Mass transfer processes induced by inhomogeneous photo-polymerisation in a multicomponent medium

POLICRYPS Composite Materials: Features and Applications

“…The POLICRYPS grating was cured by a total UV intensity of 11 mW/cm 2 , acting on the sample for τ≈1000 s at high temperature (e.g. above the nematicisotropic transition point of the 5CB liquid crystal), these being the optimal conditions for achieving a high diffraction efficiency and a morphology of good quality [Caputo et al, 2001]. Almost the same UV intensity and curing time proved also to be adequate for the realization of the PDLC grating, but in this case the sample was cured at room temperature.…”

Analytical model of light beam diffraction by one-dimensional electrically controlled non-uniform transmission photon PDLC structures

“…The holographic method of forming photon structures in PDLC is most widespread [4][5][6][7][8]. Models and results of experimental investigation of forming holographic structures in the PDLC materials with allowance for the concentration of liquid crystal molecules, their encapsulation, and phase subdivision were presented in [4][5][6][7][8].…”

“…The diffraction and selective properties of the transmitting and reflecting photon structures with uniform amplitude profiles were investigated in [4][5][6][9][10][11][12][13] in the approximation of interaction of plane light waves. To investigate the potential characteristics of the photon structures in the PDLC materials used in electrically controlled spectrally selective switching elements of photonics, the influence of the non-uniform refractive index profile and light beam divergence on the diffraction and selective properties of holographic photon structures must be investigated [3,7,8,12].…”

Electro-optical characterization of switchable Bragg gratings based on nematic liquid crystal–photopolymer composites with spatially ordered structure

“…Studies reported by many authors showed that among critical factors are the types of components used to prepare the initial composition, energy characteristics of the curing radiation, and material morphology [1,3,[5][6][7][8][9][10][11][12]. In spite of the great body of reported studies in which holographically formed polymer-dispersed liquid crystals (PDLC) were examined, noise figures of such materials still remains a scantily investigated matter.…”

“…Since individual NLC layers in such gratings are structurally uniform, losses for scattering within the layers turn out to be minimal and the switching field, low (3-8 V/lm). On the other hand, in gratings prepared at elevated temperatures the detrimental effects due to shrinkage and mutual diffusion of components at the cooling stage on the final structure of the grating and its performance characteristics become more pronounced [9,10].…”