title: Multiscale dispersion-state characterization of nanocomposites using optical coherence tomography.
abstract: Nanocomposite materials represent a success story of nanotechnology. However, development of nanomaterial fabrication still suffers from the lack of adequate analysis tools. In particular, achieving and maintaining well-dispersed particle distributions is a key challenge, both in material development and industrial production. Conventional methods like optical or electron microscopy need laborious, costly sample preparation and do not permit fast extraction of nanoscale structural information from statistically relevant sample volumes. Here we show that optical coherence tomography (OCT) represents a versatile tool for nanomaterial characterization, both in a laboratory and in a production environment. The technique does not require sample preparation and is applicable to a wide range of solid and liquid material systems. Large particle agglomerates can be directly found by OCT imaging, whereas dispersed nanoparticles are detected by model-based analysis of depth-dependent backscattering. Using a model system of polystyrene nanoparticles, we demonstrate nanoparticle sizing with high accuracy. We further prove the viability of the approach by characterizing highly relevant material systems based on nanoclays or carbon nanotubes. The technique is perfectly suited for in-line metrology in a production environment, which is demonstrated using a state-of-the-art compounding extruder. These experiments represent the first demonstration of multiscale nanomaterial characterization using OCT.
authors.affiliation: Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Schneider
authors.affiliation: Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Eppler
authors.affiliation: Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Weber
authors.affiliation: Fraunhofer Institute for Chemical Technology (ICT), 76327 Pfinztal, Germany.
authors.forename: Ganiu
authors.initials: G
authors.lastname: Olowojoba
authors.affiliation: Fraunhofer Institute for Chemical Technology (ICT), 76327 Pfinztal, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Weiss
authors.affiliation: Fraunhofer Institute for Chemical Technology (ICT), 76327 Pfinztal, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Hübner
authors.affiliation: Fraunhofer Institute for Chemical Technology (ICT), 76327 Pfinztal, Germany.
authors.forename: Irma
authors.initials: I
authors.lastname: Mikonsaari
authors.affiliation: Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.|Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, German.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Freude
authors.affiliation: Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.|Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, German.
authors.forename: Christian
authors.initials: C
authors.lastname: Koos