Perfectly Organized Gold Nanorings

Perfectly Organized Gold NanoringsCreating well-organized conducting nanostructures in a flexible polymer matrix provides platforms for numerous applications in optics, sensors, and wave-guiding structures. Working in the Materials Research Science and Engineering Center on Polymers at the University of Massachusetts Amherst, Thayumanavan and Russell achieved self-assembled hybrid structures from diblock copolymers and gold nanoparticles, where the nanoparticles are exquisitely arranged in circular patterns as directed by the polymer template. Key to this process was the synthesis of block copolymers having a photocleavable junction point; after light-initiated polymer fragmentation, the template is left with sulfur-rich functional groups having an affinity for metallic surfaces, such as gold and silver nanoparticles. The accompanying image shows the results of this process, with the dark circular areas indicating the presence of gold nanoparticles arranged along the edges of the circular polymer pattern.