Bio-inspired multifunctional composite phase change films for synergistic thermal management and microwave absorption

Wearable electronics devices face dual challenges of thermal failure and electromagnetic interference (EMI). While phase change materials (PCMs) offer efficient thermal management material, their inherent limitations-low thermal conductivity, rigidity, and limited electromagnetic loss hinder practical applications. Flexible composite PCMs (FCPCMs) with multifunctional integration present a promising solution. Herein, mimicking the lamellar “brick-and-mortar” architecture of natural nacre, a flexible phase-change composite film featuring a multi-dimensional hierarchical encapsulation structure is ingeniously engineered for synchronous thermal management and microwave absorption. This bioinspired design incorporates polyethylene glycol (PEG) within a robust scaffold of one-dimensional (1D) aramid nanofibers (ANFs), zero-dimensional (0D) nanodiamonds (NDs), and two-dimensional (2D) single-layer graphene (SG), bonded by waterborne polyurethane (WPU). The resulting nacre-mimetic, multi-dimensional architecture ensures exceptional encapsulation of PEG, effectively suppressing leakage while maintaining high phase-change cycling stability (>300 cycles). The optimized composite achieves synergistic performance: enhances thermal conductivity (1.13 W/(m·K)) strong microwave absorption performance (-41.36 dB), high phase-change enthalpy (104 J/g) and mechanical performance (tensile strength: 15.10 MPa). This work provides a platform for next-generation smart thermal-regulation systems and anti-interference electronics.