N-Isopropylacrylamide andN-Isopropylmethacryl-amide: Cloud Points of Mixtures and Copolymers

The cloud point curve of aqueous solutions of poly(N-isopropylacrylamide), poly(N-isopropylmethacrylamide) and their statistical copolymers were determined turbidimetrically. All the Systems demix upon heating at the cloud point temperature and mix reversibly upon cooling. The cloud points are independent of the total concentration of the solutions (dilute range) and of the sample thickness. Mixtures of the homopolymers poly(N-isopropylacrylamide) and poly(N-isopropylmethacrylamide) in water (ternary systems) exhibit two cloud points, which are nearly the same as the cloud points of the two binary systems homopolymer/water. A quantitative correlation was found between the cloud point temper…