NH3 on a BC3 nanotube: effect of doping and decoration of aluminum.

The adsorption of the NH3 molecule was investigated on pristine, Al-doped and Al-decorated BC3 nanotubes (BC3NT) using density functional theory calculations. It was found that NH3 prefers to be adsorbed on a B atom of the tube wall, releasing energy of 1.02 eV. Al-doping increases the acidity of the tube surface and, therefore, its reactivity toward NH3 so that the released energy in this case is about 1.62 eV, while decorating the BC3NT with Al atom decreases the acidity and reactivity. Although Al-doping has no significant effect on the electronic properties of the BC3NT, Al-decoration significantly reduces its HOMO/LUMO energy gap from 2.37 to 1.16 eV so that the tube becomes an n-type semiconductor. However, we believe that the acidity of the BC3NTs may be controlled by doping or decoration of Al atoms.

Cosolvent effects on the spontaneous formation of nanorod vesicles in catanionic mixtures in the rich cationic region.

The aggregation behavior of cation-rich catanionic mixtures of cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) was investigated in water-ethylene glycol (EG) solutions by performing surface tension, electrical conductivity, pulsed field gradient nuclear magnetic resonance, transmission electron microscopy, and cyclic voltammetry measurements. Different physicochemical properties such as the critical micelle concentration, degree of counterion dissociation (α), interfacial properties, aggregation numbers, morphology of aggregates, and interparticle interaction parameters were determined. Cosolvent effects on the interactions between the two surfactants CTAB and SDS were analyzed on the basis of regular solution theory, both for mixed monolayers at the air/liquid interface (ß(δ)) and for mixed micelles. It was shown that an excess of cationic surfactant resulted in the formation of nonspherical vesicles. These were predominantly nanorod vesicles in water-EG mixed solvents. The interparticle interactions were assessed in terms of cosolvent effects on the micellar surface charge density, the sphere-to-rod morphology change, and the phase transition from vesicles to mixed micelles. Moreover, the variation of the repulsive electrostatic potential energy between two pairs of aggregates was investigated for two modes of nanostructural transition, namely the transition between spherical and rod-like micelles and the transition between rod-like micelles and nanorod vesicles.