Ferroelectric Particles in Liquid Crystals: Recent Frontiers

Maier-Saupe-type theory of ferroelectric nanoparticles in nematic liquid crystals

“…One particularly interesting case occurs if the particles are ferroelectric. Experiments have shown that low concentrations of ferroelectric Sn 2 P 2 S 6 or BaTiO 3 nanoparticles increase the orientational order parameter, increase the isotropic-nematic transition temperature, and decrease the switching voltage for the Frederiks transition [7][8][9][10][11][12][13][14]. Thus, they provide a new opportunity to enhance the properties of liquid crystals for technological applications.…”

Terahertz properties of liquid crystals doped with ferroelectric BaTiO3 nanoparticles

“…The first sol-gel process we used was based on tetrabutyl titanate Ti(OC 4 H 9 ) 4 and barium acetate Ba(CH 3 COO) 2 . The nanoparticles were in solution with heptane, as a solvent, and with oleic acid, as a surfactant.…”

“…Additionally, the synthesis of a material with desired physical properties typically requires to use of more than ten components; the more components are included, the more difficult it is to predict final material properties. The ferroelectric nanoparticles can improve the LC materials properties without chemical synthesis and the properties can be varied by changing the type and the amount of nanoparticles mixed with LC [2,7,8]. The improved properties of liquid crystals doped with ferroelectric nps are likely to be caused by a strong dipole-dipole interaction between the ferroelectric nanoparticles and the surrounding liquid crystal molecules.…”

“…The doping of a nematic liquid crystal (LC) with a small amount (<1%) of ferroelectric nanoparticles (nps) can cause significant changes in their properties such as clearing temperature, threshold voltage, elastic constants, dielectric anisotropy and birefringence in visible range [1][2][3][4][5][6]. The alternative method for improving or changing such LCs properties is by using chemical synthesis, which is time-consuming and expensive.…”

Doping the nematic liquid crystal 5CB with milled BaTiO3nanoparticles

“…BaTiO 3 nanoparticles. For example, ferroelectric nanoparticles coated with a surfactant and dispersed in nematic LCs were reported to enhance the optical diffraction efficiency of beam coupling [7,8], alter the dielectric anisotropy, shift the phase transition temperatures [9,11], and cause asymmetry in the electro-optic response of LCs [11]. Recently, it was reported that dispersions of BaTiO 3 nanoparticles can be prepared by milling cubic BaTiO 3 in heptane with oleic acid in a planetary ball mill [12].…”