[rotschift]

I have a question regarding the proper preparation of solid thin films for IR spectroscopy. I have cast a few different polymer films but, due to the nature of the polymer solution, the films are not the same thickness. Will this affect the results of the resulting IR spectrum (for example, will a peak be more intense if the film is thicker)? I’m basically trying to find out if I can get semi-quantitative data from non-uniform films.

Thanks!

[marquis]

Yes, you can get semi quant information from those solvent cast films. 

If your films are all relatively close in thickness, the major peaks will all be close in size.  The weak peaks will show the major differences.  If the semi quant you are trying is something like estimating the percentage of different polymers in a blend, this is no issue.

There are other sample prep methods that could help.  Sometimes ATR will give good spectra.  Unless your sample is very thin, thickness won't be an issue.

There are other prep methods, such hot press films.  We modified a pair of vice grips and used a bunsen burner for this sample prep.  There can be a large variation in sample thickness, so hot press probably won't help.