Atomic Scale Design of Nanostructures Using In Situ Characterization-Based Kinetic Models

Virginia Polytechnic Institute And State University, Blacksburg VA

Investigators

Abstract

Atomic Scale Design of Nanostructures Using In Situ Characterization-Based Kinetic Models Nanomaterials have properties that depend on their size, shape, and composition, and have the potential to create technological advances in applications with significant societal impacts in renewable energy, communication and medicine. However, designing nanoparticles with specific, desired sizes and shapes remains a grand challenge and a trial-and-error approach is still often employed to make nanoparticles with the appropriate size and morphology. To reduce the number of demanding and costly laboratory trials, a fundamental understanding of the synthesis mechanisms, coupled with predictive models, is required but currently is lacking. In this project, Dr. Karim and Dr. Lu are developing predictive kinetic models based on detailed chemical information obtained from "watching" metal nanoparticles grow using microreactors and advanced characterization techniques. The work provides opportunities for graduate and undergraduate students to learn advanced characterization tools and to participate in cutting edge nanoscience research leading to major technological advances. The Macromolecular, Supramolecular and Nanochemistry Program funds Dr. Karim's and Dr. Lu's research at Virginia Polytechnic Institute and State University where they are developing a microfluidic nanoparticle nucleation and growth reactor with in situ nanoparticle characterization capabilities. The unique combination of techniques integrates thermodynamics, kinetics and advanced in-situ characterization tools to develop a methodology for enabling the a priori design of metal colloidal nanoparticles with specific sizes and shapes. Drs. Karim and Lu use their microfluidics methodology to follow the nanoparticles synthesis with millisecond time resolution using in-situ X-ray spectroscopy and dynamic light scattering to determine the synthesis mechanisms and rates. The molecular structures and interactions between the metal, ligands and solvent are measured by a combination of techniques and are used along with the nucleation and growth kinetics to develop thermodynamically consistent kinetic models capable of predicting the evolution of precursors into nanoparticles during the nucleation and growth. The work focuses on colloidal palladium nanoparticles and the formulation of models used to predict the experimental conditions for specific nanoparticle sizes, size distributions and morphologies.