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 μm 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.