Patches of chain-like molecules placed across nanoscale particles can radically transform the optical, electronic, and magnetic properties of particle-based materials. Understanding why depends critically on the three-dimensional features of these “polymer nano-patches”—which are tantalizingly difficult to reveal at a scale spanning just billionths of a meter.

Now, scientists have used cutting-edge electron tomography techniques—a process of 3D reconstructive imaging —to pinpoint the structure and composition of the polymer nano-patches. The results, published earlier this month in the journal Nature, “lay the foundation for new nanoscale architectures that could potentially enhance technologies such as self-assembled solar cells and catalysts,” said lead author Eugenia Kumacheva of the University of Toronto.

The scientists tracked the patches formed by different synthetic polymers—versatile and common compounds used in everything from plastics to electronics —on the surface of gold nanospheres thousands of times smaller than the width of a single human hair. To visualize the elusive surface structures, Kumacheva and her team turned to cutting-edge facilities at the Center for Functional Nanomaterials (CFN), a U.S. Department of Energy (DOE) Office of Science User Facility at DOE’s Brookhaven National Laboratory.