Capture probabilities in pair-wise collisions of emulsion drops - measurement and application : report submitted in fulfilment of the requirements for the Doctoral Degree (PhD Course) in the Biophysics and Soft Matter Group, School of Fundamental Sciences, Massey University, New Zealand

Abstract

This project seeks to measure and model particle interactions under different environmental conditions with a view to being able to control these interactions. The interactions of emulsion drops will be investigated using an optical tweezer set-up and the results considered in the context of measurements of the zeta potential of the emulsion. Specifically, how the zeta potential of emulsion drops changes with the physio-chemical environment (pH and ionic environment) is captured in a concise mathematical model, the effects of depletion interactions are considered, and a novel experimental procedure is developed to allow hundreds of pairwise stickiness measurements to be taken in an automated fashion. The major research questions are: 1. Is it possible to address the effects of changes in environmental conditions which are not easily quantifiable with a pragmatic capture probability or pairwise "stickiness" measured at a single particle level? 2. Can we link these pairwise measurements to induced changes in the surface properties and understand how they yield the rheological behaviour of the system?