Depth-profiled positronium lifetime spectroscopy is used to probe the pore characteristics ~size, distribution, and interconnectivity! in porous, low-dielectric silica films. The technique is sensitive to the entire void volume, both interconnected and isolated, even if the film is buried beneath a metal or oxide layer. Our extension of a simple quantum mechanical model of Ps annihilation in a ...

According to IUPAC nomenclature, mesoporous materials are those materials having a pore size ranging from 2 to 50nm in diameter [1-6]. Mesoporous silica nanoparticles (MSNs) are promising and novel drug vehicles due to their unique mesoporous structure, which preserve a level of chemical stability, surface functionality and biocompatibility and ensure controlled release and targeted delivery of...

We present a model for pore stabilization in membranes without surface tension. Whereas an isolated pore is always unstable (since it either shrinks, tending to reseal, or grows without bound until membrane disintegration), it is shown that excluded volume interactions in a system of many pores can stabilize individual pores of a given size in a certain range of model parameters. For such a mul...

Novel mesoporous BN and BCN materials with cage type porous structure and spherical morphology have been synthesized using carbon nanocages with 3D porous structure as a template via an elemental substitution method at a low synthesis temperature. The obtained materials exhibit a large specific pore volume with uniform pore size distribution and the specific surface area ranging from 945 to 102...

The use of NMR spin-lattice relaxation experiments on water, or other proton-containing fluids, in a porous solid as a pore structure/size measurement tool has been recently reported for porous solids with pore size greater than ~ 5 nm. This approach has numerous advantages, as compared to nitrogen sorption/ condensation and mercury porosimetry, including no network/percolation effects, no pore...

Acetylene-black paste without a light scattering layer was applied to meso-porous TiO2 photo-electrode films with a crystalline framework, a low residual carbon, and a tunable morphological pore size. The thermal-treated TiO2 photo-electrode films had an increased acetylene-black concentration with an increase in artificial pores and a decrease in residual carbon. The performance of dye-sensiti...

Recently, Kowalczyk et al (2011 Nanotechnology 22 315101) introduced a model for calculating the conductance of an hourglass-shaped nanopore, and the conductance change when DNA is introduced into such a pore. Here, we comment on their model in the context of other literature addressing the same general problem. Existing work includes widespread use of an alternative model, contradicts the aut...