Electro-optical response of PDLC films with conical boundary conditions

Polymer dispersed liquid crystals (PDLC) are the liquid crystal (LC) droplets dispersed in polymer matrix. Optical properties of such composite materials depend on the orientational structure inside droplets which, in turn, depends on the boundary conditions at LC-polymer interface. For instance, the bipolar director configuration with two point defects at the opposite droplet's poles is formed within droplets at tangential surface anchoring. An electric field applied to this PDLC film causes the transformation of orientational structure and reorientation of bipolar droplet axis along the field. In the result, PDLC film can be switched from a ight-scattering state to transparent one

Spectral dependences of transmittance and polarizing ability of stretched PDLC films with homogeneous and inhomogeneous interface anchoring

Polymer dispersed liquid crystal (PDLC) films, consisting of non-absorbing uniaxially-elongated liquid crystal (LC) droplets within polymer matrix effectively polarize light in the entire transparency region (visible and near IR) of the components used, while the dichroic polarizers can do that only in the dichroic band of own or impurity absorption. Besides, PDLC films allow modulating the intensity, polarization and phase of light by applying the electric or magnetic field.They are particularly promising in the collimated laser devices and projection systems

Experimental results and theoretical model to describe angular dependence of light scattering by monolayer of nematic droplets

Light scattering by a monolayer of bipolar nematic droplets encapsulated in polymer film is examined both experimentally and theoretically. A method for the simulation of the angular distribution of scattered light is based on the anomalous diffraction and interference approximations taking into account the director configuration within liquid crystal droplets and their bipolar axes orientation. The director configuration in nematic droplets is calculated using the relaxation method of the free energy minimization. The characteristics of the sample, including distribution of droplet sizes and shape anisometry, are measured in details. The experimental results and theoretical data agree closely with each other

Small-Angle Scattering and Radiation Polarization by a Stretched Polymer Film with Nematic Liquid Crystal Droplets Having a Single-Domain Structure

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.The coefficient of directed transmittance of a stretched polymer-dispersed liquid crystal film with a defect-free single-domain liquid crystal droplet structure formed by a stretched surfactant-doped film and the polarization degree of forward-transmitted light in the visible and near-infrared spectrum ranges are studied. Results are presented for the 5CB, E7, and E44 nematic liquid crystals. Dependences of the transmission coefficient and polarizing ability of the film on the photodetector field of view are studied. Relationships allowing one to determine film parameters at which the transmission coefficient and polarizing ability of the films simultaneously reach values close to limit ones (0.5 and ±1.0, respectively) are obtained in the Foldy–Twersky and anomalous diffraction approximations

Experimental results and theoretical model to describe angular dependence of light scattering by monolayer of nematic droplets

Light scattering by a monolayer of bipolar nematic droplets encapsulated in polymer film is examined both experimentally and theoretically. A method for the simulation of the angular distribution of scattered light is based on the anomalous diffraction and interference approximations taking into account the director configuration within liquid crystal droplets and their bipolar axes orientation. The director configuration in nematic droplets is calculated using the relaxation method of the free energy minimization. The characteristics of the sample, including distribution of droplet sizes and shape anisometry, are measured in details. The experimental results and theoretical data agree closely with each other