Self-Healing Polymers Based on Host-Guest Interactions Between Cyclodextrin and Different Types of Guest Molecules

Self-healing polymers can spontaneously repair cracks or fractures themselves thatthis property increases their service life. Propagation of the microcracks in polymerstructures may leads to material failure, so the research on self-healing polymeric materialshave attracted significant attention. The fundamental mechanism for self-healing polymericmaterials involves reversible damage-restoring bonds. Usually external stimuli is requiredto repair the damaged bonds and self-healing process. There is a number of influentialparameters on self-healing behaviors, including healing efficiency (a ratio of mechanicalproperty measured after and before healing), healing rate, healing times at the same fracturepoint, and storage time (after which the broken parts still show the healing property). Hostguestinteractions occur when two or more chemical species interact with each other vianon-covalent bonds. In supramolecular host-guest interactions, one moiety (the guest)is physically inserted to another moiety (the host) and is held together by non-covalentinteractions. Since the interactions are reversible, polymer networks constructed by suchinteractions can exhibit self-healing properties. Cyclodextrins are suitable resources forpreparation of the host-guest interactions because of their biocompatibility, good solubilityand the ability for chemical surface modification. The purpose of this paper is to investigatethe characteristics, mechanisms and different methods for synthesis of self-healing polymerhydrogels.