Polythiophene/SiO2 nanocomposites prepared in the presence of surfactants and their application to glucose biosensing

Conducting polythiophene/SiO2 (PT/SiO2) nanocomposites were prepared in the presence of three different surfactants (anionic, cationic and non-ionic) via chemical oxidative polymerization in an anhydrous medium to create an enzyme-immobilized polymeric amperometric biosensor. An anionic surfactant, sodium dodecylbenzenesulfonate (DBSNa), a cationic surfactant, tetradecyltrimethylammonium bromide (TTAB), and a non-ionic surfactant, poly(ethylene oxide) (20) sorbitan monolaurate (Tween 20), were used as additives. The properties of the nanocomposites were investigated, as a function of surfactant type and the amount of PT contained, by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The SEM results reveal that all PT/SiO2 samples form nanometer-dimensioned globular structures. The highest conductivity obtained was 2.7 × 10−2 S cm−1 for a PT/SiO2-Tween 20 nanocomposite. Thermogravimetric analysis (TGA) shows that the residue decreases with increasing amount of PT. Glucose oxidase (GOX) was immobilized by crosslinking to the conducting PT/SiO2 composites and was used for amperometric detection of glucose.