Photo-induced changes of bulk and surface liquid crystal properties

The bulk and surface properties of liquid crystals are very important for The performance of liquid crystal displays and devices. The bulk properties of thermotropic liquid crystals depend strongly on the molecular structure and on the molecular interactions. The liquid crystal surface properties, which is of vital importance for the alignment of the liquid crystals and thus for the appearance and operation of these devices, depends. in addition, on the solid surface-liquid crystal interactions. Both liquid crystal physical properties can effectively be controlled by external factors that result in changes of the molecular structure and, hence, of the molecular properties. Here, we report on the reversible changes of bulk and surface liquid crystal properties caused by the photoisomerisation process that takes place in the organic photochromic materials. The photocontrol of these physical properties could be utilized in liquid crystal devices such as all-optical switches, light modulators and optical memories.