Self-organised patterns in polymeric films solidified from diluted solutions - The effect of the substrate surface properties

Abstract

The effect of the substrate surface free energy on the formation of organised structures developed during solvent evaporation was studied. Aqueous solution of 2-hydroxyethyl cellulose in temperature gradient under the Bénard-Marangoni convective flow conditions was used as a model system. Polystyrene was used as a model substrate and its surface properties were modified with the low-temperature plasma. Changes in the substrate surface and their stability were monitored with contact angle measurement and atomic force microscopy. Solidification of the polymeric solutions was carried out in the specially constructed apparatus (Micro-condensation drying system) at defined temperature gradient and solvent evaporation rate. The effect of molecular weight distribution width, time of substrate surface plasma treatment, homogeneity of plasma treatment, size of the container with the polymeric solution and polymeric solution initial height was examined. Experimental results indicate crucial influence of the substrate surface energy on the development of self-organised patterns in films solidified from diluted polymeric solutions with broad molecular weight distribution. © 2014 Elsevier Ltd. All rights reserved.