Manufacture of Aerosol Gels Using Flame Synthesis
Dr. Chakrabarty’s group has invented a method for the manufacture of aerosol gels using flame synthesis offering a cost-effective, scalable, and versatile mode of production as compared to the conventional wet chemistry-based sol-gel technique (Patent filed). Using this technique, his research group has demonstrated the bulk production of titania, silica, and other advanced material-based aerosol gels for energy applications, such as hydrogen storage, CO2 photo-reduction catalysts, etc. This advanced aerosol-based technology is currently undergoing technology transfer to Cabot Corporation for utilization in manufacturing of their products.
Kinetics of AEROSOL-to-GEL
Gelation is a result of sol-to-gel transition–a universal phenomenon–in irreversible non-coalescent aggregation systems . When the average size of aggregates reaches the length-scale of average nearest neighbor separation, an aerosol system is said to gel–this condition is defined as the ideal gel point (IGP). Beyond IGP, the kinetics of particle growth remains elusive because of the break down of the governing Smoluchowski equation. Dr. Chakrabarty and his group systematically studied the dynamics of gelling systems in this regime using the off-lattice diffusion limited cluster-cluster aggregation model. They showed that beyond IGP, the sol phase particles ceased to grow without forming into gels and their corresponding normalized mass distribution remained invariant with respect to the geometric mean and standard deviation. This invariant mass distribution also implied that the conversion of particles from the sol phase to gel phase during a unit time is independent of particle size. They elegantly parameterized the relationship between conversion rate and time using a power-law analytical expression which accurately predicts both the decrease in the total number of sol phase particles and the increase in average mass of the gel phase particles. It is to be noted that this complete, quantitative description of the time-evolution of monomers to aggregate to gel phase has not been accomplished before in our field.
Relevant Publications:
- Chakrabarty and Liu (2019). Synthesis of aerosol gels comprising macro-aggregates in a buoyancy-opposed flame reactor by a diffusion-limiting cluster aggregating process. US Patent, https://patents.justia.com/patent/20210246045
- Liu, P., W. R. Heinson, C. M. Sorensen, and R. K. Chakrabarty (2019). Kinetics of sol-to-gel transition in irreversible particulate systems, J. Colloid. Interface. Sci., https://doi.org/10.1016/j.jcis.2019.04.067
- Liu, P., I. J. Arnold, Y. Wang, Y. Yu, J. Fang, P Biswas, and R. K. Chakrabarty (2015) Synthesis of Titanium Dioxide Aerosol Gels in a Buoyancy-Opposed Flame Reactor, Aerosol Sci. Tech., 49:12, 1232-1241, DOI: 10.1080/02786826.2015.1112356.