23–26 Sept 2026
Metropol Lake Resort
Europe/Zurich timezone

Interpreting Positive and Negative IR Reflectance-Absorbance Intensities in 2T2D Correlation Spectroscopy of Siloxane Films on Silicate Glass

Not scheduled
10m
Metropol Lake Resort

Metropol Lake Resort

Naselba Dolno Konjsko bb, 6000 Ohrid, N. Macedonia
E-poster Physical, structural chemistry, spectroscopy and electrochemistry

Speakers

Katerina KraljevskaDr Vladimir Ivanovski

Description

Katerina Kraljevska, Vladimir Ivanovski
e-mail: kraljevskakaterina0808@gmail.com

Ss. Cyril and Methodius University in Skopje, Faculty of Natural Science and Mathematics, Arhimedova 5, 1000 Skopje, Macedonia

Organosilanes can be used to engineer silicate glass surfaces, creating water repellent coatings that enhance hydrophobicity without compromising transparency. The process involves forming a nanometric siloxane film and altering surface roughness to achieve hydrophobicity. In this work, glass substrates were modified with hydrolyzed or non-hydrolyzed 3 aminopropyltriethoxysilane (APTES). Contact angle measurements, calculated surface energy, AFM and Raman measurements demonstrated successful silanization of the surface1. We used two-trace two-dimensional correlation spectroscopy (2T2D-COS) as a tool in distinguishing the IR bands between the substrate silicate glass and the ultrathin nano-film of siloxane formed on its surface. For that purpose, both, originally recorded IR Specular Reflectance spectra (IR-SR) and calculated IR Reflectance-Absorbance (IR-RA) spectra were used for creating the 2T2D-COS maps. While 2T2D-COS obtained from IR-SR can be used as an independent method for localizing the film band’s wavenumber, compared to IR-RA spectra, the 2T2D-COS obtained from IR-RA has the advantage of comparing the structure of two siloxane films2. However, since the IR-RA spectra can have positive and negative bands (contrary to the IR-SR), this has its impact on the interpretation of the positive and negative peaks in the 2T2D-COS maps. This work tries to turn attention on the consequences if this fact is not taken into account and gives solution to the problem.
Keywords: silicate glass, hydrophobicity, APTES, IR-SR, IR-RA, 2T2D COS

References:
1 V. Ivanovski, G.A. Mousdis, V. Likodimos, T. Deckert-Gaudig, T.A. Shaik, V. Deckert, Th.G. Mayerhöfer, J. Popp, A. Ivanovski, Investigation of thin siloxane films on silicate glass obtained from low concentration 3-aminopropyltriethoxysilane using reflectance FTIR and Raman confocal in-depth measurements, Colloids Surf. A Physicochem. Eng. Asp. 742 (2026) 140432. https://doi.org/10.1016/j.colsurfa.2026.140432
2 V. Ivanovski, Th.G. Mayerhöfer, 2T2D-correlation analysis of infrared specular reflectance and ratio-reflectance spectra for investigating siloxane nanofilms on silicate glass substrates, Spectrochim. Acta A Mol. Biomol. Spectrosc. 336 (2025) 126038. https://doi.org/10.1016/j.saa.2025.126038
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