Structure peculiarities and optical properties of nanocomposite: 5CB liquid crystal–CTAB-modified montmorillonite clay

Bezrodna, T.; Chashechnikova, I. T.; Nesprava, V.; Puchkovska, G.; Boyko, Yu. P.; Baran, J.; Drozd, M.

doi:10.1080/02678290903511677

Cited by 15 publications

(4 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our calculations, we use 0 = 0.044 × 10 6 J m −3 , = 0.816 × 10 6 J m −3 , = 0.45 × . We use = 5 × 10 −4 J m −2 , or 10 −4 J m −2 , corresponding to the surface anchoring strengths of interactions for substrates coated with CTAB [47][48][49] .…”

Section: Simulation Of Director Structures and Elastic Interactionsmentioning

confidence: 99%

See 1 more Smart Citation

Colloidal interactions and unusual crystallization versus de-mixing of elastic multipoles formed by gold mesoflowers

2020

View full text Add to dashboard Cite

Colloidal interactions in nematic liquid crystals can be described as interactions between elastic multipoles that depend on particle shape, topology, chirality, boundary conditions and induced topological defects. Here, we describe a nematic colloidal system consisting of mesostructures of gold capable of inducing elastic multipoles of different order. Elastic monopoles are formed by relatively large asymmetric mesoflower particles, for which gravity and elastic torque balancing yields monopole-type interactions. High-order multipoles are instead formed by

show abstract

Section: Simulation Of Director Structures and Elastic Interactionsmentioning

confidence: 99%

“…For these values of the model parameters, the bulk correlation length 46 , 24𝑎𝑎𝑐𝑐 𝑏𝑏 2 = 1 ⁄ . We use 𝑊𝑊 = 5 × 10 −4 J m −2 , or 10 −4 J m −2 , corresponding to the surface anchoring strengths of interactions for substrates coated with CTAB [47][48][49] .…”

Section: Simulation Of Director Structures and Elastic Interactionsmentioning

confidence: 99%

Colloidal interactions and unusual crystallization versus de-mixing of elastic multipoles formed by gold mesoflowers

2020

View full text Add to dashboard Cite

show abstract

“…Methods for preparing the Na-forms of MMT samples from the aforementioned deposits and modification of them by CTAB have been described in detail [10,15]. We used CTAB SA (Fluka, Germany) of 99% purity.…”

mentioning

confidence: 99%

Photoluminescence of montmorillonite clay minerals modified by cetyltrimethylammonium bromide

et al. 2011

View full text Add to dashboard Cite

The structure and photoluminescent properties of natural montmorillonite (MMT) aluminosilicates from three mineral deposits that were modified by cations of sodium or the surfactant cetyltrimethylammonium bromide (CTAB) have been investigated. X-ray fluorescence analysis showed significant differences in the concentrations of the inorganic dopants in these materials. An x-ray diffraction analysis established that incorporation of the CTA + long-chain cations into the MMTs expands remarkably the mineral interplanar distances, the values of which are close to each other for all organoclay samples under study and equal to 1.8-2.0 nm. The photoluminescent properties of the Na-form of the MMTs are shown to depend on the amount of introduced dopant capable of either enhancing or quenching the emission. Deposition of CTAB on the mineral surface influences the luminescence pattern, the spectral contour and wavelength range being practically the same for all modified samples. The emission may intensify or weaken because of such surface modification.Introduction. Natural layered clay minerals (CM) with the 2:1 structure type are highly disperse and have a large specific surface area. They are known to be selective sorbents and effective ion-exchangers [1, 2], active catalysts for various processes (isomerization, polymerization, addition, etc.[3]), fillers of organic media, plastifiers of polymeric materials [4-8], etc. The particles of these CM are stratified in a liquid medium. Their thickness is of the order of nanometers; the width/length, 25-1000 nm. Their surface is organophobic in the unaltered state. Owing to the presence in the CM interplanar space of metal cations that are susceptible to ion exchange, it is rather easy to convert the surface into an organophilic one via exchange of the inorganic cations by organic ones using ion exchange. As a result, the affinity of the resulting organoclays for an organic medium [polymers, liquid crystals (LC), aromatic compounds, etc.] increases sharply. Heterocomposites with a homogeneous structure (coagulation network) consisting of nanoparticles of the organoclay and the organic matrix are formed at a certain concentration of them. For example, LC filled with CM particles modified by various surfactants (SA) exhibit a variety of electro-optical properties [9][10][11].The starting CM in the present work was montmorillonite (MMT) from three deposits: Pyzhev (Ukraine), Cherkassy (Ukraine), and Askan (Georgia). MMT is a layered natural aluminosilicate of the 2:1 structure type that consists of two layers of SiO 2 tetrahedra between which a layer of Al 2 O 3 octahedra is located. These samples differ in the impurity profile, dispersion, cation-exchange capacity (CEC), and magnitude of surface charge. This should affect their properties (in particular, optical ones). We studied two series of these CM. One of them was the Na-form of the samples; the other, MMT modified with an organic molecule. The organic surface modifier was cetyltrimethylammonium bromide (CTAB) because this SA...

