Abrasive Wear of Polymer Fibers Investigated by Reciprocal Scratching in an Atomic Force Microscope

Three-dimensional (3D) woven fabrics have been considered by biomedical researchers to be used as load-bearing surfaces in joint and ligament replacements. In this regard, wear is a crucial phenomenon that determines material failure as well as biological response of body to wear debris. The current study evaluates various microscale screening methods with the aid of atomic force microscopy (AFM) for biocompatible polymer fibers that are used in 3D woven fabrics. Fibers in mono- and multi-filament forms were subjected to indentation, scratching, and line wear testing in dry and soaked conditions, and the effect of key parameters such as applied normal load, sliding velocity, and number of wear cycles was investigated. The area of worn material was determined by geometric approximation superimposed on the measured residual scratch of line wear. Moisture was found to lower the indentation hardness of some fibers while increasing the hardness of others. Line wear results clearly suggest ultrahigh molecular weight polyethylene (UHMWPE) to be the primary material for further investigation and that monofilament fibers should be avoided.