title: Combined quartz crystal microbalance with dissipation (QCM-D) and generalized ellipsometry (GE) to characterize the deposition of titanium dioxide nanoparticles on model rough surfaces.
abstract: Measuring the interactions between engineered nanoparticles and natural substrates (e.g. soils and sediments) has been very challenging due to highly heterogeneous and rough natural surfaces. In this study, three-dimensional nanostructured slanted columnar thin films (SCTFs), with well-defined roughness height and spacing, have been used to mimic surface roughness. Interactions between titanium dioxide nanoparticles (TiO2NP), the most extensively manufactured engineered nanomaterials, and SCTF coated surfaces were measured using a quartz crystal microbalance with dissipation monitoring (QCM-D). In parallel, in-situ generalized ellipsometry (GE) was coupled with QCM-D to simultaneously measure the amount of TiO2NP deposited on the surface of SCTF. While GE is insensitive to effects of mechanical water entrapment variations in roughness spaces, we found that the viscoelastic model, a typical QCM-D model analysis approach, overestimates the mass of deposited TiO2NP. This overestimation arises from overlaid frequency changes caused by particle deposition as well as additional water entrapment and partial water displacement upon nanoparticle adsorption. Here, we demonstrate a new approach to model QCM-D data, accounting for both viscoelastic effects and the effects of roughness-retained water. Finally, the porosity of attached TiO2NP layer was determined by coupling the areal mass density determined by QCM-D and independent GE measurements.
authors.affiliation: Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588, United States.
authors.forename: Negin
authors.initials: N
authors.lastname: Kananizadeh
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588, United States.
authors.forename: Charles
authors.initials: C
authors.lastname: Rice
authors.affiliation: Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Department of Water Environmental Engineering Research, National Institute of Environmental Research 22755, Republic of Korea.
authors.forename: Jaewoong
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Biolin Scientific, Inc., Paramus, NJ 07652, United States.
authors.forename: Keith B
authors.initials: KB
authors.lastname: Rodenhausen
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588, United States.
authors.forename: Derek
authors.initials: D
authors.lastname: Sekora
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588, United States.
authors.forename: Mathias
authors.initials: M
authors.lastname: Schubert
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588, United States.
authors.forename: Eva
authors.initials: E
authors.lastname: Schubert
authors.affiliation: Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588, United States.
authors.forename: Shannon
authors.initials: S
authors.lastname: Bartelt-Hunt
authors.affiliation: Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, NE 68588, United States. Electronic address: yli7@unl.edu.
authors.forename: Yusong
authors.initials: Y
authors.lastname: Li
keywords: Engineered nanoparticles; Generalized ellipsometry; Nanoparticle deposition; Quartz crystal microbalance; Rough surfaces