The research is based on the finding that an aerosol based process can be designed to prepare hollow submicron particles in a consistent and rapid manner. The novelty of the finding is that the shells of these particles can be designed to constitute two distinct layers, an outer hydrophilic silica layer and an inner hydrophobic carbon layer. Additionally, the particles contain iron based nanoparticles which makes them magnetically responsive. The concepts behind the research are all based on a simple hypothesis that specific salts form bridging complexes with surfactants that negate the templating effects of the surfactant in the synthesis of ordered mesoporous materials. Rather, a thin ceramic shell forms that locks in chemical constituents in the core of a hollow particle. This sealing of the particle can be exploited to design a variety of new particulate morphologies including silica-carbon and silica-titania bilayer systems and a system of protrusions leading to the generation of a nanohorn type particulate system. All these particle morphologies are new, and are consistently obtained at appropriate constituent levels. The research attempts to firmly understand the formation of the particulate morphologies and validate the hypothesis behind the shell formation and understand its generality. In addition to fundamental research to understand the process, new applications will be developed in stimuli induced delivery, in photocatalysis and in the development of novel classes of colloidosomes.
Hollow submicron particles are intrinsically of much relevance to a variety of technologies including encapsulation and controlled delivery. Titania based hollow particles have a host of applications in photocatalysis and solar cell technologies, and magnetic hollow particles can be used in imaging technologies. Additional applications of the research include the development of materials to stabilize oil droplets and is thus relevant to oil spill mitigation technologies. The research will be integrated strongly with graduate education, undergraduate research experiences, and outreach efforts at the community college level.
