Janus composite nanorings by combinational template synthesis and skiving micro-process

Janus composite nanorings are fabricated by skiving the corresponding arrayed nanotubes. Polymer nanotubes and their arrays are polymerized from the pore surface via ATRP inside porous anodic aluminium oxide membrane (AAO) templates. By a selective partial modification of the interior surface of the polymer nanotubes followed by a favorable growth of other materials, double-shelled composite nanotubes and their arrays are derived. After skiving, the corresponding Janus composite nanorings are obtained with two different compositions compartmentalized onto both interior and exterior surfaces, respectively. Characteristic dimension, microstructure and composition of the Janus composite nanorings can be tuned. As examples, Janus composite nanorings of sulfonated PS/PS, titania/PS, silica/PS and PANi/PS are prepared.