Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.
Conservation & Science, Rijksmuseum, Amsterdam, The Netherlands.
Phys Chem Chem Phys. 2023 Feb 15;25(7):5701-5709. doi: 10.1039/d2cp04861b.
The crystallization of metal soaps in polymer matrices is a complex process that affects the stability of oil paintings, as well as the properties of commercial ionomer materials. In the context of conservation of paintings, it is crucial to investigate the influence of solvent exposure on such detrimental chemical processes. Using Fourier transform infrared spectroscopy and a polymer model system that contains metastable amorphous zinc soaps, it is shown that water induces zinc soap crystallization, while solvent swelling alone has no effect. In particular fast-diffusing polar organic solvents with water impurities are able to induce extensive crystallization, delivering high concentrations of water quickly deep into paint layers. Finally, it is demonstrated, both with the model system and real oil paint samples, that even with very short solvent exposure times, significant quantities of crystalline zinc soaps are formed. This strong effect of water impurities in common solvents gives reason to be cautious when conservation treatments are being considered for oil paints that contain zinc white or other water-sensitive chemicals.
金属皂在聚合物基质中的结晶是一个复杂的过程，它会影响油画的稳定性以及商业离聚物材料的性能。在绘画保护方面，研究溶剂暴露对这些有害化学过程的影响至关重要。本文使用傅里叶变换红外光谱和含有亚稳无定形锌皂的聚合物模型体系表明，水会诱导锌皂结晶，而单纯的溶剂溶胀则没有影响。特别是含有水杂质的快速扩散极性有机溶剂能够诱导广泛的结晶，将高浓度的水迅速输送到漆膜深处。最后，通过模型体系和实际油画样本的研究表明，即使溶剂暴露时间非常短，也会形成大量结晶的锌皂。常见溶剂中水分杂质的这种强烈影响使得在考虑含有锌白或其他对水敏感化学物质的油画的保护处理时需要谨慎。