show abstract

“…These differences can affect the structures and optical properties of these CMs. The surface modifier was CTAB because it exhibits unique adsorptive properties [18][19][20] and increases drastically the affinity of CMs modified by it for an organic medium, in particular, for 5CB liquid crystal molecules [21]. This is important for fabricating heterogeneous nanocomposites.…”

Section: Introductionmentioning

confidence: 99%

Structure and spectroscopic properties of organoclays doped by multiwall carbon nanotubes

et al. 2011

Self Cite

View full text Add to dashboard Cite

A method to modify a montmorillonite (MMT) clay mineral (CM) surface by surfactant (SA) cations with simultaneous doping by multiwall carbon nanotubes (MWNT) has been proposed. The structure and spectroscopic properties of composites based on MMT from two deposits (Cherkassy and Pyzhevsk, Ukraine) that differ in the inorganic impurity contents and cation-exchange capacities (CEC) have been investigated. Cetyltrimethylammonium bromide (CTAB) was used as the SA. According to x-ray diffraction analysis, CTA + cations intercalated into MMT interplanar spaces expand them significantly whereas MWNTs do not affect the MMT galleries due to the much larger sizes of the former. Studies of the composite materials by IR spectroscopy revealed the mutual influence of the components appearing as the ordering of near-surface layers in the aluminosilicate framework and a change in the modifier methylene chain conformation at the interphase boundary. The majority of CTAB (~90%) is shown to be located inside the MMT galleries, the packing arrangement of which depends on the CEC value and affects the interplanar distances in MMT. The alkyl chains of the CTA + cations on the outer surface of the MMT plates are sorbed by nanotubes, thus providing contact between the organoclay and MWNT surfaces.Introduction. Multi-functional heterosystems consisting of an organic component and multiwall carbon nanotubes (MWNT) are currently under intense scrutiny. The incorporation of small quantities of the latter into an organic medium changes drastically its physical properties such as electrical and thermal conductivity, mechanical and optical characteristics, etc. [1-3]. However, MWNT exhibit a high capability to aggregate. This makes it very difficult to create composites with a uniform distribution of MWNT in the organic matrix because of their lipophobic nature. MWNTs are treated with surfactants (SAs) in order to give their surface a higher affinity for the organic medium [4,5]. Another method for preparing homogeneous composites is to add nanoparticles of organoclays to the organic matrix and MWNT. It was shown [6,7] that these fillers produce a synergistic effect on the mechanical and thermal properties of nanocomposites when added simultaneously to ethylene-vinylacetate copolymer or chitosan (polysaccharide). Furthermore, the effect of adding organoclay particles and MWNT to various polymers on not only the mechanical properties of the resulting composites but also their flammability was investigated [8][9][10][11][12]. It was shown that the ability of such heterocomposites to ignite was sharply reduced even with low (~1%) concentrations of nanofillers owing to the synergistic effect produced in such systems.MWNTs were intercalated into layered clay minerals (CMs) by catalytic decomposition at 700

show abstract

Structure peculiarities and optical properties of nanocomposite: 5CB liquid crystal–CTAB-modified montmorillonite clay

Cited by 15 publications

References 20 publications

Colloidal interactions and unusual crystallization versus de-mixing of elastic multipoles formed by gold mesoflowers

Colloidal interactions and unusual crystallization versus de-mixing of elastic multipoles formed by gold mesoflowers

Photoluminescence of montmorillonite clay minerals modified by cetyltrimethylammonium bromide

Structure and spectroscopic properties of organoclays doped by multiwall carbon nanotubes

Contact Info

Product

Resources

About