Fig. 11.

Electromechanically driven mechanochromic polymers. a Structure of electromechanical photonic crystals using dielectric elastomer actuator. b Photonic organogel is electrically operated with Maxwell stress induced by a DC bias, which results in areal expansion of the photonic gel. c Digital images show various colors from red to blue. d The electromechanical photonic device can generate sound in the audible frequency regime. e Piano notes to be programmed as an input signal to the device and recorded sound waves from a microphone. f A short-time Fourier transformation data, allowing for visualization of the frequencies over time. g Schematic structures for electro-mechano-chemically responsive(EMCR) color change displays. h Mechanism for the device using mechanochromic spiropyran materials. The applied voltages induce a large deformation in the elastomer, which causes ring open reaction of spiropyran resulting in color change 

(Figure reproduced from a–f [82], Copyright 2018, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim; g, h [83], Copyright 2014, Springer Nature)