Details

Autor(en) / Beteiligte

• Erbaş, Aykut
• Horinek, Dominik
• Netz, Roland R

Titel

Viscous Friction of Hydrogen-Bonded Matter

Ist Teil von

• Journal of the American Chemical Society, 2012-01, Vol.134 (1), p.623-630

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2012

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Amontons’ law successfully describes friction between macroscopic solid bodies for a wide range of velocities and normal forces. For the diffusion and forced sliding of adhering or entangled macromolecules, proteins, and biological complexes, temperature effects are invariably important, and a similarly successful friction law at biological length and velocity scales is missing. Hydrogen bonds (HBs) are key to the specific binding of biomatter. Here we show that friction between hydrogen-bonded matter obeys in the biologically relevant low-velocity viscous regime a simple law: the friction force is proportional to the number of HBs, the sliding velocity, and a friction coefficient γHB. This law is deduced from atomistic molecular dynamics simulations for short peptide chains that are laterally pulled over planar hydroxylated substrates in the presence of water and holds for widely different peptides, surface polarities, and applied normal forces. The value of γHB is extrapolated from simulations at sliding velocities in the range from V = 10–2 to 100 m/s by mapping on a simple stochastic model and turns out to be of the order of γHB ≃ 10–8 kg/s. The friction of a single HB thus amounts to the Stokes friction of a sphere with an equivalent radius of roughly 1 μm moving in water. Cooperativity is pronounced: roughly three HBs act collectively.