Polyamines adsorbed onto silica gel: A Raman microprobe analysis

Abstract

Polyamine [especially poly(ethylenimine) and poly(4-vinylpyridine)] adsorption onto silica gels for chromatography and water-decontamination experiments, using a Raman microprobe, is reviewed. First, the bare silica are characterized. Then, the polyamines and the adsorbed polyamines spectra are compared. We show that polyamine adsorption onto silica occurs with two kinds of polymer populations: chemisorbed (trains due to important interactions between silanol and the nitrogen atom) and physisorbed (multilayers) polymer. The modifications of chemisorbed polymer bands are stronger than are the physisorbed ones.

Controlling the Formation of Hydroxyapatite Nanorods with Dendrimers

“…In addition, in these spectra, it is possible to resolve three peaks attributed to asymmetric stretching mode (ν 3 ) of the PO 4 group at 1073, 1048, and 1030 cm −1 as well as three peaks attributed to bending mode (ν 3 ) of the PO 4 group at 608, 591, and 579 cm −1 . The OH stretching frequency appears at 3572 cm −1 , 39 while it is also possible to discern peaks at 2934 cm −1 assigned to CH 2 asymmetric stretching mode and at 2875 and 2825 cm −1 assigned to CH 2 symmetric stretching modes 40,41 . The same CH 2 peaks are also observed in the spectra of calcium phosphate prepared at room temperature in the presence of DAB (Fig.…”

Porous Substrates for Label-Free Molecular Level Detection of Nonresonant Organic Molecules

“…Three of them at 1355, 1367, and 1382 cm Ϫ1 with virtually unchanged positions can be assigned to CH 2 wagging vibrations of PEI matrix and CTAB molecules (Figures 6 and 7). 34,35 The last peak which corresponds to a characteristic NO 2 stretching band, showed at unchanged position, 1342 Ϯ 2 cm Ϫ1 at all concentrations ( Figure 7).…”

Synthesis and characterization of polypyrrole‐au coated SiO2@poly(4‐vinylpyridine) composites

“…Figure 3 shows the Raman spectra of SiO 2 , SiO2@P4VP microspheres, and SiO 2 @P4VP@PPy‐Au composites. As shown in Figure 3(b), the spectrum of SiO 2 @P4VP microspheres has three strong bands centered at 996, 2922, and 3052 cm −1 , which are assigned to ring breathing, aliphatic CH 2 asymmetric stretching, and CH asymmetric ring stretching in the P4VP, respectively 27. However, these peaks are absent in the spectrum of the SiO 2 @P4VP@PPy‐Au composites [Figure 3(c)].…”