Electrical characterization of flexible CNT/polydimethylsiloxane composite films with finite thickness

Abstract Two group of CNT/polydimethylsiloxane flexible films were spin coated by using two kinds of CNTs with different length and same aspect ratio. Results shows that the film conductivity decreases as the film thickness decreases, while the film thickness is less than 40 times of the CNT length. And the downward trend of two groups of films are different. Besides, CNT junctions with structure distortion were well observed experimentally. By introducing CNT structure distortion, film size effect and interface constraint effect into the percolation network model, Monte Carlo simulation results can well fit the experimental data. Simulation results show that the decrease in film conductivity is mainly due to the film size effect. And the interface constraint effect is more obverse for the film prepared by long tubes, which lead to a different downward trend between two groups of films. The influence of some important experimental parameters on the film conductivity are also obtained through calculation. All of these experiment and simulation results could benefit for design of flexible conductive films.