Due to their soft and “green” performance with structural stability in a wide temperature range1, sugar surfactant based microemulsions are promising carrier media for the decontamination of sorptive hydrophobic surfaces (interior and exterior technical equipment, human skin) exposed to highly toxic and lipophilic compounds, such as chemical warfare agents, pesticides or toxic industrial compounds. The main advantages of the sugar surfactant based microemulsion rely on their ability to extract out of a surface and simultaneously transform the soluble toxic compounds into innocuous products. The aqueous phase is used as host medium for the enzyme Diisopropyl fluorophosphatase (DFPase) which efficiently hydrolyses organophosphates2. Beside the kinetics of the enzymatic degradation of the toxic organophosphate compounds, the decontamination efficiency of the microemulsion is also determined by two major factors: 1) the ability of the microemulsions to wet and eventually pentrate the sorptive hydrophobic surfaces and 2) the capacity to extract the lipophilic contaminant out of the surface and to solubilize it in the oil phase of the microemulsion. Here, we discuss extraction properties and wetting behaviour of sugar surfactant based microemulsions of different microscopic structures on model and realistic surfaces with smooth and porous structures and different hydrophobicities. The extraction capacity of different microemulsion structures was investigated by HPLC and confocal microscopy using a series of test molecules (ethyl salicilate fluorescence dyes). Extraction out of sorptive surfaces is strongly affected by the structure of the microemulsion, where a effective extraction of the model molecules is achieved by the employment of bicontinuous microemulsions.
1) S. Wellert, et al. PCCP, 2011, 13, 3092-3099
2) S. Wellert, et al, Eur. Biophys. J . 2011, 40 , 761-774
