Scientists emulate biological assembly mechanisms to form synthetic materials with unique and technologically useful structure-function relationships. Biological systems often form structures at liquid surfaces or within liquid solutions. This Faculty Early Career Development (CAREER) Program grant will investigate the assembly of polymer films on liquid crystal surfaces and support fundamental research into harnessing liquid-surface-based assembly for producing materials with ordered and oriented. The liquid crystals possess a long-range order which can serve to direct the formation of an ordered or structured polymer film deposited on its surface. These naturally-structured polymer films could impact many areas of technology providing to increase national prosperity such as in the production of water filtration membranes with oriented pores that increase permeability without sacrificing selectivity. Currently, no scalable method makes oriented membranes with high pore densities. Broader impacts of this work will promote interdisciplinary innovation by combining the fields of materials engineering, physics, and polymer science. The grant provides for the broadening participation of women and underrepresented groups in STEM activities through peer mentoring programs with the Society of Women Engineers and the National Society of Black Engineers.
Harnessing continuous two-dimensional assembly at fluid interfaces opens new routes for bottom-up fabrication of hierarchical and anisotropic polymeric materials. Vapor-phase deposition methods offer unique capabilities for controlling the deposition and chemistry of polymer formation. When polymer deposition occurs on liquid substrates, surface diffusion and aggregation mechanisms at the polymer-liquid interface will processes underlying the controlled polymer assembly. Vapor-phase deposition onto liquids provides a versatile approach to control continuous materials transport to the liquid surface independently of interfacial assembly mechanisms. To address challenges in producing uniform and ordered morphologies, ordered liquid substrates, specifically liquid crystals, will be used as a template to direct nucleation and growth of polymers at the surfaces. The central goal of this CAREER grant is to elucidate underlying mechanisms in which vapor-phase transport and liquid crystal-mediated assembly are cooperatively coupled for bottom-up materials processing at fluid interfaces. The process could open up new regimes for the development of colloidal-based thin films. These films could have impact in a wide cross-section of technological applications such as membrane formation, flexible electronics, and types of sensing applications.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.