Figure 3. Controlling rate of shapeshifting.

(a) Kinetics of shape recovery (50:50 MAAc-co-DMAA gel, 70 wt% water, Protocol 2: uniaxial extension, , ɛ=0.5, T=25 °C) for different programming times t_p as indicated. Inset: The strain recovery curves collapse on a single curve upon time normalization t/τ_r. (b) Plotting rate of strain recovery versus strain (Supplementary Equation 37) allows extraction of activation volume and lifetime of the physical crosslinks (Supplementary Fig. 14) based on a ‘standard linear solid' model (Supplementary Equations 30–40).