Incorporation of poorly soluble drug Cefixime inside the micellar core of conventional and gemini surfactants

This work reports the physicochemical behavior of antibiotic drug, cefixime (CEF) in presence of cetyl trimethyl ammonium bromide (CTAB), dodecyl trimethyl ammonium bromide (DTAB), dodecyl ethyl dimethyl ammonium bromide, (DDAB),...

Activity of Polyphenoloxidase in red Fuji Apples Promoted with Cationic Surfactant – Role of Surfactant Structure

In this study, we observed the activity of polyphenoloxidase (PPO) in red Fuji apples in the presence of single-chained surfactants (including cetyl trimethyl ammonium bromide (CTAB), and dodecyl trimethyl ammonium bromide (DTAB)) and gemini surfactants (pentamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide), octamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide, dodecamethylene-α,ω-bis(dodecyl dimethyl ammonium bromide), pentamethylene-α,ω-bis(cetyl dimethyl ammonium bromide), and octamethylene-α,ω-bis(cetyl dimethyl ammonium bromide)). It was found that all these surfactants enhanced the activity of PPO in a wide range of temperature at low content. When PPO was denatured by incubating at high temperature, the surfactants caused reactivation of PPO. Compared to the single-chained surfactants, the gemini surfactants increased PPO activity at a much lower concentration. Moreover, the single-chained surfactant and the gemini surfactant acted together to further increase PPO activity, and the synergistic effect reduced the amount of surfactant used. In addition, the Michaelis-Menten constant for PPO did not change in the presence of the surfactants, suggesting the active site should remain well with the surfactants.

Quantum Chemical Study on the Influence of Dodecyl Trimethyl Ammonium Bromide on the CH4 Adsorption of Coal

The adsorption of dodecyl trimethyl ammonium bromide (DTAB) on coal can affect the wettability of coal and change the water absorption of coal. After DTAB treatment, the change in the CH4 adsorption capacity of coal is worth further study. To reveal the microscopic mechanism of the influence of DTAB on the CH4 adsorption capacity of coal, we employed the density functional theory (DFT) with the 6-311 G (d, p) basis set. DFT-based computations interpreted the adsorption process of CH4 and DTAB on coal molecules and determined the stable structure, adsorption distance, Mulliken overlapping populations, and adsorption energies of the two adsorption configurations. The results showed that the adsorption energies of CH4 and DTAB on the molecular model of coal were 2.15 and 42.69 kJ/mol and the adsorption stability distances were 0.261 and 0.238 nm, respectively. The DTAB–coal configuration was more stable than the CH4–coal configuration. When there was competitive adsorption between DTAB and CH4 on coal, the coal molecules preferentially adsorb the DTAB. Infrared spectroscopy and adsorption experiments were also carried out, and the calculation results of quantum chemistry are consistent with the experimental results.

Effects of foaming agent on properties of foamed gel

To improve foam expansion and the stability of the foamed gel selected as the starting point, three foaming agents with relatively higher foam expansion and three foam stabilizers were used to determine optimum gradient and composition of the gel. Sodium laurate and dodecyl trimethyl ammonium bromide at a proportion of 2:3 were observed to produce the desirable foaming property and also created the largest foaming volume after the addition of 0.2% polyethylene glycol as the foam stabilizer. Different concentrations of gelatinizing and cross-linking agents were added to the foamed gel containing the foaming agent and the foam stabilizer. The most suitable ratio of the gelatinizing agent and the cross-linking agent determined on the basis of volume of foam dewatering after the addition of foam stabilizer for 6 h was 0.6%:0.5%. The resulting foamed gel was evaluated for rheological and plugging properties and a decrease in the viscosity of the gel and better plugging effect on coal seam were observed.

Spontaneous Formation of DTAB/SLS Vesicles

Dodecyl trimethyl ammonium bromide/sodium dodecyl sulfate (DTAB/SLS) complex formulation of scale effect on the spontaneous formation of vesicles and the influence of different factors on the stability of vesicles were discussed, structure and morphology of vesicles were observed.

Preparation and Characterization of Al2O3 Nanoparticles with Dodecyl Trimethyl Ammonium Bromide as Surfactant

nanoAl2O3 has been synthesized by homogeneous precipitation method using dodecyl trimethyl ammonium bromide (DTAB) as surfactant. The as-prepared powder was characterized by FT-IR, XRD, TEM and SEM. The results indicate the surfactant existence in the precursors but disappeared in the products. This is mainly due to the combination of precursor and surfactant, which results in particles of nanosize. The nucleation and growth rate during the precipitation has also been controlled by the addition of surfactant. During the calcination process, the surfactant has decomposed and volatilized into air. The XRD characterization shows the calcined powders were γ-Al2O3 particles with mean size of 27 nm, which was in accordance with TEM characterization. The morphology of the prepared alumina particles has also been investigated by SEM and showed that the powder has a spherical morphology with a uniform particle size.