Speaker: Robert MacFarlane, Massachusetts Institute of Technology (MIT)
Title: Systems-Level Control of Structural Hierarchy
Abstract: Structural hierarchy is a powerful design concept where specific geometric motifs are used to influence material structure across multiple size regimes. These complex levels of organization are typically achieved in the laboratory by manipulating the thermodynamics of chemical bonding between small-scale components to control how they build up into larger length scale patterns. Conversely, complex assemblies in natural systems are commonly achieved through a more holistic approach where not only does structural information contained in molecular building blocks filter upwards to dictate material form at the nano to macroscopic levels, but also that the environment created by the larger length scale features affects the behavior of individual components. Here, we will discuss a new method to synthesize materials in a systems-focused approach that mimics nature’s ability to general complex structural motifs across a wide range of size regimes. This synthesis technique uses nanoscale design handles to deliberately control the multivalent assembly of particle-grafted supramolecular binding moieties, where control over both molecular and nanostructure of material building blocks is then used to manipulate the mesoscale structure of the resulting materials. Assembling materials in this manner therefore expands our ability to program hierarchical ordering at the molecular, nano, and macroscale simultaneously.
Bio: Rob Macfarlane joined MIT in 2015 as a faculty member in the Department of Materials Science and Engineering, where he is currently the Paul M. Cook Assistant Professor. Rob obtained his PhD in chemistry in 2013 at Northwestern University, followed by a Kavli Nanoscience Institute post-doctoral fellowship at Caltech. He is an expert in the fields of self-assembly, nanocomposites, materials chemistry, and nanomaterials processing, and his research lab sits at the interface of these fields to establish new materials fabrication techniques. His lab’s research focuses on developing systems-level approaches to materials synthesis, where structural features at the molecular, nano, and macroscopic length scales act together as integrated design handles to control a material’s hierarchical ordering. These materials range from inorganic nanoparticles to synthetic polymers to biomacromolecules like DNA, and the structures have potential utility in diverse applications ranging from energy storage to protective coatings.