Azimuthal anchoring coefficient

Fig. 4.11. (a) Aging, as observed through the time dependence of the azimuthal anchoring coefficient for 5CB on UV aligned poly-(vinyl-cinnamate) (b) Aging, as observed through the offset parameter h [59]. 

Fig. 4.9. Scattering geometry for measurements of (a) azimuthal and (b) zenithal anchoring coefficient, n is the director, i and / the polarisations of the incoming and outgoing beams, and fei and fcf the corresponding wave vectors.

A comment should be added on the rotational viscosity of the sample in the experiment. It can easily be shown that in the case of azimuthal anchoring measurements, the viscosity entering the analysis equals the rotational viscosity 71. When measuring the zenithal anchoring coefficient, the effective viscosity has to be corrected according to the scattering geometry. However, in first approximation the pure splay mode viscosity is sufficient. 

Measurements of the LC azimuthal anchoring energy coefficient W(f oi the PVCN substrates (Fig. 5.9) were performed by preparing twist cells with... 

Fig. 4.12. (a) Temperature dependence of azimuthal Wtp dots) and zenithal Wo (squares) anchoring coefficients for nematic 5CB on rubbed Nylon with Tni being the transition temperature into the isotropic phase (b) A comparison of the ratios of the two anchoring coefficients W jW p (circles) with the ratio of the corresponding Frank elastic constants KijK2 [Q5](solid line) [64]. 

Fig. 5.9. Room temperature azimuthal surface anchoring energy coefficient of the 5CB liquid crystal on LPP PVCN substrate as a function of the LP UV irradiation time. The dashed line is guide to the eye.

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