Composite films with stimulus-responsive property and self-healing ability represent a group of important biomimetic film materials.The layer-by-layer (LbL) assembly

which involves multiple dipping and rinsing steps for the fabrication of composite films

enables precise control of film composition and structure.LbL assembled films with micrometer thickness can be designed to respond quickly and effectively to various external stimuli

and are therefore promising for use as biomimetic films.We demonstrate herein that the LbL assembled polyelectrolyte multilayer films with micrometer thickness can be utilized for the fabrication of humido- and thermo-responsive bilayer free-standing films capable of bending/unbending movements

which are useful as highly efficient actuators and walking-devices.The LbL is assembly also promising in the fabrication of self-healing superhydrophobic coatings and water-enabled self-healing polyelectrolyte films capable of repairing severe damage of cuts.