Fig. 3: Mechanical properties of PEG/SIS combined film.

a Stress-strain curves of PEG/SIS combined films with different PEG contents. The inset shows local amplification at low strain of this curve, indicating that these membranes can achieve nearly 50% linear elastic deformation under stress. b Softness (1/E) of PEG/SIS combined films with different PEG contents calculated by the stress-strain curves in (a). c Demonstration of PEG/SIS combined films’ high softness by bending, stretching, folding and twisting. d Comparison of softness between the PEG/SIS combined film and common organic piezoelectric materials. e Comparison of strain range between the linear elastic deformation of PEG/SIS combined film and the deformation ranges of biological tissues.