Attenuation and Dispersion of Acoustic Waves in Nematic Liquid Crystals

Abstract

Abstract The propagation of forced infinitesimal harmonic plane waves in a compressible nematic liquid crystal uniformly aligned in an external magnetic field is theoretically studied. The linearized balance laws and constitutive relations of the Ericksen-Leslie continuum theory are used to solve for the attenuation and dispersion of the waves. Low frequency approximations are used to invert the relations and to express viscosity coefficients in terms of the attenuation. Using data published in the literature for N-p-methoxybenzylidine-p'-n-butylaniline (MBBA), numerical calculations for the attenuation and dispersion are given and compared to acoustic experiments. Also, some errors in the literature on values of viscosity coefficients derived from acoustic experiments on MBBA are pointed out.