AOT microemulsions: droplet size and clustering in the temperature range between the supercooled state and the upper phase boundary

作者：Domschke Markus^*; Kraska Martin; Feile Rudolf; Stuehn Bernd

来源：Soft Matter, 2013, 9(48): 11503-11512.

DOI：10.1039/c3sm51632f

The main focus of this work is the investigation of the mechanism of droplet aggregation and the droplet structure of water-AOT (sodium bis(2-ethyl hexyl) sulfosuccinate)-decane microemulsions between the supercooled state and the upper phase boundary by means of SAXS. We study the temperature dependent droplet structure and size in detail at compositions of droplet volume fractions phi = 0.1-0.4 and water/AOT molar ratios of omega = 5-40. We found a change in droplet size at varying temperatures and explain our results by the change of the effective droplet surface covered by an AOT molecule (between the two phase boundaries) and by macro-phase separated water ice below a certain supercooling temperature. We monitor the continuous change of droplet interaction by means of a phenomenological structure factor combining hard sphere interactions with a Lorentzian function accounting for droplet density fluctuations in the system. We analyse the droplet aggregates in dependency on phi and omega leading to a better understanding of droplet aggregation with increasing temperature.

• 出版日期2013