title: Quantifying the structural integrity of nanorod arrays.
abstract: Arrays of aligned nanorods oriented perpendicular to a support, which are accessible by top-down lithography or by means of shape-defining hard templates, have received increasing interest as sensor components, components for nanophotonics and nanoelectronics, substrates for tissue engineering, surfaces having specific adhesive or antiadhesive properties and as surfaces with customized wettability. Agglomeration of the nanorods deteriorates the performance of components based on nanorod arrays. A comprehensive body of literature deals with mechanical failure mechanisms of nanorods and design criteria for mechanically stable nanorod arrays. However, the structural integrity of nanorod arrays is commonly evaluated only visually and qualitatively. We use real-space analysis of microscopic images to quantify the fraction of condensed nanorods in nanorod arrays. We suggest the number of array elements apparent in the micrographs divided by the number of array elements a defect-free array would contain in the same area, referred to as integrity fraction, as a measure of structural array integrity. Reproducible procedures to determine the imaged number of array elements are introduced. Thus, quantitative comparisons of different nanorod arrays, or of one nanorod array at different stages of its use, are possible. Structural integrities of identical nanorod arrays differing only in the length of the nanorods are exemplarily analysed.
authors.affiliation: Institut für Chemie neuer Materialien der Universität Osnabrück, Barbarastr. 7, 49069, Osnabrück, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Thöle
authors.affiliation: School of Power and Mechanical Engineering, Wuhan University, South Donghu Road 8, Wuhan, Wuchang, 430072, Hubei, China.
authors.forename: Longjian
authors.initials: L
authors.lastname: Xue
authors.affiliation: Institut für Chemie neuer Materialien der Universität Osnabrück, Barbarastr. 7, 49069, Osnabrück, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: HEß
authors.affiliation: Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany.
authors.forename: Reinald
authors.initials: R
authors.lastname: Hillebrand
authors.affiliation: Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24118, Kiel, Germany.
authors.forename: Stanislav N
authors.initials: SN
authors.lastname: Gorb
authors.affiliation: Institut für Chemie neuer Materialien der Universität Osnabrück, Barbarastr. 7, 49069, Osnabrück, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Steinhart
keywords: Arrays; clustering; image analysis; nanorods; scanning electron microscopy; self-ordered nanoporous alumina; surfaces; template synthesis