Cholesteric liquid crystal–carbon nanotube composites with photo-settable reversible and memory electro-optic modes

Abstract

The photoresponsive electro-optical composites based on cholesteric liquid crystal (CLC) with optically controlled chirality and a minute amount of carbon nanotubes (CNTs) are studied. In cells with homeotropic anchoring, these composites exhibit a transition from fingerprint texture to homeotropic nematic texture in the course of photoinduced unwinding of the cholesteric helix. Compared with the CLC counterpart, this transition is much delayed, because of the stabilization of cholesteric filamentary domains by CNTs. The CLC-CNT composites demonstrate dual-mode operation with optical switching between reversible and memory mode. It is found that the memory response is associated with the elastic network of filamentary cholesteric domains that stabilizes the planar CLC texture reached in an electric field. In turn, the reversible mode corresponds to the unwound cholesteric state. Potential applications of this effect are discussed.

Memory effects in chiral nematic liquid crystals doped with functionalised single-walled carbon nanotubes

“…We believe that the interaction between surface anchoring and π−π electron stacking contributes towards the space charge polarisation at the interface and hence enhances the ac conductivity. [31] The ac conductivity σ ac can be computed by [32] σ ac ¼ ε 0 ε 00 ω…”

Suppressed ionic effect and low-frequency texture transitions in a cholesteric liquid crystal doped with graphene nanoplatelets

“…Among recent developments of the nanomaterials dispersion in CLCs, fascinating features, such as the reduction of the operation voltage by the ferroelectric NPs [17], variation of spectral properties by quantum dots [18], carbon nanotubes and clay platelets [19] as well as texture stabilization by polyhedral oligomeric silsesquioxane (POSS) [20] or gold NPs [21], have been reported. In addition, practical applications for gas detection and dual-mode optical devices have also been suggested on the basis of the CLC colloids doped with carbon nanotubes [22,23]. While the ionic effect suppression by the nanodopants have extensively been studied for nematic and ferroelectric LCs, only few works on the ionic behaviors in the nanomaterial/CLC suspensions have been reported [21].…”

Nanocomposites Based on Liquid Crystal Polymers and Inorganic Nanoparticles

“…Другая группа самоорганизованных матриц для наночастиц представлена низкомолекуляр-ными жидкими кристаллами [10][11][12][13][14][15] и ЖК-поли-мерами [16][17][18][19][20]. Такие нанокомпозиты обладают новыми свойствами, отличающимися от свойств входящих в их состав жидких кристаллов и наночастиц.…”