| AVS 57th International Symposium & Exhibition | |
| Spectroscopic Ellipsometry Focus Topic | Thursday Sessions |
| Session EL+AS+EM+MS+TF-ThP |
| Session: | Spectroscopic Ellipsometry Focus Topic Poster Session |
| Presenter: | E. Antunez de Mayolo, Linköping University, Sweden |
| Authors: | H. Arwin, Linköping University, Sweden E. Antunez de Mayolo, Linköping University, Sweden M. Eita, Royal Institute of Technology (KTH), Sweden H. Granberg, Innventia Ab, Sweden L. Wågberg, Royal Institute of Technology (KTH), Sweden |
| Correspondent: | Click to Email |
High quality micro fibrillated cellulose (MFC) prepared from wood fibers can be used to prepare thin films on solid substrates by a layer-by-layer deposition technique. In applications MFC layers can be used alone or as a constituent in functional coatings, where the MFC can make a significant contribution to mechanical properties of the coating. Examples of potential applications are sensor layers, decorative coatings or mirrors. Here the optical properties in terms of the refractive index of MFC are studied with in situ spectroscopic ellipsometry (SE) and the effects on thickness and index due to humidity are investigated.
Films of MFC and polyethyleneimine (PEI ) in the thickness range 30 - 300 nm are deposited on silicon substrates. Such MFC/PEI samples are exposed to water vapor in nitrogen (0-90% RH) and the ellipsometric response are measured in situ in the spectral range 245 – 1700 nm at an angle of incidence of 70 degrees using a dual-rotating compensator ellipsometer. From the SE-data the MFC/PEI film thickness and layer index are modeled.
Due to water exposure, the thickness of an MFC/PEI film is found to increase up to 15% or more, whereas the refractive index decreases. The effects are fully reversible and the dynamics of these changes are monitored with SE and are discussed.