Ammonium Gemini Surfactants Research Articles

Gemini surfactant based-organomontmorillonites: preparation, characterization and application in pickering emulsion

To investigate the efficiency of gemini surfactant based organoclays (OMts) for the stabilization of O/W emulsions, different ammonium gemini surfactants with semi-rigid hydrophobic chains and spacer lengths were used for the modification of sodium montmorillionite (Mt). The composition and morphology of the resulting organoclays were characterized by Fourier transform infraredspectroscopy, X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy and thermogravimetric analysis. The results showed that these surfactants are more efficient than conventional surfactants and hydrocarbon type gemini surfactant analogous in the modification of Mt. An important increase of the d-spacing values was obtained particularly for long hydrocarbon chains and spacers. The OMt’s thermal properties and hydrophobicity were also governed by the structure of surfactants. The stabilizing behavior of gemini surfactants, OMt as well as surfactant/OMt mixtures in oil/water (1:1, v/v) emulsions was investigated by macroscopic and microscopic morphological observations. Better stabilization was achieved by G(10-4-10) surfactant bearing decyl chains and OMts with high surfactant concentration.

Structural Characterization of dsDNA Nanocomplexes based on Ammonium Gemini Surfactants

One of the most intensively studied groups of chemical compounds are gemini surfactants, because of their specific and attractive properties, especially the capability of stable binding of the nucleic acids, formation of spatial structures with high symmetry and relatively low cytotoxicity. They have found a broad range of applications in medicine, chemical technology, pharmaceutical industry [1]. These complexes can be applied as nonviral transfection delivery systems in gene therapy, a novel and most promising method for the treatment of a broad range of genetic diseases. Dicationic surfactants allow introduction of a transgene without inducing natural immunological response, and release it undamaged inside the cell. However, the successful completion of this process is difficult, because of the need for many studies in order to determine all necessary parameters [2-5].In our study we analysed nanocomplexes of cationic gemini surfactants (1,n-dodecanebis[(oxymethyl)alkyldimethylammonium]chlorides) with DNA oligomers using synchrotron radiation of small angle X-ray scattering, circular dichroism spectroscopy, agarose gel electrophoresis, polarization microscopy and transmission electron microscopy. We also analysed the cytotoxicity of our systems using MTT colorimetric assay on model cell cultures.We observed the formation of complexes, their morphology, spatial nanostructure, conformation of nucleic acid inside them and influence on the cells. The systems studied were found to be stable and the process of their formation was reproducible.This research project was financed by National Science Centre (Poland), decision no.DEC-2011/01/B/ST5/00846.[1] R. Zielinski, Surfactants - structure, properties, applications, WUP, 2009, Poznan.[2] P. C. Bell, et al. J. Am. Chem. Soc. 125 (2003) 1551-1558.[3] W.C. Brunner, M.F. Maestre Biolpolym.13 (1974) 345-357.[4] D. Simberg, D. et al., J. Biol. Chem. 276 (2001) 47453-47459.[5] S.D. Wetting, et al., J. Gene Med. 9 (2007) 649-658.

Synthesis of imidazoline‐based dissymmetric bis‐quaternary ammonium gemini surfactant and its inhibition mechanism on Q235 steel in hydrochloric acid medium

AbstractAn imidazoline‐based dissymmetric bis‐quaternary ammonium gemini surfactant has been synthesized. Its surface active properties at equilibrium in water at 25 °C were determined. The inhibitive effect of the compound on Q235 steel in 1 M hydrochloric solution was investigated by the weight‐loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) analysis, and quantum chemical calculations. The results indicate that the compound has high surface properties and the inhibition efficiency (IE) increases with the increase in inhibitor concentration, which attain the maximum value around the CMC value. The imidazoline‐based dissymmetric bis‐quaternary ammonium acts as a mixed type inhibitor mainly inhibiting the cathodic processes and does not change the mechanism of either hydrogen evolution reaction or mild steel dissolution. The best IE is obtained at the immersion time of 144 h. The adsorption of the studied inhibitor on Q235 steel can be fitted to a Langmuir isotherm and the adsorption process is a spontaneous chemical adsorption. Quantum chemistry calculation results show that the imidazoline ring and heteroatoms of N, O, are the active sites of the inhibitors.