  We investigate the self-assembly process of a surfactant with inverted
polarity in water and cyclohexane using both all-atom and coarse grained hybrid
particle-field molecular dynamics simulations. Unlike conventional surfactants,
the molecule under study, proposed in a recent experiment, is formed by a rigid
and compact hydrophobic adamantane moiety, and a long and floppy triethylene
glycol tail. In water, we report the formation of stable inverted micelles with
the adamantane heads grouping together into a hydrophobic core, and the tails
forming hydrogen bonds with water. By contrast, microsecond simulations do not
provide evidence of stable micelle formation in cyclohexane. Validating the
computational results by comparison with experimental diffusion constant and
small-angle X-ray scattering intensity, we show that at laboratory
thermodynamic conditions the mixture resides in the supercritical region of the
phase diagram, where aggregated and free surfactant states co-exist in
solution. Our simulations also provide indications about how to escape this
region, to produce thermodynamically stable micellar aggregates.
