T. J. "Lakis" Mountziaris

T. J. "Lakis" Mountziaris, Professor and Head of Chemical Engineering

Chemical Engineering
159 Goessmann Lab
686 North Pleasant St.
University of Massachusetts Amherst
Amherst, MA 01003-3110
413-545-2359 (Office)
413-545-0724(FAX)
tjm@ecs.umass.edu

Education

Diploma, Chemical Engineering, Aristotle University, Greece, 1982 (with "Highest Honors")
M. A., Chemical Engineering, Princeton University, 1983
Ph.D., Chemical Engineering, Princeton University, 1989 

Research Interests

Electronic and photonic materials
Biosensors
Chemical kinetics
Transport phenomena
Reactor design
Multiphase flows

Electronic and photonic materials, nanoparticles, biosensors, multiphase flows
Working in the field of nanotechnology, a research team led by Professor T.J. Mountziaris is developing novel techniques for templated growth of compound semiconductor nanocrystals (quantum dots) and nanorods with applications in photonics and clinical diagnostics.

Synthesis of Nanostructured Electronic and Photonic Materials
With the advent of nanotechnology, there is an increased need for the development of processes for controllable growth of nanostructured materials. The current focus of our research in this field is on the growth of compound semiconductor nanocrystals (quantum dots) and nanowires. These are typically single crystalline structures of II-VI semiconductors like CdSe, ZnSe, etc. Quantum dots have unique optical properties, such as size-dependent luminescence, and find applications in optical tagging of biomolecules for clinical diagnostics, high density information storage and solar cells. Nanowires are envisioned as the interconnects in futuristic ultra-high-density integrated circuits. We are using both liquid phase and vapor-phase synthesis routes to synthesize these materials. An important issue that we are pursuing is the control on size and shape by using templates, such as microemulsions for liquid phase synthesis and nano-patterned surfaces for vapor phase synthesis. We are also studying the kinetics and transport phenomena underlying the metalorganic vapor-phase epitaxy of thin films of compound semiconductors (e.g. III-V arsenides and nitrides, II-VI selenides and sulfides) and magnetic semiconductors (e.g. (Zn,Fe)Se and (Zn,Mn)Se). Multi-layer nanostructures of these materials form the basis of advanced optoelectronic devices and futuristic spintronic devices. The ultimate objective of our research is to discover new synthesis routes and develop better reactors that provide superior control on materials properties, while allowing easy scale up for industrial production (Collaborators: Prof. P. Alexandridis and Prof. A. Petrou).

Multi-scale Models of Reaction-Transport Processes
We are studying the underlying transport and kinetic mechanisms during nanostructured materials synthesis by liquid and vapor-phase routes using a combination of stochastic atomistic simulations (e.g., lattice Monte Carlo) and macroscopic simulations (e.g., finite element descriptions of conservation equations). We are also employing "equation-free" techniques to obtain the macroscopic behavior of the reacting systems in time and space using microscopic atomistic simulators. The objective of this work is the development of robust multi-scale modeling approaches that can reveal the fundamental links between macroscopic reactor parameters (temperature, pressure, flow rates, inlet concentrations) and microscopic properties (size, shape, crystallinity). (Collaborator: Prof. I. Kevrekidis, Princeton University).

Development of Sensors for Clinical Diagnostics
We are developing techniques for linking quantum dots to biomolecules, such as DNA fragments, for use in clinical diagnostics. By using cap exchange techniques we are functionalizing the quantum dots with molecules that render them water soluble and we subsequently link them to the desirable biomolecule. By using different populations of quantum dots we are developing multiplexed arrays that can simultaneously detect several molecules. We are also studying the performance of more conventional optical biosensors based on immunoassays using transport phenomena and chemical kinetic descriptions of the underlying antigen-antibody interactions. The objective of this work is the development of optical biosensors with high sensitivity, short response time, robustness, and wide range. (Collaborators: Prof. S. Andreadis and Prof. J.M. Nitsche).

Gas-Particle Flows and Granular Flows
Transport processes involving granular materials are very common in the pharmaceutical and chemical industries. These materials can exhibit both fluid-like and solid-like behavior and the underlying physics are still not fully understood. We are interested in gas-particle flows that are related to fluidization, pneumatic transport, and gravity flow in tubes (standpipes). Standpipes are vital particle transport links in many important industrial processes, like fluid catalytic cracking, and are known to be pathogenic due to instabilities and abrupt changes in the particle flow rate. We are especially interested in understanding the flow regimes and stability of granular flows in vertical standpipes to identify procedures for precisely controlling the particle flow rate and stability of the flow.

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