In-situ sol-gel synthesis of zirconia networks in flexible and conductive composite films

The conductive and stretchable films with improved hardness are suitable for the fabrication of flexible electronic devices. This study describes the sol-gel technique to prepare a novel conductive and flexible film consisting of epoxidized natural rubber (ENR), doped polyaniline (PD) and zirconia. The zirconia networks were directly synthesized in-situ in ENR/PD solution and flexible conductive composite film with improved hardness was obtained. The morphology study revealed the size of PD decreased significantly from 77.89 +/- 43.95 nm to 4.32 +/- 1.13 nm and highest electrical conductivity of 1.9 x 10(-3) S/cm was achieved with 10 wt.% percolation threshold of zirconia precursor. The binding energy of Zr3d(5/2) and Zr3d(3/2) decreased, suggesting that zirconia was converted to the lower oxidation state. Furthermore, the shape of PD changed from spherical to rod-like structure with root mean square value of 2 nm, while the hardness and reduced modulus improved to 1.72 MPa and 36.7 MPa, respectively.