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

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ABSTRACT

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.

No MeSH data available.


Raman spectrum at different driving voltages (0 V, 1.5 V, 2.5 V, 3.5 V and 4.5 V). The microscope images confirm the light scattering difference between un-switched (0 V) and switched state (5.5·Vp).
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Figure 4: Raman spectrum at different driving voltages (0 V, 1.5 V, 2.5 V, 3.5 V and 4.5 V). The microscope images confirm the light scattering difference between un-switched (0 V) and switched state (5.5·Vp).

Mentions: The SWCNT Raman peaks decrease when the electric field is applied to the cell and disappear at voltages greater than 5.5·Vp (Vp, peak voltage). This indicates a SWCNT reorientation from planar to perpendicular, variable with the applied electric field. Due to the alignment characteristics explained above, the LC molecules do not reorient when the electric field is applied. As can be appreciated from the Raman spectrum (Fig. 4), the LC peaks do not change when a field is applied.


Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field
Raman spectrum at different driving voltages (0 V, 1.5 V, 2.5 V, 3.5 V and 4.5 V). The microscope images confirm the light scattering difference between un-switched (0 V) and switched state (5.5·Vp).
© Copyright Policy - Beilstein
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4979768&req=5

Figure 4: Raman spectrum at different driving voltages (0 V, 1.5 V, 2.5 V, 3.5 V and 4.5 V). The microscope images confirm the light scattering difference between un-switched (0 V) and switched state (5.5·Vp).
Mentions: The SWCNT Raman peaks decrease when the electric field is applied to the cell and disappear at voltages greater than 5.5·Vp (Vp, peak voltage). This indicates a SWCNT reorientation from planar to perpendicular, variable with the applied electric field. Due to the alignment characteristics explained above, the LC molecules do not reorient when the electric field is applied. As can be appreciated from the Raman spectrum (Fig. 4), the LC peaks do not change when a field is applied.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

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.

No MeSH data available.