Reviewed by Lexie CornerDec 4 2024
A recent study published in ACS Sustainable Chemistry & Engineering reports the development of an innovative hydrogel designed to rapidly neutralize harmful acids and stabilize waterlogged wood from an 800-year-old shipwreck. This advancement represents a significant contribution to the preservation of fragile marine artifacts.
Researchers have developed a hydrogel that melts into and preserves ancient waterlogged wooden artifacts. Without the gel, the artifacts need to be dried, and that risks damaging the relics. Image Credit: Adapted from ACS Sustainable Chemistry & Engineering
Shipwrecks like the SS Endurance and RMS Titanic offer valuable insights into the past but deteriorate quickly. Conservators typically dry marine wooden artifacts to preserve them, though this process can cause damage.
Waterlogged wood from shipwrecks is often saturated with seawater, promoting the growth of fungi and bacteria that produce acid. To mitigate this, conservators commonly use freeze-drying or replace water in the wood with pressurized carbon dioxide or viscous polymers to reduce microbial activity and acid damage. However, these methods are time-intensive and can leave artifacts brittle or warped.
An emerging approach involves applying a gel to wet wooden artifacts. This gel infuses the wood with antimicrobial and acid-neutralizing compounds. To improve this technique, Xiaohang Sun and Qiang Chen developed a hydrogel that gradually releases these compounds throughout the wood while minimizing surface damage.
The researchers combined two polymers with silver nitrate to create antimicrobial nanoparticles that bind the polymers into a gel and potassium bicarbonate, an acid-neutralizing agent.
They produced hydrogels with varying stability by adjusting the amount of silver nitrate. Gels with higher silver content remained solid for three to five days, while those with lower silver content liquefied over the same period.
As a proof of concept, the team applied hydrogels with different silver concentrations to 800-year-old wood from the Nanhai One shipwreck, discovered off the southern coast of China. After 10 days, all gels neutralized acid up to 1 cm deep. However, the liquefying gels with lower silver content acted faster, completing the process within one day. These gels also preserved the wood’s cellular structure better and reduced brittleness compared to solid gels.
The researchers suggest that their hydrogel could preserve and strengthen shipwreck wood without causing additional damage, facilitating the study and preservation of historical artifacts.
The study was supported by the National Natural Science Foundation of China and the Guangdong Basic and Applied Basic Research Foundation.
Journal Reference:
Chen, J., et al. (2024) Alginate–Nanosilver Hydrogels: A Self-Dissolving System for Comprehensive Preservation of Waterlogged Wooden Artifacts. ACS Sustainable Chemistry & Engineering. doi.org/10.1021/acssuschemeng.4c06707.