Ethanol Driven Micro-Robots with Photonic Colloidal Crystal Hydrogel for Exploring and Sensing Stimuli

Photonic colloidal crystal hydrogels are expected to be a powerful tool for environmental monitoring and healthcare. The photonic colloidal crystal hydrogel reflects visible-light, so the intensity of the stimulus can be converted to visible color. However, these sensors required taking a measured sample from the target environment. To detect a specific substance in a vast environment, exploring and detecting systems are required. Therefore, we proposed ethanol driven micro-robots with photonic colloidal crystal hydrogel. We achieved the color changes of micro-robots response to the external stimuli. Proposed micro-robots propelled over 600 s by the Marangoni effect caused by ethanol diffusion.