Novel fabrication of soft microactuators with morphological computing using soft lithography

Abstract

A simple and cost-effective method for the patterning and fabrication of soft polymer microactuators integrated with morphological computation is presented. The microactuators combine conducting polymers to provide the actuation, with spatially designed structures for a morphologically controlled, user-defined actuation. Soft lithography is employed to pattern and fabricate polydimethylsiloxane layers with geometrical pattern, for use as a construction element in the microactuators. These microactuators could obtain multiple bending motions from a single fabrication process depending on the morphological pattern defined in the final step. Instead of fabricating via conventional photolithography route, which involves multiple steps with different chromium photomasks, this new method uses only one single design template to produce geometrically patterned layers, which are then specifically cut to obtain multiple device designs. The desired design of the actuator is decided in the final step of fabrication. The resulting microactuators generate motions such as a spiral, screw, and tube, using a single design template.

3D Printing Microactuators for Soft Microrobots

“…The resulting performance of the 3D printed microactuators was similar to those fabricated using conventional methods such as photolithography and laser ablation. 21,[27][28][29][30][31][32] To extend the adaptability of the 3D printing process, we developed a new patterning process to define the conductive layer using just one extra step of printing to transfer the design. The new method of ''patterning by printing'' using lift-up is a simple and promising solution for patterning the structures, which would be favorable for polymers that are sensitive to extreme processing conditions.…”

“…Upon electrochemical reduction the PPy layer expanded leading toward the bending of microactuator and the tip moved 3500 lm in 30 s. This is comparable to the performance of the soft microactuators fabricated with conventional microfabrication techniques. 27…”

“…This behavior can be understood from the fact that the displacement of a bending beam, with moment of inertia I and Young's modulus E, is inversely proportional to the bending stiffness I Á E of the beam which scales with the thickness cubed. 27,35 A thicker polypyrrole would, therefore, not only generate more force but also oppose the bending motion due to the increased stiffness. At higher frequency, the duration of actuation is not long enough for the ions to diffuse completely into the polymer matrix.…”

“…These microrobots can potentially be used to grasp and release objects or as microwalkers. To enable in air operation, the microactuators have to be combined with ionogels, 41,42 or other solid-state ion sources into a so called trilayer actuator, 21,27,28 which is ongoing work.…”

A Review of End-Effector Research Based on Compliance Control

“…Manav et al [77] proposed a simple and economical soft polymer micro-actuator incorporating morphological computation. They successfully applied the concept of morphological computation to the actuator to control the bending motion in two different ways.…”