Electric-Field Assisted Desorption of Water Molecules in DNA Functionalized CNT Network

This paper introduces the concept of electric field assisted desorption (EAD) of water molecules from the surface of DNA functionalized carbon nanotube (DFC) resistive network when a bias voltage VDS is applied across it. EAD at a given VDS is measured in terms of the characteristic life-time of desorption τ. The bias voltage produces an electric field E that aligns the molecular dipoles of water parallel to E. Mutually aligned neighboring dipole moments of water maximize the potential energy and drives them into a nonequilibrium state. The molecular dipoles return to the minimum potential energy state when water molecules escape from the surface of DFC. We find an exponential decrease in τ for V_DS <; V_cr, which is attributed to EAD. Beyond Vcr, we observe a linear increase in τ which is due to charge entrapment within ultrathin layer of water sandwiched between dielectric layers of DNA and air that prevents fast desorption of water molecules.