Surface and liquid crystal interlayer interactions : characterizations and applications

For investigation of the interaction between alignment layer and nematic liquid crystal a simple method for determination of liquid crystal polar anchoring energy by electrical measurements was proposed. This method is based on two-channel scheme for capacitance measurements. The proposed method allows investigating anchoring properties of both planar and vertical aligned LC materials. This method was used for investigation the polar anchoring properties of photoaligning material before and after illumination and for LC structures with a high pretilt angle. Other method is the optical method for the determination of LC polar anchoring energy based on measurement of the reflection from LC cell versus voltage was proposed. The “bulk” electrooptical response of LC cell is not involved here at all. Best conditions for measurement are realized in twist configuration of LC cell. Polar and azimuthal anchoring energy can be measured in one cell. For smectic liquid crystal was done theoretical investigation of the interlayer interaction in the ferroelectric and antiferroelectric smectic phases. This description is based on the distribution of dipole moment in molecule of liquid crystal and dislocation them inside smectic layer. Tilt of molecules in the smectic layer is followed from the ordering of the dipole moments in one direction of one layer. Three ordered phases are found, first is synclinic, second is anticlinic and third is twisted structure. In twisted structure the angle between two layers is 90 degree. Theoretical investigation of the ferroelectric liquid crystals and the effects interaction liquid crystal with surface was used for develop a stabilization system for interferometer based on Zeeman laser. Received result, accuracy 10-7 for measurement of the linear dimensions, is better then can give other analogical systems. Application of liquid crystal technology decrease size of interferometer, weight and price. Company “Lasertex” (Poland) uses this stabilization system in interferometers which they produce