Modeling of the detachment of a molecule from a surface: illustration of the "Bell-Evans effect".
This article deals with the modeling of the detachment of a molecule initially adsorbed on a surface and submitted to an external force whose strength increases with time. By means of an atomic force microscope (AFM), it is possible to measure the force when the molecule separates from the substrate. However, it is known that this force depends to a large extend on the rate at which the pulling force is applied ("Bell-Evans effect"). Two models are described to illustrate this behavior. First, a random walk approach is suggested to reveal the fundamental principle of the escape over a time-dependent energy barrier. Second, a multi bead-and-spring model is proposed to mimic the AFM experiment and numerical simulations, based on Brownian dynamics, are performed.
Hemmerlé
J
J
Institut National de la Santé et de la Recherche Médicale, Unité 424, UFR d'Odontologie, Université Louis Pasteur, 11, rue Humann, 67085 Strasbourg Cedex, France.
Picart
C
C
Gergely
C
C
Schaaf
P
P
Stoltz
J-F
JF
Voegel
J-C
JC
Senger
B
B
D001665:Binding Sites; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D011485:Protein Binding; D013314:Stress, Mechanical; D013499:Surface Properties