Low-temperature phase transformations in 4-cyano-4′-pentyl-biphenyl (5CB) filled by multiwalled carbon nanotubes

Abstract

The effects of multiwalled carbon nanotubes (NTs) on low-temperature phase transformations in 5CB were studied by means of differential scanning calorimetry (DSC), low-temperature photoluminescence and measurements of electrical conductivity. The concentration of NTs was varied within 0-1% wt. The experimental data, obtained for pure 5CB by DSC and measurements of photoluminescence in the heating mode, evidenced the presence of two crystallization processes at T≈229 K and T≈262 K, which correspond toC phase transformations. Increase of temperature T from 10 K до 229 K provoked the red shift of photoluminescence spectral band that was explained by flattening of 5CB molecule conformation. Moreover, the photoluminescence data allow to conclude that crystallisation at T≈229 K results in conformation transition to non-planar 5CB structure characteristic to ideal crystal. The non-planar conformations were dominating in nematic phase, i.e., at T>297 K. Electrical conductivity data for NTs-5CB composites revealed supplementary anomaly inside the stable crystalline phase C 2 , identified earlier in the temperature range 229 K-296.8 K. It can reflect the influence of phase transformation of 5CB in interfacial layers on the transport of charge carriers between NTs.

Temperature-dependent electro-optical and elastic properties of carbon nanotube doped polar smectogen octylcyanobiphenyl

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HIGH-TEMPERATURE PHASE TRANSFORMATIONS AND DYNAMICS OF ZnO NANOPARTICLES INCORPORATED 4- CYANO-4'-PENTYLBIPHENYL MESOGEN

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Optimized molecular structures of guest–host system for highly efficient coatable polarizer

“…The mesogen of each liquid crystalline polymer has a similar molecular structure to the nematic liquid crystals, which have transition temperatures that range from 30 to 75 o C [17][18][19]. To investigate the gust-host effects in relation to the molecular structures of the guest and host, various dyes were synthesized and applied to each liquid crystalline polymer.…”