Contrary Hydration Behavior of N-Isopropylacrylamide to its Polymer, P(NIPAm), with a Lower Critical Solution Temperature

The number of hydrated water molecules per N-isopropylacrylamide in homogeneous aqueous solution was determined to be a constant with a value of 5-6 below and above the lower critical solution temperature, LCST (32 degrees C), of its polymer, poly(N-isopropylacrylamide), by high-frequency dielectric relaxation techniques.