Measurement of the dielectric, conductance and pyroelectric properties of MWCNT:PVDF nanocomposite thin films for application in infrared technologies

摘要

In this work, we have determined the dielectric and conductance properties of multi-wall carbon nano-tubes (MWCNT) in polyvinylidene fluoride (PVDF) nanocomposite thin films as a function of temperature and frequency. Samples, ranging from 15 - 280 microns in thickness, were measured in the temperature range from 21 to 90~0C and in frequencies from 50Hz to 110MHz. The samples were prepared by the solution casting technique. Measures indicate that at constant temperatures, the real dielectric constant decreases at lower frequencies, stays steady at low frequencies but rise at higher frequencies over towards the strong resonance. The dielectric loss, a particular concern as it is inversely related to the conductance, decreases also at lower frequencies but rise at higher frequencies with a steeper slope in each case. Additionally, we have measured the pyroelectric coefficient in the same temperature range, compared the pyroelectric coefficient results with previous measures made on silver nanoparticle in PVDF thin films and provided preliminary evidence of the causative microscopic response mechanism. Our MWCNT:PVDF thin films yield higher figures of merit than that indicated by pure PVDF thin films and results indicate a usage of MWCNT:PVDF thin films in infrared uncooled sensors and vidicon technology.