The nanostructure of a microemulsion can be strongly affected by the liquid-to-solid transition during polymerization. Here, we examined the evolution of nanostructures of different ternary mixtures, including two microemulsions and a single lamellar phase that upon polymerization are quantitatively studied by SAXS/WAXS and DSC experiments systematically performed before and after the polymerization of both aqueous and organic phases. Samples are mixtures of the poly(2-acrylamido-2-methylpropanesulfonic acid) network as the aqueous phase and poly(hexyl methacrylate) as the organic phase stabilized by Brij35 surfactant. Upon polymerization, the surfactant is excluded from the water/oil interface and crystallizes, strongly changing the nanostructure of samples where it is the main component. In samples where the aqueous phase is the main component, only a few changes in structure are observed upon polymerization. This study demonstrates quantitatively the possibility to preserve nanostructures during polymerization, thus inducing a templating effect.