Self-healing, reprocessing and 3D printing of transparent and hydrolysis-resistant silicone elastomers

Various intrinsic self-healing silicone elastomers have been developed by incorporating different dynamic noncovalent or covalent bonds into elastomeric crosslinked networks. However, these self-healable silicone elastomers are either nontransparent or nonresistant to hydrolysis. In this study, a transparent and hydrolysis-resistant silicone elastomer with self-healability, reprocessability and 3D printability is facilely fabricated by successively thiol-ene UV-curing between thiol and vinyl functionalized polysiloxanes, and thermocuring between carboxyl and amido functionalized polysiloxanes. These obtained elastomers show an excellent healing efficiency of 97%, and the healing processes are repeatable for many times. Moreover, these elastomers can be repeatedly reprocessed with a recovery of 90% of virgin mechanical strengths, and the reprocessed elastomers can still repair damages with an efficiency over 90%. These self-healing and reprocessing behaviors mainly derive from the rearrangement of crosslinked networks via reversible breakage and reformation of ionic bonds. Importantly, the silicone elastomers are transparent with a transmittance of over 90% in visible light and hydrolysis-resistant to hydro-thermal treatment. Besides, the silicone elastomers can be fabricated into various self-healable architectures via 3D printing. Therefore, a feasible approach is provided to impart reversible ionic association induced self-healing and reprocessing to 3D printable silicone elastomers.