Composite Films of Prussian Blue and N-Substituted Polypyrroles:  Fabrication and Application to Optical Determination of pH

Abstract

A new and simple chemical method for deposition of thin blue films composed of Prussian Blue and N-substituted polypyrroles on nonconductive supports is presented. It is found that only pyrroles which are difficult to polymerize can be used for the preparation of such films. The resulting composite films were examined by SEM-EDAX, vis-NIR, and IR spectroscopy. The films are stable, thin, homogeneous, and optically transparent. The absorption maxima are at 720 nm, and spectral changes can be monitored using semiconductor light sources and detectors. The composite films are shown to be suitable for optical determination of pH over the pH 5-9 range because their absorbance strongly depends on pH in the physiological pH range. However, they undergo irreversible spectral changes if exposed to pH's >9. The films represent an alternative to indicator-based pH sensor materials because they do not require a dye to be immobilized. The pH measurements are highly reproducible, reversible in the physiological range, and not affected by ionic strength, alkaline cations, and typical oxidants and reductants.

Morphological characterization and analytical application of poly(3,4-ethylenedioxythiophene)–Prussian blue composite films electrodeposited in situ on platinum electrode chips

“…Research carried out recently in electrochemical sensor technology revealed that modification of the electrode surfaces with organicinorganic coatings avoids the drawbacks associated with bare electrodes. For instance, inorganic coatings consisting of transition metal hexacyanoferrates have been used in preparation of various sensors and biosensors based on electrochemical and optical transducers [10][11][12][13][14][15][16][17][18][19]. One of the inorganic modifiers, Prussian blue (PB, ferric ferrocyanide Fe 4 III [Fe II (CN) 6 ] 3 ) is a mixed-valence compound that can be deposited on the electrode surface as an electroactive film.…”

Communication—Accessing Stability of Oxidase-Based Biosensors via Stabilizing the Advanced H2O2Transducer

“…Among a number of approaches used for stabilization of Prussian Blue: covering with organic polymers, 17,18 entrapment in sol-gel [19][20][21] or conductive polymer matrixes 22,23 -building of multilayers with non-iron hexacyanoferrates isostructural to Prussian Blue seems to be the most progressive. 24 We already reported on the open circuit interfacial deposition of Prussian Blue 22 allowing to avoid electrochemical techniques, highly required for cost-effective mass production.…”

Application of Prussian Blue Based Composite Film with Functionalized Organic Polymer to Construction of Enzymatic Glucose Biosensor

“…Similar composite films were previously used in PB-based optical sensors [20,27,35], and they were demonstrated to be robust and crack-free materials. In the present work, we also refer to the recent concepts of fabrication (electrodeposition) of three-dimensional composite (hybrid) films in which negatively charged inorganic cyanometallate species are attracted and electrostatically stabilized by positively charged conducting polymer backbone [36].…”

“…Electrodeposition of PB/PPyBA composite film on glassy carbon involved prolonged potential cycling in the range from À 0.4 to 0.8 V. In view of the earlier studies, reductive deposition of PB [23] was occurring during negative potential scans whereas, by analogy to the formation of polypyrrole [37], the polymerization of 4(pyrrole-1-yl) benzoic acid [35] was most likely operative during positive potential scans. The exact mechanism of the latter process will be a subject of our separate work.…”