Human beings throw plastic waste into the environment, and the environment responds with microplastics. Today, microplastics in the environment have already penetrated into our food, air and water, but it is very difficult to remove them from the environment, especially once they are deposited at the bottom and crevices of rivers, lakes and seas.
In a new study published in "Nano Letters" on June 22, 2022, the team of Professor Zhang Xinxing from the State Key Laboratory of Polymer Materials Engineering of Sichuan University developed a robotic fish that can swing The body flaps its " fins " and swims around to absorb microplastics in the water; moreover, it can "heal itself" after being cut and continue to maintain its ability to absorb microplastics. This invention promises to bring light to the planet's plastic crisis. The design of
robotic fish is inspired by mother-of-pearl . It is less than 1.3 centimeters from nose to tail. A near-infrared laser that rapidly opens and closes at the tail propels it forward.
Usually, the traditional materials used for soft robots are hydrogels and elastomers, which are easily damaged in water; while the mother-of-pearl found inside clam shells is strong and elastic, composed of layers with microscopic gradients.
In this study, the team developed mother-of-pearl-like structures to create durable and bendable materials for the robotic fish. They made nanosheets from a mixture of chemicals, including graphene, and assembled them layer by layer to form ordered concentration gradients, like mother-of-pearl. The researchers then used the new material to create a robotic fish.
In the experiment, the robot fish was proven to have a maximum swimming speed of 2.67 body lengths per second, setting a mobile record for soft marine robots and reaching the same speed as the active phytoplankton in an untethered state. Repeatedly adsorb nearby polystyrene (PS) microplastics and transport them to designated places.
Incredibly, the robotic fish can "heal itself" after being cut and still maintains the ability to pick up microplastics. This durability and speed make it ideal for monitoring microplastics and other contaminants in harsh aquatic environments. "This study breaks the mutual exclusivity of functional execution and rapid movement. We anticipate that this nanostructure design will provide an effective expansion path for other robots that require multi-functional integration," the
researchers wrote in the paper. Link:
https://doi.org/10.1021/acs.nanolett.2c01375
