Issue 4, 2013

Redox reactions in Prussian blue containing paint layers as a result of light exposure

Abstract

Prussian blue, a mixed valence pigment, typically KFeIII[FeII(CN)6xH2O, was the most widely used blue artistic pigment from ca. 1720 to the 1970's but, unfortunately, its paint layers, especially when used in conjunction with a white pigment, tend to fade or turn green upon extended exposure to light. In order to identify the mechanism underlying these changes, paint layers have been prepared with differing amounts of these white pigments and subjected to accelerated light exposure fading. The resulting unfaded and faded paint layers as well as both the Berlin white pigment, Fe2II[FeII(CN)6], and the partially oxidized Berlin green pigment, {KFeIII[FeII(CN)6]}x{FeIII[FeIII(CN)6]}1−x, have been characterized by Raman and iron-57 Mössbauer spectroscopy. The results indicate that, upon fading, the Prussian blue pigment painted with a linseed oil binder and (PbCO3)2Pb(OH)2 or ZnO, and to a lesser extent with TiO2, undergoes a reduction at the exposed paint surface and an oxidation in the bulk of the paint layer. This combined reduction and oxidation disrupts, at least in part, the FeIII–N–C–FeII intervalent electron transfer pathways in Prussian blue thus leading to pigment fading through a reduction in the intervalent electron transfer absorbance at about 700 nm.

Graphical abstract: Redox reactions in Prussian blue containing paint layers as a result of light exposure

Supplementary files

Article information

Article type
Paper
Submitted
05 Dec 2012
Accepted
29 Jan 2013
First published
31 Jan 2013

J. Anal. At. Spectrom., 2013,28, 524-535

Redox reactions in Prussian blue containing paint layers as a result of light exposure

L. Samain, B. Gilbert, F. Grandjean, G. J. Long and D. Strivay, J. Anal. At. Spectrom., 2013, 28, 524 DOI: 10.1039/C3JA30359D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements