PhD Doctor of Philosophy
Henry M. Rowan College of Engineering
National Science Foundation
bijels, emulsions, nanoparticles, phase separation, silica, surfactants
Microfluidics; Chemical reactors
Bijels are made of non-equilibrium particle-stabilized emulsions with a bicontinuous arrangement of the constituent fluid phases. They spontaneously form through arrested spinodal decomposition in mixtures of partially miscible liquids and neutrally wetting colloidal particles. Soon after their discovery over 10 years ago, Prof. Mike Cates, Lucasian Professor of Mathematics, predicted their future use as continuously operated cross-flow reactors for chemical reactions between immiscible reactants.
Towards this goal, work in this thesis focuses on designing bijels via Solvent Transfer Induced Phase Separation (STrIPS) for microfluidic transport applications. Structure-function relationships of STrIPS bijels stabilized by silane functionalized nanoparticles are developed. In-situ surfactant modification controls the morphology of bijels and significantly improves their long-term stability with reinforcement capabilities. We develop a criteria to manipulate the interfacial properties of colloids, enabling the fabrication of STrIPS bijels with charged (zeta potential = -40 mV) particles. Bijel structural control is enabled via ternary phase equilibria and functional particles. We demonstrate the use of bijels for flow-through applications using electrokinetics. High dye migration speeds (approximately 400 mm/hr.) with ideal profiles are derived in STrIPS bijels having homogeneous structures, showing ideal conditions necessary for future transport applications in bijels.
Boakye-Ansah, Stephen, "Bijels made by solvent transfer induced phase separation: Formation principles and transport" (2020). Theses and Dissertations. 2816.
Available for download on Thursday, June 23, 2022