Shape-Memory and Self-Healing Polymers Based on Dynamic Covalent Bonds and Dynamic Noncovalent Interactions: Synthesis, Mechanism, and Application

Abstract

Shape-memory and self-healing polymers have been a hotspot of research in the field of smart polymers in the past decade. Under external stimulation, shape-memory and self-healing polymers can complete programed shape transformation, and they can spontaneously repair damage, thereby extending the life of the materials. In this review, we focus on the progress in polymers with shape-memory and self-healing properties in the past decade. The physical or chemical changes in the materials during the occurrence of shape memory as well as self-healing were analyzed based on the polymer molecular structure. We classified the polymers and discussed the preparation methods for shape-memory and self-healing polymers based on the dynamic interactions which can make the polymers exhibit self-healing properties including dynamic covalent bonds (DA reaction, disulfide exchange reaction, imine exchange reaction, alkoxyamine exchange reaction, and boronic acid ester exchange reaction) and dynamic noncovalent interactions (crystallization, hydrogen bonding, ionic interaction, metal coordination interaction, host–guest interactions, and hydrophobic interactions) and their corresponding triggering conditions. In addition, we discussed the advantages and the mechanism that the shape-memory property promotes self-healing in polymers, as well as the future trends in shape-memory and self-healing polymers.

Electroactive Self-Healing Shape Memory Polymer Composites Based on Diels–Alder Chemistry

“…U-shape samples were used. A power source was set to four different voltages (20,30,40, and 50 V), while the temperature and the current was measured by a thermocouple and a multimeter, respectively.…”

“…The thermo-reversible Diels–Alder (DA) reaction between furan and maleimide groups has been extensively used in developing these reprocessable and self-healing polymers, since the reaction has fast kinetics and undergoes reversible changes within a moderate and practical temperature range (60–110 °C, with the lower temperatures favoring the formation of the adduct and the higher ones favoring the cleavage of it). ,− Different authors have described these furan/maleimide based cross-linked polymers capable of both SHE and SME. ,− Zhang and co-workers reported an epoxy-based self-healing SMP with furan pendant groups and reversibly cross-linked with bismaleimide, showing great recyclability and shape reprogramming. In another report, Zheng et al described a biobased polyurethane using soy oil and furan-maleimide dynamic chemistry, which showed efficient SME, SHE, and reprocessability.…”

An Overview of Self‐Healable Polymers and Recent Advances in the Field

“…Such reversible reactions allow self-healing and often exhibit shape memory abilities as well. [96][97][98][99] The main advantage of this reversibility is the theoretically infinite cycles of healing sequences. [100][101][102][103] An advancement in this field was the presentation of novel polymers of poly(𝜖-caprolactone) (PCL) based polyurethane (PU) networks with DA bonds that exhibit shape memory and self-healing mechanisms in response to the ultrasound as shown in Figure 6 using high intensity focused ultrasound (HIFU).…”

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

“…When the material has a fracture or damage, it is possible to repair or self-heal. So, this material can be used before replacing it with a new one [44][45][46][47][48][49][50][51]. [44].…”