AC Electric Field-Induced Alignment and Long-Range Assembly of Multi-Wall Carbon Nanotubes Inside Aqueous Media

2007 ◽  
Vol 7 (12) ◽  
pp. 4322-4332 ◽  
Author(s):  
Zhihui Guo ◽  
Jeffery A. Wood ◽  
Krista L. Huszarik ◽  
Xiaohu Yan ◽  
Aristides Docoslis
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Resistivity ◽  
Carbon Nanotube ◽  
Electric Field ◽  
Long Range ◽  
Applied Voltage ◽  
Three Dimensional ◽  
Field Frequency ◽  
Ac Electric Field ◽  
Ac Field

The present work examines the behavior of multiwall carbon nanotubes (MWCNT) inside AC electric fields created by three-dimensional electrodes. The response of carbon nanotubes stably suspended in water with the aid of a nonionic surfactant is monitored by combining microscopic observations with on-line measurements of the suspension resistivity. It is found that polarization effects induced by the externally applied AC electric field on MWCNTs can cause their unidirectional orientation and end-to-end contact that result in formations of spatially distributed, long-range, three-dimensional and electrically conducting structures that span the entire gap between the electrodes. The length of the formed structures, which in the present case was approximately 30 times larger than that of an individual carbon nanotube, can be controlled by adjusting the spacing between the electrodes. The influence of main experimental parameters, namely, MWCNT concentration, applied voltage, AC field frequency, and electrode surface topography on the suspension behavior is experimentally examined. Results are demonstrated for applied voltage values, AC field frequencies, and carbon nanotube concentrations in the range 4–40 Vptp, 10 Hz–5 MHz, and 0.001–2.0 wt%, respectively. While higher electric field strengths accelerate the formation of aligned structures, higher frequency values were found to result in suspensions that exhibit smaller electrical resistivity. Carbon nanotube dispersions exposed to an AC electric field exhibit a 100-fold or more decrease in their electrical resistivity, even when carbon nanotube concentrations as low as 0.005 wt% are used.

scholarly journals Growth and structural discrimination of cortical neurons on randomly oriented and vertically aligned dense carbon nanotube networks

2014 ◽  
Vol 5 ◽  
pp. 1575-1579 ◽  
Author(s):  
Christoph Nick ◽  
Sandeep Yadav ◽  
Ravi Joshi ◽  
Christiane Thielemann ◽  
Jörg J Schneider
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Cortical Neurons ◽  
Three Dimensional ◽  
Vertically Aligned Carbon Nanotubes ◽  
Aligned Carbon Nanotubes ◽  
Vertically Aligned ◽  
The Individual ◽  
Carbon Nanotube Networks ◽  
Communication Paths

The growth of cortical neurons on three dimensional structures of spatially defined (structured) randomly oriented, as well as on vertically aligned, carbon nanotubes (CNT) is studied. Cortical neurons are attracted towards both types of CNT nano-architectures. For both, neurons form clusters in close vicinity to the CNT structures whereupon the randomly oriented CNTs are more closely colonised than the CNT pillars. Neurons develop communication paths via neurites on both nanoarchitectures. These neuron cells attach preferentially on the CNT sidewalls of the vertically aligned CNT architecture instead than onto the tips of the individual CNT pillars.

Hydrogenated carbon nanotube-based spin caloritronics

2017 ◽  
Vol 19 (32) ◽  
pp. 21507-21513 ◽  
Author(s):  
Hong-Li Zeng ◽  
Yan-Dong Guo ◽  
Xiao-Hong Yan ◽  
Jie Zhou
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electric Field ◽  
Gate Voltage ◽  
Seebeck Effect ◽  
Partial Hydrogenation ◽  
Spin Caloritronics ◽  
Spin Seebeck Effect ◽  
Or Gate

The spin-Seebeck effect (SSE) in linearly hydrogenated carbon nanotubes (CNTs) is realized, where partial hydrogenation makes CNTs acquire magnetism. Moreover, an odd–even effect of the SSE is observed, and the even cases could be used as spin-Seebeck diodes, without the need for an electric field or gate voltage.

