Particles at fluid interfaces and Emulsions

a.) Particles at fluid interfaces

We investigate the mechanism driving the assembly of nanoparticles to the oil-water interface. The interface between two immiscible liquids, such as oil and water, holds promise as an assembly ground for organizing and exploiting the unique optoelectrical properties offered by nanoparticle arrays. The optical transparency of oil and water, combined with the dynamic liquid-liquid interface, makes colloidal crystals formed at fluid interfaces especially attractive. Moreover, the mechanical flexibility of the interface is amenable to forming a wide range of geometries – from planar sheets, to curved lenses, and three-dimensional objects- coated with nanoparticles. A better understanding of the complex driving forces that direct nanoparticles to the liquid-liquid interface could allow for the external modulation of the interfacial assembly of nanoparticles.

Related Publications:

• X. Hua, J. Frechette, and M.A. Bevan, “Nanoparticles adsorption dynamics at fluid interfaces”, Soft Matter 14, 3818-3828, 2018. 10.1039/C8SM00273H

• X. Hua, M.A. Bevan, and J. Frechette, “Competitive Adsorption between Nanoparticles and Surface Active Ions for the Oil–Water Interface”, Langmuir, 34, 4830-4842, 2018. 10.1021/acs.langmuir.8b00053

• X. Hua, M. A. Bevan, and J. Frechette, “Reversible partitioning of nanoparticles at the oil-water interface”, Invited Feature Article, Langmuir, 32, 11341-11352, 2016. 10.1021/acs.langmuir.6b02255

• T. Yin, D. Shin, J. Frechette, C. Colosqui, and G. Drazer, “Mobilization of deposited nanoparticles by a moving liquid-liquid interface: non-equilibrium effects”, Physical Review Letters, 121, 238002, 2018. 10.1103/PhysRevLett.121.238002

• M. Luo, G. Olivier, and J. Frechette, “Electrostatic interactions to modulate the reflective assembly of nanoparticles at the oil-water interface “, Soft Matter, 8, 11923-11932, 2012. 10.1039/C2SM26890F

b.) Spontaneous and Pickering emulsions

Nanoemulsions are a versatile means to create a variety of consumer products and complex materials. Producing nanoemulsions with a high-volume fraction of the dispersed phase is generally limited to mechanically intensive processes, and often result in polydisperse droplet size distributions. Low energy methods, such as spontaneous emulsification, can produce monodispersed droplets, but the volume fraction of the dispersed phase is usually much lower. We aim to develop strategies to produce high yield nanoemulsions (and Pickering nanoemulsions) using low energy methods.