Expanding Materials Selection for Self-Limiting Electrospray Deposition Postprocessing of 3D Geometries

Electrospray deposition is a spray coating process that utilizes a high voltage to atomize a flowing solution into charged microdroplets. These self-repulsive droplets evaporate as they travel to a target grounded substrate, depositing the solution solids. In self-limiting electrospray deposition (SLED), specific manipulation of the electrostatic repulsion, hydrodynamic forces, and evaporation kinetics can be employed to conformally cover 3D architectures or targeted microscale electrodes with microcoatings. The generated coatings are hierarchical, possessing either nanoshell or nanowire microstructure. For these reasons, SLED is a spray method that is highly compatible with additive manufacturing due to its ability to coat re-entrant and shadowed features. Here, we report on strategies to expand the materials selection possible with SLED including: (1) deposition on non-conducting substrates, (2) deposition using only materials that would be considered not compatible with SLED, and (3) deposition at nanoscopic coating thickness. These capabilities expand the applicability of SLED for the functionalization of a wide range of surfaces with (i) bioactive vaccine or drug, (ii) plasmonic, (iii) elastomerically-toughened composite, (iv) anti-corrosive epoxy or sol gel, (v) catalytic, or (vi) electrically conductive coatings.