Production and Characterization of Multi Nanosensors Based on MWCNTS and Poly (Metyl Metacrylate) - PMMA Matrix
Ana Tomova, Anita Grozdanov, Perica Paunović, Aleksandar Petrovski, Aleksandar T. Dimitrov
University Ss. Cyril and Methodius in Skopje, Faculty of Technology and Metallurgy,Republic of Macedonia
Sensors are devices that detect or measure physical and chemical quantities, such as temperature, pressure, sound, concentration etc. They have numerous applications which range from biomedicine to automobile industry. Lately, gas sensors have been attracting tremendous interest and intensive research due to the great demand for sensitive, selective, fast response, stable, low cost sensors applied for environmental monitoring. As many researchers on this topic report, due to their unique characteristics carbon nanotubes CNTs/polymer nanocomposites are a perfect sensing material displaying improved performances. The aim of the experiments presented in this paper is to produce a gas sensor based on MWCNTs and Poly (Methyl Methacrylate) – PMMA for organic vapours detection (acetone and chloroform). Three types of different MWCNTs have been used: MWCNTs produced by pyrolysis (d=50÷100nm, purity ~ 84%) and by CVD (d=10÷40nm, purity ~ 94%). MWCNTs were further activated by thermal oxidation (at 490°C), acid (HNO3) and base (NH4OH) treatment. Purified/activated MWCNTs were incorporated in PMMA matrix and nanocomposite films were obtained. Functionalized MWCNTs and produced nanocomposite films were then investigated by TGA, DSC, FTIR, SEM, Raman, UV and ZETA spectroscopy, as well as dielectric measuring of the sensors activity. Results show that incorporated MWCNTs inside the polymer matrix improve thermal stability of the produced films. Different purification/activation treatments of MWCNTs exhibit different sensor activity. It was shown that PMMA/MWCNTs films prepared by this method act as efficient sensors for –CO groups.
Key words: Nanosensors, MWCNTs, purification/functionalization, polymer nanocomposites, polymer matrix