KCS

Polyaniline (PANI) has widely been studied as one of promising conducting polymers for uses in a range of electrochemical devices. Good environmental/chemical stability, high electrical conductivity, and easy of synthesis have been highlighted as desirable characteristics of PANI towards future electronic materials. Decades of research on PANI have further revealed that the electrical properties of PANI can be largely tailored by changing the dimensionality of nanostructures. This imprinted the importance of developing 2D morphologies to achieve enhanced conductivity, especially along desired directions, towards their applications in high density integrated electronic devices. Despite their positive aspects, successful fabrication of 2D PANI nanostructures with improved properties is in its infancy because of the difficulties in controlling surface and interfacial properties. Here, we present a facile synthesis of 2D PANI nanosheets via chemical oxidative polymerization using ice as a template. The ice offers unique surfaces of water molecules that are arranged in layers of hexagonal rings, facilitating hydrogen bonding interactions with aniline monomers in an organized manner. The easy removal of ice also enables the attainment of template-free PANI nanosheets in tens of nanometers thickness. Notably, the ice-templated PANI nanosheets revealed two orders of magnitude higher electrical conductivity than conventional PANI thin films prepared by electrochemical deposition methods. The origin of the improved electrical properties of the PANI nanosheets was found in a unique edge-on π-stacking, attributed to ordered hydroxyl groups at the ice surfaces. Our work should open a new chapter in advancing organic electronics upon putting forward a new methodology.