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O: Fachverband Oberflächenphysik
O 38: Poster Session III: Tribology: Surfaces and nanostructures I
O 38.4: Poster
Tuesday, March 2, 2021, 10:30–12:30, P
On-surface synthesis and mechanical stabilization of class 1 atropoisomers — •Philipp D'Astolfo1, Guilherme de Vilhena1, Carl Drechsel1, Jung-Ching Liu1, Xunshan Liu2, Silvio Decurtins2, Shi-Xia Liu2, Rémy Pawlak1, and Ernst Meyer1 — 1Department of Physics, University of Basel, Basel, Switzerland — 2Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
The torsion and rotation about single carbon-carbon bonds is a natural process that is ever-present in Chemistry- and Surface-Sciences. Due to their small magnitude, measurements of force-induced rotational changes between units of a long polymeric chain have proven difficult until now. To shed light on these processes, we synthesized sterically frustrated asymmetric cyclopentaaceanthrylene-polymers on a gold surface and performed lifting- and redeposition experiments using atomic force microscopy (AFM) at 4.8K. We detected repeating jumps in the frequency shift signal related to successive unit detachments of the poly-aceanthrylene units vertically lifted from the Au(111) surface. After performing a lifting experiment, we also redeposited the polymer on the surface while preserving the distinct bond-motif. Molecular dynamic (MD) simulations of the lifting- and redeposition experiments with different tethering of one end, ranging from hard anchored to slightly bonded and free ends, provide an atomistic understanding of the experimentally observed molecular anchoring on the peeling process and shed further light on the stabilization mechanism of sterically frustrated polymers.