Silver-based conductive films on the filter paper template with the interfacial aid of PEI

Technological advancements in flexible and wearable electronics have driven a boom in high-performance flexible electrodes. In this study, a simple and low-cost bio-inspired filter paper (FP) template method using the interfacial-aided polyethyleneimine-functionalized filter paper (FP-PEI) was developed to fabricate highly flexible silver-based conductive films. The FP was modified through amination to obtain FP-PEI with the rigid cellulose backbone and the flexible side chain of grafted amino groups, which played a key role as an interfacial layer during the chemical deposition of fractal-structured silver particles (FSSPs). The naturally porous and rough network structures of FP templates provided structural support and network for the deposition of conductive materials. In addition, the high porosity of FP facilitated the effective transfer of electrons, and its nano- or micro-scale rough surface structure promoted the formation of strong adhesion between the cellulose substrate and the conductive layer, which was crucial for the conductive stability of the device. The obtained conductive films (FP-PEI/FSSPs) exhibited a low sheet resistance of 1.47 Ω sq −1 , a conductivity of 3401 S m −1 , and good mechanical properties with a stress strength of 6.17 MPa. Moreover, FP-PEI/FSSPs exhibited a stable electrical conductivity (the sheet resistance only increased by 0.06 Ω sq –1 through 500 bending cycles), thermal stability (the maximum thermal decomposition rate increased from 349.3 to 357.8 °C), and oxidation resistance (the sheet resistance increased by only 0.04 Ω sq –1 after FP was exposed to the air for 15 days). The results indicate that FP-PEI/FSSP conductive films can be a potential green flexible electronic material. Graphical abstract