Stimuli responsive carbon nanocomposite hydrogels with efficient conducting properties as a precursor to bioelectronics

Stimuli responsive conducting carbon nanocomposite hydrogels were synthesized from glycerol methacrylate, ethylene glycol methacrylate and diethylene glycol methacrylate by thermal polymerization techniques. Carbon nanoparticles of size <50 nm were incorporated into the polymer at a concentration of 0.005% (w/w) during synthesis. The hydrogels were characterized by Fourier Transform-Infrared Spectroscopy, thermogravimetric analysis, Scanning Electron Microscopy techniques and X-ray diffraction study. The hydrogels have excellent absorption properties in aqueous solvents which is sensitive to pH, temperature, ionic strength, etc. For instance, the pH sensitive swelling behavior of Polyglycerylmethacrylate-carbon nanocomposite increases from acidic medium (SR∼24, pH = 3) to basic medium (SR∼130, pH = 12). The hydrogels also showed significant swelling behavior in presence of different biological samples such as folic acid, uric acid, DNA and RNA. The electrical impedance value decreases to a large extent after the addition of carbon nanoparticles into the gels. It was observed that the conductivity rises to a maximum of about 1000 folds in the nanocomposite hydrogels. The increase in electrical conductivity is also verified by current-voltage measurements.