Polar and nonpolar contributions to liquid-crystal orientations on substrates

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Abstract
Both experimental and theoretical evidences are presented for polar and nonpolar contributions to liquid‐crystal orientations on surface‐treated substrates. Polar and nonpolar components of substrate surface energies are determined from contact angle measurements using polar liquids. Liquid‐crystal orientations are characterized using orientation angles and anchoring strength coefficients at substrate surfaces, both of which are measured by the magneto‐capacitance method. Numerical calculations give correlations between liquid‐crystal orientation and substrate surface energy components, which are in good agreement with experimental results. These calculated correlations involve the critical surface tension hypothesis as a limited case when polar interfacial interactions are negligible.