Temperature-driven precipitation of poly(N-isopropylacrylamide-co- methacrylic acid) in cationic, anionic and nonionic surfactant solutions

摘要

The temperature-driven precipitation of poly(N-isopropylacrylamide-co- methacrylic acid) (P(NIPAM-co-MAA)) in anionic, cationic, and non-ionic surfactants solutions was investigated under an acidic (e.g. pH 3.0) and an alkali condition (pH 9.0). Under the acidic condition, sodium dodecyl sulfate (SDS, anionic) and cetyltrimethylammonium chloride (CTAC, cationic) increased the cloud point of the copolymer and they suppressed the temperature- sensitivity. Under the alkali condition, SDS suppressed the temperature sensitivity as under the acidic condition, but CTAC boosted the temperature sensitivity and it decreased the cloud point of the copolymer. The effect of CTAC on the phase transition under the alkali condition was opposite to the effect observed under the acidic condition. Tween 20 (non-ionic) had little effect on the cloud point and the temperature-sensitivity under both the acidic and the alkali conditions.