Hydrogels in Heritage Conservation: A Comparative Evaluation on Composite Objects

Area of Science:

• Materials Science
• Conservation Science
• Chemistry

Background:

• Composite ethnographic objects with metal components are susceptible to iron corrosion damage, especially in humid conditions.
• Removing iron corrosion is critical for the long-term preservation of these valuable artifacts.
• Chelating agents are used to remove metal ions, but their application in gel form requires optimization for different materials.

Purpose of the Study:

• To evaluate the cleaning efficacy of Desferrioxamine B (DFO-B) and ethylenediaminetetraacetic acid (EDTA) in various gel formulations.
• To compare the performance of xanthan gum, agarose, and Nanorestore extra-dry gel (nano-MWR) on wood and textile substrates.
• To assess the potential for chemical damage to substrates during the cleaning process.

Main Methods:

• Preparation of wooden and textile mock-ups stained with iron corrosion products.
• Application of DFO-B and EDTA chelators using three different gel formulations: xanthan gum, agarose, and nano-MWR.
• Visual assessment and analysis of cleaning effectiveness and substrate integrity after treatment.

Main Results:

• Xanthan gum gel showed high cleaning effectiveness but risked residue and surface damage.
• Agarose and nano-MWR gels were less effective initially but showed potential with repeated applications.
• Agarose gel improved chelator efficacy on textiles, while nano-MWR gel performed better on wood.
• No chemical damage was observed on either wood or textile substrates across all gel applications.

Conclusions:

• A single gel formulation is insufficient for effective cleaning of both wood and textile components in composite artifacts.
• Agarose gel, particularly in a semi-rigid state, enhances textile treatment and may be effective on wood with multiple applications.
• A combined strategy using agarose for textiles and nano-MWR for wood could optimize chelator performance on composite artifacts.