X-ray radiation effects on thin film nanocomposites of functionalized and copper coated multi-walled carbon nanotube and poly(methyl methacrylate)

Multi-walled carbon nanotube (MWCNT) and poly(methyl methacrylate) (PMMA) nanocomposites have the potential to be deployed as sensing elements for various applications including ionizing radiation detection. In this work, a 160 kV x-ray ionizing radiation source has been used to study the ionizing radiation dose rate effects on Ferrocene doped MWCNTs, MWCNTs functionalized with - carboxylic acid (COOH), hydrogen peroxide, amine, and MWCNTs coated/ modified with copper. Solution blending method was used in synthesizing the nanocomposites and the synthesized composites were cast on interdigitated electrodes (IDEs) to perform radiation sensing experiments by monitoring changes in the films' resistance. We have observed a clear, repeatable and proportionate response curve for radiation dose rate measurements with Ferrocene doped MWCNT/PMMA thin film composites. A weaker response is observed for functionalized MWCNT/PMMA films. Ferrocene doped MWCNT/PMMA composite showed the most increased sensitivity to x-ray radiation when compared to all other functional groups reported here and as compared to unfunctionalized MWCNT/PMMA composites. Ferrocene doped MWCNT/PMMA films' resistance changed over 18% compared to changes observed for unfunctionalized MWCNT/PMMA films of about 6%. Accelerated post radiation recovery of Ferrocene doped MWCNT/PMMA composites using a heat treatment technique is presented. The results of this study suggest that simple sensor elements based on relatively economical MWCNTs could be useful for the detection of ionizing radiation.