Improved Methods for Characterizing Emulsions by Low‑Resolution Nuclear Magnetic Resonance via Surface Relaxation and One‑Dimensional Images

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 Grgdient 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.