CHARACTERIZATION OF ULTRATHIN MEMBRANES TO ENABLE TEM OBSERVATION OF GAS REACTIONS AT HIGH PRESSURES

摘要

In-situ, atomic scale imaging of chemical reactions at high gas pressures and elevated temperatures is crucial to characterize structural changes in catalysts. To enable transmission electron microscopy (TEM) imaging in realistic environments, a MEMS device that confines the gas flow and reactions to a micromachined channel was developed. The device consists of two parts that were brought into contact to form a channel. At the central part of the structure there is a large square region containing several 10-15 nm thick membranes that act as electron transparent windows, hence, allowing TEM imaging. The present design was previously demonstrated to sustain 0.1 MPa pressure, yet, to accurately mimic industrial conditions, the device should survive gas pressures as high as 1 MPa. In this article, we study the mechanical performance of individual components using simulations and nanoscale bulge tests and determine the necessary modifications to improve device functionality.