Static and dynamic behavior of a nematic liquid crystal in a magnetic field. Part II : Dynamics

2014 The dynamics of the distortion of a well-oriented nematic liquid crystal film in a perpendicular field around the Freedericks critical field value is studied both theoretically and experimentally. The experimental thermal and optical techniques have already been used for the description of the equilibrium properties of the transition. Their use for the measurement of transition rates leads to an accurate verification of the Leslie-Ericksen hydrodynamic theory and to a demonstration of the role of back flow effects. The divergence of the characteristic time close to the critical value follows accurately the general Landau model of second order phase transitions. The value of the twist viscosity coefficient 03B31 is obtained. LE JOURNAL DE PHYSIQUE TOME 34, JANVIER 1973,