Zhejiang University If you feel that two gold rings are old-fashioned, you can ask a goldsmith to re-make a pair of rings by melting the old ones under high temperature. However, you are bothered by a twinge of regret after the rings are melted into liquid. Is it possible to get back the two original gold rings? The answer is self-evident. Even if the remade gold rings look exactly identical to the former ones in appearance, corresponding internal components have been disrupted and re-distributed randomly. For ordinary materials, once two objects are fused, it will hardly be reversible. Even when separated, they won’t be the same any more. Nonetheless, with four years’ efforts, the research team led by Prof. GAO Chao at the Zhejiang University Department of Polymer Science and Engineering discovered that graphene oxide (GO) sheets are able to deform adaptively. Corresponding macroscopic GO fibers have the capability of precisely reversible fusion and fission. A number of GO fibers can not only fuse into a thicker one but also separate into original individual fibers, as if they came with a “return key”. This study is of considerable importance to the reversible assemblies in the future. The research findings were published in the journal Science on May 7.