Parylene-C film as hydrophobic surface in glasses microfluidic devices for double emulsions

Abstract

Double-emulsions are an important strategy to encapsulate drugs and pharmaceutical ingredients. In this way microfluidic devices have offered a successful tool to produce controlled size droplets with high homogeneity. In spite of many advantages of the use of microfluidic devices to produce double emulsions, these devices require two different surface characteristics on the same device. In this work we present the use of Parylene-C, a polymeric film obtained by chemical vapor deposition, as a hydrophobic surface over a hydrophilic substrate. Parylene-C deposition occurs under room temperature. A mechanical mask can be used to protect regions of interest. The deposition renders a 2–5 μm of Parylene-C film inside a device that have microchannels with depths of 87μm. The regions covered with Parylene-C offered a contact angle of 105° and with a conformal deposition. The microfluidic device was used to produce water-in-oil-in water double emulsion and was possible to encapsulate B12 vitamin inside an oil droplet. This work is still in progress, and adjustments on the solutions concentrations used must be pursued. However, the use of Parylene-C presents a promising technique to produce microfluidic devices useful for double emulsions.