Physico-Chemical nanomaterials science

Topological soliton in a crystal formed by aliphatic molecules with dimer rings

Alekseev O. M., Lazarenko M.M., Brytan A.V.1, Vasylyuk S.V. 1  
1 Physics faculty of Kyiv National Taras Shevchenko University, Volodymirska,64
E-mail: svetlanafvasylyuk@gmail.com

A broad class of substances whose structure contains an aliphatic chain, with different end groups, forms lamellar crystals during crystallization. When heated in these crystals, the transition from the crystalline phase to the rotation-crystalline phase in the solid state occurs, and further melting occurs.  The main question about  the mechanism of thermal motion in the rotational crystalline phase remains unclear. We have shown that in the rotational-crystalline phase, the thermal motion of the chains is most likely associated with the emergence and propagation of topological solitons in crystallites. It was shown that in (1-octadecene) systems with stoichiometric obstacles (double bond), topological solitons can originate in methyl groups and pass along the molecule to reorient stoichiometric obstruction and translate it from the crystal [1].  In systems with ion bonds, topological solitons originate in flammable groups and pass along the molecule, breaking the ion bond and transmitting the molecule from the crystal [2]. In systems with branched chains, topological solitons are reflected from the branching while there is no translation of the molecule from the tristearin crystal. The question arises in the system of hydrogen bonds (dimer rings) that topological solitons will be discarded from hydrogen bonds, will break them or transfer dimer from the crystal as a whole.
Therefore the purpose of the work was to study the mechanism of thermal motion in lamellar crystals of aliphatic molecules (with end-groups of COOH fatty acids) with hydrogen bonds (dimer rings).

1.    Alekseev O.M.,  Alekseev S.O.,  Bulavin L.A., Lazarenko M.M., Maiko O.M.  Phase Transitions In Chain Molecular Polycrystals Of 1-Octadecene Ukrainian Journal Of Physics 53 (0503-1265): 882
2. Alekseev O.M., Lazarenko M.M., Puchkovs'ka G.O., Bezrodnaya T.V. & Sendzyuk A.A. (2010). Peculiarities of thermal motion in crystals formed by cetyltrimethylammonium bromide molecules. Ukr J. Physics, 55 (9), 973-979