Orientation-controlled crystallization of γ-glycine films with enhanced piezoelectricity

Abstract

Glycine, the simplest amino acid, is considered a promising functional biomaterial owing to its excellent biocompatibil-ity and strong out-of-plane piezoelectricity. Practical applications require glycine films to be manufactured with their...

Natural Piezoelectric Biomaterials: A Biocompatible and Sustainable Building Block for Biomedical Devices

“…Bottom: Crystal growth kinetics of glycine-PVA films when the liquid film had a convex (green) or concave (red) edge. Reprinted with permission from ref . Copyright 2022 Royal Society of Chemistry.…”

“…Because the misalignment was due to the tilted interface where the nucleation occurs, Sui et al presented a modified strategy to move the nucleation site of γ-glycine crystals to the flat interface area. 71 In their approach, a hydrophilic wall was added around the liquid precursor film. This changed liquid film edge from a convex surface to a concave surface.…”

“…One of the main reasons for their materials not showing higher d 33 is that the piezoelectric polar [001] direction was not aligned perpendicularly to the film surface. Because the misalignment was due to the tilted interface where the nucleation occurs, Sui et al presented a modified strategy to move the nucleation site of γ-glycine crystals to the flat interface area . In their approach, a hydrophilic wall was added around the liquid precursor film.…”

Manipulating the Piezoelectric Response of Amino Acid-Based Assemblies by Supramolecular Engineering

“…Previous works to obtain noncentrosymmetric crystals of amino acid derivatives have been reported by the groups of Leiserowitz and Lahav. − To complete the reductionist approach for minimal building blocks of proteins and peptides, recent studies have shown that extremely simple amino acids could self-assemble into well-ordered noncentrosymmetric architectures exhibiting significant piezoelectric characteristics. ,,− For example, γ-glycine crystals showed a piezoelectric longitudinal strain coefficient d 33 of 9.93 pm V –1 , comparable to inorganic AlN or Al 3 AsO 7 , which could be applied to fabricate a piezoelectric nanogenerator for an energy harvesting of 0.45 V . Furthermore, high-quality piezoelectric crystalline thin films were synthesized by aligning γ-glycine crystals between polymer layers, serving as an implantable electromechanical device. , In another example, tyrosine crystals with tightly packed face-to-face dimers possessed high thermal stability and robust mechanical properties . The predicted piezoelectric response of tyrosine crystals (d 25 = 9.73 pm V –1 ) was shown to be comparable to those of traditional inorganic materials (e.g., ZnO, CdS) and biological materials (e.g., bone, viruses, fibrillar rat tail collagen).…”

“…4,5,38−40 V −1 , comparable to inorganic AlN or Al 3 AsO 7 , which could be applied to fabricate a piezoelectric nanogenerator for an energy harvesting of 0.45 V. 14 Furthermore, high-quality piezoelectric crystalline thin films were synthesized by aligning γ-glycine crystals between polymer layers, serving as an implantable electromechanical device. 41,42 In another example, tyrosine crystals with tightly packed face-to-face dimers possessed high thermal stability and robust mechanical properties. 43 The predicted piezoelectric response of tyrosine crystals (d 25 = 9.73 pm V −1 ) was shown to be comparable to those of traditional inorganic materials (e.g., ZnO, CdS) and biological materials (e.g., bone, viruses, fibrillar rat tail collagen).…”