The simple spin-on based approach makes use of the entropic gain of functionalized nanoparticles initially dispersed in a polymer system when instantly subjected to temperatures beyond the decomposition temperature of the polymer. The random Brownian motion of the nanoparticles due to the increased thermal energy results in a fraction of the nanoparticles crosslinking with each other thereby kinetically arresting the system. This eventually leads to the formation of highly porous nanostructures with tunable properties.

Viable approach

The team has shown that the optical and physical properties of the films can be finely tuned as a function of the curing/calcination temperature as well as the amount of polymer loading. The group demonstrates the viability of this approach by choosing an organosilicate nanoparticle-polypropylene glycol system.

As shown in the images above, the coatings feature nanoparticles and pores with sizes less than 10 nm, which give very smooth surfaces. These systems are highly dependant on the surface properties of the substrates thereby enabling a novel approach to pattern porous and non-porous regions simply by patterning the surface energy of the substrates. Because of their easy and rapid fabrication together with their unique properties, these coatings are expected to have a major impact in biosensing, photonics and separation technologies.

The researchers presented their results in the journal Nanotechnology.