(324g) Effects of Impurity Nanoparticles in Microfluidic Non-Photochemical Laser Induced Nucleation of Potassium Chloride

Nucleation, as the foremost step in the crystallization process, has been investigated for many years but not much is understood about this crucial step. Non-Photochemical Laser Induced Nucleation (NPLIN) utilizes short laser pulses, on the order of nanoseconds, to trigger nucleation and has been shown to induce solid crystals from liquid solution. NPLIN offers spatial and temporal control during the crystallization process. However, the mechanism by which NPLIN occurs is not yet clear. A key observation from the literature is that filtration of the solution prior to laser irradiation produces fewer nuclei when compared with unfiltered samples. However, the extent to which these nano-impurities aid nucleation has not been investigated. There should exist a threshold nano-impurity concentration and system pressure at which nucleation is hindered, despite varying solution supersaturation and laser peak densities. To probe for this set of conditions, a high-pressure glass microfluidic device was fabricated and integrated with a nanosecond pulsed laser. Real-time optical microscopy and Dynamic Light Scattering was used to monitor for the on-set of nucleation and crystal growth. Isolation of the effects of nano-impurities on the nucleation process provides a pathway to study other proposed mechanisms of NPLIN and further advance knowledge of the crystallization space.