Experimental testing of the Prandtl-Tomlinson model: Molecular origin of rotational friction

Fuente: arXiv
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Autore principale: Zheng, Weichao
Natura: Preprint
Pubblicazione: 2023
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author Zheng, Weichao
author_facet Zheng, Weichao
contents Structural superlubricity, one of the most important concepts in modern tribology, has attracted lots of interest in both fundamental research and practical applications. However, the underlying model, known as the Prandtl-Tomlinson (PT) model, is oversimplified and not for real processes, despite its prevalence in frictional and structural lubricant studies. Here, with a realistic system, cholesteric liquid crystals, confined between two atomically smooth surfaces, we measure both the surface torque during rotational friction and the molecular rotation from the commensurate to incommensurate configuration at the onset of structural lubricity. Furthermore, by changing the surface potential or the strain, the Aubry transition is confirmed. The results agree well with the description by a quasi-one-dimensional version of the PT model and provide molecular evidence for rupture nucleation during static friction. Our study bridges the gap between theories and experiments and reinforces the connection between friction and fracture.
format Preprint
id arxiv_https___arxiv_org_abs_2305_06191
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Experimental testing of the Prandtl-Tomlinson model: Molecular origin of rotational friction
Zheng, Weichao
Soft Condensed Matter
Mesoscale and Nanoscale Physics
Structural superlubricity, one of the most important concepts in modern tribology, has attracted lots of interest in both fundamental research and practical applications. However, the underlying model, known as the Prandtl-Tomlinson (PT) model, is oversimplified and not for real processes, despite its prevalence in frictional and structural lubricant studies. Here, with a realistic system, cholesteric liquid crystals, confined between two atomically smooth surfaces, we measure both the surface torque during rotational friction and the molecular rotation from the commensurate to incommensurate configuration at the onset of structural lubricity. Furthermore, by changing the surface potential or the strain, the Aubry transition is confirmed. The results agree well with the description by a quasi-one-dimensional version of the PT model and provide molecular evidence for rupture nucleation during static friction. Our study bridges the gap between theories and experiments and reinforces the connection between friction and fracture.
title Experimental testing of the Prandtl-Tomlinson model: Molecular origin of rotational friction
topic Soft Condensed Matter
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2305.06191