scholarly journals Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field

2016 ◽  
Vol 7 ◽  
pp. 825-833 ◽  
Author(s):  
Amanda García-García ◽  
Ricardo Vergaz ◽  
José F Algorri ◽  
Gianluigi Zito ◽  
Teresa Cacace ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon ◽  
Self Organized ◽  
Crystal Properties ◽  
Microscopic Inspection ◽  
Liquid Crystal Orientation

Single-wall carbon nanotubes (SWCNT) are anisotropic nanoparticles that can cause modifications in the electrical and electro-optical properties of liquid crystals. The control of the SWCNT concentration, distribution and reorientation in such self-organized fluids allows for the possibility of tuning the liquid crystal properties. The alignment and reorientation of CNTs are studied in a system where the liquid crystal orientation effect has been isolated. Complementary studies including Raman spectroscopy, microscopic inspection and impedance studies were carried out. The results reveal an ordered reorientation of the CNTs induced by an electric field, which does not alter the orientation of the liquid crystal molecules. Moreover, impedance spectroscopy suggests a nonnegligible anchoring force between the CNTs and the liquid crystal molecules.

Liquid crystal behavior of single wall carbon nanotubes

Carbon ◽  
2010 ◽  
Vol 48 (12) ◽  
pp. 3531-3542 ◽  
Author(s):  
M. Bravo-Sanchez ◽  
Trevor J. Simmons ◽  
M.A. Vidal
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystal ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

Electric field alignment of single wall carbon nanotubes (SWNT) in polymers

2005 ◽  
Author(s):  
Sumanth Banda ◽  
Zoubeida Ounaies ◽  
Tyler St Clair ◽  
Jared Rud ◽  
Kristin Burney ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electric Field ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

Alignment and Deposition of Single Wall Carbon Nanotubes under the Influence of an Electric Field

2002 ◽  
Vol 761 ◽  
Author(s):  
Paul Jaynes ◽  
Thomas Tiano ◽  
Margaret Roylance ◽  
Charles Carey ◽  
Kenneth McElrath
Keyword(s):  
Carbon Nanotubes ◽  
Electric Field ◽  
Electronic Devices ◽  
Physical And Mechanical Properties ◽  
Single Wall Carbon Nanotubes ◽  
Enabling Technology ◽  
Single Wall Carbon ◽  
Nanoelectronic Devices ◽  
Wide Range ◽  
Field Lines

ABSTRACTSingle wall carbon nanotubes have aroused a great deal of interest because of their unique combination of electrical, physical and mechanical properties. However, the widespread use of SWNTs in composites and electronic devices is limited because of the difficulty of dispersing and processing these materials. This paper describes a method for depositing and aligning SWNTs from a dispersed solution onto a substrate under the influence of an electric field. Results indicate that SWNTs can be aligned in bulk in the direction of electric field lines, and that individual SWNT ropes may be deposited between two electrodes. The extent and type of deposition depends upon the electrode geometry and processing time. Electrical alignment of SWNTs is an enabling technology allowing manipulation of nanomaterials using standard processing. It could eventually lead to a wide range of products, such as nanocomposites with aligned fillers and nanoelectronic devices.

scholarly journals Electrical Resistivity of Pristine and Functional Single-Wall Carbon Nanotubes

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Yijiang Lu ◽  
Jing Li ◽  
Haiping Hong
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Resistivity ◽  
Electric Field ◽  
Polymer Nanocomposites ◽  
Functional Group ◽  
Single Wall Carbon Nanotubes ◽  
Electrical Field ◽  
Interdigitated Electrode ◽  
Single Wall Carbon ◽  
Lower Resistivity

The resistance of several pristine and functional single-wall carbon nanotubes (SWNTs) deposited and dried on interdigitated electrode (IDE) chips was investigated to better understand how functional groups influence their resistivity. Without the external electrical field, the resistance was generally increased for the sulfonated and fluorinated SWNTs but not for COOH-SWNTs. With a 3 V electric field applied during depositing, while no change in resistance was found for the purified pristine SWNTs, fluorinated SWNTs, COOH SWNTs, and Ni-SWNTs, a significant decrease in resistance was observed in sulfonated SWNTs and unpurified pristine SWNTs, which could be due to the alignment of SWNTs in an electric field. The alignment of the sulfonated SWNTs is most likely due to the charge of the sulfate functional group. It is interesting to note that the alignment was found in the unpurified pristine SWNTs but not in the purified pristine ones which have lessened resistivity. The lower resistivity in the purified pristine SWNTs may be due to the smaller number (<5%) of impurities. The significance of this research is that hydrophilic COOH-SWNTs could be a better candidate than the hydrophobic pristine SWNTs for being used in many applications, especially in polymer nanocomposites.

scholarly journals Electrical response of liquid crystal cells doped with multi-walled carbon nanotubes

2015 ◽  
Vol 6 ◽  
pp. 396-403 ◽  
Author(s):  
Amanda García-García ◽  
Ricardo Vergaz ◽  
José Francisco Algorri ◽  
Xabier Quintana ◽  
José Manuel Otón
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystal ◽  
Electric Field ◽  
Electrical Response ◽  
Characteristic Impedance ◽  
Self Organized ◽  
The Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
Elongated Nanoparticles ◽  
Walled Carbon Nanotubes

The inclusion of nanoparticles modifies a number of fundamental properties of many materials. Doping of nanoparticles in self-organized materials such as liquid crystals may be of interest for the reciprocal interaction between the matrix and the nanoparticles. Elongated nanoparticles and nanotubes can be aligned and reoriented by the liquid crystal, inducing noticeable changes in their optical and electrical properties. In this work, cells of liquid crystal doped with high aspect ratio multi-walled carbon nanotubes have been prepared, and their characteristic impedance has been studied at different frequencies and excitation voltages. The results demonstrate alterations in the anisotropic conductivity of the samples with the applied electric field, which can be followed by monitoring the impedance evolution with the excitation voltage. Results are consistent with a possible electric contact between the coated substrates of the LC cell caused by the reorientation of the nanotubes. The reversibility of the doped system upon removal of the electric field is quite low.

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