Bridge polysilsesquioxane xerogels with a bifunctional surface layer of the ≡Si(CH2)3NH2/≡Si(CH2)3SH composition

Plasma-deposited hybrid silica membranes with a controlled retention of organic bridges

“…7b, it can be seen that almost 30% of the Si-CH 2 -CH 2 -Si group is preserved from the original monomer structure. This identication is conrmed by the increase of the CH 2 wagging vibration in Si-CH 2 -CH 2 -Si 49,50 as F BTESE increases.…”

“…7a shows the FTIR spectra in the region between 1350 and 1500 cm À1 . The tting of the absorption band in this region reveals the presence of peaks associated with CH 2 deformation in Si-CH 2 -CH 2 -Si (1360-1410 cm À1 ) [43][44][45][46][47][48][49][50][51] and CH 3 Fig. 4 Deconvolution of the FTIR Si-H x stretching absorption band of plasma deposited hybrid silica films using different F BTESE values.…”

“…deformation vibrations in the -OCH 2 CH 3 groups (1440-1480 cm À1 ). [43][44][45][46][47][48][49][50][51] The retention percentage of the ethylene bridge was evaluated by using the following formula…”

“…3. Band assignments were taken from the literature 22,[43][44][45][46][47][48][49][50][51] and are summarized in Table 1. The FTIR spectra of the deposited lms are characterized by the appearance of absorption bands such as -OH stretching (3100-3600 cm À1 ), Si-H x stretching (2150-2300 cm À1 ), Si-(CH 3 ) x (x ¼ 1-2) symmetric bending (1250-1275 cm À1 ), Si-O-Si asymmetric stretching (1000-1200 cm À1 ), Si-OH bending ($950 cm À1 ), Si-O-Si bending (880 cm À1 ) with a shoulder at around 840 cm À1 corresponding to Si-CH 3 rocking mode.…”

On the enhancement of pervaporation properties of plasma-deposited hybrid silica membranes

“…Fig. 2 highlights the decrease in intensity of the vibration band associated to Si-(CH 3 ) x , 18 Si-CH 2 -CH 2 -Si, 8,19,20 Si-OCH 2 CH 3 21 and CH x groups in favour of Si-O-Si chain development. Fig.…”