Characterization of cross-linked poly(N-isopropylmethacrylamide) microgel latexes

 This article reports the colloidal and physicochemical characterization of crosslinked poly (N-isopropylmethacrylamide) (poly[NIPMAM]) latexes. The latex particles were first characterized by determining the lowest critical solubility temperature by measuring the optical density variation as a function of temperature. In addition, the electrophoretic mobility behaviors of all latexes were examined as a function of pH and temperature. Finally, the colloidal stability was investigated by determining the critical coagulation concentration and the critical flocculation temperature, and the corresponding results were discussed by taking into account both the effect of salinity and temperature on the solvency of poly[NIPMAM]. Received: 25 March 1999 Accepted: 5 May 1999