Fabrication of Liquid Crystal Sol Containing Capped Ag−Pd Bimetallic Nanoparticles and Their Electro-Optic Properties

Abstract

Liquid crystal molecule-capped Ag−Pd bimetallic nanoparticles (atomic ratio = 1/9, 1/4, 1/1, 4/1, and 9/1) were prepared by photoirradiation of the tetrahydrofuran solution of silver perchlorate and palladium(II) acetate in the presence of liquid crystal molecule, 4′-pentylbiphenyl-4-carbonitrile. (5CB is often used for this compound based on conventional nomenclature 4′-pentyl-4-cyanobipenyl. Thus, 5CB is used in this paper.) The prepared bimetallic nanoparticles had an average diameter of 1.8−3.6 nm. Infrared spectra of carbon monoxide adsorbed on the bimetallic nanoparticles suggested that bimetallic nanoparticles had a random alloy structure. The nanoparticles were dispersed in liquid crystal 5CB to construct novel twisted nematic liquid crystal devices (TN-LCDs). The TN-LCDs containing Ag−Pd bimetallic nanoparticles revealed the electro-optic properties depending on the composition of nanoparticles, especially surface composition of nanoparticles, which was shown to be of importance to control not only the properties but also the stability of nanoparticle-doped LCDs by bimetallization.

Electro‐Optic Function of Liquid Crystal Displays Doped with Poly(γ‐cyclodextrin)‐Protected ZrO2/Au Nanoparticles

“…The chemical method involves simultaneous or coreduction, successive or two‐step reduction of two kinds of metal ions, and “self‐organization” of bimetallic nanoparticles by physically mixing two kinds of already‐prepared monometallic nanoparticles with or without after treatments. Previously, we reported 4′‐pentyl‐4‐cyanobiphenyl (5CB)‐protected Ag/Pd bimetallic nanoparticles by the photoirradiation of the tetrahydrofurane solution of silver perchlorate and palladium(II) acetate in the presence of a liquid crystal molecule . Infrared spectra of carbon monoxide adsorbed on the bimetallic nanoparticles suggested that bimetallic nanoparticles had a random alloy structure.…”

The ferroelectricity effect of nanoparticles on thermodynamics and electro-optics of novel cyanobiphenyl eutectic binary mixture liquid crystals

“…Many colloidal particles in nematic LCs having complex self-assembled structures, resulted from nematic-mediated anisotropic interaction between the particles, have been widely studied [3,4]. Nematic LCs are particularly interesting because of their coupling ability with external electric and magnetic fields.…”

Effect of Particle Size on Electro-Optic Properties of Liquid Crystal Devices Doped with γ-Cyclodextrin Stabilized Barium Titanate Nanoparticles

“…The modification of physical properties of liquid crystals by doping nanomaterials has received much attention from the view point of the enhancement of the performance of LCDs. Reflecting these trends several research groups reported on heterogeneous liquid crystal suspensions using; ferroelectric nanoparticles [1], ferromagnetic particles [2], fullerene [3], carbon nanotubes [4], diamond powders [5], metal nanoparticles [6,7], and metal nanorods [8]. In particular, strong activities have been reported for barium titanate (BaTiO 3 ) nanoparticles doped in nematic liquid crystalline mixtures [9].…”