Version 5

FEA was conducted using commercial software (COMSOL, version 5.6, COMSOL Inc.). To understand the transformation behavior of the investigated structures, a nonlinear elastic material was used to simulate the nonlinear responses of the aniso-deposited microstructures to changes in the environmental pH. The 3D current density distribution (C) is calculated by $$C=\sigma E$$
where σ represents the electroconductivity and E is the electric field strength. The swelling ratio (λ₀) is related to the current density (C₀) as measured in Fig. 2G, and the data are fitted in the curve as shown in Eq. 4 (R² = 0.997). Equation 4 is applicable to a current density from 5 to 40 A/m², where the alginate hydrogel can be normally electrodeposited. Relative to the retractile network, the network in this state swells with isotropic stretches. We denote this free-swelling stretch by λ₀ and the deformation gradient by F₀ as $${\lambda }_0=-0.14C_0+6.5$$ $$\begin{gathered} {\mathbf{F}}_0=\left(\begin{array}{ccc}{\lambda }_0& 0& 0\\ \\ 0& {\lambda }_0& 0\\ \\ 0& 0& {\lambda }_0\end{array} \\ \right) \end{gathered}$$
A 3D model was established and meshed using a superfine element type, and numerical analysis was carried out. The transformation of the 3D model included a nonlinear transformation analysis using the Newton’s method. Similarly, FEA was carried out to design the morphological changes in other microstructures before aniso-electrodeposition, and the detailed model design and parameters were shown in fig. S5.