This study investigates the biological activity of two cationic gemini surfactants, hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) C6 and pentamethylene-1,5-bis-(N,N-dimethyl-N-dodecyla,.mmonium bromide) C5, and their two neutral analogs, hexamethylene-1,6-bis-(N-methyl-N-dodecylamine) (A6) and pentamethylene-1,5-bis-(N-methyl-N-dodecylamine) (A5). Experiments were performed wit...

Self-assembly in mixtures of cationic and anionic surfactants occurs synergistically because of attractive interactions between the oppositely charged headgroups. Here, such effects are exploited to obtain highly viscoelastic fluids at low total surfactant concentration. The systems considered are mixtures of the C18tailed anionic surfactant, sodium oleate (NaOA), and cationic surfactants from ...

Zeta potential, effective diameter and sedimentation rate of TiO2 (Degussa P-25) suspension were studied in the presence of NaCl and anionic (sodium dodecyl sulfate, SDS) or cationic (dodecyltrimethylammonium bromide, DTAB; tetradecyltrimethylammonium bromide, TTAB; and hexadecyltrimethylammonium bromide, CTAB) surfactant, as well as lecithin (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC)....

Water loss in low permeability reservoirs during hydraulic fracturing well completions typically results in a decrease in natural gas production due to capillary trapping near the fractures. Shale gas reservoirs, however, have shown a trend of improved gas production with increased loss of completion fluids to the shale. This nonintuitive relationship between water imbibition and enhanced gas p...

The success rate of gene therapy depends on the efficient transfection of genetic material into cells. The golden mean between harmlessness and high effectiveness can be provided by synthetic lipid-like molecules that are similar to the components of biological membranes. Cationic gemini surfactants are one such moiety and because of their favourable physicochemical properties (double positive ...

In recent years, the ability of ionic surfactants such as sodium dodecyl sulfate (SDS) to solubilize the water-insoluble protein Zein in aqueous solution, referred to as the Zein solubilization test, has been investigated to rank the skin irritation potential and protein denaturation potential of surfactants. However, the potential of cationic surfactants towards solubilization of Zein has not ...

The effect of surfactants on the treatment of chemical mechanical polishing (CMP) wastewater by electro-coagulation-flotation (ECF) process was studied. Two surfactants, cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) were employed in this study to compare the effect of cationic (CTAB) and anodic (SDS) surfactants on ECF. The cationic surfactant can enhance the removal of ...

The dissociation equilibria of ascorbic and maleic acids have been studied in certain cationic, anionic and non-ionic micellar media and their pK(a) values have been evaluated by the potentiometric, conductometric and spectrophotometric techniques. These pK(a) values have been found to shift in micellar media as compared to those in pure water. The differences in the values have been attributed...

Kinetics of the title reaction has been carried out by studying the reaction spectrophotometrically at 80 oC and pH 5.0 in presence of cationic gemini (alkanediyl-α, ωbis(dimethylhexadecylammonium bromide)) surfactants. The reaction followed first-order kinetics in [Zn(II)-Gly-Tyr]T complex and fractional-order kinetics in [ninhydrin]T. Typical rate constant (kΨ) increase and leveling-off regio...

The use of surfactants to reduce the number of residual particles following chemical-mechanical planarization during integrated circuit manufacturing is relatively new. Recent results using cetyl pyridinium chloride and other cationic surfactant molecules show that surfactants are very effective in reducing the number density of residual polishing particles. The effectiveness of the surfactants...