Phase-separated polymer blends: Complementary studies between scanning electron microscopy, epifluorescence microscopy, and fluorescence microspectroscopy

Abstract

In this work a morphological description of poly(vinyl alcohol) (PVA)/poly(vinyl acetate) (PVAc) incompatible blends was carried out combining scanning electron microscopy, epifluorescence microscopy, and fluorescence microspectroscopy, and using anthracene and fluorescein probes dissolved in the polymer blends. Because the blends were prepared by casting from a water/ethanol solution over a polyethylene surface, two topologically different faces were formed and analysed: blend/air and blend/support faces. Droplets in matrix morphologies were observed for any composition here studied and sample annealing resulted in the coalescence of domains. Fluorescence micro-spectroscopy of several parts of the material revealed that the dye distribution over the domain-matrix interface is different of the internal or external parts of each domain and it is indicative of the interpenetration of both polymers at the interface region.