Effect of Functional Group Topology of Carbon Nanotubes on Electrophoretic Alignment and Properties of Deposited Layer

Abstract

Thin films of aligned carbon nanotubes (CNTs) have several interesting properties including the ability to transport ions, electrons, and thermal energy. The current study employed molecular dynamics (MD) simulations to determine the effect of varying functionalization topologies of CNTs on their deposition characteristics under applied electric fields of varying strength. The results indicate that the dynamics of CNT alignment along the direction of applied electric field is relatively faster and smoother in case of pristine CNTs compared to that of functionalized CNTs. Considering CNTs of identical length, pristine CNTs are aligned the closest to the direction of the electric field followed by side-functionalized and end-functionalized CNTs with the total alignment time being roughly similar. With increase in the strength of electric field, E, total alignment time decreases and is inversely proportional to E 2. The final alignment angle (θ∞) and extent of oscillatory response in the case of side- and end-functionalized CNTs are diminished. In contrast with the alignment dynamics, the migration dynamics of pristine CNTs, which tend to agglomerate, is slower and shows some discontinuity compared to the functionalized CNTs. Analysis of the final structure of the deposited CNTs indicate that side-functionalized CNTs produce the most uniformly aligned deposit at relatively weaker electric fields followed by end-functionalized, and pristine CNTs, due partly to their greater extent of solvation, and are therefore a better choice for deposition of uniform CNT films on substrates.

Electronic, Electrical, and Magnetic Behavioral Change of SiO2-NP-Decorated MWCNTs

“…The interaction of silicon atoms with other elements in MWCNTs has been explained elsewhere with possibilities of reducing sp 2 while increasing sp 3 hybridization. 40,43…”

Predictive model for alignment and deposition of functionalized nanotubes using applied electric field

“…This computational approach was reported in our recent work on modeling the effect of functional group topology on the structure of CNT deposits. 36 We employed GAMESS version 1 MAY 2013 R1 45 for the calculations. The choice of basis set has been justified by several recent studies that reported accurate properties of CNTs using lower basis sets.…”

“…We assumed that f is a function of CNT length and solvent viscosity and is given as f ¼ gC D l k , where k is an independent constant and C D is a function of CNT diameter, type of functionalization, 36 concentration and other solvent properties. Therefore, in this study, C D remains a constant.…”

“…35 On the contrary, Shao-Jie and Wan-Lin 32 have proposed a relationship for induced torque based on quantum mechanics calculations. Previous work of Mostafa and Banerjee 36 has studied the effect of functional group topologies on the structure of CNT deposits on substrates based on molecular dynamics simulations. However, the literature lacks a detailed and comprehensive study that accounts for the intermolecular interactions between CNT and solvents and evaluates the integrated mechanics of alignment, migration and deposition of CNTs on substrates.…”

Ion Storage in Nanoconfined Interstices Between Vertically Aligned Nanotubes in Electric Double-Layer Capacitors

“…In a realistic EDLC, however, arrays of CNTs are deposited on the current collectors, which serve as electrodes. The precise architecture of these CNT arrays is dependent on the synthesis and processing conditions [34,35]. The ion storage pattern inside and around CNT arrays will affect the potential drop across the double-layer and thereby the electrode double-layer capacitance [33].…”