Dielectric study of azo-doped aerosil/7CB nematic nanocomposite upon UV light

INERA Workshop 2016: Membrane and Liquid Crystal Nanostructures

Marinov, Y.G.^1 ; Marinov, M.P.^1 ; Hadjichristov, G.B.^1 ; Petrov, A.G.^1 ; Prasad, S.K.^2 ; Marino, L.^3 ; Scaramuzza, N.^3

Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko chaussee, Sofia

1784, Bulgaria^1

Centre for Nano and Soft Matter Sciences, P.O.Box 1329, Jalahalli, Bangalore

560 013, India^2

Dipartimento di Fisica, Università della Calabria, Via Pietro Bucci, Cubo 31C, Rende (CS)

87036, Italy^3

关键词: Azobenzene liquid crystals;    Dielectric permittivities;    Dielectric studies;    Frequency ranges;    Photo-responsive;    Silica nanospheres;    UV illuminations;    UV light intensity;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/780/1/012009/pdf
DOI  :  10.1088/1742-6596/780/1/012009

来源: IOP

【 摘 要 】

We studied three-component nanocomposite produced from nano-filled nematic by doping with photoactive azobenzene liquid crystal 4-(4′-ethoxyphenylazo)phenyl hexanoate (EPH) at concentration of 3 wt.%. The photo-insensitive host nanocomposite material (the filled nematic) was a gel formed from the nematic 4-n-heptyl cyanobiphenyl (7CB) and 3 wt.% of silica nanospheres (hydrophilic Aerosil 300) of size ca. 7 nm. The electrochemical impedance spectroscopy was applied to determine the UV-light-produced effect in EPH-doped aerosil/7CB upon continuous trans-to-cis photoisomerization of EPH molecules by varying the UV light intensity. The effect from UV illumination on the dielectric permittivity function of the studied photoresponsive nematic nanocomposite was analyzed at a room temperature in the frequency range 0.5 Hz - 200 kHz.