Understanding on Swelling and Exfoliation of Layered Materials

Fengxia Geng, ICYS-MANA

Two-dimensional crystals or nanosheets peeled from layered materials represent a novel class of materials of scientific and technological interest because they manifest many extraordinary physical and chemical characteristics. A typical strategy to obtain the nanosheets is by intercalating guest molecules along with solvent, mostly H₂O, into the gallery space to expand the layers and weaken the bonding forces between the layers, after which the layers are readily delaminated by procedures like shaking. Although a deep understanding on the swelling process or mechanism is of significant importance both to understanding of traditional swelling of layered materials and to the optimal selection of exfoliation reagents to produce high-quality nanosheets, the relative studies are very rare, which is mainly due to the structural instabilities of the swollen phases. In this talk, taking protonated titanate oxide as an illustrating example, I will introduce our recent progress on elucidating the mechanism and nature of swelling process and its effect on the following delamination into nanosheets.