J. Phys. II France
Volume 5, Numéro 1, January 1995
Page(s) 159 - 170
DOI: 10.1051/jp2:1995120
J. Phys. II France 5 (1995) 159-170

Density Functional Model of Anchoring Energy at a Liquid Crystalline Polymer - Solid Interface

E. M. Terentjev

Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE, U.K.

(Received 30 November 1993, revised 5 July 1994, accepted 28 September 1994)

A statistical mechanical expression for the anisotropic surface (anchoring) energy of a nematic polymer melt is derived in the molecular field approximation using the density functional approach. It is shown that this energy can be very large, $W\, \widetilde{>}\, 10$ erg/cm 2. It is shown that a crossover exists between the two characteristic scaling regimes of W. At low nematic order parameter S the anchoring energy is determined by the change in the single chain entropy due to the steric restriction near the wall and is proportional to the large longitudinal persistence length l|| of the folded chain. In highly ordered system ( S>0.55) W is dominated by pair interactions between the chain segments, modulated by the steric effect of the wall, and is proportional to the higher power, l||7/4.

© Les Editions de Physique 1995