UH professor finds new method to improve strength of silicone-based devices

A new method improving the bonding strength of silicone-based materials could enhance the durability and performance of soft biomedical devices, wearable technology, and soft robots.

Silicone elastomers — rubbery, gel-like materials made from silicone — are used in items such as artificial muscles, flexible medical implants, and fitness trackers. These devices need to bend, stretch, and move with the human body without deteriorating over time.

They are also widely used in soft devices because they are flexible, chemically stable, and compatible with human tissue. However, a key challenge in their use has been controlling how well layers or components adhere during manufacturing, particularly when curing temperatures and durations vary.

In a new “Science Advances” study, published July 16, lead author and University of Hawaiʻi at Mānoa Department of Mechanical Engineering Assistant Professor Te Faye Yap and her co-authors developed a new framework to predict how well silicone materials will adhere by examining curing time and temperature.

Bonding too late results in a weak connection because the materials lack sufficient chemical interaction to hold together, while bonding at the right time creates stronger, more durable joints.

“Strong, consistent bonding is crucial to prevent leaks and device failure,” Yap said. “This framework expands the design and fabrication toolkit for silicone elastomeric devices — an advancement that aligns with the College of Engineering’s vision for on-island advanced manufacturing and innovation in Hawaiʻi.”

This method helps identify when a material will fail by peeling or breaking, allowing manufacturers to adjust curing and bonding processes to mitigate the risk of devices coming apart.

While a Ph.D. student at Rice University, Yap and her co-authors built soft robotic parts using the new method. The silicone parts curved 50% more, and 3D-printed pieces adhered better than usual.

The model worked well even when curing temperatures were changed to speed up production or enable printing.

The research offers valuable guidance for building silicone devices using both molding and 3D printing. This straightforward and generalizable method can make soft devices stronger and more reliable and has the potential to shape future advances in flexible electronics and 3D-printed technology.