45.2: Electro-Optics of Liquid Crystals Doped with Ferroelectric Nano-Powder

Cheon, Chae Il; Li, L.; Glushchenko, Anatoliy; West, John L.; Reznikov, Yuri; Kim, J. S.; Kim, D. H.

doi:10.1889/1.2036286

Cited by 25 publications

(17 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, we have shown that even at low concentrations (c part 1%), LC colloids differ strongly from the pure host material [7,8,9,10]. These colloids consist of submicron ferroelectric particles suspended in the LC host.…”

Section: Introductionmentioning

confidence: 99%

“…In such systems aggregated particles produce director distortions extending over macroscopic scales. These suspensions scatter light strongly, and possess unique structural, mechanical, electro-and magneto-optical properties [5,6].Recently, we have shown that even at low concentrations (c part 1%), LC colloids differ strongly from the pure host material [7,8,9,10]. These colloids consist of submicron ferroelectric particles suspended in the LC host.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Orientational Coupling Amplification in Ferroelectric Nematic Colloids

et al. 2006

Self Cite

View full text Add to dashboard Cite

We investigated the physical properties of low concentration ferroelectric nematic colloids, using calorimetry, optical methods, infrared spectroscopy and capacitance studies. The resulting colloids normally remain homogeneous, but the nematic orientational coupling is significantly amplified. In particular cases, the nematic orientation coupling increases by 10% for particle concentrations of 0.2%. A manifestation of the increased orientational order is that the clearing temperature of a nematic colloid increases up to 40 Celsius degrees compared to the pure LC host. A theoretical model is proposed in which the ferroelectric particles induce local dipoles whose effective interaction is proportional to the square of the orientational order parameter.PACS numbers: 64.70. Md, 82.70.Dd, Colloids in which the solute is liquid crystalline (LC) are known to possess an extremely rich set of behaviors [1,2,3,4,5]. The anchoring between the LC and microcolloidal particles ( 1µm) can produce long-range orientational distortions around the particles. This results in strong inter-particle interactions -sometimes repulsive and sometimes attractive -in the mesophase. The interactions can give rise to well-ordered structures of particles in the liquid crystal matrix (both lattices and chains) [2,3]. However, in most cases a prerequisite for interesting LC colloidal behavior has been a high concentration dispersion, typically with particle volume fraction c part 30%. In such systems aggregated particles produce director distortions extending over macroscopic scales. These suspensions scatter light strongly, and possess unique structural, mechanical, electro-and magneto-optical properties [5,6].Recently, we have shown that even at low concentrations (c part 1%), LC colloids differ strongly from the pure host material [7,8,9,10]. These colloids consist of submicron ferroelectric particles suspended in the LC host. In these systems, unlike in classic LC colloids, the suspensionmatrix interaction is insufficient to disturb the LC orientation. This small concentration dramatically increases the dielectric anisotropy, significantly decreases the Freedericksz transition voltage, and significantly accelerates electric field-induced director reorientation.In this letter, we report results which show that these phenomena are general properties of liquid crystal suspensions containing ferroelectric colloidal nanoparticles. The addition of impurities normally decreases the nematic clearing temperature T N I [11]. However, our measurements show massive increases in T N I , of the order of 40 • C, for mass impurity concentrations of the order of 0.2%. These results imply an increase in the effective nematic interaction parameter. Measurements of the birefringence, dielectric anisotropy and order parameter in the suspension are consistent with this picture.We have also constructed a theoretical model. The ferroelectric particles in the suspension produce large electric fields in their neighborhood. These electric fields produce induce...

