A low-cost method for producing high-performance nanocomposite thin-films made from silica and CNTs on cellulose substrates

We show that thin films of silica loaded with 22 wt% of carbon nanotubes (CNTs) can be deposited on cellulose substrate via the sol–gel route by a well-controlled process. The high loadings are obtained by airbrush spraying of a diluted sol solution (which contained a much smaller concentration of CNTs) followed by drying at 200 °C. The films are nearly continuous despite the fibrous structure of the substrate. The high degree of connectivity of the stranded structure of the CNTs yields a specific electrical conductivity of 3 × 10³ Ω⁻¹ m⁻¹. In contrast, films made with high loadings of carbon black have poor electrical conductivity. Results from mechanical tensile tests of samples are also reported. This economical method of producing CNT dispersed thin films could find application in catalysis, as electrodes in fuel cells and batteries, and in sensor technologies.