The thermomutability of single-walled carbon nanotubes by constrained mechanical folding

The thermomutability of single-walled carbon nanotubes (SWCNT) with an ultrahigh aspect ratio has been systematically investigated by molecular dynamics simulations. A constraining matrix is necessary to transform the tube-long Euler instability to a localized cross-section flattening which can effectively hinder phonon transportation at the throttling kinks. A thermal conductivity reduction of ~ 50% was obtained for a 100 nm (5, 5) SWCNT when embedded in a compliant matrix (E ~ 0.4 GPa). An even larger reduction (~80%) can be achieved for a stiffer matrix (40 GPa). The thermal conductivity decreases abruptly at the buckling portion which further develops into folding and connected spirals. The constrained mechanical folding is highly desirable for realizing ultra-sensitive thermal sensors or switches.