Stress induced topological fluctuations in confined lamellar systems

We investigate the role of defects in a model order-disorder transition, the lamellar-microemulsion transition. We focus on the effect of an applied external stress on the transition mechanism. We first analyse the thermodynamical consistency of the usual Landau-Ginzburg modelling of these systems, and show that thermodynamical, mechanical and structural quantities can all be probed at the same time, which allows for a deeper understanding of the transition mechanisms. We apply this formalism to the case of a lamellar system confined between two plates, the model geometry for a surface force apparatus.