Microreactor-Assisted Nanoparticle Deposition: An Efficient, Green Route to Functionally Gradient Films

Oregon State University, Corvallis OR

Investigators

Abstract

PROPOSAL NUMBER: 0654434 PRINCIPAL INVESTIGATOR: Paul, Brian K. INSTITUTION: Oregon State University Intellectual Merit: We propose to investigate the underlying science and technology for assembling functionally-gradient, hierarchical (nano to micro) structures from nanomaterial building blocks synthesized within compact, highly-paralleled microreactor systems. The proposed research concept combines the merits of microreaction technology with solution-phase nanoparticle deposition (hybrid). In synthesis, microreactor technology offers large surface-area-to-volume ratios within microchannel structures to accelerate heat and mass transport. This accelerated transport allows for rapid changes in reaction temperatures and concentrations leading to more uniform heating and mixing. Consequently, microreactors have been demonstrated to have dramatic reductions in the dispersity of nanoparticle size distributions. The possibility of synthesizing nanomaterials in the required volumes at the point-of-application, eliminates the need to store and transport potentially hazardous materials while providing new opportunities for tailoring novel functionally gradient structures. In the proposed work, this technology will be extended to fabricate a variety of new, functionally-gradient structures that are currently too cumbersome to produce by other means. With the large and growing library of nanotechnology synthesis and assembly techniques based on wet chemistry (e.g. precipitation, sol-gel, etc.), we believe Microreactor-Assisted Nanoparticle Deposition will open a green (environmentally benign), low cost route for producing novel, high-performance films. In this proposal, our research will culminate with the fabrication of high-performance, "moth-eye" anti-reflective films for glass consisting of size, shape and compositionally gradient layers having subwavelength structures. It is expected that the development of these new techniques will enable a host of new functionally gradient films with a broad set of applications including fuel cell electrode membranes, photovoltaic films, wearable electronics and biomedical films among others. Broader Impacts: This concept has the potential to transform current batch nanofabrication practices into continuous processes for mass production having precise process control without the need for expensive infrastructure such as particulate control, high vacuum and high temperatures. These qualities could revolutionize the future nano/microfabrication facility while reducing environmental impacts. This new process has the potential to help reduce the environmental impact of nanoproduction through the inclusion of integrated microchannel separation techniques and reagent recycling. The possibility of synthesizing nanomaterials at the point-of-use will significantly reduce the carrying costs and obsolescence of expensive nanomaterials while reducing the human exposure to potentially hazardous materials. We will develop educational materials for graduate, undergraduate, and existing K-12 outreach programs on the OSU campus and for recruiting and retaining underrepresented groups (young women and ethnic minorities) into science and engineering. Our approach is two-pronged. First, we seek to recruit a new generation of science, engineering and business students to perform hierarchical manufacturing research, development and commercialization by creating educational modules and laboratory activities and delivering these to undergraduate and high school students. Second, we aim to engage new recruits in various development and commercialization activities which will yield a new crop of students with the motivation for understanding and extending the science underlying hierarchical manufacturing technology.