Growth of silver nanowires on carbon fiber to produce hybrid/waterborne polyurethane composites with improved electrical properties

One dimensional silver nanowires (AgNWs) were grown on carbon fiber (CF) by a facile polyol method. Fourier transform infrared spectrometer (FTIR), laser Raman spectrometer (Raman), field-emission scanning electron microscopy (FESEM), X ray diffraction instrument (XRD), energy dispersive spectrometer (EDS), and X-ray photoelectron spectrometer (XPS) were carried out to reveal the structure, morphology, and formation mechanism of the CF-AgNWs. It was found that AgNO3 concentration of 1.5 mM, reaction temperature of 160 degrees C, and reaction time of 120 min were appropriate conditions for growth of AgNWs on CF. Moreover, a mechanism was suggested that the cysteamine on CF acted as nucleation centers for growth of silver nanoparticles and then small sized silver nanoparticles reduced from silver nitrate were grown on CF via the silver bonding to sulfur. Through an Ostwald ripening process, small sized silver nanoparticles were grown into larger particles. With the assistance of polyvinylpyrolidone (PVP), these larger particles were directed to grow in a definite direction to form nanowires. It was found that the resistance of CF-AgNWs was decreased to 19.5 Omega, compared with that of CF (102.6 Omega) with the same quality. Thus, the CF-AgNWs was added into waterborne polyurethane (WPU) to improve the electrical and dielectric properties of WPU. Results showed the WPU/CF-AgNWs composite presented a lower percolation threshold than WPU/CF composite. When the content was 2.5 wt %, the volume resistivity of the WPU/CF-AgNWs (1.90 x 10(4) Omega cm(-1)) was lower by approximately three orders of magnitude than that of WPU/CF (4.19 x 10(7) Omega cm(-1)). When the content was 2.5 wt %, the dielectric constant and dielectric loss of the WPU/CF-AgNWs were improved to 15.24 and 0.21, which were 34.5 and 40.8% higher than that of WPU/CF. (c) 2015 Wiley Periodicals, Inc.