Abstract
In order to develop thermo-sensitive powders, talc bearing poly (N-isopropylacrylamide) (P-NIPAM) or porous silica including N-isopropylacrylamide (NIPAM) gel, were prepared and then dispersion behaviors of the talc and water content of the silica were investigated. P-NIPAM shows a lower critical solution temperature (LCST) due tohydrophobic interaction about 33°C near skin surface temperature.
Talc bearing P-NIPAM was aggregated in water above LCST of P-NIPAM, though non-bearing talc was dispersed. Water content of silica including NIPAM gel was higher than that of parent silica below LCST. Such behaviors are attributable to hydrophilic-hydrophobic transition of the polymer fixed on talc surface or encapsulated in porous silica.
It is expected that these thermo-sensitive powders will be applied to development of new cosmetics which can control skin moisturization according to change of skin temperature.
