Effect of small molecule surfactant structure on the stability of water-in-lubricating oil emulsions.

During automotive engine operation, water may contaminate engine oil, inhibiting its role in maintaining safe engine operation. In many cases, engine oil must be capable of emulsifying any water contamination to avoid such problems. This study focuses on the impact of small molecule surfactant concentration structure and concentration in emulsions comprised of engine oil, water, and E85 fuel to understand the effects on emulsion stability and formulation optimization.

Achieving Independent Control over Surface and Bulk Fluid Flows in Microchambers.

To fully realize the potential of microfluidic platforms as useful diagnostic tools, the devices must be sufficiently portable that they function at the point-of-care, as well as remote and resource-poor locations. Using both modeling and experiments, here we develop a standalone fluidic device that is driven by light and operates without the need for external electrical or mechanical pumps. The light initiates a photochemical reaction in the solution; the release of chemical energy from the reaction is transduced into the spontaneous motion of the surrounding fluid.

Light-Induced Convective Segregation of Different Sized Microparticles.

Using computational modeling, we design a facile method for sorting particles of different sizes in a fluid-filled microchamber. The microchamber is inclined at an angle with respect to the horizontal direction and contains suspended gold nanoparticles as well as the microparticles. With the application of ultraviolet light, the heat generated by illuminating the gold nanoparticles gives rise to thermal buoyancy effects, which drive the flow of the fluid in the chamber.

Organization of Particle Islands through Light-Powered Fluid Pumping.

The field of active matter holds promise for applications in particle assembly, cargo and drug delivery, and sensing. In pursuit of these capabilities, researchers have produced a suite of nanomotors, fluid pumps, and particle assembly strategies. Although promising, there are many challenges, especially for mechanisms that rely on chemical propulsion.

Micromotors Powered by Enzyme Catalysis.

Active biocompatible systems are of great current interest for their possible applications in drug or antidote delivery at specific locations. Herein, we report the synthesis and study of self-propelled microparticles powered by enzymatic reactions and their directed movement in substrate concentration gradient. Polystyrene microparticles were functionalized with the enzymes urease and catalase using a biotin-streptavidin linkage procedure.