FABRICATION OF DISPERSED ALIGNED CARBON NANOTUBE ARRAY BETWEEN METAL ELECTRODES

2006 ◽  
Vol 05 (04n05) ◽  
pp. 389-394
Author(s):  
CHANGXIN CHEN ◽  
YAFEI ZHANG
Keyword(s):  
Carbon Nanotube ◽  
Electric Field ◽  
High Frequency ◽  
Metal Electrodes ◽  
Nanotube Array ◽  
Carbon Nanotube Array ◽  
Ac Electric Field ◽  
High Volatility ◽  
Surface Decoration ◽  
High Frequency Ac

Dispersed aligned single-wall carbon nanotube (SWCNT) array has been formed between electrodes by electric field assisted alignment of surface decorated SWCNTs. The surface decoration of SWCNTs with functional molecules allows them to dispersedly bridge metal electrodes and effectively obviates the entanglement between SWCNTs. The influences of solution volatility and electric-field type on the alignment are investigated. It is indicated that the well-oriented SWCNT array can be achieved by using the high-volatility solvent and the high-frequency AC electric field to align SWCNTs.

The Effect of Nanotube Loading and Dispersion on the Three-Dimensional Nanostructure of Carbon Nanotube-Conducting Polymer Composite Films

2002 ◽  
Vol 739 ◽  
Author(s):  
Mark Hughes ◽  
George Z. Chen ◽  
Milo S. P. Shaffer ◽  
Derek J. Fray ◽  
Alan H. Windle
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Conducting Polymer ◽  
Polymer Composite ◽  
Electrochemical Polymerization ◽  
Composite Films ◽  
Three Dimensional ◽  
Ionic Diffusion ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

ABSTRACTNanoporous composite films of multi-walled carbon nanotubes (MWNTs) and either polypyrrole (PPy) or poly(3-methylthiophene) (P3MeT) were grown using an electrochemical polymerization technique in which the nanotubes and conducting polymer were deposited simultaneously. The concentration and dispersion of MWNTs in the polymerization electrolyte was found to have a significant effect on the thickness of polymer coated on each MWNT and hence the loading of MWNTs in the films produced. It has been shown that for an increasing concentration of MWNTs in the polymerization electrolyte, the thickness of polymer coated on each MWNT decreases. This relationship made it possible to minimize ionic diffusion distances within the nanoporous MWNT-PPy films produced, reducing their electrical and ionic resistance and increasing their capacitance relative to similarly prepared pure PPy films.

scholarly journals Ions in an AC Electric Field: Strong Long-Range Repulsion between Oppositely Charged Surfaces

2020 ◽  
Vol 125 (5) ◽  
Author(s):  
Łukasz Richter ◽  
Paweł J. Żuk ◽  
Piotr Szymczak ◽  
Jan Paczesny ◽  
Krzysztof M. Bąk ◽  
...  
Keyword(s):  
Electric Field ◽  
Long Range ◽  
Charged Surfaces ◽  
Ac Electric Field ◽  
Oppositely Charged

Highly sensitive compression sensors using three-dimensional printed polydimethylsiloxane/carbon nanotube nanocomposites

2019 ◽  
Vol 30 (8) ◽  
pp. 1216-1224 ◽  
Author(s):  
Mohammad Charara ◽  
Mohammad Abshirini ◽  
Mrinal C Saha ◽  
M Cengiz Altan ◽  
Yingtao Liu
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Carbon Nanotube ◽  
Scanning Electron Microscope ◽  
Three Dimensional ◽  
Multi Walled Carbon Nanotube ◽  
Highly Sensitive ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

This article presents three-dimensional printed and highly sensitive polydimethylsiloxane/multi-walled carbon nanotube sensors for compressive strain and pressure measurements. An electrically conductive polydimethylsiloxane/multi-walled carbon nanotube nanocomposite is developed to three-dimensional print compression sensors in a freestanding and layer-by-layer manner. The dispersion of multi-walled carbon nanotubes in polydimethylsiloxane allows the uncured nanocomposite to stand freely without any support throughout the printing process. The cross section of the compression sensors is examined under scanning electron microscope to identify the microstructure of nanocomposites, revealing good dispersion of multi-walled carbon nanotubes within the polydimethylsiloxane matrix. The sensor’s sensitivity was characterized under cyclic compression loading at various max strains, showing an especially high sensitivity at lower strains. The sensing capability of the three-dimensional printed nanocomposites shows minimum variation at various applied strain rates, indicating its versatile potential in a wide range of applications. Cyclic tests under compressive loading for over 8 h demonstrate that the long-term sensing performance is consistent. Finally, in situ micromechanical compressive tests under scanning electron microscope validated the sensor’s piezoresistive mechanism, showing the rearrangement, reorientation, and bending of the multi-walled carbon nanotubes under compressive loads, were the main reasons that lead to the piezoresistive sensing capabilities in the three-dimensional printed nanocomposites.

