CAREER: Understanding 2D confinement driven phase transitions of non-polar liquids

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Non-technical Abstract:Friction and wear are ubiquitous phenomena which often lead to significant energy losses and adverse environmental impact. For instance, automotive applications alone account for approximately 4-5% of global energy consumption due to friction losses. Inefficient mechanical systems also result in shorter lifecycles, increasing material wastage and environmental burdens. To address these challenges, the lubricant industry requires efficient, low-pollutant lubricants. Two dimensional (2D) materials, such as atomically thin layers of graphite and molybdenum sulfide, have emerged as promising lubricant additives to protect engine walls. The layered structure of the 2D materials allows intercalation of small molecules, such as hydrocarbon oil, which can modify interfacial interactions and tune mechanical and frictional properties. In this project, we aim to advance and utilize the atomic force microscopy and vibrational spectroscopy techniques to investigate the physical behavior and viscoelastic properties of the intercalated liquids at the buried interfaces. The goal is to tune the intercalant phase for achieving highly lubricious surfaces. This project will also provide a training in interdisciplinary and integrative for undergraduate and graduate students, fostering skills that enable acceleration of material discovery and development across diverse applications. Additionally, this project aims to promote dialogue and outreach in the tribological community to facilitate accessible and curated data for data-driven advancements in tribology.Technical Abstract:This proposal aims to investigate how the phase behavior of liquids, specifically alkanes, is influenced by structural and thermodynamic parameters when intercalated within the confinement generated by a 2D material. The impact of the chemistry of confining walls, intercalant alkane structure, and the substrate morphology on the intercalation process and their interfacial properties will be explored. Through this study, advances in the methodologies of force spectroscopy and vibrational spectroscopy will be made to quantify the physical properties of sub-nanometer intercalant layers at the buried interface. By integrating experimental results with simulation methods, a mechanistic understanding of the mechanical and tribological behavior of intercalated interfaces will be achieved. The outcomes of this research will advance the applications of 2D materials as interfacial coatings in gear and engine lubrication, as well as in nanofluidics. Furthermore, summer research training opportunities will be developed to encourage underrepresented undergraduate students to engage in interdisciplinary research for the development of next-generation advanced materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.