Molecular motion and ¹H NMR relaxation of aqueous poly(N‐isopropylacrylamide) solution under high pressure

Abstract

Abstract In order to obtain useful information about the molecular motion and structure of poly( N ‐isopropylacrylamide) (PNiPAM) in aqueous solution, proton spin‐lattice relaxation times, proton spin‐spin relaxation times, and volume changes were measured at pressures from 1 to 400 kg/cm 2 as a function of temperature. We found that the molecular motion and the structure of water and PNiPAM in PNiPAM/water solution transitionally change at gelation temperature (31°C). The effect of pressure on such transitional changes is studied. It is suggested that application of pressure to the system prevents the gelation.