Researchers have engineered an innovative robotic “eye” that can automatically focus in response to light without needing an external power source. This advanced lens is capable of detecting minute details, such as the hairs on an ant”s leg or the lobes of a pollen grain. This breakthrough could pave the way for “soft” robots that possess robust vision without relying on electronics or batteries, according to Corey Zheng, a doctoral student in biomedical engineering at the Georgia Institute of Technology.
Traditional robots typically utilize rigid sensors and electronic components for vision. However, Zheng noted that for softer, more flexible robots, alternative sensing methods must be considered. The newly developed lens is made from a hydrogel that consists of a polymer framework capable of trapping and releasing water. This property allows the hydrogel to transition between liquid-like and solid-like states, which is essential for its functionality.
The hydrogel reacts to temperature changes by releasing water and shrinking when heated, and conversely, it absorbs water and swells when cooled. The researchers designed a ring of hydrogel surrounding a silicon polymer lens, creating a structure that mimics the human eye. Embedded within the hydrogel are tiny particles of graphene oxide, which are dark and light-absorbing. When sunlight or equivalent light intensity strikes the graphene oxide, it heats up, causing the hydrogel to change shape and thus adjust the lens focus.
In a study published in the journal Science Robotics, Zheng and his advisor, Shu Jia, demonstrated that this lens could replace traditional glass lenses in light microscopes, enabling the imaging of extremely small details, such as the 4-micrometer gap between a tick”s claws and 5-micrometer fungal filaments.
Looking forward, the team is working on integrating this lens into a microfluidic system of valves, which also utilizes the responsive hydrogel. This integration suggests that the light used for imaging could simultaneously power an intelligent camera system. Additionally, due to the adaptable nature of the hydrogel, it may allow for vision capabilities that extend beyond human limitations, potentially replicating features found in animals such as cats or cuttlefish.
Zheng expressed excitement about the unique control they have over the lens, indicating that its potential applications could revolutionize how soft robots perceive their environment.
