Regensburg 2022 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 15: Protein Structure and Single Molecules
BP 15.2: Vortrag
Mittwoch, 7. September 2022, 10:15–10:30, H13
Angle-dependent strength of a single chemical bond by stereographic force spectroscopy — Wanhao Cai1, •Jakob Tómas Bullerjahn2, Max Lallemang1,3, Klaus Kroy4, Bizan Balzer1,3,5, and Thorsten Hugel1,3 — 1Institute of Physical Chemistry, University of Freiburg, Germany — 2Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany — 3Cluster of Excellence livMatS@FIT - Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Germany — 4Institute for Theoretical Physics, Leipzig University, Germany — 5Freiburg Materials Research Center, University of Freiburg, Germany
A wealth of chemical bonds and polymers have been studied with single-molecule force spectroscopy, usually by applying a force perpendicular to the anchoring surface. However, the direction-dependence of the bond strength lacks fundamental understanding. Here we establish stereographic force spectroscopy to study the single-bond strength for various pulling angles. Surprisingly, we find that the apparent bond strength increases with increasing pulling angle relative to the anchoring surface normal, indicating a sturdy mechanical anisotropy of a chemical bond. This finding can be rationalized by a fixed pathway for the rupture of the bond, resulting in an effective projection of the applied pulling force onto a nearly fixed rupture direction. Our study is fundamental for the molecular understanding of the role of the direction of force application in molecular adhesion and friction.