Browsing by Author "Mircheva K.M."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Monolayer formed by l-Asp-based gemini surfactants self-assembled in 1D nanostructures
    (2019-01-01) Anchev B.A.; Tsekova D.S.; Mircheva K.M.; Grozev N.A.
    Herein, studies on the surface activities of newly synthesized l-Asp-based gemini surfactants, both nonionic and anionic, are presented. Conductometry, tensiometry, and the Langmuir-Blodgett (LB) film technique were applied for this purpose. π-A isotherms were obtained with a Langmuir trough and Wilhelmy balance. The structures of the monolayers assembled at the air/water interface and those deposited as LB films were studied via Brewster angle microscopy (BAM) and atomic force microscopy (AFM). The 2D films formed by the anion-active compounds show a well-known pattern of a monolayer film, whereas the nonionogenic amphiphiles have been found to be 1D structures with nano-widths and micro-lengths that align with each other during the process of compression; this is the first study where the organization of 1D fibrils in 2D films during compression is reported. The scanning electron microscopy (SEM) study reveals that 1D nanostructure formation is an intrinsic tendency of these molecules as not only nonionogenic surfactants, but also the anion active representatives have been constructed in the solid state by fibrillary structures.
  • No Thumbnail Available
    Item
    On the synthesis, surface activity and supramolecular structures of pseudo double-chained L-Asp based amphiphiles
    (2020-01-01) Anchev B.; Grozev N.A.; Mircheva K.M.; Tsekova D.S.
    Eight new final compounds derivatives of L-Asp are synthesized. They contain L-Asp linked by an amide bond both to n-hexyl chain on its C-side and an acyl chain linked to the N-side. Four different acylic residues are condensed to the N side. The newly synthesized compounds belong to two series of structures, as four of them contain L-Asp-b-benzyl ester, while the other four-a typical L-Asp-b-carboxylic group. The structures of the surfactants are categorized as pseudo-double alkyl chained amphiphiles, because one of the tails has a constant length of only six carbon atoms. Some of the newly synthesized surfactants are studied as monolayers on the air/water interface. The properties of the rest of them are determined by tensiometric and conductometric methods. Nano-and micro-sized supramolecular complexes of the compounds studied are observed in monolayers using Brewster Angle Microscopy (BAM) and Scanning Electron Microscopy (SEM) for samples after solvent evaporation.