INMA Impulso: Leveraging x-ray coherence to probe the complexity of realistic interfaces at the nanoscale

El próximo miércoles 19 de enero tendrá lugar una nueva sesión del ciclo de conferencias INMA-Impulso, un ciclo de conferencias que trata de acercar la investigación más puntera a la sociedad.

La próxima sesión titulada: “Leveraging x-ray coherence to probe the complexity of realistic interfaces at the nanoscale” correrá a cargo de Irene Calvo-Almazán - Interfacial Processes Group. Chemical Sciences and Engineering division. Argonne National Laboratory.

Resumen de la charla: The advent of the world’s first coherent hard X-ray sources in France (ESRF) and the USA (APS) represents an unprecedented opportunity to conduct operando (i.e., in situ and time-dependent) studies on the structure and behavior of surfaces, interfaces, and single crystalline grains in reactive environments. In this talk, I will start by explaining the basis of coherent diffraction imaging (CDI) to extract information at the nanoscale about the structure, morphology, defects and strain fields of realistic systems such as 3D crystalline grains or amorphous films. Then, I will introduce two new approaches which push forward the capabilities of CDI to observe the microscopic dynamics underlying growth and dissolution at mineral-water interfaces with coherent x-rays. In the first study coherent X-ray reflectivity was used to reveal the morphology and the active sites for growth and dissolution of an otavite (CdCO3) thin film grown on a dolomite substrate. The second study shows a novel approach to extract structural information from a coherent diffraction pattern based on the reinterpretation of the Patterson Function as an auto-hologram and a mathematical graph. These two studies form the initial basis of a research program aiming to develop advanced coherent x-ray imaging methodologies to characterize the dynamic and chemical behavior of crystalline grains at the nanoscale and under realistic environments (e.g. mineral matrices, multilayered compounds, liquid solutions, etc.). Lubricants consist of a base fluid and 5-30% of an additive package (AP), which provides functionalities to the base fluid. The AP is a complex mixture of chemical compounds having a direct impact on the environment due to leakages and poor recycling methods. Every function of a lubricant additive is fulfilled by single chemicals carefully designed to avoid competition with each other. This makes it difficult to develop recycling strategies and limits finding and developing greener alternatives with the same functionality.

Environmentally acceptable lubricants are typically more polar than classical mineral oils or synthetic oils used in machine elements. This directly influences the selection of additives responsible for frictional reduction, corrosion protection, pour point depression or viscosity. Many approaches are taken in industry to tackle this challenge, in our group we believe the best technology for a greener lubricant industry is water-based lubricants since water is readily available and any formulation based in water is potentially easier to recycle. Unfortunately, water has never been considered a good lubricant due to its low viscosity, poor corrosion and frictional properties. The performance of water-based lubricants must be therefore improved by carefully selecting the additive package to best match the operational conditions.

La conferencia tendrá lugar el miércoles 19 de enero de 2022 a las 12 horas, se podrá seguir o bien presencialmente, asistiendo a la Sala de Grados de la Facultad de Ciencias de la Universidad de Zaragoza, o bien a través de la plataforma zoom (https://zoom.us/j/97514564609?pwd=SERFZ1dRRGlkRmxlWmFWSm5BV3JkZz09 ID de reunión: 975 1456 4609; Código de acceso: 556104).