Film formation from concentrated emulsions studied by simultaneous conductometry and gravimetry

We present a simple, yet effective, technique involving simultaneous conductometry and gravimetry, to study the drying process of films made from concentrated oil-in-water emulsions. We exemplify the technique by drying experiments on paraffin oil/Triton X100/brine emulsion films. The drying process is demonstrated to consist of three regimes: (1) evaporation of ‘free water’, (2) dehydration of the bi-liquid (o/w) foam and (3) the rupture of the foam structure into an inverted (w/o) emulsion. Conclusive statements about the morphology of the emulsion film in each of these stages are made based on observations using the above technique.