Tip-assisted electrohydrodynamic jet printing for high-resolution microdroplet deposition

The controlled patterning of microdroplets or microwires at precise positions plays an essential role in micro/nano device applications. In this context, we propose a novel and efficient method called tip-assisted electrohydrodynamic (EHD) printing that combines the tip-assisted electric field intensity enhancement effect and the high-resolution capability of EHD printing. The tip-assisted electric field enhancement effect is first systematically investigated by simulation analysis. Under optimized experimental conditions, we obtain microdroplet arrays and microwires down to sizes of 2.3 mu m and controlled micropatterns composed of droplet arrays or microwires with sizes smaller than the inner diameter of nozzle by means of the tip-assisted technique. We find that with our designed tip-assisted nozzle, solutions with a high viscosity of >2000 cps can be extracted from the nozzle, and the printing resolution can increase by nearly five times the current resolution. Our results demonstrate that tip-assisted EHD printing provides a potential and flexible method for precision and controlled manufacturing of micropatterns. (C) 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license