Fig. 6.

Glassy GO solid with enhanced and isotropic mechanical properties. a–c Uniaxial compression turns a freeze-dried GO foam to a GO pellet with lamellar microstructure, which is denoted as l-GO. d–f A glassy GO pellet made of disorderly packed sheets, denoted as g-GO, is made by first gently molding the dough into a pellet by hand, followed by drying in air. g XRD patterns and h nanoindentation curves of the two types of GO pellets. The g-GO pellet does not have a strong diffraction peak corresponding to lamellar ordering, and exhibits largely isotropic properties and higher hardness. Scale bars in c and f are 10 μm