Exfoliation of crystals

The review is concerned with progress in methods for exfoliation of crystals, from mechanical exfoliation using sticky tape to modern techniques involving sonication-assisted exfoliation, shear exfoliation in liquids using intercalating agents and stabilizers, direct liquid exfoliation and cosolvent exfoliation. The potential of methods of osmotic swelling in water and in organic dispersion media with constant and variable chemical composition of nanosheets, chemical and electrochemical intercalation, exfoliation by hydrazine (including versions resulting in changes in the chemical composition of nanosheets), ionic liquids and supercritical fluids is discussed. Methods for size sorting of nanosheets by density-gradient and cascade centrifugation and the possibility of nanosheet size control are analyzed. The bibliography includes 136 references.