Fig. 1: Schematic of Marangoni microswimmers with multifunctional parts for highly programmable motion.
From: Photopatterned microswimmers with programmable motion without external stimuli
a PVA released from the fuel part lowers the surface tension of the adjacent areas and enables propulsion through the Marangoni effect. The hydrophobic body (red) enables swimmers to float on the surface of the solution. Middle (in black and white): FastCam images of a microswimmer with linear motion; scale bars represent 250 µm (black box and FastCam images) and 1 cm (zoom-out pictures). b Circular motion of swimmers enabled by selectively designing balance of the swimmer structure and surface tension profile; scale bars represent 250 µm (black boxes) and 1 cm (zoom-out pictures). c Rotary motion of the microswimmer. The asterisk marks the same wing of the microswimmer; the scale bar represents 100 μm. d Time-course motion change of the microswimmer. The size of the hydrogel rudder placed on the microswimmer changes due to swelling, which leads to a change in their motion from circular to linear. The volume ratio of PEGDA:Ethanol for the porous hydrogel rudder fabrication is 5:5; scale bar represents 250 µm (black boxes) and 1 cm (zoom-out pictures). e By bridging two swimmers with water-soluble PVA, swimmers are disassembled after a designated time. Scale bar represents 1 cm.
