SYNTHESIS AND SOLUTION PROPERTIES OF POLY(N-ISOPROPYLACRYLAMIDE-CO-DIALLYLDIMETHYLAMMONIUM CHLORIDE)

A series of copolymers of N-isopropylacrylamide (NIPAM) and diallyldimethylammonium chloride (DADMAC) were synthesized and characterized. Copolymer molecular weight decreased with increasing DADMAC content. The copolymers were soluble in water at temperatures below the cloud point temperature (CPT) and formed stable colloidal particles above the CPT. The CPT of the copolymer decreased as the salt concentration increased. The size and stability of the colloidal particles were NaCl concentration dependent. At salt concentrations higher than 0.1 M, coagulation was observed. At lower ionic strengths the particles were colloidally stable and the average diameters increased with salt concentration. Particle sizes were also pH dependent, and it was concluded that pH sensitivity was simply an ionic strength effect.