We would like to invite you to the habilitation lecture by Prof. Michal Kohout from University of Chemistry and Technology. The topic of his lecture is Design and applications of photosensitive liquid crystals.
Liquid crystals (LCs), a phenomenon that significantly influences our daily lives. We use technologies based on LCs in mobile phones, TV screens and many other optoelectronic devices. Apart from materials science, LCs reach far into the realm of biochemistry since cell walls as well as short fragments of DNA are liquid crystalline. The discovery of liquid crystals dates back to the 19th century, when Friedrich Reinitzer, a professor at Charles University in Prague observed an interesting behaviour during melting of cholesteryl benzoate, which, with the help of Otto Lehmann, he later described as crystals that flow – liquid crystals.
Contemporary research on LCs in the area of materials chemistry is mainly focused on advanced self-assembling systems that, apart from response to the mechanical stress and electric field, feature a special functionality responsible for their instant response to a magnetic field or light. Among them, photosensitive materials play a prominent role due to broad application potential in non-linear optics and photonics. From the variety of photosensitive units applied in the design of liquid crystals, the azo group stands out for the distinct conditions of photoisomerization of the thermodynamically stable E-(trans-) isomer to the photochemically preferred Z-(cis-) isomer and vice versa.
Recently, we have focused on the design and synthesis of chiral photosensitive materials and their application as chiral photosensitive ligands to stabilize magnetic nanoparticles. The nanomaterial represents the first example of a multifunctional dopant, which upon mixing with an achiral liquid crystal gives rise to the photosensitive and magnetic nanocomposite showing a chiral mesophase. Moreover, we prepared a series of photosensitive bent-core materials based on a 4-chlororesorcinol central core featuring various linking units in the side arms. Certain combination of the azo group in one elongating side arm and a particular linking unit in the other gave rise to the broad range of a nematic phase. We have utilized these compounds in a prototype of an optical memory device.
The lecture will take place in person, in the hall CH3, Faculty of Science, Hlavova 8, Praha 2.