Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 14: Membranes

CPP 14.3: Talk

Tuesday, February 26, 2008, 15:30–15:45, C 230

Mechanical properties of freestanding nanomembranes from self-assembled monolayers — •Xianghui Zhang, Nils Mellech, Christoph Nottbohm, Andre Beyer, and Armin Gölzhäuser — Fakultät für Physik, Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany

Ultrathin membranes are promising materials in science and nanotechnology. Here we report the characterization of nanomembranes with a thickness of approximately 1.5 nm, which have a remarkable high tensile strength and excellent elasticity. The nanomembranes are aromatic self-assembled monolayers (SAMs) that are laterally crosslinked by electron irradiation. The SAMs are prepared on silicon-nitride windows, supported by a silicon frame. Afterwards the silicon nitride is dissolved, providing freestanding nanomembranes that cover openings in silicon substrate with sizes from 10 µm to 50 µm. Bulge testing is used to determine Young´s modulus and residual stress of the freestanding nanomembranes. Rupture testing is performed to measure tensile strength. The nanomembranes display outstanding performance in tensile strength of up to 700 MPa, which is 4∼7 times higher than the highest currently known value for nanomembranes. The electron dose dependences of tensile strength, the Young´s modulus and the residual stress of the nanomembranes have been systematically studied. This allows to tailor its mechanical properties for the fabrication of nanoelectromechanical (NEMS) devices.