Electrohydrodynamic patterning in a curable resin over a wide range of fabrication parameters

Abstract

This work reports the first use of a room-temperature curing epoxy resin to produce microscopic arrays of ordered 2-D structures via electrohydrodynamic instability (EHD) patterning. The measured spacing of these structures, and the formation of novel ‘starburst’ shapes, support a leaky dielectric theoretical model over perfect dielectric ones. The existence of the starbursts implies that traces of ionic residues in the uncured epoxy should be taken into account in any model of the patterning process, and their formation implies that mobile surface charges arising from trace ionic impurities must be considered when seeking to achieve smaller length-scale structures in epoxy by EHD using flat electrodes. Samples patterned in the μm range showed mid-infrared spectral features with wavelength maxima that broadly scaled with the pillar spacings in the films.