Changes of surface morphology in UV-irradiated poly(acrylic acid)/poly(ethylene oxide) blends

Thin polymer films of PAA, PEO and PAA/PEO blends with different components ratio were obtained by means of casting their aqueous solutions and water evaporation. All samples were then exposed to short-wavelength UV-radiation (λ=254 nm). The morphology of samples, as observed in polarized light of optical microscope, exhibited the existence of spherulitic structures. Surface properties were studied using the SEM technique and contact angle measurements. It was found that UV-irradiation changes the size of spherulites in pure PEO and in blends containing its major amount. The contact angle measurements indicate that UV-radiation induces some changes of hydrophilicity of samples.