The liquid crystalline state of linear polymers. Review

Effect of Magnetic and Mechanical Fields on Phase Liquid Crystalline Transitions in Solutions of Cellulose Derivatives

“…These values are 2.3 and 2.0 kOe for the HPC -DMAA and CEC -DMAA systems, respectively, and 2.3 kOe for the PBG -DMF system. In order of magnitude, these values are consistent with H cr necessary for the nematic liquid crystalcholesteric liquid crystal phase transition (Papkov & Kulichikhin, 1977, Chandrasekhar, 1980. In this case, ∆T = Kln(E/E 0 ) or T ph (H > H cr ) = T ph (H = 0) + Kln(E/E 0 ).…”

“…7), thus suggesting formation of large supramolecular structures-domains. A similar phenomenon was reported for other polymer-solvent systems (Papkov & Kulichikhin, 1977). It was discovered that after the magnetic field was switched off, an increased Tph was preserved in solutions for many hours.…”

“…4). This fact is indicative of the formation of the domain supramolecular structure (Papkov & Kulichikhin, 1977, Aharoni & Walsh, 1979. Since, compared to cholesteric liquid crystals, nematic liquid crystals exist at higher temperatures, the temperature-concentration region corresponding to the existence of anisotropic solutions under the mechanical field should change.…”

“…Flory (1956) has suggested the phase diagram for a polymer -solvent system with the liquid crystalline transition. At a later date such diagrams were built for the systems: PBG -DMF (Wee & Miller, 1971), polycarbobenzoxyline -DMF (Miller et al, 1974, poly-pbenzamide -DMA (Papkov et al, 1974), poly-p-benzamide -DMA, LiCl (Iovleva et al, 1976), poly(p-phenyleneterephthalamide) -H 2 SO 4 (Papkov & Kulichikhin, 1977, Andreeva et al, 1981, PBG -ethylene chloride, PBG -benzyl alcohol (Sasaki et al, 1983), poly(pphenyleneterephthalamide) -H 2 SO 4 -water (Nakajima et al, 1978), PBG -m-cresol (Kiss & Porter, 1977), copolymer on the bases of p-phenylenediamine + terephthalic acid and 4,4"-diphenyldicarboxylic acid) -H 2 SO 4 Lukashova et al , 1978), PBG -DMF and PBG -dicloracetic acid (Konevets et al, 1985), poly(p-benzamide) -DMA -LiCl (Salaris et al, 1976), polyhexylisocyanate and poly(50 % butyl + 50 % p-anisole-3-propyl)isocyanat in tetrachlorethane (Aharoni & Walsh, 1979), copolymer on the bases of pphenylenterephyhalaamide + benzimidazole) -H 2 SO 4 (Iovleva & Banduryan, 2010). The influence of a magnetic field on the liquid crystal structure was studied by Meuer (1968), de Gennes (1968.…”

Re-entrant cholesteric phase in DNA liquid-crystalline dispersion particles

“…Therefore, the hexagonal packing corresponds to only a short-range translation (and long-range, nematiclike, orientation) order. In this structure (as well as in the case of a hexagonal phase that is formed as a result of an increase in the DNA concentration in a water-salt solutions) and following the authors of previous works [64,65], we admit the existence of three kinds of orientationally ordered molecular layers according to the three main directions of the hexagonal structure (one series is marked by the arrows in Fig. 8).…”