Hyperbranched lignin nanoparticles-enabled nanohybrid film for high-performance electromagnetic interference shielding and dual-mode thermal management

Electromagnetic interference (EMI) becomes a critical environmental and health concern with the proliferation of numerous electronic devices. However, achieving uniform dispersion and alignment of magnetic and conductive nanofillers to prepare EMI shielding films remains challenging. In this study, a bio-based multifunctional nanohybrid film, namely CNFs/MXene/T-Fe₃O₄/H-LNPs (CMFL), was constructed by integrating hyperbranched lignin nanoparticles (H-LNPs), cellulose nanofibrils (CNFs), MXene, and tetraethyl orthosilicate (TEOS) modified Fe₃O₄ (T-Fe₃O₄). It is hypothesized that the hydroxyl-rich H-LNPs, serving as effective dispersants, facilitate the uniform dispersion of T-Fe₃O₄ through electrostatic repulsion. Furthermore, these H-LNPs, acting as nano-bonding agents, not only promote the ordered alignment and interfacial bonding of MXene lamellae, but also endow the resultant CMFL film with excellent mechanical properties with tensile strength of 41.89 MPa. Thanks to the synergy of polarization, conduction, and hysteresis losses, the optimized CMFL film sample can achieve 61.3 dB of EMI shielding effectiveness at a thickness of 67 μm. Moreover, the nanohybrid film demonstrates dual-mode thermal management enhanced by photothermal conversion and Joule heating effects. It can rapidly heat to 76.1 °C under 1.0 kW·m⁻² of solar irradiation and stabilize at 68.3 °C under a 3 V input. This study offers a sustainable approach to developing advanced bio-based materials for EMI shielding and thermal management applications.