Electrohydrodynamic direct-writing orderly pattern with sheath gas focusing

Laminar sheath gas is introduced to increase the stability of Electrohydrodynamic Direct-Writing (EDW). The external stretching force from sheath gas promotes the ejection threshold, the diameter of jet and printed fibers as well. The critical voltage decreases with the increase of sheath gas pressure. The stretching force from sheath gas decreases the diameter of printed fiber as well as that of charged jet. As sheath gas pressure increases from 0 to 25 kPa, the average diameter of micro/nano structure reduces from 4.46 mu m to 845.25 nm. The laminar field flow of sheath gas shelters the charged jet free from the surrounding interferences, and helps charged jet to move in a straight line. With the help of sheath gas, the stability of charged jet can be improved to direct-write precise complex micro-pattern. The position precision of direct-written pattern is less than 5 mu m. As a novel method, EDW with laminar sheath gas would promote the deposition precision of printed micro/nano structure and its application. (C) 2016 Author(s).