The presence of optical anisotropy in liquid crystals (LCs) has caused these materials to have dual refractive indices: ordinary (no) and extra-ordinary (ne). Many fundamental information about LCs can be found by looking at these refractive indices. In this work, the refractive indices of four mixtures nematic liquid crystal (NLC) have been studied as a function of temperature, and the relevant functions were then calculated. Subsequently, the order parameter of mentioned LCs was determined using three methods: Vuks, Haller, and the effective geometry parameter method. It was concluded that the obtained values are not significantly different and exhibit the same temperature dependence. The obtained results were evaluated in relation to the approach utilized.

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Recently, the design and fabrication of light-powered actuators have attracted immense attention because of the manufacturing of intelligent soft robots and innovative self-regulating devices. Accordingly, a liquid crystal polymer network (LCN) provides a promising platform due to its reversible and multistimulus-responsive shape-changing behaviors. In particular, doping nanoparticles with exclusive properties into the LCN can produce interesting results. In this work, we investigated a TiO2 nanoparticle-based LCN polymer light-powered actuator. TiO2 nanoparticles as an inorganic ultraviolet (UV)-light absorber can substantially affect the LCN polymer’s oscillatory behavior. Our results demonstrate that the oscillation characteristics are directly influenced by the presence of nanoparticles, and we studied the influencing factors. The effectiveness of the elastic modulus, thermomechanical force, and curvature was investigated using different weight percentages of TiO2 nanoparticles. Our results show that, in the presence of TiO2 nanoparticles, the polymer chain order and inter-chain interactions in the polymer matrix as well as the structural deformation of relevant polymer surfaces are changed.