"Preparation and Characterization of Some Cationic Surfactants Capped Metal Nanoparticles and Their Applications"

Abstract

Twelve cationic surfactants were prepared by condensation reaction between dimethylaminopropylamine (DMAPA) and different aldehydes like benzaldehyede, vanillin, 3,4dimethoxybenzaldehyde and butyraldehyde was performed. The produced Schiff base was quaternized with three fatty alkyl bromide with different carbon chain length separately to form the desired cationic surfactants. The chemical structures of synthesized cationic surfactants was confirmed by FTIR, HNMR and mass spectroscopy. Silver nanoparticles were prepared using sun light as a gratis source of reducing agent with assistance of the prepared cationic surfactants in addition of their role as capping agent (control size and shape). The formation of AgNPs was confirmed using different techniques like transmission electron microscope (TEM), FTIR, UV-Vis spectroscopy, energy dispersive X-ray (EDX) and dynamic light scattering (DLS). The chemical structure of prepared compounds has an effect on surface properties, where increasing the hydrophobic chain length decrease the values of critical micelle concentration (CMC), maximum surface excess (Г) while minimum surface area value was increased. The Thermodynamic parameters showed that the adsorption and micellization processes are spontaneous. It is clear that the prepared cationic surfactants at first tend to adsorb at surface, then it aggregate to form micelle. Three techniques were used for the corrosion inhibition evaluation, namely; weight loss, polarization and electrochemical impedance. The results showed that all synthesized surfactants were good inhibitors and their inhibition efficiencies were significantly increased with increasing both the concentration and temperature. Polarization curves revealed that the studied inhibitors represent a mixed-type of inhibitors. The adsorption of these inhibitors was found to obey Villamil adsorption model. The prepared surfactants and silver nanoparticle capped by these surfactants showed good biological activity against Gram positive and negative bacteria and fungi. The serial dilution method was used to evaluate the inhibiting effect of these compounds on the sulfate reducing bacteria growth.