Thin ferroelectric liquid crystal layers: mechanical stability and fast electro-optical response, connection between molecule design and surface properties

The storage of information after mechanical stimuli even without applied electrical field is based on the elastic properties of the ferroelectric liquid crystal (FLC) material and the anchoring energy. It is favourable for chiral molecules with extended length, such as 4,4′-di-substituted quaterphenyls and 4,4′-di-substituted quinquephenyls, which have in series-connected benzene rings, but not separated by bridging fragments. To obtain the required stability with a reasonable switching speed of about 50 μs 4,4′-di-substituted chiral quaterphenyls with two chiral centres on the same wing has been synthesised. Here, the switching is much faster compared to compounds with same quaterphenyl fragment, but only with one chiral centre.