Mesoscale Mechanics of Nanoparticle Sheets
Abstract
PROJECT ABSTRACT:The project investigates ultrathin films of closely packed nanoparticles, each comprised of a metallic core coated with a thin shell of short molecules that act as both spacers and linkers. As monolayer sheets, such films represent the ultimate two-dimensional limit of ananoparticle-based material. Interpenetrating molecules from neighboring particles convey remarkably large tensile stiffness and strength to the nanoparticle sheets, resulting in Young~s moduli of several GPa for a variety of different metallic nanoparticle cores and organic shells. The ability of the sheets to form freestanding membranes makes it possible to perform substrate-free measurements and to manipulate planar sheets intothree-dimensional structures. The overall objective of the project is to develop a detailed understanding of thefundamental structure-function relationships that control the unique mechanical properties of nanoparticle sheets. A focus is on the mesoscale properties that enable thedesign of next-generation functional coatings and nanostructured materials. The research combines advanced synthesis of size-controlled nanoparticles with innovative methods for the assembly, characterization and manipulation of nanoparticle sheets. Experimentswill be linked with extensive computer simulations.The project consists of three thrusts. Thrust 1 investigates monolayer sheets on surfaceswith Gaussian curvature. Due to their inorganic-organic hybrid nature, nanoparticle sheets can accommodate large amounts of strain and therefore promise to be well suited for conforming tightly to non-planar surfaces without introducing wrinkles or folds. Defects in the particle configurations will be tracked and their statistics analyzed, thereby testing the limits of applicability of models based on standard elasticity. Thrust 2develops a toolkit to transform planar sheets to 3D structures by bending or folding. This effort employs a combination of ion-beam cutting and electron-beam irradiation to generate spatially localized strain gradients in a controlled manner. Results from this effort are expected to pave the way for new types of nanoscale actuators or surface coatings with adaptive roughness. Thrust 3 investigates the fabrication of ultra-permeablemembranes with nanoscale pores and it explores the potential of these membranes for size- and shape-specific nano-separation and filtration applications. Expected outcomes from the project are new guiding principles that correlate the mesoscale, ligand-mediated interactions between nanoparticles with the overallmechanical properties of the sheets, as well as new experimental protocols to tailor these properties.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 03, 2017
- Source ID
- N000141712342
Entities
People
- Heinrich Jaeger
Organizations
- Office of Naval Research
- United States Navy
- University of Chicago