(161ak) Robust Amphiphilic Elastomer Coatings with Dual-Healing Mechanism Based on Urea and Aromatic Disulfide Bonds

Self-healing polymers, with an ability to recover lost functionalities, are attractive in several fields of work, for increasing the useful lifespan of materials prepared using them. Intrinsic self-healing polymers based on dynamic urea bonds [1] are of particular interest because of their good healing efficiencies and relatively straightforward synthesis and scale-up. In this work, low modulus self-healing polyurethane-urea copolymer coatings, consisting of hydrophobic PDMS segments, hydrophilic poly(ethylene glycol) segments, and aromatic disulfide were designed and synthesized. Transparent thin elastomers with high stretchability and excellent healing ability were obtained. Tensile testing and nanoindentation measurements were used to characterize the extent of self-healing at the interface of a cut specimen, at room temperature, in air and underwater. Almost 100 % recovery was observed within 24 h. Furthermore, the incorporation of aromatic disulfide groups increased the elastomer’s room temperature modulus by a factor of about 2.5 and tensile strength by a factor of 3. However, advantageously, there was no decrease in elongation at break. The amphiphilic copolymers developed in this work are potentially useful in facilitating the underwater release of adhered objects, for example, in marine antifouling coatings [2].

References

[1] Ying H, Zhang Y, ChengJ (2014) Dynamic urea bond for the design of reversible and self-healing polymers. Nature Communications 5: 3218.

[2] Krishnan S, Weinman CJ, Ober CK (2008) Advances in polymers for anti-biofouling surfaces. J. Mater. Chem. 18: 3405-3413.