Phenomenon of the interaction of strings formed in homochiral solutions with the surface of solids

Abstract

A phenomenon of the interaction of elastic supramolecular strings forming in homochiral solu� tions with the surface of solids was described. It was established that, in the interaction with a conducting surface, strings do not form; with a dielectric surface, strings efficiently form; and with a weakly or nonuni� formly conducting surface, strings form, but their for� mation is either less intense or nonuniform. A long� range mechanism of decomposition, pulling, and rup� ture of a string while interacting with a conducting sur� face was proposed. We previously described a phenomenon of the spontaneous formation of strings in lowconcentra� tion chiral solutions (1-4). In this work, we detected and studied a phenome� non of the interaction of the forming strings with the surface of a solid at the solution interface. Longrange physicochemical mechanisms were considered that lead to the vanishing and rupture of a string in a surface solution layer to 300 µm in thickness and to the forma� tion of domain structures. In the experiments, we used homochiral solutions of trifluoroacetylated amino alcohols (TFAAA) in heptane and cyclohexane (99.9%, Khimmed), and also xerogels formed upon evaporation of the solvent from these solutions. TFAAA were synthesized according to a published procedure (5). The study was performed with a MIKMED�6 opti� cal microscope and a Solver HV atomicforce micro� scope (NDMDT, Zelenograd, Russia). The xerogels were produced by applying a solution drop to various microscopically smooth solid surfaces (mica, glass, graphite, metal mirror) and, after drying, were exam� ined with the optical and atomicforce microscopes. The atomicforce microscopy was carried out in two standard complementary modes: tapping and phase contrast. Hermetically sealed solutions were examined with the optical microscope under normal conditions. Let us consider specific features of the typology of