Tuning of self-organizing and electro-optical behaviour for orthoconic ferroelectric liquid crystal by non-chiral dopants

Formulation of multicomponent mixtures possessing the self-organizing behaviour and suitable for specific practical applications is preceded by the design and investigation of bicomponent mixtures as test systems. For this reason, six non-chiral compounds with different molecular structure were tested as functional dopants on the orthoconic ferroelectric liquid crystalline (FLC) material used as base. These dopants (3 containing only phenyl rings and 3 containing also one pyrimidine ring in the rigid core) were differing with the length of both alkyl terminal chains and the type of linkage groups between the alkyl chain and rigid core. The miscibility studies show different behaviours in mixtures, namely destabilization, induction, enhancement and suppression of the liquid crystalline phases. The main aim of this work is to establish the influence of the dopant structure on basic parameters of the resulting binary mixtures, specifically on the mesomorphic behaviour, values of the spontaneous polarization, tilt angle, helical pitch length and dielectric behaviour. Discussion of the effect of the molecular structure on the above mentioned properties should contribute to better understanding of the relationships arising during design and formulation of binary mixtures with properties suitable for specific applications in opto-electronics and photonics.