Preparation of superhydrophobic conductive micro/nano-graphite/PDMS films on paper by simple spraying method

Paper-based materials are widely used in various fields due to their advantages, such as environmental friendliness and sustainability. However, the highly hydrophilic nature of the cellulose that makes up paper-based materials limits their use. In this paper, micron/nano-graphite/polydimethylsiloxane (PDMS) coatings with excellent superhydrophobic and conductive properties were prepared on the surface of filter paper by a simple spraying method. A mixture of micro-graphite and nano-graphite was used to form a multistage rough structure on the surface of the filter paper by spraying, and the low surface energy PDMS enhanced the adhesion of the micro-graphite and nano-graphite on the surface of the filter paper. The results showed that the samples possessed the best superhydrophobic properties when the ratio of micro-graphite to nano-graphite was 1:1, at which time the contact and rolling angles of the samples were 165.4 degrees and 3.2 degrees, respectively. The prepared superhydrophobic samples have good bounce and self-cleaning properties, while the samples have good mechanical stability and chemical resistance. Additionally, due to the conductivity of micro-nano-graphite, both particle sizes closely contact the sample surface, creating a conductive network. With a 1:1 ratio of micro- and nano-graphite, the coating exhibits minimal resistance at 1.89 K Omega, and the sample maintains stable conductivity even underwater. The above properties greatly extend the application range of paper-based superhydrophobic materials.