Flexible polyvinylidene fluoride film with alternating oriented graphene/Ni nanochains for electromagnetic interference shielding and thermal management

y Flexible polyvinylidene fluoride (PVDF) films with various heterogeneous alternating multilayer structure (HAMS) containing high-aligned graphene nanosheets and Ni nanochains were designed for electromagnetic interference (EMI) shielding and heat dissipation applications. Because of the unique structure and highly aligned nanofillers, effective electron and phonon conductive paths were formed in HAMS films with optimal electrical and thermal conductivity of 76.8 S/m and 8.96 W/mK, respectively. Combining the high electrical conductivity and the synergetic electromagnetic loss, as well as multi-level electromagnetic multireflection, the optimal HAMS film with thickness of 0.5 mm exhibits a high EMI shielding effectiveness (SE) of 43.3 dB, showing 98.6% increment compared to homogeneous film (21.8 dB), which can further improve to 51.4 dB when increasing the thickness to 0.7 mm. Simultaneously, the highly concentrated and aligned graphene in alternating layers can contribute to the significant improvement in in-plane thermal conductivity of HAMS films with 14.3% and similar to 1200% increment comparing to the homogeneous film (7.84 W/mK) and pure PVDF (0.69 W/mK), respectively. Considering the outstanding performance and high-efficiency stacking hot-pressing preparation technique, HAMS films with alternating aligned graphene/Ni nanochain layers present a huge potential in practical large-scale application as advanced EMI protection and thermal management materials.