The effect of graphene on liquid-crystalline blue phases

Abstract

The stabilization of liquid-crystalline blue phases is recently attracting considerable interest because of the envisioned applications in fast optical displays and tunable photonic crystals. We report on the effect of surface-functionalized graphene nanosheets on the blue phase range of a chiral liquid crystal. Calorimetric and optical measurements, reproducible on heating and cooling, demonstrate that the resulting soft nanocomposite exhibits an increased blue phase temperature stability range for a minute concentration of dispersed graphene. The impact is stronger on the ordered, cubic structured blue phase I. These findings suggest that anisotropic nanoparticles may be of great usefulness for stabilizing blue phases.

Blue Phase Range Widening Induced by Laponite Nanoplatelets in the Chiral Liquid Crystal CE8

“…The present results are in agreement with recent findings in mixtures of CE8 with molybdenum sulfide nanoplatelets [9] and graphene nanosheets [10]. It has been shown that spherical quantum dots of similar surface coating stabilise mostly the macroscopically amorphous BPIII [4,5], whereas the anisotropic ones (nanoplatelets) affect mainly BPI [9,10]. The relatively large surfaces of nanoplatelets induce some ordering of liquidcrystalline molecules when cooling from the I phase, favoring the faster appearance of the more-ordered structure of BPI and reducing the stability range of BPIII and BPII.…”

“…The cubic structure of BPI is favored by the presence of laponite NPs with respect to BPIII and BPII that appear in a narrower range with respect to pure CE8. The present results are in agreement with recent findings in mixtures of CE8 with molybdenum sulfide nanoplatelets [9] and graphene nanosheets [10]. It has been shown that spherical quantum dots of similar surface coating stabilise mostly the macroscopically amorphous BPIII [4,5], whereas the anisotropic ones (nanoplatelets) affect mainly BPI [9,10].…”

“…In particular, the spherical nanoparticles have a tendency to increase the stability range of BPIII [4,5], whereas the anisotropic ones target mostly the ordered structure of BPI [9,10]. Here we report that a small amount of anisotropic laponite nanoplatelets can effectively increase the temperature stability range of BPI of a chiral liquid crystal.…”

“…More recently, spherical [3][4][5][6][7][8] or anisotropic nanoparticles [8][9][10] have been exploited as stabilisation agents. In all these cases nanoparticles are surface-functionalised in order to achieve a homogeneous dispersion in the liquid crystal hosts [4][5][6].…”

Measurement of magnetic anisotropy of multiwalled carbon nanotubes in nematic host

“…There have been developed many devices based on NLC with inserted dyes, micro-particles or nano-particles. These mixtures can be used for the study of particle's physical properties as well as in engineering to improve existing devices or to develop new ones [10][11][12][13][14][15][16][17][18][19]. The liquid crystals, mainly used in LCD's, combine the properties of crystalline structure of solid state with those of liquid phase, leading to an organized movement of inserted to CNT.…”