Bleaching cotton in textile conservation: a closer look using atomic force microscopy

Salem, R. T.A., Thompson, K. and Uttamlal, M. (2022) Bleaching cotton in textile conservation: a closer look using atomic force microscopy. Heritage Science, 10, 195. (doi: 10.1186/s40494-022-00830-2)

Abstract

Aqueous bleaching may be used in textile conservation to improve the appearance of historic and culturally significant textiles. It is generally accepted amongst conservators that bleaching imparts damage. The aim of this research is to characterise the condition of cotton fibre's surface pre- and post-bleaching using atomic force microscopy (AFM). Unprocessed cotton calico (‘raw’ cotton), scoured cotton, and a historic cotton dress shirt (circa. 1920) were bleached using three separate methods: NaBH4 for 15 min; H2O2/NaBO3 for 1 h; and H2O2/NaBO3 buffered to pH 8.4 for 1 h. AFM was used in tapping-mode to obtain height, amplitude, and phase images. AFM imaging was able to distinguish between the cuticle, primary walls, and secondary walls of the cotton fibres. The data shows that bleaching has the effect of softening and removing individual layers of the cotton structure. Unprocessed cotton calico and scoured cotton fared better against the impact of bleaching. This was in stark contrast to the historic shirt where the already damaged surface of cotton fibres underwent further degradation using both oxidative and reductive bleaching. In general, reductive bleaching was more aggressive on the fibre surface compared to oxidative bleaching. The use of AFM provides further evidence of the physical effects of bleaching on historic textiles, and cotton textiles more broadly, and it has the potential to influence the conservator’s decision-making.

• Item Type: Articles
• Additional Information: Financial support in the form of summer studentships and consumables for Rana T. A. Salem were provided by the Royal Microscopical Society and Glasgow Caledonian University.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Thompson, Mrs Karen
• Authors: Salem, R. T.A., Thompson, K., and Uttamlal, M.
• College/School: College of Arts & Humanities > School of Culture and Creative Arts > History of Art
• Journal Name: Heritage Science
• Publisher: SpringerOpen
• ISSN: 2050-7445
• ISSN (Online): 2050-7445
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in Heritage Science 10: 195
• Publisher Policy: Reproduced under a Creative Commons License