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Piezoelectric Nanogenerators
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Nanogenerators, 2023
Bhavya Padha, Sonali Verma, Sandeep Arya
Glycine (G) is a zwitterionic amino acid that serves as an excellent model for studying polymorphic crystallization [112–114]. At ambient conditions, crystalline glycines exhibit three different structures, α, β, and γ, among which β- and γ-structures exhibit shear piezoelectric effect owing to their acentric configuration [115–118]. As with inorganic materials, piezoelectricity is produced when an ion is displaced inside the crystal, and this displacement results in the formation of the dipole in the local material as well as net polarization in the bulk material, as illustrated in Figure 6.2(c). β-structure exhibits good shear piezoelectric constant, d16 = 190 pm/V [119], that is analogous to barium titanate's (BaTiO3) piezoelectric constant [120]. Diphenylalanine (FF) consists of two phenylalanine (F) amino acids and can self-assemble into semi-crystalline peptide NTs and microrods as well as exhibits several desirable properties such as morphological and functional diversity, good biocompatibility as well as a high Young's modulus [121]. Diphenylalanines with NSs are extensively investigated piezo-materials with non-centrosymmetric hexagonal space group (P61) [122]. Such crystalline material demonstrates a variety of physical properties such as piezoelectric, pyroelectric, ferroelectric effects, as well as enantiomorphism [123]. The shear piezoelectric constant of peptide NTs has been increased to d15 = 60 pm/V [124]. For enhancing scalability and homogeny of the semi-crystalline film, unidirectionally polarized as well as aligned diphenylalanine NTs films were synthesized via meniscus-driven self-assembly method [125], resulting in d15 = 45 pm/V that is equivalent to highly crystalline materials. Additionally, Nguyen et al. focused on achieving piezoelectric effect (up to d33 = 17.9 pm/V) in nano-scaled peptides through vertical alignment of every microrod [126, 127].
Self-assembly of a cholesteryl-derived diphenylalanine in ethylenediamine-water mixed medium
Published in Journal of Dispersion Science and Technology, 2021
Juntan Zhou, Jingxuan Yang, Li Zhao, Ce Wang, Baocai Xu
As a typical low-molecule-weight peptide, diphenylalanine (FF), a core recognition motif of Alzheimer’s β-amyloid polypeptide, is a captivating building block that can self-assemble into one-dimensional structures through the combination of hydrogen bonding and side-chain π-π stacking.[12] The regulation of FF-based self-assemblies was studied in depth from then on.[13, 14] Meanwhile, FF-based derivatives have been developed abundantly through the chemical modification of N- and/or C-terminus to introduce new intermolecular interactions or functions into the self-assemblies.[15–17] For example, Fmoc-FF molecule with increased π-π interactions can rapidly self-assemble into fibers found by Gazit,[18] which showed pH sensitivity.[19] He et al designed a redox-active ferrocene-modified FF (Fc-FF), which showed a morphological transformation from metastable nanospheres to nanofibers after shaking.[20] Solvent-controlled self-assembly has been a common strategy adopted to construct various FF-based morphologies in water, organic solvents or their mixtures.[21, 22]