Institution: | aGraduate School of Environment and Information Sciences, Yokohama National University, Yokohama, 79-7 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan bDepartamento de Ingeniería Quimíca, Facultad de Ciencias, Universidad de Granada, Avenida Fuentenueva s/n, 18071, Granada, Spain cChemical Division, Daikin Industries Ltd., 1-1 Nishi Hitotsuya, Settsu-shi, Osaka 566-8585, Japan |
Abstract: | Phase behavior and surface tension of aqueous solutions of fluorinated random copolymers perfluoroalkylacrylate]–poly(ethyleneoxide)methacrylate], CmRf-acrylate]-EOn-methacrylate] with fluroalkyl carbon number m = 8, 6, 4, 2 and number of ethyleneoxide unit, n = 9 and 4.5 were investigated as a function of composition and different combinations of m and n. Isotropic solutions are formed at lower temperatures over wide concentration range of copolymer but at higher temperature phase separation occurs. The cloud point of copolymer decreases with decreasing n as well as m, and also with decreasing the number of poly(ethyleneoxide)methacrylate chain per perfluorinatedalkylacrylate chain, suggesting that the copolymers become more hydrophobic on decreasing m and n. Equilibrium and dynamic surface tension measurements show that copolymers become increasingly surface active as m as well as n decrease but the adsorption at the air–water interface is very slow due to bulkiness of the molecules. No clear evidence of the formation of micellar aggregates could be obtained from surface tension–composition curves. |