Thermally assisted coating of PVA for hydrophilic surface modification of PMMA microchannel for oil in water emulsion

Abstract

Microfluidics plays a significant role in the field of engineering and modern sciences. It has various applications especially in bio-medical science, reaction engineering to improve the reaction rates for better yield, electro chromatographic separations, chemical synthesis and drug screening. A surface modification method for bonded poly methyl methacrylate (PMMA) micro channels is presented in this study. Coating was performed from aqueous solution of polyvinyl alcohol (PVA) along with subsequent heat treatment of PMMA micro channels. This surface modification improves hydrophilic wettability of channels. It permits the generation of oil-in-water (O/W) emulsion in PMMA microchip. To evaluate the PVA coating in microchannels of bonded microfluidic device, polymer hydrophilicity with aging time and surface properties were studied. Surface hydrophilicity and chemistry was evaluated by measuring contact angle on PMMA substrate and performing energy dispersive x-ray spectroscopy (EDX) respectively. Also, the stability of the PVA coated hydrophilic surfaces was confirmed by successfully generating oil in water emulsion.