Incomplete ionic interactions and hydrogen bonds constructing elastomers with water accelerated Self-Healing and self-healing strengthening capacities

Abstract

Self-healing polymers with microphase separation structure typically require external stimuli to achieve self-healing, and their performance often degrades. To solve these issues, we introduce tertiary amine and carboxyl groups into polymer. The intermolecular ionic interactions and H-bonds contribute to the formation of microphase separation structures, endowing polyurethane elastomers (PU-n) outstanding mechanical properties with a maximum tensile strength and toughness of 20.61 MPa and 59.02 MJ/m3, respectively. The self-healing of the prepared PU-n can be achieved at room temperature and accelerated significantly by water because hard phases can be dissociated, resulting in enhanced molecular movement. After self-healing with water, the enhanced molecular movement and further ionization of ionic groups lead to stronger H-bonds and ionic interactions, promoting more distinct microphase separation. Thus, the mechanical strength is strengthened and the self-healing efficiency can reach 104.72 %. The enhanced molecular movement and strengthened intermolecular interactions when self-healing with water can also be verified through in-depth analysis of molecular dynamics (MD) simulations of the self-healing process. Furthermore, PU-n display remarkable shape memory and can be recycled through exposure to solvents and hot water. This study provides a novel and general method for preparing materials that can self-heal with water and self-strengthen after self-healing.