Dresden 2014 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 16: Interfaces and Thin Films II
CPP 16.9: Vortrag
Dienstag, 1. April 2014, 11:45–12:00, ZEU 114
Tuning the mechanical properties of ultrathin carbon nanomembranes via molecular design — •Xianghui Zhang1, Polina Angelova1, Christof Neumann1, André Beyer1, Jürgen Schnack2, and Armin Gölzhäuser1 — 1Physics of Supramolecular Systems and Surfaces, University of Bielefeld, Universitätstr. 25, 33615 Bielefeld — 2Condensed Matter Theory Group, University of Bielefeld, Universitätstr. 25, 33615 Bielefeld
Self-assembled monolayers (SAMs) of polyaromatic molecules can be cross-linked via low energy electron irradiation and form carbon nanomembranes (CNMs) with a thickness ranging from 0.5 to 3 nm. Freestanding CNMs were fabricated by transferring them onto a Si substrate with an array of orifices and an in-situ bulge test in an atomic force microscope (AFM) was used to characterize mechanical properties of CNMs. A differential pressure was applied to a freestanding CNM and the deflection at the centre of the membrane was recorded by AFM. We observe that the structure of precursor molecules has some effect on the mechanical stiffness of CNMs: CNMs from more rigid condensed polyaromatic precursors like naphthalene and pyrene thiols exhibit higher Young's moduli of 16-18 GPa; CNMs from non-fused oligophenyl molecules like biphenyl and terphenyl thiols possess lower Young's moduli of 8-10 GPa; CNMs from non-condensed hexaphenylbenzene and hexabenzocoronene thiols possess Young's moduli of 13-15 GPa. Finite element method (FEM) was also used to examine the deformation profiles and simulate the pressure-deflection relationship.