Discovery of Nanoscale Folding Properties of Atomically-Layered Materials by Atomic Lattice Interferometry and Simulation

Brown University, Providence RI

Investigators

Abstract

This award supports fundamental research on the mechanics of atomically-layered materials. When one folds atomically-layered materials, only a few atoms thick, unprecedented nanoscale material properties can manifest. For example, the lateral compression of graphene, a multi-layered material of carbon atoms, leads to patterns of sharp ridges. Along the ridges of these atomic-scale crinkles a strip with the width of a few atoms is electrically charged. The strip of charges attracts oppositely charged molecules. The controlled deformation of such a graphene crinkle network potentially regulates adsorption of biomolecules and, consequently, the adhesion of biological cells to solid surfaces in real time. The research results would enable various applications for atomic-scale materials engineering in nanotechnology, and molecular engineering in biomedical technology. This includes but is not limited to bio-adhesion control for cancer treatment and molecular manipulation techniques for genetic engineering. Further, the results would have impact on nano- and micro- metrology, and environmental filter and sensor technology. The scientific tool, the atomic lattice interferometer, will enable observation of the behavior of advanced nanostructures, not only for scientific research, but also for education in both life and physical science and technology. An outreach program will be developed in the Institute of Molecular and Nanoscale Innovation at Brown University. This program will educate students from underrespresented groups in STEM through summer internship programs, introduce them to real world problems with an industrial seed project. The PI will develop new course materials on the mechanics of folding. Continuum/ab-initio and experimental hybrid analyses of atomic-layer crinkle structures and associated flexoelectric characteristics in graphene or graphene-analogous materials will provide a fundamental understanding of the mechanical behavior, as well as of the electronic states of a deformation jump like a crinkle ridge. The PI's laboratory experimentally observed such crinkle networks for the first time by using a newly invented atomic lattice interferometer. This novel interferometer opens up unique experimental capabilities of measuring atomic-scale surface deformations over a wide field of view. The resultant understanding of the electro-mechanical behavior will establish a systematic framework for regulating molecular adsorption and cellular adhesion for biomechanics research. In addition, many important multi-scale modeling and experimental capabilities, such as high performance computing and testing of atomic-scale structures, will be advanced. Furthermore, mathematically difficult and historically unsolved bifurcation problems of ruga (wrinkle, crease, fold, ridge and crinkle) mechanics will be unraveled.