Abstract: Embodiments of the present disclosure generally relate to variable stiffness materials and devices, and methods of use thereof. In one embodiment, a variable stiffness robotic material is disclosed, which in one example, is useful for forming a robotic material based sleeve for endoscopes. In another embodiment, a single tool variable stiffness endoscope and working channel is disclosed, which is useful for performing multi-site thermoblation in a physician's office. In yet another embodiment, a micro-wave based tissue ablation or volume reduction tool and procedure are provided for treating sleep apnea.