Humidity-Controlled Dynamic Engineering of Buckling Dimensionality in MoS 2 Thin Films.

Dynamic engineering of buckling deformation is of vital importance as it provides multiphase modulation of thin film devices. In particular, dynamic switch of buckles between one-dimensional (1D) and two-dimensional (2D) configurations in a single film system on rigid substrates is intriguing but very challenging. The current approach to changing buckling configuration is mainly achieved by varying the built-in stress at the film-substrate interface, but it is difficult to realize dynamic engineering on rigid substrates. Herein, we report a dynamic engineering of buckling deformation in MoS 2 thin films by humidity-tuned interfacial adhesion. With the change of humidity, the MoS 2 thin films deform from 1D telephone-cord buckles to 2D web-like buckles due to the hydrophilic nature of both MoS 2 and substrate. Such 1D-to-2D evolution of buckles is attributed to the weakened interfacial adhesion of mixed deformation modes induced by humidity, which is verified by finite-element modeling. These buckled films further find potential applications as patterned templates for liquid condensation and sensing units for tactile sensors. Our work not only demonstrates the humidity-controlled dimensionality engineering of buckles in MoS 2 thin films but also sheds light on the functional applications of buckled films based on their profile features.