The effects of multiwalled carbon nanotubes (NTs) on low-temperature phasetransformations in 5CB were studied by means of differential scanningcalorimetry (DSC), low-temperature photoluminescence and measurements ofelectrical conductivity. The concentration of NTs was varied within 0-1% wt.The experimental data, obtained for pure 5CB by DSC and measurements ofphotoluminescence in the heating mode, evidenced the presence of twocrystallization processes at T->229 K and T->262 K, which correspond toC1a->C1b, and C1b->C2 phase transformations. Increase of temperature T from 10K to 229 K provoked the red shift of photoluminescence spectral band that wasexplained by flattening of 5CB molecule conformation. Moreover, thephotoluminescence data allow to conclude that crystallisation at T=229 Kresults in conformation transition to non-planar 5CB structure characteristicto ideal crystal. The non-planar conformations were dominating in nematicphase, i.e., at T>297 K. Electrical conductivity data for NTs-5CB compositesrevealed supplementary anomaly inside the stable crystalline phase C2,identified earlier in the temperature range 229 K-296.8 K. It can reflect theinfluence of phase transformation of 5CB in interfacial layers on the transportof charge carriers between NTs.
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