Surface heterogeneity of polysiloxane xerogels functionalized by 3-aminopropyl groups

• Published in: Applied surface science 2010-06, Vol.256 (17), p.5361-5364
• Main Authors: Zub, Yu.L., Stolyarchuk, N.V., Barczak, M., Dąbrowski, A.
• Format: Article
• Language: English
• Subjects: Amino groups; Bands; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; DRIFT; Exact sciences and technology; Heterogeneity; Hydrogen bonds; Physics; Polysiloxanes; Sol–gel method; Spectra; Surface chemistry; Surface heterogeneity; Surface layer; Transformations; Vibration; Xerogels
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2009.12.079

DRIFT spectra of xerogels synthesized by co-condensation of tetraethoxysilane (or 1,2-bis(triethoxysilyl)ethane) and 3-aminopropyltriethoxysilane have been measured using termoevacuation in the temperature range 50–350 °C. The disappearance of bands related to the vibrations of water molecule with temperature growth and shifts of absorption band related to the deformation vibrations of amino groups to the high-frequency region have been observed. The formation of a new band in the range of 3650–3660 cm −1 has been attributed to stretching vibrations of silanol groups. The simplest change of surface layer composition in the amino-containing xerogels by water removal results in transformation of one type of hydrogen bond to another. The first type is associated with forming of cyclical structure with participation of 3-aminopropyl and silanol groups and water molecule, [≡Si(CH 2) 3H 2N···HO(H)···HOSi≡], the other type is associated with the interaction of amino groups between each other.