EFFECTIVE-MEDIUM THEORY OF POLYMER-DISPERSED LIQUID-CRYSTAL DROPLET SYSTEMS - II - PARTIALLY ORIENTED BIPOLAR DROPLETS

We construct a theory of the dielectric properties of a polymer disper sed liquid crystal droplet film containing bipolar droplets whose prin cipal axes respond to an electric field. The theory involves a balance of an elastic energy term favouring an initial zero-field distributio n of droplet axes and a dielectric energy term favouring droplet orien tation parallel to an imposed field. We discuss (i) droplets initially orientationally ordered by an in-plane strain field and (ii) an initi ally random distribution of droplets. In case (i) we find a weakly dro plet concentration dependent sharp threshold field at which droplet re orientation occurs. In case (ii) we find more gradual droplet reorient ation. In the latter case the droplet axis distribution exhibits an un expectedly rich structure.