The Macfarlane Lab

Nanocomposites enable the integration of nanoscale phenomena into functional, macroscopic materials by carefully controlling the composition and spatial configuration of the constituent components. Self-assembly of smaller building blocks (tectons) is a powerful method for synthesizing nanocomposites because it can precisely dictate nanoscale structure in a scalable manner. Our group has developed a set of building blocks, Nanocomposite Tectons (NCTs), which are themselves organic/inorganic nanocomposites capable of self-assembling into larger, ordered structures. Each NCT consists of an inorganic nanoparticle grafted with a dense layer of polymer chains that terminate in molecular recognition units capable of programmed supramolecular bonding.

The modular nature of NCTs provides multiple design handles to alter the composition, size, and thermodynamics of assembly to introduce new geometric arrangements and properties of the resulting material. As a result, these structures have potential application in the areas of plasmonics and photonics, heterogeneous catalysis, and energy storage.

DNA-coated nanoparticles are a powerful synthon for materials development, as nanoparticles possess size, shape, and composition dependent physical properties, and the sequence dependent recognition properties of DNA allow one to precisely organize particles into well-defined crystalline lattices with nanometer-scale precision. The ability to generate lattices with precise control over both the identity of the particles as well as their positions in three-dimensions has implications for developing materials for applications in areas ranging from photonics to catalysis to energy generation and storage.

In this research area, we utilize both DNA-based particle assembly techniques and top-down lithographic methodologies to explore fundamental concepts of materials science (such as thermodynamics and kinetics of epitaxial deposition, thickness-induced melting suppression, lattice strain, defect structure, dewetting, etc.) using these nanoscale “atom equivalents”. We also utilize these building blocks to generate materials where we can precisely study structure-property relationships (such as their mechanical property, asymmetric reflectivity, shape-induced plasmonic response, etc.) in structures that have nanometer scale ordering, leading towards practical applications such as micro-mirrors in ultra-flat optical devices.