The wrinkle dynamics (such as reversibility and stability) of human skin are affected by the external stimuli, as well as the skin's structure and mechanical properties. Inspired by these tunable responses, three types of moisture-responsive wrinkle dynamics are achieved, for the first time, through a single film-substrate system. These dynamics include: (1) completely reversible wrinkles formation; (2) irreversible wrinkles formation I: the initially formed wrinkles can be permanently erased and never reappear; and (3) irreversible wrinkles formation II: once the wrinkles form, they can no longer be erased. The key to success is to control the stiffness and thickness ratios of the film and the substrate, and tailor the crosslink degree/gradient of the film to allow for moisture-dependent changes of modulus and swelling degree. These unique responsive dynamics motivate the invention of a series of optical devices triggered by moisture, including anticounterfeit tabs, encryption devices, water indicators, light diffusors, and antiglare films. This study also paves the road for further understanding of the skin wrinkling dynamics and manipulation.

A versatile wrinkle‐based micropatterned system with a film‐substrate structure is proposed, which contains a hydrophilic film of polyvinyl alcohol or its composite with laponite and a hydrophobic substrate of polydimethylsiloxane or its composite with carbon black. The wrinkled system features high design flexibility and multistimuli responsiveness, which can be activated by various mechanical methods, including vertical press or scratch, gentle stretch‐and‐release, bend, or analogous magneto‐mechanical and electro‐mechanical modes. The resultant wrinkles possess 1) instantaneous and reversible strain/moisture/light responsive optical modulation; 2) tunable dynamics for the aforementioned strain/moisture/light response;3) tailorable amplitude/wavelength; 4) unique surface morphologies from the coupling of wrinkles and cracks; 5) excellent reversibility and durability. A variety of applications are demonstrated based on this system, including 1) a moisture erasable highly sensitive pressure responsive device and pattern replicator with a high fidelity; 2) a moisture erasable scratch/magneto‐mechanical re‐writable tablet; 3) an electro‐mechanical controllable smart window with an ultra‐sensitive strain responsive transmittance modulation and a low operating voltage; 4) various types of strain responsive, moisture erasable, and laser writable information recording/encryption devices. This work provides new routes for designing innovative wrinkled systems triggered by diverse mechanical fashions and can decode multiple environmental stimuli into optical signals for widespread application.

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A cellulose based conductive composite hydrogel was prepared with a non-toxic crosslinking agent for application in biomedical materials.

A 3D tubular structure fabricated from the relaxation of pre-stretched 2D precursor is used to develop various 3D stretchable electronics.