Electrohydrodynamic direct-writing shaped fibers via pumping based on Micro-Weissenberg effect

In this paper, shaped fibers which are especially useful for radiative cooling have been firstly deposited by Electrohydrodynamic direct-writing based on Micro-Weissenberg effect (MWE). At first, The process of pumping viscoelastic fluids (polyethylene oxide) in micro-tube (non-circle nozzle) based on Micro-Weissenberg effect has been studied to reveal the mechanism of Micro-Weissenberg effect. We have found that the pumping based on MWE have obvious periodic fluctuation when the flow rate is small. Then the process of steel pins without small diameter pipes pumping viscoelastic fluid which is a continuous, less wall and controllable pumping manner have been studied in detail. It is found that the pumping based on MWE mainly stem from an interesting capillarity between two pins and the viscoelasticity of fluid. So compare with the traditional Electrohydrodynamic direct-writing, the shaped fibers have been more easily deposited by Electrohydrodynamic direct-writing based on MWE due to the capillarity and the shear thinning in Micro-Weissenberg effect.