Influence of AC Electric Field on Macroscopic Network of Carbon Nanotubes in Polystyrene

2007 ◽  
Vol 28 (8) ◽  
pp. 1164-1168 ◽  
Author(s):  
Xizhi Yang ◽  
Yuefeng Zhu ◽  
Lijun Ji ◽  
Chan Zhang ◽  
Ji Liang
Keyword(s):  
Carbon Nanotubes ◽  
Electric Field ◽  
Ac Electric Field

Metallic Nanowires From Carbon Nanotube Building Blocks: The Effect of Atomic Defects on the Nanotube Influencing Nanowire Growth

2003 ◽  
Author(s):  
B. Panchapakesan ◽  
Kousik Sivakumar ◽  
Shaoxin Lu
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electric Field ◽  
Building Blocks ◽  
Model Systems ◽  
Initial Surface ◽  
Sensors And Actuators ◽  
Platinum Nanowires ◽  
Defect Sites ◽  
Current Densities

Manipulation and control of matter at the nano- and atomic level are crucial for the success of nano-scale sensors and actuators. The ability to control and synthesize multilayer structures using carbon nanotubes that will enable to build electronic devices within a nanotube is still in its infancy. In this paper, we present results on selective electric field assisted deposition of metals on carbon nanotubes realizing metallic nanowire structures. Silver and platinum nanowires has been fabricated using this approach due to its applications in chemical sensing sensing as catalytic materials to sniff toxic agents and in the area of biomedical nanotechnology for construction of artificial muscles. The electric field assisted technique allows the deposition of metals with high degree of selectivity on carbon nanotubes by manipulating the charges on the surface of the nanotubes. The thickness and the growth of the nanowires was altered by inducing defects on the initial surface of the nanotubes that affected the local current densities and electrochemical reduction of silver and platinum on those defect sites. SEM and TEM investigations revealed silver and platinum nanowires between 10 nm-100 nm in diameter. Relatively higher metal deposition was achieved in defect related sites or places where the nanotubes criss-crossed each other, due to the high current densities in these sites. The present technique is versatile and enables the fabrication of host of different types of metallic and semiconduting nanowires using carbon nanotube templates for nanoelectronics and myriad of sensor applications. Further, nanowires can also serve as model systems for studying quantum size effects in these dimensions.

A Dissipative Particle Dynamics Study of Liquid Crystals Under Electric Field

2013 ◽  
Author(s):  
Man Prakash Gupta ◽  
Satish Kumar
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Response Time ◽  
Dynamic Behavior ◽  
Order Parameter ◽  
Dissipative Particle Dynamics ◽  
Critical Value ◽  
Particle Dynamics ◽  
Field Frequency ◽  
Ac Field

We study the equilibrium and dynamic behavior of liquid crystals (LCs) under dc and ac electric field using a mesoscopic simulation technique, Dissipative Particle Dynamics (DPD). We quantify the reorientation of LC molecules and the change in their anisotropic character under external perturbation by an order parameter. We find that the electric field magnitude has to be above a critical value to initiate the reorientation of the director of the LC system along the applied electric field, which is consistent with the experimental observations. The response time of the reorientation process decreases as the magnitude of the electric increases for the dc fields. The effect of ac field frequency on the order parameter is correlated with the field amplitude. The cyclic variation in the order parameter follows the ac field when the oscillation period is greater than the response time of the system and the amplitude is greater than the critical value. Results suggest that the DPD technique can provide important insights in to the dynamic behavior of LC system under both dc and ac electric fields. This technique can further be applied to examine the properties of colloidal LCs which can be very useful for many practical applications.

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