Hexagonal and lamellar mesophases induced by shear

C.M. Marques , M. E. Cates

The role of a shear flow in the formation of an hexagonal mesophase is investigated and the transition between the isotropic, lamellar and hexagonal phases described in a three dimensional phase diagram [τ, u, Δ] where τ is a temperature-related parameter, u a measure of the intrinsic asymmetry of the system and Δ the strength of the shear rate. At zero shear rate the microphase separation transition (M.S.T.) is dominated by fluctuations but it acquires a strong mean-field character as Δ is increased. We find a region in the phase diagram where the same isotropic phase may undergo a transition to a lamellar or an hexagonal structure according to whether is cooled or sheared. The relevance of our results for diblock copolymers and for microemulsions is discussed.

Mots clés: elasticity of liquids; emulsions; fluctuations; liquid crystal phase transformations; liquid crystal polymers; liquid crystals; phase diagrams

Domaines: Articles anciens

C.M. Marques, M. E. Cates. Hexagonal and lamellar mesophases induced by shear. Journal de Physique, 1990, 51 (16), pp.1733-1747. ⟨10.1051/jphys:0199000510160173300⟩. ⟨jpa-00212483⟩