Organic Coatings and Interfacial Characterization
Mechanisms of Instability in Surface Initiated ROMP Coatings
Surface-initiated ring opening metathesis polymerization (ROMP) is a coating technology which enables growth in ambient conditions and the formation of >1 µm thick films on complex metal shapes in 15 minutes. These are among the thickest coatings grown by surface-initiated polymerization and are grown >10-fold faster than other surface-initiated chemistries. While these coatings are highly promising for protecting many materials against corrosion by salt and water, they are uniquely unstable towards many common solvents, despite strong chemical linkages. Our research will investigate multiple modes of stabilization of these structures, and elucidate the underlying mechanism for coating degradation.
Coatings for High Speed, High Purity Cell Sorting
Cell-based therapies, where healthy cells are transplanted into a patient to naturally restore biological function, represent an exciting future direction in medical research and clinical care. Critically, current techniques for high-purity cell sorting are time-intensive processes which lack the speed to satisfy the emerging widespread need for purified cells in research. We recently discovered a rapid cell isolation method in which batch size is virtually unlimited and specificity rivals the current methods. Our approach, Antigen Specific Lysis (ASL), selectively coats targeted cells in a temporary protective membrane, then destroys all uncoated cells to yield viable, purified cells. Our work investigates the fundamental mechanisms governing ASL in cellular isolation.
(Left) Polymer coated cells after 10 minutes in deionized water. (Right) Polymer coated cells after 10 minutes in 5% SDS.
Low Density Monolayers
We are developing an adaptable approach towards the formation of low density monolayers of varied functionality and exceptional stability with respect to time, temperature, solvents, and shear. The resulting monolayer structures, termed “click low density monolayers” (click-LDMs), have two distinct phases: a head phase of highly-crystalline structure adjacent to the substrate surface, and a tail phase of lower packing density which interfaces with the environment (Fig 1). Each adsorbed molecule is “Y” shaped, where each unit in the tail phase will be bound to two units of the head phase. We expect the bifunctional nature of the adsorbate to work synergistically with the highly ordered packing of the head phase to provide click-LDMs improved monolayer stability over that of traditional SAMs. The orthogonality of the chemistry will enable a large library of functionalities to be examined from readily-available, inexpensive molecules.
Polymeric Coatings on Biological Substrates
The manipulation of biological function on the cellular and subcellular level holds great potential for innovation in medical diagnostics and treatment, power generation and applied materials. Central to this manipulation is the interface of the biological species and its surroundings. Cells often exist in a naturally immobilized state, and emerging biotechnology will require a similar immobilization for the protection of the cell from shear and immunological attack as well as other hostile conditions. Polymers and organic coatings are obvious choices for biocompatible interfaces as they can mimic the biological environment in structure and chemical functionality and are readily tuned owing to their wide variation in architectures, mechanical properties, surface energy and transport properties.
We are appreciative of all support for our research, including the following groups.