Bio-dielectrics based on DNA-Ceramic hybrid films for potential energy storage applications

The potential of DNA-based dielectrics for energy storage applications was explored via the incorporation of high dielectric constant (epsilon) ceramics such as TiO2 (rutile) and BaTiO3 in the DNA bio-polymer. The DNA-Ceramic hybrid films were fabricated from stable suspensions of the nanoparticles in aqueous DNA solutions. Dielectric characterization revealed that the incorporation of TiO2 (rutile) in DNA resulted in enhanced dielectric constant (14.3 at 1 kHz for 40 wt % TiO2) relative to that of DNA in the entire frequency range of 1 kHz-1 MHz. Variable temperature dielectric measurements, in the 20-80 degrees C range, of both DNA-TiO2 and DNA-BaTiO3 films, revealed that the ceramic additive stabilizes DNA against large temperature-dependent variations in both epsilon and the dielectric loss factor tan delta. The bulk resistivity of the DNA-Ceramic hybrid films, in the case of both TiO2 and BaTiO3 additives in DNA, was measured to be two to three orders of magnitude higher than that of the control DNA films, indicating their potential for utilization as insulating dielectrics in capacitor applications. As a part of a baseline study, results based on a comparison of the temperature-dependent dielectric behavior of DNA and DNA-CTMA complex films as well as their frequency-dependent polarization behavior, are also discussed.