Anisotropically High Thermal Conductive Natural Rubber/Short-Cut Carbon Fiber Composites Prepared by One-Step for Localized Heat Sources Thermal Management

Abstract

Abstract: The rapid development of next-generation portable electronic devices, including electronic skins, necessitates the use of flexible materials that possess efficient in-plane heat dissipation and superior mechanical properties. Short-cut carbon fibers (SCFs) have emerged as promising fillers due to their high thermal conductivity, strength, and cost-effectiveness. However, achieving a highly oriented structure of SCF inside the matrix, which fully capitalizes on the thermal conductivity of these one-dimensional (1D) fillers, remains a pressing challenge. In this work, we introduce a remarkably simple and integrated approach to fabricate natural rubber/oriented short-cut carbon fiber (NR/O-SCF) composites featuring an anisotropic thermal conductivity network in a single step. This method utilizes unidirectional ice templating to generate ice crystals that guide the orientation of SCFs within the NR matrix. Herein, the ice template approach demonstrates its suitability as an ideal method for preparing fillers with highly oriented structures in "ice template compatible polymers" like polystyrene foam and polyvinyl alcohol gel. The NR/O-SCF composites demonstrate a maximum thermal conductivity of 2.71 W m-1 K-1  on the face, 1706% higher than that of pure NR, thereby enabling superior thermal management capabilities for localized heat sources. Furthermore, these composites retain a substantial proportion of their compression properties in comparison to pure NR. The straightforward and feasible approach proposed in this work offers a pathway to achieve a high degree of filler orientation within the matrix, effectively addressing the challenge of thermal management for localized heat sources in a more cost-effective and efficient manner.

Keywords: Anisotropic thermal conduction network, Short-cut carbon fiber (SCF), In-plane thermal conductivity, Thermal management of localized heat sources, Ice template method