Research
Graphene synthesis
We have discovered a process to make multilayer nano-graphene by exploding hydrocarbons with oxygen in a chamber. The method has been patented and licensed to a startup company HydroGraph Clean Power, Inc.
Light scattering by particles of arbitrary size, shape and refractive index
Two decades ago we discovered formerly unknown patterns in the classic Mie description of scattering from homogeneous spheres of arbitrary size and refractive indices. These patterns are apparent when the scattered intensity is plotted versus the scattering wave vector in a logarithmic fashion rather than the scattering angle, a method we call “Q-space analysis”. Two new fundamental parameters have been discovered by means of these Q-space plots which give universal descriptions of scattering for all particle types. These advances and insights are revolutionary. Sorensen’s group is actively pursuing this point of view to develop a comprehensive description of light scattering and absorption by particles of arbitrary size, shape and complex refractive index. The research has a strong synergy between experiment and theory. Sorensen and his students have advanced the experimental art of light scattering with novel devices to detect at very small and very large scattering angles and have applied these methods to systematic studies of a variety of aerosol particulates.
The sol-to-gel transition in particulate systems, the discovery of superaggregates, and aerosol gel materials
In 1998 Sorensen and his students discovered experimentally that a flame soot aerosol could gel. This led to two decades of subsequent work to characterize and yield a comprehensive description of the sol-to-gel transition. We have shown that any fractal aggregating system will gel. We discovered in both real combustion systems and simulations that as the system gels, superaggregates of fractal dimension 2.6, due to percolation, form composed of smaller aggregates of fractal dimension 1.8, due to diffusion limited cluster aggregation (DLCA). We have set forth a complete description, including identification of new regimes of aggregation, of how a system of particles evolves from a dilute sol to a gel. We have applied this new understanding of gelation in the aerosol phase to create new, low density materials formed by gelling an aerosol. These “aerosol gel” materials have properties similar to well-known aerogels created by the sol-gel process, but have an advantage in that aerosol gels do not need a supercritical drying step. Sorensen and his group hold a patent for this process. Current work is developing an understanding of the kinetics of gelation. Our methods involve light scattering measurements for gelling sols and computer simulations.
Aggregation kinetics of particulate systems and studies of the resulting fractal aggregates
Our group has pioneered the study of fractal aggregates, which occur as a result of random aggregation of solid particles in aerosol and colloidal systems and are ubiquitous. Our studies have elucidated the detailed structure of these aggregates, the kinetics of their formation, their light scattering and absorption properties, their transport properties, and given an analytic theory of their formation. We have also pioneered the use of both static and dynamic light scattering as diagnostics of aerosol systems that form fractal aggregates including sooty flames. We have developed methods for in situ light scattering measurement of aggregate size, fractal dimension, and size distribution. We have pioneered small angle light scattering to achieve size scales up to 50 microns. Recent realizations that Fibonacci numbers, divine proportions and their higher dimension analogues occur in fractal aggregate morphology.
Research Assistant Professor
- Arjun Nepal
Research Associates
- Raiya Ebini
- Justin Maughan
Graduate Students
- Prakash Gautam
- Parker Stoops
- Shusil Sigdel
- Shamna Trivedi
- Justin Wright
Grants
- Studies of Light Scattering by Particles of Arbitrary Shape, NSF,$455,870; July 1, 2017 to June 30, 2021; AGS 1649783
- Detonation Synthesis of Advanced Materials Cortelyou-Rust endowment KSU Foundation. $49,200, August 2018 to August 2020.
- Graphene detonation lab improvements, The Laboratory Safety Renovation Program at KSU, $150,000, January 1, 2019.
- Development of Detonation Synthesis of Graphene. Phase 2, Carbon 2D, $168,000, 5/1/19 - 4/30/2020.
- Research Professor Salary, Carbon 2D $30,000 January 10, 2020.
- Production of Detonation Carbons from KSU, Revised 16 July 2020, Cabot Corp. (Dave Matheu) $17,725.
- Development of Detonation Synthesis of Graphene. Phase 3, December 1, 2020 to February 28, 2021. $62,500, Carbon 2D.
- Development of Detonation Synthesis of Graphene. Phase 3, March 1, 2021 to May 31, 2021. $62,500, Carbon 2D.
- Graphene Development, June 1, 2021 to May 31, 2022, HydroGraph Clean Power, Inc., $1,517,773; PI with seven Co-PIs.
