New Materials Inspired By Biopolymers

Research in the McDonald group will focus on the development of polymers as tailorable nanomaterials with programable self-assembly, nanostructure, and reactivity. The core philosophy of this program is to mimic the precise chemical tailoring that enables the function of nature’s assembled and reactive organic materials. Along this paradigm, research directions can be divided into two primary areas, Area 1. Polymers as Hierarchically-Structurable Soft Materials and Area 2. Polymers as Enzyme Mimetics for Sustainable Transformations. Work in Area 1 will create new opportunities for solutions to critical challenges in the areas of tissue engineering, biosensing, and conductive materials, while Area 2 will yield systems to address global challenges areas related to the plastic economy and bio-renewable fuels

Area 1. Polymers as Hierarchically-Structurable Soft Materials

Nature’s structural materials, such as wood, silk, tendon, and bone, possess mechanical strength and flexibility while being remarkably light.  This array of properties has proven impossible to create in a conventional top-down materials engineering regime. Nature realizes these properties through bottom-up hierarchical ordering. Such ordering in these fibrillar materials occurs by the entropy-driven spontaneous arrangement, i.e. liquid crystallinity, in highly crowded mixtures of fundamental building blocks. In the case of collagen, the result of this process are intermediate structures, fibrils that undergo further ordering on the meso- to macro-scales and cross-linking to yield tissues. A grand challenge is to synthetically recapitulate this multiscale hierarchical ordering to construct materials with programable interactions and thus assembly. Towards this, we will develop a modular platforms for tailorable nanoscale building blocks to yield programmable ordered materials. We intend to develop new opportunities for: the design and preparation of ultra-robust soft materials, synthetic materials able to recapitulate the multiscale biofunctions of native structural tissues, photonic sensing schemes for point-of-care devices, and nanostructured conductive carbon materials.

Area 2. Polymers as Enzyme Mimetics for Sustainable Transformations

The sustainable generation of fuel and plastics are among the most critical global challenges facing modern society. Efforts to address these critical issues often rely upon catalysis, or the use of chemical entities to lower the energy required to achieve the desired reaction. In this context, enzymes offer great inspiration as perform rapid and selective reactions, often with highly reactive intermediates, in aqueous media. This exquisite reactivity is achieved by the precise spatial arrangement of chemical functionality. While enzyme catalyzed transformations have been widely developed, a substantial limitation is the considerable effort and resources required to expand their reactivity and subsequently scale for broad application. Homogenous catalysis with small molecules is a well-developed field that has yielded a plethora of useful reactive motifs,  but often is unable to match the reactivity of enzymes. To address this considerable gap, we intend to integrate the unique aspects of polymeric materials, such as immobilizability, porosity, and facile incorporation of chemical functionality, with reactive motifs from well-developed homogenous catalysis to yield new catalyst systems that provide transformations unrealized in either small molecule or enzymatic catalytic regimes.