Friction on charged and neutral soft natural matter surfaces

Abstract

Objective: In the paper, the authors examine the surfaces of the bovine articular cartilage at varying pH solutions by measuring the friction coefficient.Design: Cartilage pairs with the same sign of charges have been investigated: positively (+/+), negatively (-/-) and neutral (IEP) cartilage surfaces under aqueous buffer solution.Results: We present evidence that the (cartilage/cartilage) pair charged with the identical positive or negative charge density exhibited the same value of the friction coefficient. Interfacial energy the "bell-shaped curve" of spherical lipid bilayers a model membrane described regarding the electrostatic repulsion of the cartilage surfaces is supporting friction curve interpretation. Conclusion:We found that charged surfaces had a smaller friction coefficient than neutral (cartilage/cartilage) pair. It was found that the friction was mostly dependent on the charge densities of the cartilage surface and the friction between charged surfaces is lower than that of neutral cartilage surfaces.