Heat-triggered poly(siloxane-urethane)s based on disulfide bonds for self-healing application

Polydimethylsiloxane (PDMS) is one of the most widely employed silicon-based polymers for its high flexibility, low usage temperature, excellent water resistance, outstanding electrical insulting property, and physiological inert, etc. However, the covalent-bonded SiO bonds are unable to heal automatically when damaged, which would result in the failure of the materials and devices. Disulfide bond based polymers show high healing efficiency at moderate temperature and have been investigated intensively. Herein, we report a PDMS-based polyurethane self-healing polymer (PDMS-PU) modified with disulfide bonds, which exhibited a reinforced thermal stability, excellent stretchability, and satisfactory self-healing ability. The effect of different ratio of PDMS and disulfide bond contents on the elastomer properties was investigated. With the increase of PDMS content, the decomposition temperature of the PDMS-PU-3 (332 degrees C) elastomer with highest content of PDMS was increased by 34 degrees C compared to PDMS-PU-1 (298 degrees C) with lowest content of PDMS and exhibited a largest elongation at break of 1204%. PDMS-PU-1 with highest content of disulfide bond possessed a highest healing efficiency of 97%. The results indicated the PDMS-PU elastomers can be used as self-healing flexible substrate for flexible electronics. (C) 2018 Wiley Periodicals, Inc.