MEMS sensor material based on polypyrrole–carbon nanotube nanocomposite: film deposition and characterization

Conductive polymer-based nanocomposite has been utilized as a MEMS sensing material via a one-step, selective on-chip deposition process at room temperature. A doped polypyrrole (PPy) variant synthesized by incorporating multi-walled carbon nanotube (MWCNT) into electropolymerized PPy has been shown to improve the sensing performance utilizing a two-terminal, micro-gap chemiresistor architecture. The dodecylbenzenesulfonate (DBS)-doped PPy–MWCNT nanocomposites are found to be responsive to oxidants, such as hydrogen peroxide (H 2 O 2 ), and this effect can be extended to glucose detection using H 2 O 2 as a proxy material. The oxidant sensing effect is demonstrated by subjecting a glucose oxidase (GOx)-laden PPy–MWCNT nanocomposite film to various concentrations of glucose solution. Such PPy–MWCNT nanocomposite, when applied in a chemiresistor configuration, obviates the need for reference electrode and electron mediators, by measuring the direct and reversible, oxidation–reduction induced conductivity change. Experimentally, GOx-laden, doped PPy–MWCNT is tested to be sensitive to glucose concentration up to 20 mM, which covers the physiologically important range for diabetics of 0–20 mM.