Electrolyte solution-assisted electrospray deposition for direct coating and patterning of polymeric nanoparticles on non-conductive surfaces

Abstract

Though electrospray deposition has significant impacts on various fields of energy, display, sensor, and biomedical engineering due to its strength in achieving functional coating or patterning of nano/microparticles on a substrate, most of the electrospray deposition techniques have been applicable only to electroconductive substrates, which limits the potential applications of the electrospray deposition. Here, we report a novel electrolyte solution-assisted electrospray deposition (ELED) process, which facilitates direct deposition of nano/micro-particles on various substrates including a non-conductive surface. Beyond the direct surface coating, the ELED enabled to pattern nanoparticles on a selected micro-scale region on 2D flat and even 3D curved surfaces by simply modulating the surface wettability followed by selectively positioning electrolyte solution. Strikingly, the ELED showed the dramatic enhancement in the deposition efficiency of the electrosprayed particles on the non-conducive surface compared to conventional electrospray deposition process with a metal collector. The individual controllability of both the diameter of nanoparticles and the thickness of the deposited nanoparticle layer was achieved by adjusting the polymer concentration, the flow rate, the applied voltage, and electrospraying time. Lastly, we demonstrated one example of biomedical engineering applications of the ELED by patterning the NIH/3T3 fibroblasts and promoting alignment of C2C12 myoblasts on line patterns of cell-friendly polycarprolactone nanoparticles on a cell-repellent polydimethylsiloxane substrate.