Orientational relaxation processes in Langmuir films under lateral compression

The orientational relaxation process of the director nˆ to its equilibrium orientation nˆeq, in the Langmuir film, during the lateral compression, is investigated. The relaxation time and rotational viscosity coefficient, during compression of 4-n-pentyl-4′-cyanobiphenyl (5CB) monolayer film on the water surface has been calculated for a number of dynamic regimes. It is also shown that the viscous and electric torques exerted per unit volume of the monolayer film may excite the solitary wave propagating along the air–water interface.