Researchers at the University of California, Los Angeles (UCLA) have developed a new material for building artificial muscles that are stronger and 10 times more flexible than naturally occurring muscles, states a university press release. .
Scientists have been eager to replicate muscles in the body, which can then be used to create soft robots and new haptic technologies with a sense of touch. There are many soft materials that are known to physicists that can do the dual job of delivering mechanical output while remaining pliable even under high stress conditions.
A class of materials called dielectric elastomers (DEs) can provide both ductility and toughness, and they are not only light in weight but also have high elastic energy densities. DEs can be made from natural or synthetic compounds and are polymers that can change shape or size when an electric field is applied. This makes them ideal materials for making actuators, machines that can convert electrical energy into mechanical work.
What was the need for improvement then?
Currently, DEs are manufactured using either acrylic or silicone and while these have been useful, they also come with some drawbacks. DEs made from acrylic can handle high levels of stress but they require pre-stretching and lack flexibility. Silicon DEs, on the other hand, can be easily made but fail to handle high strains.
Working with the non-profit organization, SRI International (formerly known as the Stanford Research Institute), the UCLA team used commercially available chemicals and an ultraviolet (UV) Used a light-based curing process.
The researchers were able to alter the cross-linking in the material’s polymer chains to make DE soft, flexible, and easy to scale without losing stamina or strength. Changes in the manufacturing process allowed the researchers to create a thin film of DE, which they call processed, high-performance dielectric elastomer or PHDE.
How can a PhD be used?
A pHE film is as thin as a human hair and also as light in weight. Laying down these films could help researchers build miniature actuators that can act like muscle tissue and produce enough mechanical energy to power a small robot.
The soft material is layered first. However, the method employed to do this involves the use of a liquid resin that first needs to be deposited and then cured. Such a “wet” process can result in an actuator with uneven layers, resulting in poor performance. This is why artificial muscles you may have seen before, they are just one layer thick.
Researchers at UCLA also worked on this aspect and implemented a dry process where PHDe films are layered using a blade and then UV-cured. The simplified process has also allowed researchers to create actuators that resemble spider legs that bend and then jump, or even windup and then spin.
The press release claims that these new actuators can generate many times more force than biological muscles and are 3-10 times more flexible than their natural counterparts. In one demonstration, the researchers showed that the actuator could bounce a ball that was 20 times its weight.
,This flexible, versatile and efficient actuator could open the door to artificial muscles in new generations of robots, or into sensors and wearable technology that can more accurately mimic or improve human motion and capabilities,” said materials science professor Qibing Pei. Said and Engineering at UCLA