Fig. 1. Preparation process of nanograting

Fig. 2. Surface morphology of nanograting. (a) Physical drawing of nanograting; (b) fitted curve of film stiffness; (c) surface structure of PDMS; (d) surface structure of GNP/PDMS

Fig. 3. Simulation model of thin film

Fig. 4. Stress distribution of flexible grating driven by low voltage

Fig. 5. Simulation results. (a) Relationship between film temperature and simulation time; (b) influence of width and length of thin film on grating period; (c) influence of thickness of thin film on grating period; (d) relationship between grating period and detection wavelength

Fig. 6. Temperature change of thin film. (a) Temperature at detection point in thin film (point represents simulated data, and solid line represents fitted curve); (b) temperature change at detection point under different driving voltages (point represents simulated data, and solid line represents fitted curve); (c) temperature rise of GNP/PDMS composite film; (d) average temperature rise rate

Fig. 7. Comparison between experiment and simulation. (a) Influence of driving voltage on grating period in experiment (dotted line represents experimental data, and solid line represents fitted curve); (b) influence of driving voltage on grating period in simulation (point represents simulation data, and solid line represents fitted curve); (c) influence of driving voltage on temperature of GNP/PDMS film in experiment (dotted line represents experimental data, and solid line represents fitted curve); (d) influence of driving voltage on temperature of GNP/PDMS film in simulation (point represents simulation data, and solid line represents fitted curve)