Submicron-resolution polymer orientation mapping by optical photothermal infrared spectroscopy

Abstract

A submicron-resolution infrared spectroscopy technique called optical photothermal infrared (O-PTIR) spectroscopy was applied to polymer orientation analysis in this work by measuring the wall cross-section of a commercial plastic bottle. Linear dichroism was observed in the O-PTIR spectra. Polarized O-PTIR mapping measurement through the entire wall thickness as wide as 350 µm with submicron spatial resolution visualized a highly oriented thin skin layer with a thickness of fewer than 10 µm near the outer surface, which has been difficult to perform using conventional IR microscopy techniques.

Keywords:

• IR spectroscopy
• photothermal
• orientation
• O-PTIR
• submicron resolution

Acknowledgments

The authors would like to thank Dr. Curtis Marcott for his inspiring comments and the people of Photothermal Spectroscopy Corp. for their technical supports. We thank David MacDonald, MSc, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript.