Advancements in silicone elastomers enhance soft robotics manufacturing

This breakthrough could streamline the manufacturing process for elastomer-based components, offering energy savings and improved throughput.

Soft robotics has experienced rapid growth over the last decade, driven by advancements in materials such as elastomers. These materials are essential for creating robots that can safely interact with human bodies and other sensitive objects. Daniel Preston, an Assistant Professor of Mechanical Engineering at Rice University, and the corresponding author of the study published in Cell Reports Physical Science, highlighted the significance of this research: “In our study, we looked at elastomers as a class of materials that enables soft robotics, a field that has seen a huge surge in growth over the past decade. While there is some related research on materials like epoxies and even on several specific silicone elastomers, until now there was no detailed quantitative account of the curing reaction for many of the commercially available silicone elastomers that people are actually using to make soft robots. Our work fills that gap.”

The silicone elastomers studied typically begin as viscoelastic liquids that solidify into a rubbery material. This transformation allows for intricate component casting, a vital process in soft robotics manufacturing.

Until this study, manufacturers had to rely on rough empirical estimates to determine the optimal temperature and duration for curing elastomers, a method fraught with inefficiencies. Te Faye Yap, a graduate student in Preston's lab and lead author of the study, emphasised the importance of the new model: “There’s a huge need to make manufacturing processes more efficient and reduce waste, both in terms of energy consumption and materials.”

Using a rheometer, the team analysed the curing behaviour of six commercially available platinum-catalysed elastomers. They developed a model based on the Arrhenius relationship, which connects the rate of curing reactions to temperature.

The research findings suggest that heating elastomers to 70°C does not compromise their mechanical integrity compared to those cured at room temperature. This discovery is crucial for the soft robotics field, particularly in applications requiring precise mechanical properties.

Preston also discussed the implications for soft robotic assembly: “Say we’ve already cured a few different components that need to be assembled together into the complete, soft robotic system. When we then try to adhere these components to each other, there’s an impact on the adhesion or the ability to stick them together. In this case, that is greatly affected by the extent of curing that has occurred before we tried to bond.”

This insight into the curing process opens new possibilities for the design and manufacturing of soft robots, especially in sensitive applications such as surgical robotics, agriculture, disaster relief, and research.

The study not only enhances the efficiency of manufacturing processes for soft robotic components but also broadens the potential applications of these technologies. The unique properties of silicone elastomers, including biocompatibility and thermal resistance, make them invaluable in various sectors.

By providing a robust framework for understanding and controlling the curing process of silicone elastomers, this research paves the way for more complex and reliable soft robotic systems. The implications for the biomedical industry, among others, are particularly promising, as softer, more compliant robots can significantly reduce the risk of injury during medical procedures or patient care.