We have designed an inexpensive and sensitive mechanochromic system. Our system is prepared by a simple emulsion procedure of nematic liquid crystal in polydimethylsiloxane (PDMS). The resulting polymer dispersed liquid crystal (PDLC) exhibits a transmission change of 50% as a response to strain. Here we characterize the morphological, optical, and mechanical factors behind this transmission ch...

The nuclear-magnetic-resonance (NMR) technique is employed to liquid-crystal-dispersed-polymer (LCDP) systems. Deuterium NMR is used to determine director distributions in LCDP cells in the presence of a magnetic field. The samples consist of a nematic liquid crystal mixed with small percentages of a monomer that is polymerized under different conditions after dissolving it in the liquid crysta...

Bragg gratings, holographically formed in polymer-dispersed liquid crystals (H-PDLCs) are studied. Mixture of the commercially available E7 liquid crystal and NOA65 polymer in ration 1:1 are employed. Polymerisation in presence of electric field is produced. A significant increase of the diffraction efficiency in the case of field-applied recording is observed. The exposure characteristics, ele...

1 The POLICRYPS structure In the last decades, great attention has been devoted to the realization of switchable holographic structures in liquid crystalline composite materials [1]. In particular, it has been shown that diffraction gratings based on Holographic Polymer Dispersed Liquid Crystals (HPDLC), that means droplets of Nematic Liquid Crystal (NLC) dispersed in a polymer matrix (see inse...

The polymer stabilized state of ferroelectric liquid crystals (FLC) is reviewed; and the effect of a dispersed polymer network in an FLC outlined and discussed. All fundamental material aspects are demonstrated; such as director tilt angle; spontaneous polarization; response time and viscosity; as well as the dielectric modes. It was found that the data can largely be explained by assuming an e...

In this work we investigate the optical properties of electrically switched transmission gratings fabricated holographically using polymer-dispersed liquid-crystal (PDLC) materials. We have found that the PDLC mixture can be used to control the diffractive properties of the liquid-crystal composite gratings. In one limit the gratings are highly isotropic and in the other limit the gratings are ...

We present an optical method of storing random cryptographic keys, at high densities, within an electronically reconfigurable volume of polymer-dispersed liquid crystal (PDLC) film. We demonstrate how temporary application of a voltage above PDLC’s saturation threshold can completely randomize (i.e., decorrelate) its optical scattering potential in less than a second. A unique optical setup is ...

In this work we analyse the fabrication of Polymer Dispersed Liquid Crystals (PDLCs) using SU8-2002-2007 photoresist and 5CB and E7 Liquid Crystals. Also we report the nonlinear optical behaviour for these materials and for Polymer Dispersed Liquid Crystals with a Twisted Cell (T-PDLC). We found that depending of several parameters, the droplets size varies from nano to micro dimensions. We rep...