Accordion-like swelling of layered perovskite crystals via massive permeation of aqueous solutions into 2D oxide galleries.

Platelet crystals of a layered perovskite showed massive accordion-like swelling in a tetrabutylammonium hydroxide solution. The permeation of the solution induced the huge expansion of the interlayer spacing as well as the crystal thickness up to 50-fold, leading to a very high water content of >90 wt%.