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) andN-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.

A hydroxylated silicon substrate was modified with 3-aminopropyltriethoxysilane (APTES) monolayer, followed by the surface initiated graft polymerization of the N-isopropylacrylamide (NIPAm). The microstructure of poly(N-isopropylacrylamide) (PNIPAm) coating was examined by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. And the results showed that about 50 nm thickness of PNIPAm coating grafted successfully.