Pickering Emulsions - A Paradigm Shift

Texas Tech University, Lubbock TX

Investigators

Abstract

ABSTRACT - 0500323 Texas Tech University Emulsions are ubiquitous in natural and industrial processes. Conventional emulsions use organic surfactants or polymers as stabilizers. Although solid particle stabilized emulsions (Pickering emulsions) are often encountered in the recovery of crude oil, oil separation and cleaning, and wastewater treatment, the phenomenon is poorly understood and has been neglected for nearly a century. There is a critical call for new experts to meet our nation's need in this research area. This proposal focuses on integrating research and education centering on Pickering emulsions. Self-assembly of micro-sized and nano-sized solid particles in Pickering emulsions will be investigated using a laser scanning co focal microscope and an environmental transmission electron microscope (ETEM). For Pickering emulsions containing microparticles, we will investigate the influence of solid particle concentration, particle size, particle wettability, and bulk viscosity on self-assembly. We will also test the applicability of the Langmuir adsorption model. For Pickering emulsions containing nanoparticles, we will investigate the structure of nanoparticles (monolayer or multilayer, ordered or randomly packed, etc.) at the emulsion interface and compare experimental results to a microscopic noncontinuum model. In addition, we will investigate the mobility of microparticles at emulsion interfaces, in particular the influence of interface curvature on the single particle movement and the mobility of multi-particle clusters. Pickering emulsions offer a new paradigm of colloidal science, and the proposed work is anticipated to contribute significantly to a better fundamental understanding of the formation of Pickering emulsions. The proposed work also contributes to the underlying mechanisms of the self assembly of solid particles at liquid/liquid interfaces since Pickering emulsions offer a novel and simple template for self-assembling solid particulates. Pickering emulsions can also serve as model systems to investigate diffusion, mobility, and in-situ structural formation of solid particles at the two dimension. In addition, the preliminary work from the PI's group offers the first work of imaging nanoparticles in a liquid medium using the ETEM technique, as well as the first work revealing the detailed structure of self-assembled nanoparticles at a liquid/liquid interface when the size of the nanoparticles is comparable to the molecular dimension of the liquids. Follow-up research using the ETEM technique will have a significant impact on nanoparticle science and technology. Broader Impacts (Extrinsic Merit) The integration between research and education will be performed to meet the NSF's goals for strategic outcomes: People, Ideas and Tools. With a strong commitment to education, the PI will establish research-related open-ended projects in the existing courses, promote undergraduate and graduate research, establish a new summer program to broaden the participation of underrepresented groups, mentor in the Pre-College Engineering Academy, and promote technology transfer. Pickering emulsions involve an innovative concept for particle use; the proposed work is anticipated to provide new opportunities for widespread practical applications and will be an outstanding example of bringing intellectual capital and emerging technologies together in ways that promote economic growth and an improved quality of life. It is also anticipated to make a meaningful impact in oil recovery, which will contribute significantly to environmental restoration and protection. Last, but not least, this project also provides a unique opportunity to meet our nation's critical need for a cutting-edge research with a potential of incredible expansion in the 21st century.