Open questions about polymer friction

Concept of polymer friction coefficient or friction normalized load explains many sliding conditions, while there are some fundamental understandings that exists of how energy dissipated in sliding couples force a squeezing phenomenon between the sliding surfaces. The friction problem is distinctly different from the extensive mainstream focus on equilibrium properties in polymer science. Polymers are used ubiquitously to control friction and wear but with insufficient recognition that their physical responses differ from those of small molecules. Directional friction and confinement offer various ways to align molecules. Decoupling, which can cause friction forces to remain small even as normal forces become large, constitutes an approach to minimizing friction that is particularly well-adapted to polymer systems. The thick end-attached polymer layers also offer useful sacrificial layers in minimizing wear and degradation of the solids beneath them.