RAMAN-SPECTROSCOPIC STUDY ON WATER IN AQUEOUS-SOLUTIONS OF TEMPERATURE-RESPONSIVE POLYMERS - POLY(N-ISOPROPYLACRYLAMIDE) AND POLY[N-(3-ETHOXYPROPYL)ACRYLAMIDE]

A Raman spectroscopic study on property changes of water in the course of a temperature-responsive solution-aggregate transition phenomenon of aqueous poly(N-isopropylacrylamide) and poly[N-(3-ethoxypropyl)acrylamide] solutions was carried out. Upon the transition of polymers from coil to globule followed by the aggregation of individual polymer chains, the height ratio of the peaks at 3 250 and 3 400 cm(-1), corresponding to the O-H stretching of water molecules, was drastically changed. Contribution of small water domains included in polymer aggregates (so-called interstitial water) to the change in the Raman spectra was suggested. Effects of polymer concentration and molecular weight of polymers on the spectra were also examined.