International researchers from the Johannes Kepler University (JKU) in Linz, Austria, the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart, Germany, and the University of Colorado (CU Boulder) in Boulder, USA. , have designed a fully biodegradable, high-performance artificial muscle that can be used to move soft robots.
This technological breakthrough opens up new possibilities for the way robots can shape the world around us, from wearable devices that can redefine our physical abilities in old age to rescue robots that can navigate rubble in search of missing people. Although these artificial muscles can have a strong social impact during use, they do not create a negative environmental impact after use.
A team of scientists develops biodegradable artificial muscles for the robotics of the future
In this sense, the scientists collaborated to design a completely biodegradable artificial muscle based on gelatin, oil and bioplastics. They demonstrated the potential of this biodegradable technology by using it to animate a robotic grip that could be especially useful in single-use deployments such as garbage collection. At the end of their useful life, these artificial muscles can be disposed of in municipal compost bins and, under controlled conditions, fully biodegrade in six months.
The electrically powered artificial muscle is called HASEL. Basically, they are oil-filled plastic bags that are partially covered by a pair of electrical conductors called electrodes. Applying a high voltage across the pair of electrodes causes opposite charges to be generated on them, generating a force between them that pushes the oil toward an electrodeless region of the bag. This oil migration causes the bag to contract, just like a real muscle. It is possible to see them in operation in a video published by the research team.
A key requirement for HASELs to deform is that the materials that make up the plastic bag and the oil are electrical insulators that can withstand the high electrical voltages generated by the charged electrodes. One of the difficulties for this project was developing a completely biodegradable, soft, conductive electrode. Researchers at Johannes Kepler University created a recipe based on a mixture of biopolymer gelatin and salts that can be poured directly onto HASEL actuators.
The next step was to find suitable biodegradable plastics. Engineers of these materials are primarily concerned with properties such as rate of degradation or mechanical strength, not with electrical insulation, which is a requirement for HASELs operating at a few thousand volts. However, some bioplastics showed high material compatibility with gelatin electrodes and sufficient electrical insulation. Even HASELs made from a specific combination of materials were able to withstand 100,000 actuation cycles at several thousand volts without showing signs of electrical failure or loss of performance. These biodegradable artificial muscles are electromechanically comparable to their non-biodegradable counterparts.
These types of technological advances can not only benefit society, but also the environment. Disposal of electronic and plastic waste is a major problem, and disposable robots only contribute to the accumulation of these materials in landfills. By designing robots with biodegradable artificial muscles, the accumulation of waste can be avoided in the long term.
Furthermore, this technology could also be useful in emergency situations. Biodegradable rescue robots could be deployed in areas affected by natural disasters and then disposed of without leaving a lasting environmental footprint. Disposable healthcare robots could also be a sustainable solution for a variety of medical applications.
Another potential benefit of biodegradable artificial muscles is their use in food and agricultural applications. The food and agricultural industry relies heavily on the use of plastics and other non-biodegradable materials for a variety of applications, from food packaging to greenhouse construction.
Care for environmental sustainability is an increasingly relevant issue today. With this concept reference is made to the balance between human needs and natural resources, so that current needs can be met without depleting natural resources for future generations. It is therefore critical that technology and innovation are developed with this balance in mind, to pave the way towards a more sustainable future for all.
