Fig. 6. Development of soft robotic microdevices actuated by fiber MAs. (a) Schematic illustration of the extrusion process and content of the nanocomposite fiber MAs. (b) Actuation strain versus time plot for a single contraction–relaxation cycle. An exponential fit to the first stage of the relaxation curve characterizes the relaxation constant. (c) The PEGDA skeleton is polymerized around the printed fiber MAs while forming physical encapsulation of fibers within the structure. (d) Selective NIR exposure leads to continuous control over the curvature of the manipulator. (e) The 2D configuration space of the device plotted by generating a polynomial fit passing through the extreme positions provided by the FEM simulations shown in (f). The non-actuated original location of the tip position is denoted by O. (g) Soft robotic microgripper controlled by an antagonistic fiber MA pair. (h) Displacement contour plot showing the displacement of the arm corresponding to the two extreme cases, fully open and fully closed. All scale bars represent 100 μm.