Stretchable electronics—electronic devices that can be elongated, compressed, or twisted to fit practically any surface— have potential for dozens of applications.
But intergrading the wide variety of materials needed to make an electronic device with stretchable components has proved to be challenging.
Researchers at the Missouri University of Science and Technology (S&T) are tackling this challenge using 3D printing, also known as additive manufacturing. This process allows manufacturers to print highly conductive materials onto an elastomer surface layer by layer to create a stretchable electronic device. They recently outlined their research on this process in Micromachines.
“Additive manufacturing has the benefit that it can easily change from one material to the other and integrate all the different materials together in one print,” said the study author Heng Pan, assistant professor of mechanical and aerospace engineering at Missouri S&T, in an exclusive interview with R&D Magazine. “You can pretty much print any material in 3D geometry. We believe the additive technique has a very strong advantage in the creation of electronics.”
At Missouri S&T, Pan and his colleagues are testing a 3D printing approach that Pan calls “direct aerosol printing”. The process involves spraying a conductive material and integrating with a stretchable substrate to develop sensors that can be placed on skin.
Pan and his team have created a working prototype of a stretchable electronic device that can adhere to the face. Their work is still in the early phases, but they believe the technology has a lot of potential, particularly in the biomedical engineering space, because of the soft and conformable nature of the device.
“The biggest benefit of these electronics is that they can be completely wearable, and they can completely form to any kind of motion,” said Pan. “They can be mounted on face, for example, and could detect any small motion from your face. Stretchable electronics could also be developed and installed in the shoes, and used to measure pressure, weigh, ect. It has a lot of applications.”
However, several challenges must be addressed before stretchable electronics become widely used as components in consumer electronics, medical devices or other fields, said Pan.
All the materials needed to make each stretchable electronic device need to be printable, which means developing ink and printable materials that have all the necessary properties for each type of electronic device.
“It has to perform similar to conventional fabricated materials, but it needs to be printable and also functional,” said Pan.
There are also integration challenges, such as varying temperature requirements among different materials. It is also important to ensure that the stretchable electronics and the malleable surfaces they’re built upon perform and age well together.
One of the biggest focuses of the research team right now is to develop an effective, long-lasting stretchable battery.
“The energy device is a very critical component in order for this to be realistic,” said Pan. “We are intensely working on the battery.”
Once the technology is perfected it will also need to be scaled-up. 3D printing does make that process more streamlined as it can be easily moved to any location, said Pan, but there are still a lot of unknown factors. The device itself will also need to be low-cost to create and eventually, they’d like to make it biodegradable. Despite these hurdles, Pan is optimistic that stretchable electronics, made using 3D printing, will become more commonplace going forward.
“There is a lot of potential to this related to human-computer interaction,” he said. “We see a lot of benefit. We think this can be the future of electronic development.”
