Origins of Negative and Positive Electromechanical Response of Oligopeptide Piezoelectrics

Abstract

In response to an applied electric field, materials and even individual molecules can exhibit electromechanical response. Previous work has demonstrated the piezoelectric distortion of polar organic crystals, biomaterials, and even single molecular monolayers, increasing length in response to the change in potential energy of interaction between the polarization or dipole moment and the applied electric field. In this work, we demonstrate through density functional calculations that helical oligopeptides, depending on sequence can exhibit both positive and surprisingly also negative piezoresponse. While the overall molecular dipole moment may favor positive piezoresponse, individual hydrogen bonding interactions along the backbone have the opposite direction, enabling tailored sequences to yield either net expansion or contraction in response to an electric field. While negative piezoresponse has largely been considered in polyvinylidene difluoride (PVDF) and related systems, understanding the atomic and molecular basis for both electromechanical effects will yield interesting new applications.

Ab-Initio Predictions of the Energy Harvesting Performance of L-Arginine and L-Valine Single Crystals

“…Piezoelectric materials have long been utilised for their ability to linearly interconvert electrical and mechanical energy. In recent years, there has been a large increase in the number of biomoleculebased materials demonstrating this phenomenon, from amino acids (Lemanov, 2000;Guerin et al, 2018a) and peptides (Baptista et al, 2019;Gayatri and Hutchison, 2019;Basavalingappa et al, 2020) to globular (Stapleton et al, 2017) and transmembrane proteins (O'Donnell et al, 2021), viruses (Lee et al, 2012), plants (Alluri et al, 2020), and food waste (Ghosh and Mandal, 2017;Ghosh et al, 2021). While a number of these materials rival established inorganic piezoelectrics such as aluminium nitrate (AlN) (Supryadkina et al, 2014) and zinc oxide (ZnO) (Kobiakov, 1980), few have demonstrated piezoelectric strain constants that can rival ceramics such as barium titanate (BaTiO3), lead zirconium titanate (PZT), and lead-free counterparts (Panda and Sahoo, 2015;Bell and Deubzer, 2018) for traditional sensing and actuating applications.…”