Researchers at Rutgers University developed a nano-device that can lift its own weight. The device weighs 1.6 milligrams and can lift 265 milligrams several hundred times in a row.
The device strength comes from an action of insert and removing ions between nano sheets of molybdenum disulfide (MoS2). The new device work like muscles and convert electrical energy to mechanical energy.
“After applying a small amount of voltage, the researchers found the device can lift something that’s far heavier than itself,” said, Manish Chhowalla, professor of material science and engineering at Rutgers.
nano sheets of molybdenum disulfide
The study is an important finding in the branch of electrochemical actuators. The atomically thin sheets of metallic MoS2 leads to actuators that can resist stresses and strains comparable to or greater than other actuator materials.”
However, actuators used in the electromechanical systems and in robotics. The applications of actuators, such as steerable catheters, aircraft wings that adapt to changing conditions and wind turbines that reduce drag.
Molybdenum disulfide, a naturally occurring mineral commonly used as a solid-state lubricant in engines. According to researchers, MoS2 is a layered material like graphite, and have strong chemical bonding within thin layers, but the weak bonding between the layers. The layers of MoS2 can easily separate into individual thin sheets.
The nanosheets, remain suspended in solvents such as water. The nanosheets can assemble into stacks by putting the solution onto a flexible material for allowing the solvent to evaporate.
The restacked sheets can use as electrodes, similar to batteries with high electrical conductivity to insert and remove ions. Inserting and removing ions lead to the expansion and contraction of nanosheets that results in force on the surface. This force activates the movement or actuation of the flexible material.
Also, the MoS2 based electrochemical device has some mechanical properties, such as stress, strain and work capacity. These properties are extraordinary considering the electrodes, made by simply stacking weakly interacting nanosheets.
Researchers said, the future studies is to scale up and try to make actuators that can move bigger things.
More information: [Nature]