Fabrication and peeling behavior of thermally conductive pressure-sensitive adhesive films with embedded graphite composite patterns

Abstract

Thermal interface materials (TIMs) have been widely employed to address the thermal issues arising in electronics. Given that heat generated at heat sources is dissipated into heat sinks through TIMs, the softer they are, the more efficient the heat transfer is. In this paper, a thermally conductive pressure-sensitive adhesive film (gr-PSA film) in which graphite composites patterns were embedded was fabricated and its thermal conductivity and peeling behavior were investigated. Because of its low storage modulus (2.4 × 104 Pa), a mixture of soft polyurethane acrylate, butyl acrylate, and 2-ethylhexyl acrylate was used to fabricate a pressure-sensitive adhesive. The in-plane and through-plane thermal conductivity of the gr-PSA film were measured as 1.56 (± 0.37) Wm−1K−1 and 0.25 (± 0.03) Wm−1K−1, respectively. The peeling behavior of the gr-PSA tape was investigated by a 90º peel test and the results were compared with simulation results obtained by cohesive zone modeling implemented in the finite element method. Both results show that the peel force oscillated when the gr-PSA tape was peeled. Because the gr-PSA tape comprises alternating stiff and compliant segments, more force is needed peeling when bending the stiff segments.