Nanoparticle nucleation exposed
Atomic force microscopy image of nucleated calcium carbonate nanoparticles (white dots) on a quartz surface.
A stunning atomic force microscopy image of calcium carbonate nanoparticles sheds new light on how the particles nucleate.
Engineers at Washington University in St. Louis, US, used small-angle X-ray scattering and AFM to discover how calcium carbonate nanoparticles nucleate.
The results provide crucial information on how to better manufacture carbonate nanomaterials and control metal carbonation during carbon dioxide sequestration.
Professor Young-Shin Jun from the School of Engineering & Applied Science, and colleagues, are the first to measure the activation energy and kinetic factors of calcium carbonate's nucleation.
"Our [experiments] show which synthesis conditions accelerate nucleation more effectively," says Jun.
"Should we change the driving force by increasing the concentration of certain ion, or should we change the surface properties of the material or [alter] the system's temperature?" she points out. "Now we can predict the outcome."
With the new information, Jun and colleagues can say definitively how concentrated the calcium carbonate nanoparticles are in a given space over a given time period, which allows them to control nucleation.
Until now, these thermodynamic and kinetic factors have remained unknown because real-time observations have been difficult to perform on particles, often as small as 8 nm.
In experiments at the Advanced Photon Source, Argonne National Laboratory, Jun's group used small angle X-ray scattering on beamline 12-ID-B for in-situ probing of the nanoparticles.
Then to visually observe calcium carbonate nucleation on quartz, the researchers used ex-situ atomic force microscopy in Jun's lab, operating the instrument in tapping mode, using 8 nm diameter probes from Bruker.
"Knowing about nucleation empowers us to create nanomaterials and allows us to control nanoparticle properties and surface functionalization of materials, helping sustainable nanomanufacturing," highlights Jun.
"Deciphering nucleation also aids in designing larger-scale engineering processes where nucleation changes the macroscopic properties of materials," she adds. "Every single material starts with nucleation, so this process can be applicable to anything."
Research is published in Nature Communications Chemistry.