Gecko-inspired ultrasensitive multifunctional mechano-optical smart membranes

Mechano-optical materials are of great importance in smart window, security, display and camouflages. However, fabricating ultrasensitive optical devices with wide range still remains great challenging. Inspired from the fast tail amputation of gecko utilizing weak non-ossificated septum, herein, we report an ultrasensitive mechano-optical membrane based on weak dye layer between silica nanoparticles and soft polydimethylsiloxane matrix. Owing to the light scattering from dye-induced internal cavitation, the transmittance dramatically decreases by ～44% at initial small strain level (15%) and a high sensitivity (S > 2) is kept within an abroad strain range (0～35%). Moreover, a high total transmittance tuning range of ～75% is exhibited. Simulation and experimental monitoring demonstrate the effective weakening of interface energy. The potential applications in smart window, sensor, anti-counterfeiting also exhibit the multifunctionality of our smart membranes. This facile and low-cost approach enables the large-scale production and applications of mechano-optical membranes and this interface design provides a general way to develop ultrasensitive mechano-responsive materials.