Macroscopic dynamics near the isotropic micellar to lamellar phase transition

Highlights: • The hydrodynamic equations near the I-L_D transition are investigated. • The macroscopic dynamic equations are presented. • The experimental consequences of the theory are discussed. - Abstract: We present the hydrodynamic equations for the lamellar phase in lyotropic liquid crystals. The hydrodynamic equations are investigated to the vicinity of the isotropic micellar to lamellar phase transition. To derive the hydrodynamic equations we make use of symmetry arguments and irreversible thermodynamics. Besides the usual order parameters to describe the lamellar phase we also keep the concentration of the surfactant molecules which are aggregated in micelles as a variable in order to describe the correct macroscopic behavior of the lamellar phase. The macroscopic dynamic equations are presented on both sides of the transition. We discuss possible experiment were our theory can be tested