Morphology of Poly(2-ethylhexyl methacrylate):Poly(butyl methacrylate) Latex Blend Films

Abstract

This paper describes the morphology of the latex films formed from a mixture of two different latex particles: poly(butyl methacrylate) (PBMA, 120 nm) and poly(2-ethylhexyl methacrylate) (PEHMA, 100 nm). Twenty percent of the PBMA phase is labeled with 1 mol % anthracene. Using confocal fluorescence microscopy, we obtained images of the internal morphology of the dry films. Atomic force microscopy was used to image the surfaces of the films. For the same blend composition, 10 wt % PBMA and 90 wt % PEHMA, we studied the effect of two factors on the blend morphology: the presence or the absence of the surfactant SDS (ca. 2 wt % of the weight of polymers) in the dispersion and the dispersion concentration. We related the different morphologies we observed to the differences in the drying mechanisms. In the case of a surfactant-free film cast from a 5 wt % dispersion mixture, the film dried homogeneously, and we observed uniform distribution of the PBMA dispersed phase in the PEHMA matrix. In the presence of...