Robust liquid marbles stabilized with surface-modified halloysite nanotubes.

We have demonstrated the fabrication of fluorine-free liquid marbles from halloysite nanotube. Halloysite is a naturally occurring inorganic nanotube that has a high aspect ratio, and the surface was modified with octadecyltrimethoxysilane. The surface-modified halloysite formed pincushion agglomerates on the surface of the liquid droplets, which create superhydrophobic surface similar to that of the plant gall surface prepared by aphids. As a result, the liquid marbles showed high mechanical strength upon impact without the use of low surface energy fluoroalkyl or fluorine-modified materials. Our results suggest a new strategy for designing novel materials for liquid marbles inspired by nature.