Design of Robust Self-Healing Silicone Elastomers Based on Multiple H-Bonding and Dynamic Covalent Bond

Abstract

A room-temperature self-healing silicone elastomer was prepared based on the synergistic effect of multiple H-bonding and dynamic covalent bond. The multiple bonds constructed by inserting thiourea into the polyurea network can inhibit the crystallization of hard urea H-bonds segments and activate the diffusion movement of polymer chains. Dynamic imine endows materials with a strong connection for the fracture interface by imine metathesis. The effect of thiourea on urea H-bonds was confirmed by the Fourier transform infrared spectrum, which showed obvious changes of H-bond density according to peak revolution of CO and N–H. Differential scanning calorimetry demonstrated the transition from the crystalline to amorphous state after the introduction of thiourea. Tensile tests and scratch-healing tests showed that this design method can improve the self-healing property without sacrificing the mechanical strength. Finally, the optimized self-healing process was analyzed from the perspectives of the contact process, the interpenetration diffusion of the polymer chain, and rebuilding of crosslinking points between the two interfaces, which would build an avenue for constructing a fast, self-healing, and tough material.

Non-Covalent Interaction on the Self-Healing of Mechanical Properties in Supramolecular Polymers

“…Sci. 2022, 23, x FOR PEER REVIEW (2022) [98]. The network structure in Figure 15 present that the mu tained by adding thiourea into the polyurea network.…”

“…This result indicated the self-healing efficiency could reach 60% after 2 min of healing time and reach 80% after 10 min of healing time at room temperature [76]. Furthermore, the synergistic effect of self-healing in the silicone elastomer based on dynamic covalent bonds and multiple hydrogen bonding was studied by Chen et al Furthermore, the synergistic effect of self-healing in the silicone elastomer based on dynamic covalent bonds and multiple hydrogen bonding was studied by Chen et al Furthermore, the synergistic effect of self-healing in the silicone elastomer based on dynamic covalent bonds and multiple hydrogen bonding was studied by Chen et al (2022) [98]. The network structure in Figure 15 present that the multiple bonds are obtained by adding thiourea into the polyurea network.…”

“…Furthermore, the Raman spectra using mapping mode presented self-healing behavior and healable efficiency of almost 79% for 1 h and 94% for 6 h of healing time. Therefore, the optimized self-healing process presented interpenetration diffusion of the rubber chain and rearrangement of network join between the two interfaces to obtain a rapidly self-healing and tough material [98].…”

“…Furthermore, the Raman spe mode presented self-healing behavior and healable efficiency of alm 94% for 6 h of healing time. Therefore, the optimized self-healing pro penetration diffusion of the rubber chain and rearrangement of netw two interfaces to obtain a rapidly self-healing and tough material [98 Raman spectra in the healing process [98]. Adapted with permission from American Chemical Society.…”

“…The self-healing model and microscope of silicone elastomers with hydrogen bonding and covalent bonds; (a) the model of broken and healing mechanism; and (b) the mapping mode of Raman spectra in the healing process[98]. Adapted with permission from[98]. Copyright 2022 American Chemical Society.…”