AVS 66th International Symposium & Exhibition
    Applied Surface Science Division Tuesday Sessions
       Session AS+BI+CA+LS-TuA

Invited Paper AS+BI+CA+LS-TuA7
Nanoscale Tomographic Mapping the Liquid-Solid Interface with Cryo-APT

Tuesday, October 22, 2019, 4:20 pm, Room A211

Session: Beyond Traditional Surface Analysis
Presenter: Daniel Perea, Pacific Northwest National Laboratory
Authors: D.E. Perea, Pacific Northwest National Laboratory
D.K. Schreiber, Pacific Northwest National Laboratory
J.E. Evans, Pacific Northwest National Laboratory
V. Ryan, Pacific Northwest National Laboratory
Correspondent: Click to Email
The liquid-solid interface plays an essential role in many phenomena encountered in biological, chemical, and physical processes relevant to both fundamental and applied science. However, study of the liquid/solid interface at the nanoscale is challenging as liquids are generally incompatible with many analytical techniques that require high to ultrahigh vacuum conditions. One strategy to probe the liquid-solid interface is to cryogenically freeze the liquid into solid form to preserve local ionic chemistry gradients and surface composition within a solid structure, making it more amendable to vacuum-based analyses such as Atom Probe Tomography (APT). However, the regular application of APT to hydrated materials is lacking due to challenges in preparing the necessary nanoscale needle-shaped specimens using a FIB-SEM and the subsequent environmentally-protected transfer of the frozen specimens to the APT instrument for analysis. In this presentation, I will discuss the development of a FIB-based site-specific liftout and attachment scheme of cryogenically cooled specimens involving a combination of redeposition and overcoating of organic and organometallic molecules. A modified commercially-available specimen suitcase shuttle device and an environmental transfer hub vacuum chamber at PNNL is used to facilitate environmentally-protected specimen transfer between the cryo FIB and the APT tool, allowing for the first time, APT analysis of a water/solid interface in 3D to reveal the complex nanoscale water-filled porous network of corroded glass. Application of this unique specimen preparation approach to biological specimens will also be discussed.