Microcurrent behavior of core-shell droplet deposition in coaxial electrohydrodynamic printing

Abstract

The core–shell droplets have the characteristics of stable micro-environment, small volume, large specific surface, which means wider application prospects in micro reactors, functional material synthesis and other fields. However, how to realize the controllable preparation of high flux, high resolution and small size for core–shell droplets is still the key point to be broken through. In this paper, the coaxial electrohydrodynamic printing (EHD) technology is used to combine the real-time microcurrent signal with the behavior characteristics of core–shell droplets, both achieve the interface behavior characteristics of the nozzle droplets to be analyzed and clarify the microcurrent behavior when the core–shell droplets are generated. At the same time, the influence of the inner and outer solution supply rate on the core–shell droplet was investigated. When the supply rate of inner solution changes from 10 μl/h increases to 90 μl/h, the average current increased from 0.0153 μA to 0.0652 μA, but also the droplet generation frequency raised by 14 times, moreover, the average diameter of droplets could be reduced by half. In contrast, the change of outer shell supply rate has less influence on the average current, generation frequency and diameter of droplets. This research provides a possibility for controllable high resolution of core–shell droplet EHD printing, which can be helpful significantly to improve the functional characteristics of the macroscopic and microstructure of the core–shell droplet.