Phase transitions in biaxial banana phases

We discuss symmetry properties of various phases that can result when biaxi al objects with at least one polar axis are orientationally ordered and pac ked on layers. The possibility of spontaneous splay, bend and twist is also investigated for biaxial nematic, smectic banana and dolphin phases. We fu rther discuss appropriate order parameters and expressions for Ginzburg-Lan dau free energies for some phase transitions involving these phases.