Laser-induced graphene for low-energy manufacturing of composites: Balancing performance enhancement and functional structural material integration

Laser-induced graphene (LIG) presents a promising solution for addressing pronounced through-thickness temperature gradients during composite curing processes when deployed as interlaminar heating elements. However, the structural-mechanical implications of LIG integration within composites and its post-cure multifunctional efficacy remain critically underexplored. This work pioneers the utilization of laser-induced graphene film (LIGF) and laser-induced graphene paper (LIGP) as both interlayer heat sources for in-situ curing and multifunctional interlayers in fiber-reinforced polymer (FRP) composites. Systematic investigations reveal that LIG joule-heating curing achieves over 90 % energy reduction compared to conventional oven-based methods while maintaining cure degrees exceeding 95 %. Notably, LIGP demonstrates superior compatibility as an interlaminar material, enhancing tensile modulus (10.09 %), maximum flexural load (20.93 %), flexural modulus (23.71 %), and propagation mode I toughness (27.3 %). Functional tests reveal that the cured interlayer LIG still provides excellent deformation sensing, electrothermal de-icing, and cure monitoring capabilities. This dual-functional integration strategy establishes a transformative framework for developing energy-efficient, structurally enhanced smart composites.