Nanoparticle Tracking Analysis used to Characterise Inorganic Nanopowders and Colloids

NanoSight reports on how Nanoparticle Tracking Analysis, NTA, is being implemented for the characterisation of various inorganic nanopowders and colloids synthesised in the Institute of High Pressure Physics at the Polish Academy of Sciences in Warsaw.

The Institute of High Pressure Physics (IHPP) was founded in 1972 by the Polish Academy of Sciences. The original focus was on high-pressure studies of semiconductors. Now, research covers ceramics, HTc superconductors, biological materials (high-pressure studies of protein folding, and high pressure food processing) and the plasticity of metals (hydroextrusion). The common axis of these studies is the use of high pressure, both as a research tool (a perturbation like temperature or magnetic field) and as a technological method (high-pressure sintering, high-pressure growth of crystals).

Agnieszka Opalinska is a research chemist working on the synthesis and practical applications of nanopowders for use in medicine, optics, optoelectronics, pharmacy and cosmetics. The Institute has developed a microwave, solvothermal technology which has enabled the group to very rapidly obtain homogenous and phase-pure nanoparticles including hydroxyapatite, zinc oxide and zirconium oxide. The size and shape of these nanopowders are easy to manipulate and may be functionalised with organic molecules. With a specialty in the preparation of colloidal solutions too, the group needs accurate and easy-to-use methods of particle characterisation.

Proper characterisation of nanostructure of powders is the key stage for the process. The Institute makes several measurements including nanopowder morphology, density, specific surface area, phase composition and crystalite size, all of which are made on dry powder samples. For the past two years, the Institute has used both NTA and DLS to produce complementary sizing results. However, when making the colloidal studies, NTA has a distinct advantage. Ms Opalinska said: "using NTA also gives us the concentration of particles. We like the use of video to be able to visualise the agglomeration process and to help us track the kinetics of the process."