Crack-resistant vertically aligned graphene film thermal Interface materials enabled by oriented pre-bending for low thermal resistance

Efficient thermal management under low assembly pressure requires thermal interface materials (TIMs) that combine continuous through-plane heat-flow pathways, low contact resistance, and resistance to compression-induced cracking. Here, we report an oriented pre-bending strategy for constructing crack-resistant vertically aligned graphene film (VGF) TIMs. In this architecture, graphene foam lamellae are directionally pre-bent and fixed within an epoxy matrix, forming a compliant vertical network with a built-in deformation allowance before device assembly. The VGF TIMs contain 77.42 wt% graphene and exhibit a through-plane thermal conductivity of 143.54 W m −1 K −1 . The pre-bent lamellar framework also maintains a low contact thermal resistance of 16.6–25.8 mm 2 K W −1 over 10–100 psi by improving surface conformity and suppressing local stress concentration. Finite-element simulations show that, compared with a randomly deformed wavy vertical lamellar structure, the oriented pre-bent architecture suppresses uncontrolled deformation and redistributes compressive stress along preset bent pathways, thereby mitigating bending-induced fracture. Under the same liquid-cooling conditions, VGF TIMs exhibited superior device-level thermal management performance, reducing the steady-state heater temperature to approximately 47 °C at 40 W cm −2 , which is 71 °C lower than the case without TIM and 35 °C lower than the commercial thermal pad. This work establishes oriented pre-bending as a structural design strategy for combining high thermal conductivity, crack-resistant compliance, and low thermal resistance in graphene-based TIMs.