Coating carbon nanotubes by spontaneous oxidative polymerization of dopamine

Carbon nanotubes were easily coated with a reactive biopolymer – polydopamine (Pdop) – by dispersing them in a dopamine solution and mildly stirring at room temperature. The coating did not ruin the nanotube sidewalls, and its thickness was finely controlled on the nanometer scale by adjusting the reaction time, pH and temperature. The resulted coating is a versatile platform for both functional organic ad-layers and electroless metallization. A high concentration of gold nanoparticles was deposited on the Pdop layer, by simply stirring within HAuCl4 solution at room temperature.