화학공학소재연구정보센터
Macromolecules, Vol.36, No.13, 4944-4953, 2003
Probing poly(n-butyl-methaerylate) latex film via diffusion of hydrophilic and hydrophobic dye molecules
In the study of holographic grating relaxation (forced Rayleigh scattering, FRS) in nascent latex films we examined poly(n-butyl methacrylate) films using two complementary diffusing probes: a hydrophobic fulgide, Aberchrome-540, and its hydrophilic salt derivative. In the former case, the grating decay follows a stretched exponential. Data analysis in terms of a two-state diffusion model yields tracer diffusion coefficients in the cores of the latex particles (10(-16) m(2) s(-1)) and the hydroplasticized interface meshes that surround them (10(-13) m(2) s(-1)). In the case of the hydrophilic tracer several distinct stages of grating decay can be isolated and interpreted as representing the dye diffusion in water (10(-10) m(2) s(-1)), in the interfaces (10(-13) m(2) s(-1)), in polymer cores (10(-16) m(2) s(-1)), and captured by surfactant clusters (10(-19) m(2) s(-1)), respectively. The contributions of particular environments depend on tracer hydrophilicity. Therefore, the two dyes employed provide complementary information on different types of spatial domains in mesoscopically heterogeneous latex films.