Kinetics of intermediate-mediated self-assembly in nanosized materials: a generic model.

We propose in this paper a generic model of a nonstandard aggregation mechanism for self-assembly processes of a class of materials involving the mediation of intermediates consisting of a polydisperse population of nanosized particles. The model accounts for a long induction period in the process. The proposed mechanism also gives insight on future experiments aiming at a more comprehensive picture of the role of self-organization in self-assembly processes.

Growth of itraconazole nanofibers in supersaturated simulated intestinal fluid.

Many drug compounds have limited solubility in water. To enhance the oral bioavailability of such compounds, pharmaceutical formulations target the creation of a supersaturated solution. Release of the compound from ordered mesoporous silica carrier is such a means for reaching supersaturation.

Investigation of the mechanism of colloidal silicalite-1 crystallization by using DLS, SAXS, and 29Si NMR spectroscopy.

Colloidal silicalite-1 zeolite was crystallized from a concentrated clear sol prepared from tetraethylorthosilicate (TEOS) and aqueous tetrapropylammonium hydroxide (TPAOH) solution at 95 degrees C. The silicate speciation was monitored by using dynamic light scattering (DLS), synchrotron small-angle X-ray scattering (SAXS), and quantitative liquid-state (29)Si NMR spectroscopy. The silicon atoms were present in dissolved oligomers, two discrete nanoparticle populations approximately 2 and 6 nm in size, and crystals.

Prospects of transition interface sampling simulations for the theoretical study of zeolite synthesis.

The transition interface sampling (TIS) technique allows large free energy barriers to be overcome within reasonable simulation time, which is impossible for straightforward molecular dynamics. Still, the method does not impose an artificial driving force, but it surmounts the timescale problem by an importance sampling of true dynamical pathways. Recently, it was shown that the efficiency of TIS when calculating reaction rates is less sensitive to the choice of reaction coordinate than those of the standard free energy based techniques.