The sphere with a heart-shaped hole that you see in the image is really a hollow nanoparticle. It was created by means of galvanic displacement, when a nanoscopic drop of liquid gallium was put into a solution of a copper polyethylenimine complex.
The reaction takes place because gallium and copper have different electrochemical reactivity. Thanks to that, copper ions oxidize gallium that is absorbed into the solution, and the deoxidized copper accumulates on the particles. The reaction’s speed and intensity is controlled by adding organic polyethylenimine molecules to the solution. As a result, gallium dissolves almost entirely, and the copper deoxidized on the liquid metal’s surface forms a hollow capsule. Capsules such as this can be used in bimetallic catalysis, optics, and for drug encapsulation.
The photo was taken with the Vega 3 TESCAN scanning electron microscope at 20 kV as part of the project on the development of simple methods for the synthesis of hollow metal particles from nonprecious metals at by the Nanopharmacy group at ITMO’s SCAMT (Solution Chemistry of Advanced Materials and Technologies) international research center.
