A dual-beam FT-IR instrument with optical null has been developed for the study of polymers adsorbed on low-surface-area solids. By the use of narrow-bandpass filters coupled with the dual-beam FT-IR, a sensitivity of 2 × 10−5 absorption units per scan has been achieved. Transmission infrared spectra are shown for poly(ethylene oxide-b-styrene) and didodecyl dimethyl ammonium bromide (DODAB) adsorbed on silicon.
C. P. Tripp and M. L. Hair, "Transmission Infrared Spectra of Adsorbed Polymers Using a Dual-Beam FT-IR Instrument," Appl. Spectrosc. 46, 100-106 (1992)