Polymer/metal interfaces, transient

A Dynamic Probe of Tribological Processes at Metal-Polymer Interfaces Transient Current... 

This work describes a new probe of dynamic processes accompanying the tribological loading of metal/polymer interfaces. We instrument the polymer substrate and a conducting stylus to measure the transient electrical currents generated as the stylus is moved across the substrate under normal load. Simultaneous measurements of the lateral and normal forces on the stylus are also performed. Both sets of measurements are readily made on ms to is time scales. To date, we have measured currents accompanying the abrasion of several insulators. 

In describing the components of total joint prostheses and their interaction with adjacent tissues, many authors identify the articulating interface (metal/polymer), the metallic prosthesis - polymethylmethacrylate bone cement interface and the bone cement-bone interface. Unfortunately, the bone cement-bone interface may be transient with a fibrous capsule eventually interposing itself between the bone cement and the bone to create the bone cement-fibrous capsule-bone interface (19,20). As described earlier, the formation of a fibrous capsule around implants is a common occurrence. In the case of total joint prostheses where situ polymerizing methyl methacrylate is used as bone cement, this fibrous capsule formation may be accelerated by the heat of polymerization or the toxicity of the monomer, both of which may lead to localized tissue destruction and cell death (21,22). 

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