By dispersing the nanoparticles of a substance into a gas, their count and size distribution can be measured. However, certain nanoparticles have the tendency to form aggregates due to the change in the surrounding conditions. University of Gothenburg researchers have demonstrated that nanoparticles can be counted and sorted even in the aggregate state.
Ann-Cathrin Johnsson of the University of Gothenburg’s Department of Chemistry stated that it is critical to detect the surface area, shape and size of nanoparticles for enhancing their properties for various fields of applications. Since gravity has no impact on nanoparticles due to their smaller size, they do not settle down but spread across the container.
Nanoparticles have large contact area with their surrounding medium, thanks to their small size. Hence, nanoparticles of a substance demonstrate unique properties, which are different from the properties of larger particles of the same substance. Some kinds of nanoparticles aggregate under unique conditions to create an alleged gel form. Johnsson has investigated colloidal silica, a kind of this type of aggregating system. The gel form, which is a result of the addition of salt into colloidal silica, can be utilized to stabilize soil and seal rock.
Johnsson stated that she improved the process being used for studying non-aggregating nanoparticles. Aggregated nanoparticles can be studied individually by diluting a colloidal silica gel containing those aggregated nanoparticles and then dispersing it into the gas phase. By analyzing the samples instantaneously after the dilution process, an accurate image of the gelated system can be obtained.
Source: http://gupea.ub.gu.se