Improved methods for characterizing emulsions by Nuclear Magnetic Resonance

Abstract

Abstract The use of Nuclear Magnetic Resonance (NMR) is an appropriate tool for studying colloids in a non-invasive manner. Droplet size distributions and one-dimensional sample profiles are readily produced to characterize an emulsion, its stability, the size distribution of the dispersed phase, and rheological behavior with respect to parameters as temperature and/or water cut. Here, we present Pulsed Field Gradient NMR methods that improve the performance as compared to existing methods. In particular, the so-called multi-echo approach is introduced to enhance the signal to noise ratio significantly making it possible to characterize emulsions in a minute or less. Thus, any evolution that takes place in the order of just a few minutes can be monitored. In addition to the multi-echo approach, an improved method for determining the droplet size distribution from a residual emulsion, i.e. in the presence of a bulk water phase, is presented.