexible coil from the molecular weight dependence of these parameters and the relation between the interpenetration function and expansion coefficients. The unique thermal behavior of this solution, temperature of phase change being independent of molecular weights and concentrations at least in the range of 1 wt%, should be mainly attributed to the hydrated structure. © 1990 The Society of Polymer Science, Japan.