Non-Linear Thermal Conductivity Enhancement in Nanocomposites with Aligned-Cnt Implementation

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. 1 Introduction Carbon nanotubes (CNTs) have been expected to enhance thermal conductivity in various materials including composites, for applications such as thermal interface materials. However, the thermal properties of bulk CNTs and CNT composites tend not to achieve the high values of individual nanotubes. Factors that cause such scaling effects include CNT morphology (length, alignment, entanglement, etc.), and inter-CNT/CNT-medium boundary properties. It is critical to evaluate and minimize these effects. However, structure-property relationships are not yet well understood, and thus effective use of CNTs has not been achieved for the majority of currently existing CNT polymer composites. In this work, consistent CNT samples with well-controlled morphology were fabricated by embedding aligned CNTs in polymer to create aligned CNT polymer nanocomposites (A-CNT-PNCs), as shown in Figure 1. A-CNT-PNCs were thoroughly evaluated for their anisotropic thermal properties, and a non-linear increasing trend of thermal conductivity has been observed with increasing CNT volume fraction (v CNT). This newly identified trend was understood through comparison