Role of Disorder in a Bi-Dimensional Lubricated Sliding Model

We investigate the role of defects and disorder in a 2D-model lubricant interposed between two sliding substrates. Specifically, we consider localized defects (vacancies) and extended defects (grain boundaries) in the lubricant confined between two perfect rigid chains. This work verifies in particular when the perfect ”quantized” dynamical sliding regime identified in previous work [1, 2] is present even in the presence of defects. The main finding is that provided twofold: (i) if the boundary layer of the lubricant in contact with the closer-in-register substrate does not hold defects in the asymmettric stationary state, the perfectly quantized velocity regime is recovered fairly easily, (ii) diffusion favors the spontaneous formation of a perfect boundary lubricant layer at the interface with the closer in register substrate. Advisor: Dr. Nicola Manini Co-Advisor: Dr. Stefano Zapperi