Structure modification by solvent addition into TEOS/PDMS hybrid materials

Vegetal nanoclusters in hybrid silica films prepared by sol-gel spin coating technique

“…In addition, for instance in the case of films prepared from S3 (Fig. 3a, b, e), the shoulder located at 1170 cm − 1 in sol, assigned to C-OH vibration band and shifted towards higher wavelengths (1179 cm − 1 in S3-RE 1 and S3-RE 2) may overlap, according to the literature, with the band of silica ring [10] and optical vibration modes of the hybrid network [2] which are formed from TEOS/OMEOS via acid catalysis together with the linear and branched species. However, the stretching vibration of silanol species (ν Si-OH ) remains unchanged during the RE incorporation, its position at 940 cm − 1 indicating the efficient hydrolysis of residual Si-OEt species to silanol species.…”

“…bulk materials and coating films) with valuable technical properties [1][2][3]. Among them, the investigation of hybrid films is a field of growing interest due to promising applications mainly based on submicronic organic and inorganic interpenetrating networks [4] that impart their functional properties to the final synthesized materials.…”

Texture and micro-nanostructure of porous silicon oxycarbide glasses prepared from hybrid materials aged in different solvents

“…21 This feature indicates that the addition of different solvents not only influences the pore structure but also the carbon (or polymer) distribution and the PDMS molecule disposition in the hybrid network. The carbon disposition may alter the redistribution reactions during pyrolysis avoiding the PDMS elimination and thus result in carbon retention in the SiOC structure.…”

“…19 Drying liquids whose properties are specifically selected were demonstrated to exert a predicted capillary pressure within the evolving pore structure. 20,21 In this sense, non-polar (n-alkanes), polar (acetone, n-alcohols) and mixtures of such solvents, have been used for modifying pore structures and porosities of silica xerogels. For these materials the use of selected solvents mainly controls the capillary pressure, however for sol-gel derived organic-inorganic hybrid materials the solvents may influence not only the capillary pressure but also the extraction of organic molecules entrapped or weakly bonded to the hybrid structure.…”

Surface and Structural Modification of Nanostructured Mesoporous Silicon Oxycarbide Glasses Obtained from Preceramic Hybrids Aged in NH4OH

“…Aging and drying conditions have been demonstrated to be crucial in the control of pore size and distribution. In the synthesis of large pieces or monoliths, nonbonded molecules are swept along by the solvent during the course of evaporation, leading to a gradient distribution of the components in the preceramic polymer and thus in the final ceramic . Singh and Pantano obtained mesoporous silicon oxycarbide glasses with narrow pore size distribution when pyrolyzed hybrid gels were synthesized from silicon alkoxides and aged in NH 4 OH solutions.…”