Fundamental Investigations of the Tribological Properties of Biological Interfaces

The objective of the proposed program is to understand the fundamental nature of forces existing at solvated polymer-polymer and protein-terminated polymer-polymer interfaces under shearing conditions, thereby allowing the future design of biological/bioinspired tribological systems lubricated by aqueous solutions. The proposed experimental program will be aimed at measuring interfacial forces over a range of length scales, for sets of systematically prepared and well-characterized polymer and biopolymer interfaces. This program will also explore the influence of solvent conditions on the measured interfacial interactions. The proposed program will explore the role of polymer architecture (composition and structure) in determining the adsorption, load-bearing, and frictional properties of self-assembling waterborne organic coatings. It will also examine the lubricious properties of a number of different adsorbed proteins, suspected to be tribologically active in biological systems. The fundamental goal of the program is to elucidate the modes of interaction between polymer surfaces (penetration, repulsion, compression) and the role of solvent (related to polymer swelling and conformational changes) in modifying interactions between the polymer surfaces. The applied aim of the program is to provide design criteria and performance limitations of low-friction biological and/or bioinspired interfaces.