An anti-stress relaxation, anti-fatigue, mildew proof and self-healing poly(thiourethane-urethane) for durably stretchable electronics

The elegant choice of non-planar ring structure and adoption of sulphur containing chemical bonds in main chain are the key factors in obtaining anti-stress relaxation, anti-fatigue, anti-fungal and self-healing poly(thiourethane-urethane) elastomer for durably stretchable device. This polyurethane successfully pass through the long term tension, cyclic tension, mildew environment and accidental damage tests. [Display omitted] •Non-planar rings increased the anti-stress relaxation and anti-fatigue properties.•The thioether and thiourethane endow the mildew proof and self-healing properties.•Anti-stress relaxation, anti-fatigue, anti-fungal and self-healing are integrated. Considering the complicated environment in daily use of stretchable devices, the capabilities of anti-stress relaxation, anti-fatigue, anti-fungal and self-healing are very much appreciated, and the above four functionalities largely depend on the elastic matrix. Here, these demands are fulfilled by a poly(thiourethane-urethane) elastomer CBPU-3. In detail, a large amount of cyclohexane rings, with completely reversible boat–chair conformational transition, are introduced into the backbone of poly(thiourethane-urethane), and such non-planar ring imparts molecular elasticity and modulus into the elastomer, resulting in remarkable anti-stress relaxation and anti-fatigue abilities. Even after 20 h fixation at 300% strain and 1000 times cyclic tensile (50% strain), the recovery ratio could still be higher than 98%, and its stable microstructure is proved by SAXS scattering patterns. In addition, the thioether bond ensures the effective mildew proof ability, and the mechanical properties and transmittance change little even after a severe mildew pollution for 30 days. Simultaneously, the relatively lower bond energy of C-S (62.0 Kcal/mol) in thiourethane bonds endowes the poly(thiourethane-urethane) with self-healing capability (highest: 40 μm/min at 80 °C). Finally, the durability and usability of the deformable resistive sensor array based on this elastomer as the matrix are drastically enhanced due to the above integrated functionalities.