COLLABORATIVE RESEARCH: STRUCTURE AND DYNAMICS OF METAL SOAP AGGREGATES AT THE PIGMENT/BINDER INTERFACE. A MULTINUCLEAR SOLID-STATE NMR STUDY

在化学系化学测量和成像项目的支持下，纽约大都会艺术博物馆的Silvia Centeno博士和特拉华大学的Cecil Dybowski教授将研究油画中羧酸铅（铅皂）的聚集机制。众所周知，在大多数情况下，油画中羧酸铅的聚集会导致突出物的形成和油漆的损失，而在其他情况下，会增加漆膜的透明度，从而损害艺术品的完整性。虽然这一现象被广泛观察到，但人们对其却没有很好的理解。合作研究人员、他们的学生和博士后学员将利用固态13C、207Pb角旋（MAS）核磁共振（NMR）、1H-207Pb和13C- 207Pb偶极重偶联实验、氘核磁共振以及其他分析工具来确定羧酸铅的结构、分子动力学和相行为。他们将阐明聚集体形成/迁移的机制，并根据结果提出阻止油画劣化过程的措施。固体核磁共振实验将提供目前文化遗产科学界无法获得的分子信息，因此有可能改变文化遗产科学领域。该实验是微核磁共振等新兴微创核磁共振技术应用于文物研究的门户。207Pb固态核磁共振技术的进步对于理解含铅电子和光电子材料的结构、高tc超导材料以及铅在环境污染材料中的形态和反应具有更广泛的意义。该项目将为希望在最先进的固态核磁共振方法和文化遗产科学方面进行培训的学生和博士后研究人员提供良好的培训机会。这项研究的结果将通过博物馆项目和出版物向公众广泛传播。

With support from the Chemical Measurement and Imaging program in the Division of Chemistry, Dr. Silvia Centeno of the Metropolitan Museum of Art in New York City and Prof. Cecil Dybowski of the University of Delaware, will study the mechanism of aggregation of Lead carboxylates (lead soaps) in oil paintings. Aggregation of Lead carboxylates in oil paintings is known to lead to the formation of protrusions and paint loss in most cases, and to increased transparency of the paint films in others, resulting in damage to the integrity of the artworks. While widely observed, the phenomenon is not well understood. The collaborating investigators, their students and postdoctoral trainees will determine the structure, molecular dynamics, and phase behavior of lead carboxylates using solid state 13C,207Pb magic-angle-spinning (MAS) nuclear magnetic resonance (NMR), 1H-207Pb and 13C- 207Pb dipolar re-coupling experiments, and deuterium NMR along with other analytical tools. They will elucidate the mechanism of aggregate formation/migration and based on the results, recommend procedures to arrest the deterioration process of oil paintings.The solid state NMR experiments have the potential to transform the field of cultural heritage science since they will provide molecular information, which is not currently available to the cultural heritage science community. The experiments are a gateway to the application of emerging minimally invasive NMR methods like micro-MAS NMR to study cultural heritage objects. Advancing the state of the art for 207Pb solid-state NMR also has broader implications for understanding the structure of lead-containing electronic and optoelectronic materials, high-Tc superconducting materials, and the speciation and reaction of lead in environmentally contaminated materials. The project will provide excellent training opportunities to students and postdoctoral researchers who wish to train in state of the art solid state NMR methods and cultural heritage science. Results of this study will be widely disseminated to the public through museum programs and publications.