Self-limiting electrospray deposition

Micro/nanoscale conformal coatings can be applied in either the molecular or condensed state. Molecular deposition techniques, such as electrodeposition, vacuum deposition, atomic layer deposition, or chemical vapor deposition, generally require either a fluid bath or high-vacuum to apply and may also require high-temperature precursor processing. This offsets their cost-benefit considerations and limits the size of the component that can be coated. Condensed deposition techniques, such as dip coating, spin coating, and brush or blade coating struggle with 3D surfaces and result in capillary or shadowing effects. The capability to deposit precise micro/nanoscale coatings onto 3D surfaces in a non-bath/vacuum method represents a huge cost savings for these coatings, and electrostatically-induced self-limiting electrospray deposition (SLED) has the potential to fill this need.

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 our technology, self-limiting electrospray deposition (SLED), manipulation of the electrostatic repulsion, hydrodynamic forces, and evaporation kinetics can be employed to conformally cover 3D architectures, including the re-entrant and shadowed features of additive manufacturing (AM), and 2D microelectronic templates. Our development of this technology has included materials capabilities, such as the deposition of hermetic coatings, antiwetting layers, supercapacitive nanoparticles, drugs and vaccines, and even living cells, as well as process capabilities, such as increased deposition rate, multilayer coatings, and water-borne formulations. This provides a coating solution for applications in healthcare, agriculture, microelectronics, or consumer coating industries.