Anomalous Electrokinetic Dispersion of Carbon Nanotube Clusters in Liquid Crystal Under Electric Field

Abstract

An anomalous electrokinetic dispersion after contraction of carbon nanotube (CNT) cluster suspended in a vertically aligned nematic liquid crystal (LC) cell is demonstrated. CNT aggregates were firstly aligned toward the field line by dielectrophoretic (DEP) torque and secondly they were elongated above a certain threshold field due to interaction between the induced dipole moment of CNTs and external ac electric field. Below a certain breakdown field, the original morphology of the CNT aggregates was restored after the removal of the field where the elongation was fully reversible. Above breakdown electric field, CNT aggregates were ruptured and fragmented into small pieces and consequently CNTs were well dispersed in LC medium.

Field-induced stretching and dynamic reorientation of functionalized multiwalled carbon nanotube aggregates in nematic liquid crystals

“…The field-induced stretching behavior of the CNT aggregates has been reported in previous works [21][22][23][24][25], which can be explained by considering applied electric field-induced dipolar reordering of CNTs from random to a linear form. After applying electric field, the CNTs in the host medium experiences the force elec F → given by (2) where ' CNTs and van der Walls interaction of CNTs in CNT aggregates.…”

“…Recently, electrically induced stretching behavior of CNT aggregates [21][22][23][24][25] has shown promising potential for macroscopic alignment of CNT aggregates along pre-determined direction, which would be favorable for large scale applications. In presence of electric field, the randomly oriented individual CNTs in aggregated form in LC matrix get unidirectional alignment along the field direction to minimize the induced dipolar energy due to their high aspect ratio and dielectrophoretic properties [26].…”

“…With further increasing field, the CNT aggregates could be stretched along the field direction above a critical field against van der Waals forces between CNTs bundles [25,26]. Extensive studies [21][22][23][24][25] to date have revealed field-dependent stretching of CNT aggregates related to the competition of applied field strength against van der Waals interaction between CNTs within aggregates. In general, functional groups on the CNT sidewalls will weaken van der Waals interaction between M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 CNTs and promote the dispersion process [27,28].…”

Parameter Optimization for Positive Dielectrophoretic Trapping Force on ZnO Nanoparticles Through Simulation

“…This large difference arises from the nanometer scale dimension of the nanoparticles, which is a critical factor in fluid friction. [19][20][21] In particular, the particle velocity due to dielectrophoresis is inversely proportional to the particle radius. Figure 7 shows the time evolution of the ZnO nanoparticle concentration inside the fluid medium.…”

Self-Assembly of Unfunctionalized Nanoparticles in Crystallization of Liquid Crystal Trimers

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] The reviews report that the interactions among nanoparticles in nematic LCs become highly anisotropic, enabling the development of the spontaneous self-assembly of nanoparticles. 1 3 4 The LC-nanoparticle blends are of importance in connection with novel hybrid materials.…”