The innovation engine for new materials

Ruben Diaz

Reben Diaz

Major: 

Mechanical Engineering

Mentor(s): 

Hans Mayer

Faculty Sponsor(s): 

Professor Rouslan Krechetnikov

Faculty Sponsor's Department(s): 

Mechanical Engineering

Project Title: 

Investigation of Surfactant-Laden Pendant Drops in Electric Fields

Project Description: 

A common technique used to measure interfacial tension between two immiscible fluids involves shape analysis of a pendant drop. In this arrangement, a droplet of one fluid is suspended from the tip of a capillary tube immersed within a fluid of lower density. We report on observations of surfactant-laden pendant drops of water in mineral oil while in an electric field. Surfactants involved in the system were either added to the fluids or produced by chemical reactions at the interface between linoleic acid in mineral oil and sodium hydroxide in water. Consequently, a variety of dynamic behavior ranging from periodic oscillations to steady streaming of small droplets from the tip of a cone-shaped drop occurred. The ejected droplets vary in size from hundreds to tens of microns. The observed dynamic behavior is influenced by the concentration and ionic nature of the surfactants. We have attempted to relate observed behavior to variations in these parameters as well as changes in the electric field strength. Further investigation of the relationship between observed behavior and adjustable parameters will allow us to control the droplet size and frequency of oscillations, which can be useful in the production of uniform micro and nano- scale emulsions used in food, pharmaceuticals, and oil industries.