Turbidity Measurements Study the Poly(N-isopropylacrylamide) Shading Agent Systems Containing Hydrophilic Vinyl Compounds Additives
The temperature sensitive behavior and the phase behavior of linear poly(N-isopropylacrylamide) (PNIPA) in water-additive systems were investigated via turbidity measurements.. Three kinds of additives, including acrylic acid (AA), acryl amide (AM) and N-vinyl-2-pyrrolidone (VP), were selected. AM and VP systems only exhibited a different lower critical solution temperatures (LCST) behavior with different additive concentrations, and in low concentration of AM or VP, LCST decreases with additive concentration increasing, but in higher concentration, LCST decreases with additive concentration increasing. However, it was first detected the coexistence of a LCST with an upper critical solution temperature (UCST) in AA system. The systems studied here are alternative functional molecular material for the shading agent in some special conditions.
Zhong Cao, Lixian Sun, Xueqiang Cao, Yinghe He
Y. Z. Liu et al., "Turbidity Measurements Study the Poly(N-isopropylacrylamide) Shading Agent Systems Containing Hydrophilic Vinyl Compounds Additives", Advanced Materials Research, Vols. 233-235, pp. 2669-2673, 2011