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Self-healing soft robotic grippers based on the Diels-Alder reaction
Book Contribution - Book Chapter Conference Contribution
Mimicking nature, many next generation robots are equipped with intrinsic compliances in the form of springs or flexible polymers. This allows absorbing shocks and protects them against mechanical impacts. Soft robots take this principle to the extreme. Their bodies are manufactured exclusively out of flexible polymer membranes. Being entirely soft, these robots can interact safely with other soft matter and are therefore suitable for food grippers, surgical applications, industrial robotic co-workers and wearable robotics. However, similar to the human soft tissue, their membranes are extremely susceptible to damage caused by sharp objects.
In this research this problem is tackled by manufacturing soft pneumatic robots out of self-healing elastomers. Their membranes are built out of reversible covalent networks based on the Diels-Alder reaction. The networks consist of a furan-functionalized triamine J5000 that is crosslinked using a bismaleimide. The thermomechanical properties were altered by changing the maleimide-to-furan ratio (r) into 1, 4/6 and 3/6. Their thermal properties were characterized using DMA, TGA, DSC and Rheology. Although having different properties, these networks can chemically bind at the interface using a heat-cool cycle. This results in a very strong interfacial connection. Single flexible components can be made consisting of multiple materials, increasing the design freedom of self-healing soft robotic designs. This is elaborated in the construction of a multi-material self-healing soft gripper using r = 1 and 4/6 Diels-Alder polymers. This gripper can heal entirely from realistic macroscopic damages using a heat-cool cycle (80°C). When decreasing the maleimide-to-furan ratio, the Diels-Alder reaction kinetics are favoured at lower temperatures. As a result the elastomer with the lowest ratio (3/6) is able to heal macroscopic damages at room temperature. This autonomous self-healing elastomer was used to construct a second soft gripper that can heal large cuts and perforations completely without the need of a heat stimulus.
In this research this problem is tackled by manufacturing soft pneumatic robots out of self-healing elastomers. Their membranes are built out of reversible covalent networks based on the Diels-Alder reaction. The networks consist of a furan-functionalized triamine J5000 that is crosslinked using a bismaleimide. The thermomechanical properties were altered by changing the maleimide-to-furan ratio (r) into 1, 4/6 and 3/6. Their thermal properties were characterized using DMA, TGA, DSC and Rheology. Although having different properties, these networks can chemically bind at the interface using a heat-cool cycle. This results in a very strong interfacial connection. Single flexible components can be made consisting of multiple materials, increasing the design freedom of self-healing soft robotic designs. This is elaborated in the construction of a multi-material self-healing soft gripper using r = 1 and 4/6 Diels-Alder polymers. This gripper can heal entirely from realistic macroscopic damages using a heat-cool cycle (80°C). When decreasing the maleimide-to-furan ratio, the Diels-Alder reaction kinetics are favoured at lower temperatures. As a result the elastomer with the lowest ratio (3/6) is able to heal macroscopic damages at room temperature. This autonomous self-healing elastomer was used to construct a second soft gripper that can heal large cuts and perforations completely without the need of a heat stimulus.
Book: Proceedings of the International Conference on Self-Healing materials (ICSHM) 2019
Pages: 151-151
Number of pages: 1
Publication year:2019
Keywords:self-healing polymers, soft robotics