Mastrangelo Rosangela, Montis Costanza, Bonelli Nicole, Tempesti Paolo, Baglioni Piero
Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, via della Lastruccia 3, Sesto Fiorentino, 50019 Florence, Italy.
Phys Chem Chem Phys. 2017 Sep 13;19(35):23762-23772. doi: 10.1039/c7cp02662e.
Nanosystems and confinement tools for the controlled release of a cleaning agent, e.g., hydrogels and microemulsions, have been used for several years for the treatment of delicate surfaces in art restoration interventions. However, notwithstanding the unprecedented achievements from an application point of view, a fundamental comprehension of their interaction mechanism is still lacking. In this study PVA hydrogels, obtained via freeze-thaw processes, are prepared as scaffolds for water-based nanostructured fluids for application in the cleaning of artworks: rheological, thermal, microscopic and scattering techniques showed that, depending on the number of freeze-thaw cycles, the hydrogels exhibit different physicochemical and viscoelastic properties, making them suitable for application in a broad range of cleaning issues. The gels have been loaded with an oil-in-water microemulsion and the diffusion of the microemulsion droplets inside the polymeric network has been investigated through Fluorescence Correlation Spectroscopy (FCS), demonstrating that the microemulsion is permanently kept inside the matrix and can freely diffuse in the network. In addition, we show that when the gel-microemulsion system is put in contact with a layer of hydrophobic grime, a dynamic interaction between the microemulsion droplets and the underlying layer is established, leading to the solubilization of the hydrophobic molecules inside the droplets in the gel matrix. Thus, for the first time, through FCS, insights into the removal mechanism of hydrophobic grime upon interaction with a cleaning agent embedded in the polymeric matrix are obtained.
用于控制释放清洁剂的纳米系统和受限工具，例如水凝胶和微乳液，多年来一直用于艺术品修复干预中精细表面的处理。然而，尽管从应用角度取得了前所未有的成就，但对它们的相互作用机制仍缺乏基本的理解。在本研究中，通过冻融过程获得的聚乙烯醇（PVA）水凝胶被制备为用于水性纳米结构流体的支架，用于艺术品清洁：流变学、热学、显微镜和散射技术表明，根据冻融循环次数，水凝胶表现出不同的物理化学和粘弹性性质，使其适用于广泛的清洁问题。这些凝胶已负载水包油微乳液，并通过荧光相关光谱法（FCS）研究了微乳液滴在聚合物网络内的扩散，证明微乳液永久保留在基质中并可在网络中自由扩散。此外，我们表明，当凝胶 - 微乳液系统与一层疏水性污垢接触时，微乳液滴与下层之间会建立动态相互作用，导致疏水分子在凝胶基质中的液滴内溶解。因此，首次通过FCS获得了与嵌入聚合物基质中的清洁剂相互作用时疏水性污垢去除机制的见解。
