Monitoring organic thin film growth in aqueous solution in-situ with a combined Quartz Crystal Microbalance and ellipsometry

A. Sarkar*, T. Viitala, T. Hofrnann, T. E. Tiwald, J. A. Woollam, A. Kjerstad, B. Laderian, M. Schubert

*Korresponderande författare för detta arbete

Forskningsoutput: Kapitel i bok/konferenshandlingKonferensbidragVetenskapligPeer review


Measuring thin films in aqueous environments poses a challenge because they may have an affinity for water (e.g. hydrogels) while adsorbed on a substrate. Typically, either the optical ellipsometry technique or the electromechanical Quartz Crystal Microbalance techniques are used to study thin films in-situ in aqueous environments. An ellipsometer measures the change in elliptically polarized light whereas the Quartz Crystal Microbalance utilizes the piezoelectric properties of an AT cut quartz crystal to measure properties of thin films. However, each technique has its limitations. The ellipsometer has the inherent limitation of coupling thickness of films of the order of a few nm with the film index of refraction. Commonly, the refractive index of the material is derived from ex-situ measurements performed on the bulk material. The Quartz Crystal Microbalance has the limitation that the density and the thickness of a film are coupled. Thus a reasonable assumption for the density must be made in order to determine the thickness. The ellipsometer can determine the actual amount of polymer present in a film. When measuring in-situ, an ellipsometer does not distinguish between water molecules attached to polymers comprising the film and the water in the ambient. However, the Quartz Crystal Microbalance measures the total mass attached to a substrate, i.e. both the polymer and the water molecules attached to it. Thus by combining the two instruments and correlating the thickness determined by each instrument, one can find the film porosity. We introduce a porosity parameter to characterize surfaces in aqueous environments. Our findings on formation of synperonic film on hydrophobic gold surface in aqueous environment are presented and discussed.

Titel på värdpublikationIn-Situ Studies Across Spatial and Temporal Scales for Nanoscience and Technology
FörlagMaterials Research Society
Antal sidor7
ISBN (tryckt)9781615677726
StatusPublicerad - 2008
Externt publiceradJa
MoE-publikationstypA4 Artikel i en konferenspublikation
Evenemang2008 MRS Fall Meeting - Boston, MA, USA
Varaktighet: 1 dec. 20085 dec. 2008


NamnMaterials Research Society Symposium Proceedings
ISSN (tryckt)0272-9172


Konferens2008 MRS Fall Meeting
OrtBoston, MA


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