Reconfigurable and Reprocessable Thermadapt Stress-Free Two-Way Shape Memory Polymers Based on a Dual Crosslinking Network with Outstanding Mechanical Properties

The reconfigurable and reprocessable thermadapt two-way shape memory polymers (2W-SMPs) are highly desirable for many advanced biomimetic applications, but the preparation of these polymers with economical raw materials and convenient approaches still remains a challenge. In this work, thermadapt 2W-SMPs based on a dual crosslinking network are synthesized by linking polyethylene glycol with hydroxylated modified SBS via dynamic covalent bonds. Benefiting from the synergistic effect of combining a dynamic covalent network and a physical cross-linking network, the thermadapt 2W-SMPs exhibit a good balance of mechanical properties and favorable two-way shape memory effect (2W-SME) with the reversible actuation strain of 11.9%. The 2W-SMPs can be reprocessed and transformed into complex 3D shapes after multiple folding processes due to the dynamic covalent exchange as well as the reversible physical crosslinking, and the obtained new samples still exhibit good 2W-SMEs. Furthermore, the transition temperature of 2W-SMPs is designed to be close to human body temperature, and it is manufactured into a biomimetic mimosa actuator that can undergo shape changes through finger contact and cooling. This work provides a new idea for the development of thermadapt 2W-SMPs, and the obtained materials show great potential applications in intelligent actuators.

Automated summary

In this study, reconfigurable and reprocessable thermadapt two-way shape memory polymers (2W-SMPs) were synthesized using polyethylene glycol and hydroxylated modified SBS through dynamic covalent bonding. The 2W-SMPs exhibit a good balance of mechanical properties and a favorable two-way shape memory effect (2W-SME) with a reversible actuation strain of 11.9%. These materials can be reprocessed and transformed into complex 3D shapes due to the dynamic covalent exchange and reversible physical crosslinking. Furthermore, a biomimetic mimosa actuator that can undergo shape changes through finger contact and cooling was manufactured. This study provides a new idea for the development of thermadapt 2W-SMPs and shows great potential applications in intelligent actuators.