Extremely small pieces of a material aren't always a chip off a bigger block. How nanomaterials behave is tremendously important to know when trying to understand the roles of mineral nanoparticles in the environment, or design devices for nanotechnology. Researchers taking data at SSRL and the Advanced Photon Source (APS) in Illinois recently found that zinc sulfide at 3.5 nanometers (nm) in size (3.5 billionths of a meter) behaves quite differently than "bulk" zinc sulfide (several hundred nm and up). The method they developed should also prove useful for studying other kinds of nanomaterials.

Ben Gilbert of the University of California Berkeley and other Berkeley and Lawrence Berkeley National Laboratory scientists published their results in the July 1 issue of Science. Their work shows that structural disorder may be common in nanomaterials and that this can modify the material's properties, which are important for designing nanotechnology. Zinc sulfide can be found in the environment as nanoparticles and is one of a class of materials potentially very useful as a semiconductor. The study uses two types of synchrotron x-ray information: small-angle x-ray scattering (SAXS) at SSRL to get size and shape information, and wide-angle x-ray scattering (WAXS) at APS for structure information. Combining the two sets of data allowed researchers to quantify the difference in behavior between 3.5 nm and bulk zinc sulfide.