Self-assembled interpenetrating networks by orthogonal self assembly of surfactants and hydrogelators.

Interpenetrating networks (IPN) consist of two or more networks of different components which are entangled on a molecular scale and cannot be separated without breaking at least one of the networks. They are of great technological interest because they allow the blending of two or more otherwise incompatible properties or functions, and furthermore synergistic effects might arise from the simultaneous operation of the two networks. So far, the preparation of interpenetrating network gels by self-assembly approaches was doomed to fail because the conventional polymers and surfactant building blocks either phase separate or form mixed assemblies, respectively. Here we report on self-assembled interpenetrating networks obtained by the orthogonal self-assembly of small molecular hydrogelators and surfactants. Preliminary studies on the self-assembly behaviour and viscoelastic properties of these systems revealed that these self-assembled IPN have a number of intriguing properties. For instance, the presence of two coexisting networks offers new possibilities for compartmentalization, and will allow one to adjust the viscoelastic properties between 'soft' and 'hard' gels. The non-covalent character of such IPN makes their formation fully reversible, which can be exploited for dual responsive systems. Most interestingly, self-assembled IPN can also act as a very primitive, yet unique, model for biological interpenetrating networks like the extracellular matrix and the cytoskeleton, and thereby contribute to our understanding of these very complex systems.