Structural Stabilization And Adjusting Of Functional Liquid Crystal Materials

This essay mainly covers researches upon different functional liquid crystal materials and the body contents of it are divided into two aspects.The first part is on account of blue phase liquid crystal,regarding to the way of introducing a bent-shaped geometry molecule dopant with acrylate end groups on both sides,into chiral nematic liquid crystal host.Blue phase was thus induced and maintained to be irradiated under controlled ultraviolet so as to photo-crosslink the unsaturated C=C double bonds of the acrylate group in the system.After the process completed,the temperature range of blue phase could be widened to 58 °C,which includes room temperature.Furthermore,the electro-optical performance was also investigated,indicating the unique characteristics such as hysteresis-free,low driving voltage and fast response profile.Our experiments filled in gaps of researches in regard to excellent electrical stability presented by bent-shaped molecules induced liquid crystalline blue phase through the fulfillments of enhanced lattice stabilization and improved electro-optical performances.The second part involves the fabrication of liquid crystal Fresnel lens integrated by means of photo-alignment technique,hybrid-aligned nematic cell and with dual-frequency liquid crystals poured into the cell,which takes microscopic molecular switches into consideration and by means of fabricating macroscopic liquid crystal Fresnel lens to explore the diffraction performance in order to further understand what happened when different stimuluses were applied onto the cell.Results indicate that under the circumstance of 40kHz high frequency ambient electric field,with 6Vrms saturation voltage applied onto the lens,the diffraction efficiency reaches maximum,38.5%in optimum,close to the theoretic limit,40.5%.What's more,the diffraction element also possesses particular strengths as low driving voltage,rapid switches between high frequency and low frequency and polarization independent.Consequently,we realized dual significant out-breakings of both techniques and materials through integration of various kinds of them,thus carrying forward the advantages of each to one promising diffraction optical element.Therefore,it provides worthy reference for the design of novel liquid crystalline diffraction devices.In conclusion,this dissertation stresses structural stabilization and tunability to achieve function maximization for different functional materials and gratifyingly,each of them acquires satisfying outcomes.The original designs and final conclusions of the experiments in this article could afford certain enlightenments for researchers devoting themselves in subjects of liquid crystals for display optimization and photonic applications.