Self-healing in crystals and pizoelectricity

Piezoelectricity is the energy conversion observed in certain materials where mechanical stress can cause an accumulation of electric charge. The accumulated charge can assist in wound healing in living matters like soft tissue and bones. This has inspired an entire branch of material sciences dedicated to studying the intrinsic properties that enable ‘self-healing’ in both natural and synthetic materials. The replication of this phenomenon in hard crystalline solids however, had not been realized until researchers from Dr. C. Malla Reddy’s group in IISER, Kolkata came forward with a new class of piezoelectric crystals. An article detailing the characterization of these crystals that upon being mechanically fractured were found to recombine with no apparent external stimulus was published in a 2021 issue of Science.

Self-repairing synthetic materials known so far are typically soft and amorphous materials that require prolonged physical contact and additional stimulus in the form of heat or pressure to aid the ‘healing’ process. As Surojit Bhunia, the first author of this article and the lead PhD student investigator points out, “the research on self-healing dates back to only about a decade or so. It is difficult even in polymers, which have been extensively studied.” Several polymer compounds and gel-like materials usable for biomedical as well as other industrial…