Voltammetric Studies on Gold Electrodes Coated with Chitosan-Containing Layer-by-Layer Films

Materials

Shigehiro Takahashi¹  Ryota Watahiki¹  Kohji Tomida¹  Baozhen Wang¹ 

[1] Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan; E-Mails:

关键词: polysaccharide;    chitosan;    layer-by-layer film;    cyclic voltammetry;    hexaammine ruthenium ion;    ferricyanide ion;   

DOI  :  10.3390/ma6115427

来源: mdpi

【 摘 要 】

Gold (Au) electrodes coated with layer-by-layer (LbL) thin films composed of chitosan (CHI) were prepared to evaluate the redox properties of hexaammine ruthenium ions, Ru(NH₃)₆³⁺, and ferricyanide ions, Fe(CN)₆³⁻ LbL films were prepared on an Au electrode by electrostatic LbL deposition using polycationic CHI and poly(vinyl sulfate) (PVS) or poly(acrylic acid) (PAA) as anionic component. Redox peak current in cyclic voltammetry of Ru(NH₃)₆³⁺ on the CHI/PVS and CHI/PAA film-coated electrodes increased with increasing thickness of the films. Interestingly, the cyclic voltammograms showed two pair of redox peaks, originating from Ru(NH₃)₆³⁺ diffusing across the LbL layers and from those confined in the film. The results were rationalized in terms of the electrostatic interactions between Ru(NH₃)₆³⁺ and excess negative charges in the LbL films originating from PVS and PAA. In contrast, Fe(CN)₆³⁻ was not confined in the LbL films due to electrostatic repulsion of Fe(CN)₆³⁻ and excess negative charges. Significant amounts of Ru(NH₃)₆³⁺ were confined in the films at pH 7.0, whereas few ions were bound at pH 3.0 due to the reduced net negative charge in the films. The results suggest a potential use of the CHI-containing LbL films as scaffold for immobilizing positively charged ionic species on the electrode surface.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.