Ultra-thin and highly flexible silver fractal dendrite/polyvinylidene fluoride composite film for efficient electromagnetic interference shielding

With the electronic products move towards to flexibility, miniaturisation and high frequency, conductive polymer composites (CPCs) with ultra-low thickness, outstanding electromagnetic interference (EMI) shielding effectiveness (SE) and excellent mechanical property are urgently needed. In this work, silver fractal dendrite/polyvinylidene fluoride (AgFD/PVDF) composite films featured with double structures (defined as two-step films) were fabricated by depositing an AgFD layer followed by the incorporating of PVDF. Thanks to the 3D fractal structures of AgFDs and highly efficient conductive network, the as-prepared two-step films exhibit high electrical conductivity of 4.18 x 104 S.m(-1) at only 10 wt% AgFD loading and about 4.18 x 10(5) S.m(-1) at 40 wt% loading. The excellent electrically conductive property endows the two-step films to achieve remarkable EMI SE of 46.8 dB in X-band and 42.7 dB in Ka-band at 10 wt% loading with thickness of 27 mu m, and 83.3 and 105.0 dB with thickness of 33 mu m as the AgFD loading up to 40 wt%, respectively. The two-step films also show high near-field EMI SE values of 46.9 similar to 61.4 dB, which fully meets the practical commercial requirements. Additionally, the two-step films possess high flexibility and mechanical strength. Considering the outstanding electrically conductive, EMI shielding performances and excellent mechanical property, the two-step composite films present a huge potential for practical applications as high-efficient EMI protection.

Automated summary

With the development of electronic products towards flexibility, miniaturization and high frequency, the demand for conductive polymer composites (CPCs) with ultra-low thickness, outstanding electromagnetic interference (EMI) shielding effectiveness (SE) and excellent mechanical properties is growing. In this study, a double-structured silver fractal dendrite/polyvinylidene fluoride (AgFD/PVDF) composite film was successfully fabricated. The film exhibited high electrical conductivity and remarkable EMI shielding performance, as well as good mechanical strength, indicating its great potential for practical applications in high-efficient EMI protection.