Thermally Induced Bending of ReS 2 Nanowalls.

Among the variety of stimuli-responsive materials, temperature-responsive materials (TRMs) can adapt to the surrounding environment in the presence of a thermal stimulus, and they have attracted considerable attention in sensors, actuators, and surface engineering. However, polymers, as the most representative TRMs, are far from ideal with respect to long-term reliability and durability. Here, for the first time, an inorganic material, ReS2, is analyzed, which possesses an unexpected temperature-responsive behavior that is triggered by stable and reversible thermally induced bending (TIB). Due to thermal fluctuations in the ReS2 layers, intrinsic ripples tend to aggravate rapidly with rising temperature. Then, the weak interlayer interaction of ReS2 is further weakened, thus resulting in interlayer sliding. Due to a decrease in bending rigidity with increasing temperature, out-of-plane bending spontaneously occurs in the ReS2 layers. Interestingly, this TIB of ReS2 can recover to its initial configuration when the temperature drops, which is further confirmed by the reversible wetting measurement. Above all, the TIB behavior of ReS2 exhibits great potential in smart applications, such as smart windows and microfluidic devices, and fills the significant gaps of inorganic TRMs.