Sequential Bending and Twisting around C-C Single Bonds by Mechanical Lifting of a Pre-Adsorbed Polymer.
Nano Lett
; 20(1): 652-657, 2020 01 08.
Article
in En
| MEDLINE
| ID: mdl-31797665
ABSTRACT
Bending and twisting around carbon-carbon single bonds are ubiquitous in natural and synthetic polymers. Force-induced changes were so far not measured at the single-monomer level, owing to limited ways to apply local forces. We quantified down to the submolecular level the mechanical response within individual poly-pyrenylene chains upon their detachment from a gold surface with an atomic force microscope at 5 K. Computer simulations based on a dedicated force field reproduce the experimental traces and reveal symmetry-broken bent and rotated conformations of the sliding physisorbed segment besides steric hindrance of the just lifted monomer. Our study also shows that the tip-molecule bond remains intact but remarkably soft and links force variations to complex but well-defined conformational changes.
Full text:
1
Database:
MEDLINE
Language:
En
Journal:
Nano Lett
Year:
2020
Type:
Article
Affiliation country:
Switzerland