show abstract

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Orientational Coupling Amplification in Ferroelectric Nematic Colloids

et al. 2006

Self Cite

View full text Add to dashboard Cite

show abstract

“…The discovery by Bachmann and Barner [14] that doping very fine dielectric particles into an isotropic liquid resulted in the enhancement of its sensitivity to electric fields heralded studies on the doping of ferroelectric nanoparticles (BaTiO 3 , Sn 2 P 2 S 6 ) into nematic liquid crystals [15,16]. In the beginning, the doping of nanoparticles was restricted to nematic liquid crystals due to their widespread applications and mature developments, as well as their relatively simple liquid crystal structure, which means that the doping of nanoparticles is less likely to destroy the alignment of the liquid crystal molecules.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the electro-optical properties of ferroelectric liquid crystals by doping ferroelectric nanoparticles

et al. 2010

View full text Add to dashboard Cite

The effects on the physical and electro-optical properties of ferroelectric liquid crystals (FLCs) after the doping of a dilute suspension of ferroelectric nanoparticles (BaTiO 3 ) have been studied. Due to the permanent electric dipole moments of the ferroelectric nanoparticles, the spontaneous polarisation of FLCs with low doping concentration was about twice that of pure FLCs, in addition to a significant improvement in the dielectric properties, the response time and the V-shaped switching in the chiral smectic C (SmC*) phase. The results obtained point the way to an alternative for improving the applicability of FLCs without resorting to chemical synthesis.

show abstract

“…displays, high contrast, large view angle and less backlight scattering [9][10][11] .In this communication, we are presenting the effect of metal oxide (zinc oxide) nanoparticles on the molecular alignment, thermal properties and crystallinity of 4-Cyano-4'-Pentylbiphenyl Mesogen (5CB), which is a well-known room temperature nematic liquid crystal. Experimental data have been obtained using a polarizing optical microscope, X-ray diffraction and Image analysis by MATLAB software.…”

Section: Introductionmentioning

confidence: 99%

HIGH-TEMPERATURE PHASE TRANSFORMATIONS AND DYNAMICS OF ZnO NANOPARTICLES INCORPORATED 4- CYANO-4'-PENTYLBIPHENYL MESOGEN

Raju¹

2017

Rasayan J. Chem.

View full text Add to dashboard Cite

Synthesis of Zinc Oxide nanoparticles through chemical precipitation method was done taking aqueous solutions of Zinc Nitrate and Sodium Hydroxide as precursors. Elemental, structural and optical absorption studies of the ZnO nanoparticles were investigated using Energy Dispersive, X-Ray Diffraction and UV-Visible spectroscopy. The prepared nanoparticles were studied for their effect on familiar display device materials called liquid crystal/mesogen. ZnO nanoparticles were introduced in the lattice of 4-cyano-4'-pentylbiphenyl (5CB) mesogen through dispersion technique. ZnO nanoparticles incorporated 5CB is characterized through Polarizing Optical Microscopy, X-Ray Diffraction and Image Analysis using MATLAB software. From these studies, it was revealed that the presence of ZnO nanoparticles in liquid crystal enhanced the properties of pure 5CB. It was observed that the transition temperatures and crystallinity of ZnO nanoparticles incorporated mesogens were remarkably increased when compared to the pure counterpart which is a preferable feature in terms of the application of these samples. In addition, novel phases were observed in the doped liquid crystal sample at very high temperatures. These changes are assigned to the enhanced surface area to volume ratio of nanoparticles, which in turn improves their catalytic activity. ZnO nanoparticles incorporated 5CB mesogen is one among the liable materials for display devices and biosensor applications due to reduced energy consumption.

show abstract

45.2: Electro-Optics of Liquid Crystals Doped with Ferroelectric Nano-Powder

Cited by 25 publications

References 17 publications

Orientational Coupling Amplification in Ferroelectric Nematic Colloids

Orientational Coupling Amplification in Ferroelectric Nematic Colloids

Enhancing the electro-optical properties of ferroelectric liquid crystals by doping ferroelectric nanoparticles

HIGH-TEMPERATURE PHASE TRANSFORMATIONS AND DYNAMICS OF ZnO NANOPARTICLES INCORPORATED 4- CYANO-4'-PENTYLBIPHENYL MESOGEN

Contact Info

Product

Resources

About