Intrinsically Polar Piezoelectric Self‐Assembled Oligopeptide Monolayers

Abstract

Flexible, bio-compatible piezoelectric materials are of considerable research interest for a variety of applications, but many suffer from low response or high cost to manufacture. Herein, novel piezoelectric force and touch sensors based on self-assembled monolayers of oligopeptides are presented which produce large piezoelectric voltage response and are easily manufactured without the need for electrical poling. While the devices generate modest piezoelectric charge constants (d33) of up to 9.8 pC N −1 , they exhibit immense piezoelectric voltage constants (g33) up to 2 V m N −1. Furthermore, a flexible device prototype is demonstrated that produces open-circuit voltages of nearly 6 V under gentle bending motion. Improvements in peptide selection and device construction promise to further improve the already outstanding voltage response and open the door to numerous practical applications. Piezoelectric materials find use in a wide range of applications from touch and vibration sensors [1] to energy harvesters [2] to micromechanical actuators. [3] These devices rely on the piezoelectric effect to interconvert mechanical stress and electrical charge. In the direct piezoelectric effect, an applied force produces a resultant charge, whereas, in the converse effect, an applied voltage causes a mechanical deformation. Most existing piezoelectric materials are hard, brittle, leadcontaining ceramics such as lead zirconium titanate (PZT). [4] As such, these materials have limited ranges of motion, are liable to crack, and are not bio-compatible. While there is a large research focus on developing flexible, bio-compatible piezoelectric materials, [5] much of this work has involved placing traditional piezoelectrics on or into flexible substrates, often sacrificing electrical performance for added flexibility and ease of manufacturing (i.e., d-values <200 pC N −1 instead of 500 pC N −1-600 pC N −1 for PZT). [2,6,7] In addition to well known piezoelectric polymers such as semi-crystalline poly(vinylidene fluoride) (PVDF), researchers have begun to develop fundamentally new piezoelectric materials such as helicenes, amino acids, viruses, and peptides. [5,8-12]

How Can Static and Oscillating Electric Fields Serve in Decomposing Alzheimer’s and Other Senile Plaques?

“…However, these latter effects cannot be probed by classical MD simulations. The role of hydrogen bonding has also recently been used to describe the piezoelectric responses of oligomeric peptides …”

Identification of biomolecule-based electronic materials from a first-principles study of aliphatic amino acids

“…Like most biomaterials, they all have low dielectric constants. 33 The low dielectric constant may be beneficial for enhancing the piezoelectric properties and leading to high-response piezoelectric sensors, 6 which will be elaborated upon in the next section on piezoelectricity. The calculated piezoelectric strain tensor (d ij ) is included in Table S3 (ESI †).…”

A Cr2O3-doped graphene sensor for early diagnosis of liver cirrhosis: a first-principles study

“…72 Notwithstanding the limonene molecule has been left to relax on the graphene side of the Cr 2 O 3 -graphene heterostructure from different relative directions, the most thermodynamically stable -and hence likely -orientation resulted to be in the direct chemisorption of the molecule. Albeit a richer statistical analysis of this aspect would be in order by exploiting, e.g., ab initio molecular dynamics and metadynamics, 75 as recently done by some of ours for chelation and sequestration 76,77 as well as for other chemical reactions, [78][79][80][81] it falls out of the scope of the current investigation which is mainly focused on the electronic rather than nuclear properties of the adsorption phenomenon of PCCP Paper limonene on the Cr 2 O 3 -graphene heterostructure. Moreover, although a dynamical description of the system would enable the incorporation of other factors concerning the gas sensing capabilities, the recovery time -being order of magnitudes longer than simulation timescales affordable by classical and quantum molecular dynamics simulations -can be easily estimated according to transition state theory from the adsorption energy 82 as:…”