A type of polyurethane elastomer with excellent self-healing ability has been fabricated through digital light processing 3D printing. First, a type of polyurethane acrylate containing disulfide bonds is synthesized and then compounded with reactive diluent and photoinitiators to get a photopolymer resin. Due to the good fluidity and high curing rate, the photopolymer resin can be applied in DLP 3D printing, and various 3D objects with complicated structures, high printing accuracy, and remarkable self-healing ability have been printed. The tensile strength and elongation at break of the polyurethane elastomer are 3.39 ± 0.09 MPa and 400.38 ± 14.26%, respectively, and the healing efficiency can get to 95% after healing at 80 °C for 12 h and can be healed for multiple times. With the ease of fabrication and excellent performance, the polyurethane elastomers from DLP 3D printing have great potential applications in flexible electronics, soft robotics, and sensors.

Recycling process of epoxy vitrimers based on siloxane equilibration.

Flexible sensors that can transduce various stimuli (e.g., strain, pressure, temperature) into electrical signals are highly in demand due to developments in human–machine interaction. However, it is still a great challenge to fabricate high-performance sensors with high sensitivity, short response time, and long-term reliability simultaneously. Herein, a series of chemically crosslinked ionogels with dynamic disulfide bonds in the polymer chains were synthesized and high-performance ionotronic devices were prepared. The ionogels displayed ultrahigh elasticity and durability in the cyclic loading–unloading tests, and a simultaneous remarkable self-healing performance under UV irradiation at room temperature. Moreover, the ionogels possessed tunable mechanical properties, of which the tensile strength ranged from 0.29 to 7.42 MPa and the break elongation was from 546% to 1011%. The ionogel sensors exhibited a short response time and high sensitivity in a wide range of strains and pressures. Digital light processing (DLP) 3D printing technology was applied to fabricate micro-structured pressure sensors and their sensitivity was greatly increased. The coupling effects of good mechanical properties and remarkable self-healing performance significantly increased the long-term reliability of the ionotronics. Furthermore, I-TENGs with a high energy-harvesting performance and high sensitivity were prepared. Benefiting from the remarkable mechanical, self-healing, and 3D printing performance, the ionogels have great potential applications in biomedical and intelligent fields.