Nanoscale friction: Sliding charges

Robert Szoszkiewicz and Elisa Riedo state that multiwalled boron nitride nanotubes are found to exhibit ultrahigh interlayer friction as a result of their ionic character in contrast to the ultralow friction that exists between carbon layers in multiwalled carbon nanotubes. They state that researchers have attached the outer tubes of individual multiwalled nanotubes to a nanomanipulator on one side and to a sensitive tuning-fork force sensor on the other measure the forces necessary both to tear apart the outer tube and to slide the resulting two pieces against the inner tubes. The researchers have been able to calculate variations in stiffness and dissipation forces during the stretching, fracture, and telescopic sliding of the fractured layers in multiwalled carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs).