Straube, Arthur V. and Kowalik, Bartosz G. and Netz, Roland R. and Höfling, Felix (2019) Emergence of molecular friction in liquids: bridging between the atomistic and hydrodynamic pictures. Emergence of molecular friction in liquids: bridging between the atomistic . (Submitted)

PDF
5MB 
Abstract
Friction in liquids arises from conservative forces between molecules and atoms. Although the hydrodynamics at the nanoscale is subject of intense research and despite the enormous interest in the nonMarkovian dynamics of single molecules and solutes, the emergence of friction from the atomistic scale so far could not be demonstrated. Here, we fill this gap based on frequencyresolved friction data from highprecision simulations of three prototypical liquids, including water. Combining with rigorous theoretical arguments, we show that friction in liquids is nonlocal in time and emerges abruptly at a characteristic frequency, beyond which viscous liquids appear as nondissipative, elastic solids. At the same time, the molecules experience Brownian forces that display persistent correlations and longlasting memory. A critical test of the generalised Stokes–Einstein relation, mapping the friction of single molecules to the viscoelastic response of the macroscopic sample, disproves the relation for Newtonian fluids, but substantiates it exemplarily for a supercooled liquid. The employed approach is suitable to yield novel insights into vitrification mechanisms and the intriguing mechanical properties of soft materials.
Item Type:  Article 

Subjects:  Mathematical and Computer Sciences > Mathematics > Applied Mathematics 
Divisions:  Department of Mathematics and Computer Science > Institute of Mathematics 
ID Code:  2403 
Deposited By:  Monika Drueck 
Deposited On:  18 Feb 2020 11:05 
Last Modified:  18 Feb 2020 11:05 
Repository Staff Only: item control page