Virtual surfaces, director domains and the Freedericksz transition in   polymer stabilized nematic liquid crystals
  The critical field of the Freedericksz transition and switching dynamics are investigated for polymer stabilized nematic liquid crystals as a function of polymer concentration. A simple phenomenological model is proposed to describe the observed critical field and dynamic response time behaviors as a function of concentration. In this model the polymer fibrils form director domains, which are bounded by virtual surfaces with a finite anchoring energy. The Freedericksz transition occurs independently within each of these domains. 
Pavel A. Kossyrev, Jun Qi, Nikolai V. Priezjev, Robert A. Pelcovits,   and Gregory P. Crawford