CDS&E: Design Principles for Ordering Nanoparticles into Super-crystals

Iowa State University, Ames IA

Investigators

Abstract

NONTECHNICAL SUMMARY The Division of Materials Research, the Division of Chemistry, and the Division of Advanced Cyberinfrastructure contribute funds to this award which supports computational research, computer algorithm and software development, and education to develop software that will predict properties of materials made from a class of nanoparticles - tiny particles with dimensions some 10,000 to 100,000 times smaller than a human hair and in this case include long chain molecules, such as DNA, in their structure. The nanoparticles are arranged in regular spatially periodic arrays known as superlattices. Because of the internal structure of each nanoparticle, these nanoparticle superlattices can have unique physical and chemical properties that are difficult or impossible to achieve with ordinary crystals of atoms and simple molecules. Understanding nanoparticle superlattices can lead to the ability to design light but very strong materials, engineer efficient solar or hydrogen cells or identify and destroy cancer tumors, just to name a few. The research focus of this award is to develop a comprehensive theoretical and computational framework for the prediction of the structure, dynamics and properties of nanoparticle superlattices. The PI will combine new theories with start of the art computational tools developed by the PI. The research will include close collaborations with leading experimental groups. The expected impact of the research is to advance toward the capability to predict the properties of nanoparticle materials and to design novel nanoparticle materials and interfaces with new or given properties. The PI will collaborate with the SUCCESS program of the Des Moines public school system. Students are identified and referred to the SUCCESS program based on the DMPS Early Indicator System which identifies students who are at risk of dropping out of school due to poor attendance, lack of identification to school/behavior, poor or failing grades, and low achievement scores. The PI will organize several STEM activities for SUCCESS kids, both in Des Moines and Iowa State University, and also convey that pursuing a college education is a very valuable goal. Other educational activities include recruitment of high school students for STEM fields, making computational tools available to non-specialists, and mentoring of undergraduate and graduate students. TECHNICAL SUMMARY The Division of Materials Research, the Division of Chemistry, and the Division of Advanced Cyberinfrastructure contribute funds to this award which supports computational research, cyberinfrastructure development, and education focused on developing a computational framework that makes it possible to design materials made of nanoparticle superlattices. The PI's will focus on nanoparticles that have grafted ligands comprised of hydrocarbon chains or DNA. The research combines theory and algorithms with experiments to develop a realistic description of the dynamics of formation and thermodynamics of nanoparticle superlattice materials. The goals of this project will be achieved by developing HOODLT, software for Graphics Processor Units (GPUs) that facilitates the exact calculation of free energies, which will be in turn used to predict nanoparticle superlattice structure with simple and universal potentials. The PI will also develop HOOSRIS, software for GPUs that will implement a new microscopic theory for the interaction between the capping ligands grafted to the nanoparticles, which determine the actual structure and many of its physical properties. The role of two-body versus many-body potentials will also be investigated. The last goal of the project is the combination of these developments to the prediction of superlattices with given and/or new structural and physical properties. Although the project is mostly focused on nanoparticles where the capping ligands are hydrocarbons, the methods are general and can also be applied to DNA mediated programmable self-assembly or other strategies. The PI has a long commitment to promoting STEM activities for under-represented groups and minorities. As part of this project, a series of hands-on activities, focused on materials and nanomaterials for airplanes, will be carried out with kids from the SUCCESS program of the Des Moines public school. Rigorous evaluation and assessment on the impact of these activities will be carried out every year, and the activities modified accordingly. Other broader impact activities include making software available to the broader community, both for technical and non-technical audiences. The project will also support and mentor graduate and undergraduate students.