Lorenz Matthias, Wagner Ryan, Jesse Stephen, Marsh Jennifer M, Mamak Marc, Proksch Roger, Ovchinnikova Olga S
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
University of Tennessee, Knoxville, Tennessee 37996, United States.
ACS Nano. 2020 Dec 22;14(12):16791-16802. doi: 10.1021/acsnano.0c05019. Epub 2020 Nov 24.
Materials ranging from adhesives, pharmaceuticals, lubricants, and personal care products are traditionally studied using macroscopic characterization techniques. However, their functionality is in reality defined by details of chemical organization on often noncrystalline matter with characteristic length scales on the order of microns to nanometers. Additionally, these materials are traditionally difficult to analyze using standard vacuum-based approaches that provide nanoscale chemical characterization due to their volatile and beam-sensitive nature. Therefore, approaches that operate under ambient conditions need to be developed that allow probing of nanoscale chemical phenomena and correlated functionality. Here, we demonstrate a tool for probing and visualizing local chemical environments and correlating them to material structure and functionality using advanced multimodal chemical imaging on a combined atomic force microscopy (AFM) and mass spectrometry (MS) system using tip-enhanced photothermal desorption with atmospheric pressure chemical ionization (APCI). We demonstrate enhanced performance metrics of the technique for correlated imaging and point sampling and illustrate the applicability for the analysis of trace chemicals on a human hair, additives in adhesives on paper, and pharmaceuticals samples notoriously difficult to analyze in a vacuum environment. Overall, this approach of correlating local chemical environments to structure and functionality is key to advancing research in many fields ranging from biology, to medicine, to material science.
传统上，从粘合剂、药物、润滑剂到个人护理产品等材料都是使用宏观表征技术进行研究的。然而，它们的功能实际上是由通常为非晶态物质的化学组织细节所定义的，这些物质的特征长度尺度在微米到纳米量级。此外，由于这些材料具有挥发性和对电子束敏感的性质，传统上很难使用基于真空的标准方法对其进行纳米级化学表征分析。因此，需要开发在环境条件下运行的方法，以便能够探测纳米级化学现象及其相关功能。在此，我们展示了一种工具，该工具利用原子力显微镜（AFM）和质谱（MS）联用系统上的先进多模态化学成像技术，通过针尖增强光热解吸与大气压化学电离（APCI）相结合的方式，来探测和可视化局部化学环境，并将它们与材料结构和功能相关联。我们展示了该技术在相关成像和点采样方面的增强性能指标，并说明了其在分析人发上的痕量化学物质、纸张上粘合剂中的添加剂以及在真空环境中 notoriously difficult to analyze（此处原文有误，推测可能是“notoriously difficult to analyze”，意为“极其难以分析”）的药物样品方面的适用性。总体而言，这种将局部化学环境与结构和功能相关联的方法是推动从生物学、医学到材料科学等众多领域研究的关键。
