Premium
Development of Methods to Determine the Infrared‐Optical Properties of Polymer Films
Author(s) -
Oreski Gernot,
Tscharnuter Daniel,
Wallner Gernot M.
Publication year - 2008
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200850513
Subject(s) - comonomer , transmittance , materials science , infrared , integrating sphere , infrared spectroscopy , analytical chemistry (journal) , refractive index , optics , copolymer , fourier transform infrared spectroscopy , polymer , optoelectronics , chemistry , physics , composite material , chromatography , organic chemistry
Summary: In this paper, two methods for the determination of infrared optical properties of thick polymer films, based on FTIR spectroscopy, were implemented and used. Complex index of refraction data were generated for various ethylene copolymer films. Transmittance and reflectance spectra were measured in the mid infrared range using a gold‐coated 100 mm‐diameter integrating sphere. For the investigated films n and k values ranging from 1.3 to 1.6 and from 10 −4 to 0.25 were determined, respectively. Regarding n, a good agreement was obtained for both methods, the transmittance/reflectance procedure (T/R method) used for transparent and semitransparent regions, and Single Substractive Kramers‐Kronig (SSKK) algorithm applied for non‐transparent regions. The highest k values were determined for the CH 2 stretching vibration. The k values are dependent on comonomer content and film thickness. The combination of both methods allows for an accurate determination of n and k in the entire IR region relevant for solar application.