The coordinated buckling of carbon nanotube turfs under uniform compression

Abstract

Complex structures consisting of intertwined, nominally vertical carbon nanotubes (CNTs),referred to as turfs, have unique properties that arise from their complex nanogeometry andinteractions between individual CNT segments. For applications such as contact switchesfor electrical or thermal transfer it is necessary to understand the properties that arise fromthe collective behavior of an assemblage of CNTs rather than the properties of a singletube. In this study, the mechanical response of turfs bonded to substrates undercompressive loading is demonstrated experimentally; coordinated alignment and bucklingtakes place under uniform loads. The mechanical response of turf structures providessome surprising results regarding parameters that control permanent deformationand buckling in assemblages of nanostructures; buckling of the turf structure iscontrolled by the height and effective modulus of the turf, but not the aspect ratio ofthe structure. We present and verify a model which describes the coordinatedbuckling phenomena relevant for applications such as CNT turfs for thermal transfermedia.