Sub‐Micron Thickness Self‐Limiting Electrospray Deposition via Voltage Bias of Spray Target

Abstract

AbstractElectrospray deposition (ESD) is a technique with emerging relevance for applications requiring micro‐/nano‐scaled coatings. Self‐limiting electrospray deposition (SLED) is a regime of ESD where upon satisfying the criteria for self‐limiting behavior, the charge buildup of the material will eventually begin to repel itself until an asymptotic thickness is achieved, based primarily on the properties of the spray solution and deposited material. This work focuses on controlling the coating thickness further to achieve sub‐micron thicknesses. By applying a voltage bias of the same polarity of the spray onto the target substrate while providing a secondary grounded surface, the thickness of a payload can be manipulated for thinner and more precise thicknesses. The magnitude of the voltage bias is varied to show the effect of voltage bias on thickness, and 2‐D and 3‐D structures are used to demonstrate the generality of this technique for complex substrates. The results show how SLED can be included as a potential alternative for conformal coatings deposited at ambient conditions at the sub‐micron scale.