Optical singularities induced in a nematic-cell by carbon nanotubes

Ponevchinsky, V. V.; Goncharuk, A. I.; Васильев, В. И.; Lebovka, Nikolaï; Soskin, M. S.

doi:10.1117/12.840384

Cited by 8 publications

(15 citation statements)

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“…Experimental studies of these effects were discussed in details [13,111,124,125,140,143]. Figure 10.14 shows the typical curves of electrical conductivity σ as a function of concentration of MWCNTs, C, in EBBA [111] and 5CB [124] obtained at the fixed temperatures that were just above the solid-to-nematic phase transition temperatures.…”

Section: Electrical Conductivitymentioning

confidence: 99%

“…Hence, the nature of incubation can reflect the aggregation caused by Brownian motion of MWCNTs. Many experimental data for nematics filled by CNTs evidenced in favor of the percolation mechanism of electrical conductivity [13,111,124,125,140,143]. The percolation is accompanied by the abrupt changes in different physical properties of LC + CNT composite, and this transition may be identified as a geometrical phase transition related with formation of the spanning network of CNTs [144][145][146][147].…”

Section: Aggregation and Incubationmentioning

confidence: 99%

“…Thus, the boundary layer of the 5CB nematic phase visualizes submicron MWCNT clusters, which are below the resolution threshold of the usual optical microscope. The effect of perturbation of the LC structure in the interfacial shells surrounding the MWCNT aggregates was visually demonstrated by analyzing the optical microscopy images of aggregates at different values of applied AC voltage, u [125].…”

Section: Surface Anchoring and Alignment Of Cntsmentioning

confidence: 99%

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Carbon Nanotubes in Liquid Crystals: Fundamental Properties and Applications

Lisetski

Soskin

Lebovka

2015

Springer Proceedings in Physics

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The structure and properties of liquid crystalline suspensions filled by carbon nanotubes (CNTs) are critically reviewed. Special attention is paid to interactions between CNTs and molecules of the liquid crystals (LC), which lead to formation of ordered supramolecular structures. These structures, in turn, determine unique physical properties of LC + CNT suspensions, including electrical conductivity, dielectric permittivity, phase transitions, optical transmission, memory effects that can be used in electrooptic and optoelectronic devices, etc. Great variety of LC phases are considered as a host media, such as nematics, cholesterics, smectics of different types (including ferroelectrics), lyotropic, chromonic, ionic and hydrogen-bonded liquid crystals. Alongside multi-and single-walled carbon nanotubes, the suspensions can also contain the platelets of organoclays used for facilitation of CNT dispersing. Recent practical applications of LC + CNT suspensions and nanomaterials based thereon are also outlined.

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Section: Electrical Conductivitymentioning

confidence: 99%

Section: Aggregation and Incubationmentioning

confidence: 99%

Section: Surface Anchoring and Alignment Of Cntsmentioning

confidence: 99%

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Carbon Nanotubes in Liquid Crystals: Fundamental Properties and Applications

Lisetski

Soskin

Lebovka

2015

Springer Proceedings in Physics

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“…Clusters are enlarged with concentration grow up to formation of the percolation structure when all neighbor cluster touch [7,8,11]. This moment electrical conductivity enlarged nonlinearly on three-four orders [8]. It is natural to wait that due to stochastic process of clusters formation, density of CNTs inside clusters is not fully homogeneous.…”

Section: Lc Carbon Nanocompositesmentioning

confidence: 99%

“…The 'long'/'short' MWCNTs with 5÷10/1÷2 μm length were exploit. The first our measurements have shown that nanotubes form clusters [7,8]. The theory of CNT aggregation process was elaborated also [9].…”

Section: Lc Carbon Nanocompositesmentioning

confidence: 99%

Fine topological structure of coherent complex light created by carbon nanocomposites in LC

Ponevchinsky¹,

Goncharuk

Minenko

et al. 2012

SPIE Proceedings

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Fine complex light structure, optical singularities and electroconductivty of nematic 5CB doped by multi-walled carbon nanotubes (MWCNTs) were investigated. MWCNTs gather spontaneously to system of micro scale clusters with random fractal borders at small enough concentration. They are surrounded by the striped micro scale cladding which creates optical singularities in propagating laser beam. Applied transverse electric field above the Freedericksz initiates homeotropic arrangement of 5CB and the striped inversion walls between nanotubes clusters what diminishes free energy of a composite. Theory of their appearance and properties was built. Simultaneously the striped cladding disappears what can be treated as new mechanism of structure orientation nonlinearity in nonlinear photonics. Polarization singularities (circular C points) were measured firstly. Percolation of clusters enhances strongly electrical conductivity of the system and creates inversion walls even without applied field. Carbon nanotubes composites in LC form bridge between nano dopants and micro/macro system and are promising for applications. Elaborated protocol of singular optics inspection and characterization of LC nanocomposites is promising tool for applications in modern nanosience and technique.

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Light Beams with Spatially Variable Polarization

Galvez

2015

Photonics

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Optical singularities induced in a nematic-cell by carbon nanotubes

Cited by 8 publications

References 0 publications

Carbon Nanotubes in Liquid Crystals: Fundamental Properties and Applications

Carbon Nanotubes in Liquid Crystals: Fundamental Properties and Applications

Fine topological structure of coherent complex light created by carbon nanocomposites in LC

Light Beams with Spatially Variable Polarization

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