Quantitative analysis of the stimuli-responsive SELP/CNF bilayer actuators. (A) Bending curves for the bilayer strip actuators depending on the thickness ratio of the SELP to the CNF layer in 0.5 M NaCl solutions at room temperature. (B) MDC curves of the bilayer strip actuators with various thickness ratios, and (C) MDC versus time curves of bilayer strip actuators with thickness ratio of 10 in response to 0.5, 5, 50, and 500 mM NaCl solutions at room temperature, respectively. The Insets are photographs of bending strip actuators at the corresponding time points. (Scale bar, 5 mm.) (D) Cyclic stability of the MDC of the bilayer strip actuators with thickness ratio of 10 under stimuli changes from 4 °C DI water to NaCl solutions at room temperature.