Fundamental studies of adhesion, friction and lubrication are important for understanding cell adhesion, colloidal stabilization, nanomolding, nanofabrication, and drug delivery. Many biological systems demonstrate superior adhesion and lubrication properties; for example, cartilage in human joints can withstand pressures on the order of ten atmospheres and have remarkably low friction coefficients. A unique feature of these biomaterials is that they consist of bio-macromolecules with charged groups. This award supports research and training of graduate students in modern analytical and computational methods with application to adhesion, friction and lubrication in biological and polymeric systems. The main goal of this research is to develop a fundamental understanding of the role of electrostatic interactions in adhesion and friction in biological and biomimetic polymeric systems. This will be achieved through a synergistic approach combining theoretical and computational techniques. The predictions of the theoretical models will be tested in computer simulations and verified experimentally through collaboration with experimental research groups in the US. This project will have an impact on science and technology of materials design with desired adhesive and lubricating properties.
This project will also provide special opportunities for involvement of graduate and undergraduate students in cutting-edge research. Mentoring of students is integrated into every aspect of the research. Graduate students will work with undergraduate students in physics, chemistry or chemical engineering, as well as with talented high school students. This experience will prepare them for future STEM careers.
Many biological systems demonstrate superior adhesion and lubrication properties. A unique feature of these biomaterials is that they consist of bio-macromolecules with ionizable groups. In aqueous solutions, properties of these materials are influenced by electrostatic interactions between ionized groups, by interactions with surrounding media, and by the ionic strength of the solutions. The main goal of this research is to understand the specific role of electrostatic interactions on adhesion and lubrication in biological and polymeric systems. This will be achieved through a combination of molecular dynamics simulations, self-consistent field calculations, and scaling analysis. These techniques will be used to develop a model of lubrication for the glycoprotein-collagen network layer covering cartilage surfaces. Theory and simulations will be used to study the system's static and dynamic properties as a function of salt concentration, solution pH, fraction of charged groups, molecular architecture, and sliding velocity. The overarching objective of this research will be to understand the effect of dielectric discontinuity on adhesion and friction at the nanoscale. The predictions of the theoretical models will be tested in computer simulations and verified experimentally through collaboration with experimental research groups in the US. This project will have an impact on the science and technology of materials designed with desired adhesive and lubricating properties.
The proposed research will also offer special opportunities for involvement of graduate and undergraduate students in cutting-edge research. Mentoring students is integrated into every aspect of the proposed research. The results of the proposed research will be incorporated into graduate level and special topics courses.
