New interpenetrating polymer networks (IPNs), i.e., the combinations of two or more polymer networks synthesized in juxtaposition, have been synthesized with controlled structure using microemulsions as templates. Poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) was chosen as the hydrophilic network, and poly(hexyl methacrylate) (PHMA) as the hydrophobic network. Initially, a ternary phase diagram was constructed in order to determine the microemulsion structure versus its composition, with the phases containing corresponding monomers and polyoxyethylene lauryl ether (Brij35) as surfactant. Four different structures (reverse, lamellar, bicontinuous and direct) were characterized. Then, the free radical polymerization/cross-linking reaction was carried out for the different monomers in each phase of the microemulsions. Materials obtained after polymerization were analyzed to confirm the IPN architecture and the preservation of the original morphology of the microemulsions used as the template. (c) 2013 Elsevier Ltd. All rights reserved.