fig2

Figure 2. Piezoelectric properties of small biomolecules with non-centrosymmetric structure. (A) Schematic illustration of an amino acid molecule. (B) Crystal structure and molecular dipoles of β- glycine and γ-glycine. Reproduced with permission^[20]. Copyright 2019, American Chemical Society. (C) Crystal structure of L-alanine and DL-alanine, and the latter has a stronger net polarization. Reproduced with permission^[27]. Copyright 2019, American Physical Society. (D) Molecular dynamic (MD) simulation of the step-dependent driving force of diphenylalanine (FF) peptide nanotubes. Reproduced with permission^[35]. Copyright 2018, American Chemical Society. (E) In-plane (IP) signal of two FF peptide nanotubes (A and B) with opposite polarizations demonstrate a strong d15 shear piezoelectric response. Reproduced with permission^[31]. Copyright 2010, American Chemical Society. (F) Entire matrix of piezoelectric constants of FF peptide nanotubes obtained from the solution. piezoelectric response. Reproduced with permission^[33]. Copyright 2016, Elsevier.