Research Area #1: A Universal Ligand for Materials by Design:
Particle assembly is a powerful means of achieving a “materials by design” strategy, where a target structure can be first envisioned, then assembled from a tool box of particle-based building blocks. However, current assembly methods are limited by the need to redevelop new ligands or assembly techniques for each type of desired structure; a universal ligand would overcome this limitation and allow for the use of a single set of principles to generate all of these materials by design. My research will achieve this goal by developing a set of modular, polymer-based ligands that combine the beneficial aspects of previous assembly strategies in order to overcome their respective limitations. Because polymer physical properties (e.g. solubility, flexibility) can be readily tuned separately from the rigid inorganic core, this system will enable fundamental insights into how combinations of soft and hard matter behave in tandem. As a result, this new strategy for materials synthesis will allow us to generate architectures with controllable physical properties via the establishment of a universal set of design principles.
Key Concepts: Nanotechnology, Self-Assembly, Soft Matter, Inorganic Nanoparticles, Polymer Chemistry, Photonic/Plasmonic/Mechanical Properties
Potential Applications: Catalysis, Plasmonic/Photonic Materials, Energy Storage
Research Area #2: Matrix-Controlled Particle Assembly:
In order for assemblies of particles to be useful as materials, it is necessary for them to be physically stable in the desired environment of application. This is particularly difficult for low-volume fraction or non-close packed materials, and thus these geometric arrangements are either only stable in solution, or cannot be realized as stable structures at all. In this research, we will examine how replacing traditional solvent matrices with polymer melts can be used to enhance the stability of assembled structures, as well as investigate how this new matrix affects the particle assembly process. Additionally, we will develop methods to allow particle-matrix and particle-particle binding interactions to compete with one another, making the matrix a participatory component of the assembly process. This research will elucidate how particles behave and interact with one another in dense and crowded environments, and how competitions between particle and matrix binding affect the stability of different assembly architectures. The knowledge gained from this work will prove useful not only in understanding the basic concepts of how assembly occurs in different media, but also as an enabling technology for stabilizing useful structures, and as a fundamentally new tool for controlling assembly processes.
Key Concepts: Nanotechnology, Self-Assembly, Structure/Property Relationships, Materials Processing
Potential Applications: Energy Storage, Plasmonically Active Materials, Catalysis
Research Area #3: Hybrid Inorganic/Polymer Hydrogels:
Traditional hydrogels consist primarily of either small molecule or flexible linear polymer building blocks, where the physical properties of gels are determined as a function of their internal structures. In principle, utilizing semi-rigid bottlebrush polymers and/or rigid inorganic materials (both of which have drastically different mechanical properties than traditional linear polymers) should allow for gels that have different material properties (stiffness, porosity, etc.) than those made out of highly flexible building blocks. In this research, we will examine how making gels out of unique organic and inorganic components that are more rigid than typical hydrogel materials affects hydrogel mechanical properties. This work will establish core relationships between the design of hydrogel components and the physical properties of a gel, elucidating a set of principles for synthesizing hydrogels specifically tailored for various applications.
Key Concepts: Hydrogels, Polymer Chemistry, Mechanical Properties, Structure/Property Relationships
Potential Applications: Drug delivery, Cell/Tissue Scaffolding, Energy Storage
Research Area #4: The Materials Science of Nanoparticles as “Programmable Atom Equivalents”
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 nm-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 will utilize both DNA-based particle assembly techniques and top-down lithographic methodologies to explore fundamental concepts of materials science (such as lattice strain, defect structure, thermodynamics and kinetics of bonding behavior, etc.), as well as generate materials where we can precisely study structure-property relationships with nanometer scale ordering in order to develop materials for the aforementioned applications
Key Concepts: Biomaterials, Nanotechnology, Self-Assembly, Soft Matter, Structure/Property Relationships
Potential Applications: Fundamental materials science at the nanoscale, Plasmonic/Photonic Properties of Materials