Self-Assembled Liquid Particles: How to Modulate their Internal Structure - Food Colloids: Self-Assembly and Material Science - page 84

possibility to create hierarchically structured particles by using, for instance,
the convenience of ultrasonication and the ability to tune their confined
structures reversibly in a dispersion that is formed with kinetic stability with
or without incorporated oil. The dispersed particles are in real thermodynamic
equilibrium with the corresponding continuous aqueous phase.
We have also demonstrated that a microemulsion can be emulsified through
addition of oil to the monoglyceride + water system. This is possible since the
addition of n-tetradecane induces a transition of the internal particle structure
from Pn3m to H 2 and L 2 at a given temperature. The same phase transition can
be induced by increasing the temperature at a constant content of oil. In fact,
both the increase of temperature at a constant oil content or the increase of the
oil content in the particles at a constant temperature allow the spontaneous film
curvature of the self-assembled structure formed inside the particles to become
more negative. We also found that the temperature increase induces the
microemulsion droplets to pack first on an Fd3m cubic lattice prior to the
isotropic microemulsion phase being formed. The inner particle structure is
easy to control by altering the composition of the system and/or varying the
temperature. The use of surface-active molecules may tune the internal struc-
ture back to a less negative curvature of the interfaces so as then to recover
bicontinuous cubic structures.
These self-assembled structured aqueous dispersions seem to offer a useful
approach in the development of novel food. Indeed, these types of particles
have a great potential to host lipophilic, hydrophilic, and amphiphilic func-
tional molecules, which can be important for complex formulations in food-
drug delivery, solubilization of active molecules, selective molecular transport,
or the utilization of these systems as nano-reactors. They are stable over
periods of months, if not years, when stored in aqueous solution. But as soon
as they are mixed with other solutions, particles, etc., they will start to exchange
material for entropic reasons. In the future, we plan to study such transfer
phenomena and their kinetics.
References
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Chem. Chem. Phys., 2004, 6, 1524.
4. O. Glatter and L. de Campo, in Self-Assembly, B.H. Robinson (ed), IOS
Press, Amsterdam, 2003, p. 284.
5. K. Larsson, Curr. Opin. Colloid Interface Sci., 2000, 5, 64.
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