Constructing a stable high conductive network: Exploring AgNW distribution in bacterial nanocellulose for tunable...

The distribution of structural and conductive nanofillers within polymer matrices is of paramount importance for developing effective electromagnetic interference (EMI) shielding materials. In this study, a stable conductive network of silver nanowires (AgNW) was constructed in a bacterial nanocellulose (BNC) matrix using a modified step-by-step in situ biosynthesis method, resulting in both discontinuous and continuous gradient distributions of AgNW within the BNC. Additionally, the thickness and porosity of the AgNW/BNC composites were controlled through mechanical compression. The high and stable conductivity of the AgNW/BNC can be primarily attributed to the effectively entangled and tightly interconnected networks formed between the BNC nanofibers and AgNW. The gradient distribution of AgNW in BNC creates a low-reflection surface, which facilitates the entry of electromagnetic waves into the material and increases their propagation path within the structure. As the spacing between AgNW/BNC conductive layers increases, resulting in markedly enhanced electromagnetic wave attenuation. Although reduced porosity due to AgNW/BNC composites compression may negatively impact EMI shielding, the significantly increased conductivity enhances shielding efficiency when the material thickness exceeds the skin depth. Overall, the EMI shielding performance of AgNW/BNC can be tailored by controlling the distribution and porosity of the conductive filler within the BNC matrix.