Electrical and electrochemical characterization of proton transfer at the interface between chitosan and PdH_x

Abstract

Advancing electronic devices that interface with biology will require a thorough understanding of the electrochemical pathways that transduce electronic currents into the ionic currents.

Cephalopod‐Derived Biopolymers for Ionic and Protonic Transistors

“…However, the utility of such devices is constrained by the practical limitations of the palladium hydride contacts, such as difficult‐to‐control chemical compositions and potentially poor long‐term stability (after exposure to hydrogen gas) . Moreover, the charge transfer mechanisms and electrochemical reactivity at protonic transistors' biopolymer/palladium hydride interfaces are likely critically dependent on the active material and certain to be exceedingly complicated . Thus, the discovery of alternative electrode materials for protonic transistors or the investigation of organic electrochemical transistor‐type device architectures will certainly remain of paramount importance for any envisioned applications.…”

Electronic and protonic transport in bio-sourced materials: a new perspective on semiconductivity

“…13,64 The same group compared protonic currents for hydrated chitosan films sandwiched between PdH x electrodes and Pd contacts. 76 Direct current measurements were acquired by enclosing the samples in a chamber with controllable relative humidity (ca 75% RH). The I-V response, acquired from 0.2 V to 1 V, featured higher currents with PdH x than with Pd contacts (Fig.…”

Proton Conductivity of Glycosaminoglycans

“…This conduction follows the Grotthus mechanism in which a hydrogen bond is exchanged with a covalent bond contributing to the effective transfer of an H + from a molecule to its next-door neighbor (7). Following this mechanism, proton conductivity in hydrated biopolymers and macromolecules is widespread including collagen (8), keratin (9), chitosan (10), melanin (11), peptides (12), and various proteins such as bovine serum albumin (13) and reflectin (14,15). In addition to the ability to support proton wires, typically these materials include an acid or a base group that serve as H + or OHdopants and provide charge carriers for proton conductivity (16)(17)(18).…”

“…We postulated that keratin sulfate (KS), a glycosaminoglycan (GAG) was the material responsible for proton conductivity due to its similarity to chitosan and Nafion, and the ability form proton wires when hydrated. Here, we have measured the proton conductivity of KS derived from bovine cornea (21,22) and other GAGs using Pd based proton conducting devices (10 Device Fabrication. Two-terminal measurements were performed on Si substrates with a 100nm SiO2 layer.…”