Assemblies of fluorine containing bent-shaped liquid crystal molecules studied by using scanning tunneling microscopy

In this work we prepared a fluorine containing bent-shaped liquid crystal from biphenyl as the central core and rod-like azobenzene mesogens as the side arms, namely 4',3-biphenyl bis4-(4'-hexadecanloxy-3-fluorophenylazo)benzoate] (L104). The self-assembly behaviors of L104 molecules on graphite surface were investigated by using scanning tunneling microscopy (STM) under ambient conditions. The high-resolution STM images of L104 assemblies revealed three kinds of structures showing the joint effects of dipole-dipole interactions originated from the fluorine and the bent-core alignments for maximizing pi-pi interactions. These observations may be beneficial for understanding the assembly mechanism and designs for novel banana-shaped liquid crystal molecules.