NANOSCALE INFRARED SPECTROSCOPY continued
Figure 5 – AFM-IR spectra and AFM images of a cross-section of epoxy- embedded PET round fibers treated with 90 TMA SVI cycles at 90 °C. Spectra are normalized at 2968 cm–1 at 1268 cm–1
in the low-wavenumber region.1
Figure 3 – SEM micrographs of a) untreated and b) 30 TMA cycle SVI- treated round PET fibers showing the change in fiber morphology upon SVI treatment at 60 °C. TEM micrograph of cross-sections of PET round fibers treated with c) 90 TMA SVI cycles at 60 °C and d) 60 TMA SVI cycles at 150 °C.1
treatments cause a barrier layer to be formed at the surface of the polymer that slows the diffusion of the reactant. More uniform hybrid layers that extend deeper into the fiber are possible when the TMA SVI treatments are performed at lower temperatures.
The ability to perform nanoscale IR spectroscopic measurements can provide insight into the surface-modified polymers. This approach to depth-profiling the surface of SVI-treated fibers at submicrometer-length scales will help enable advances in this emerging field and lead to the development of other inexpensively modified polymers that can be ap- plied to a wide range of constructs.
References 1. Akyildiz, H.I.; Lo, M. et al. Formation of novel photoluminescent hybrid
materials by sequential vapor infiltration into polyethylene tere- phthalate fibers. J. Mater. Res. 2014, 29, 2817–26.
2. Dazzi, A.; Prater, C.B. et al. AFM-IR: combining atomic force microscopy and infrared spectroscopy for nanoscale chemical characterization. Appl. Spectrosc. 2012, 66, 1365–84.
3. Akyildiz, H.I.; Padbury, R. et al. Temperature and exposure dependence of hybrid organic-inorganic layer formation by sequential vapor infil- tration into polymer fibers. Langmuir 2012, 28(44), 15697–704.
Figure 4 – AFM-IR spectra and AFM images of a cross-section of epoxy- embedded PET round fibers treated with 60 TMA SVI cycles at 150 °C. Spectra are normalized at 2972 cm–1 at 1268 cm–1
in the low-wavenumber region.1
PET fibers has been shown to be useful for chemically characterizing the hybrid layer produced by SVI treatments with a TMA precursor as a function of treatment temperature and number of SVI cycles. When this chemically specific information is combined with mass gain, TEM and SEM images of the same sample, a picture emerges that suggests high-temperature SVI
in the high-wavenumber region and
Curtis Marcott, Ph.D., is a senior partner, Light Light Solutions, P.O. Box 81486, Athens, Ga. 30608, U.S.A.; tel.: 513-720-0171; e-mail: marcott@
lightlightsolutions.com;
www.lightlightsolutions.com. Michael Lo and Eoghan Dillon are application scientists with Anasys Instruments, Santa Bar- bara, Calif., U.S.A. Halil I. Akyildiz is a Ph.D. candidate in the Department of Textile Engineering, Chemistry, and Science at North Carolina State University, Raleigh, N.C., and Jesse S. Jur is an assistant professor in the Department of Textile Engineering, Chemistry, and Science at North Carolina State University, Raleigh, N.C. This research was supported in part by NSF-SBIR grants 0750512 and 0944400.
AMERICAN LABORATORY • 14 • MARCH 2015
in the high-wavenumber region and
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