Siloxane Modified Sio<sub>2</sub>-TiO<sub>2</sub> Glasses Via Sol-Gel

Parkhurst, C. S.; Doyle, W.F.; Silverman, L. A.; Singh, Surendra Prasad; Andersén, Mikael; McClurg, D.; Wnek, Gary E.; Uhlmann, D. R.

doi:10.1557/proc-73-769

Cited by 28 publications

(13 citation statements)

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“…A similar mechanism has also been proposed for the oligomerization based on the depolymerization and monomer to oligomer condensation for the TEOS (tetraethoxysilane). 42 With respect to the acid-catalyzed sample, its envelope presents some deviations from the regular sine bell shape, a fact that could be attributed to an oligomerization mechanism that involves stepwise monomer condensation along with condensation of larger oligomers.…”

Section: -10mentioning

confidence: 99%

New insights on organosilane oligomerization mechanisms using ESI-MS and 29Si NMR

et al. 2009

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The use of electrospray ionization mass spectrometry (ESI-MS) in parallel with 29 Si and 1 H NMR to elucidate the aqueous speciation and temporal evolution of the organosilane methyldiethoxysilane (MDES) through hydrolysis and condensation processes is reported here. A suitable methodological approach for the monitoring of the oligomerization of MDES under different pH conditions has been developed revealing details on the particular oligomerization mechanism of this organosilane.

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Section: -10mentioning

confidence: 99%

New insights on organosilane oligomerization mechanisms using ESI-MS and 29Si NMR

et al. 2009

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“…The high elasticity, excellent relaxation properties, hydrophobicity and transparent of polydimethylsiloxane (PDMS) have made it widely studied as an organic precursor in the polymer sol-gel reaction [8][9][10][11][12][13][14][15][16][17][18][19]. Two types of PDMS, hydroxyl terminated and methyl terminated, are suitable candidates for the synthesis of hybrids which can co-condensate with metal alkoxides to form a covalently bonded network.…”

Section: Introductionmentioning

confidence: 99%

In situ Synthesis of High Refractive Index PDMS/Metal Oxide Nanocomposites

Mullins

2012

MRS Proc.

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Organic-inorganic hybrids have been prepared with tailorable and enhanced properties which are unachievable using polymers or ceramics alone. By combining the flexibility of polymers with the electronic and optical properties of ceramic materials, these hybrids offer great potential for many optical, electrical and mechanical applications. Silicone polymers because of their desirable surface properties, excellent physical properties, heat stability, and high resistance to chemical and UV attack, have been widely used. Hybrid siloxane-metal oxide gels have been prepared via sol-gel techniques, by using hydroxyl-terminated polydimethylsiloxanes (PDMS) crosslinked by metallic alkoxides, M(OR)n. In this technique, the use of organic solvents permits organic and inorganic components to be combined at a molecular level with the desired composition. By varying the type and percentage of metal alkoxides during synthesis, transparent and homogeneous organic-inorganic hybrid materials with unique properties were obtained. Also a secondary metal oxide species was introduced to synthesize binary metal oxide-PDMS hybrids. Systematic experiments were carried out to study the effect of the reaction conditions and metal alkoxides-PDMS ratios on the properties of the final hybrids. These hybrids were spin coating on silicon wafers or molded into bulk films to be tested. The composition and the properties of the transparent inorganic-organic hybrids were investigated and characterized by ellipsometer and Fourier Transform Infrared (FTIR) spectroscopy. Experimental results showed that the refractive index of the hybrid materials exhibits a proportional relationship with the metal oxide content, the higher the metal oxide content the higher the refractive index. The refractive index was increased from 1.4 of PDMS to 1.7 of metal oxide-PDMS hybrid with highest prepared metal oxide loading. From the FTIR spectra, the structures of the hybrids for various metal oxide-PDMS compositions were examined.

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“…De esta forma estos polímeros pueden reaccionar no solo con el TEOS hidrolizado (con los grupos Si-OH), sino también con los grupos hidroxilo de otros alcóxidos tales como los de titanio, aluminio, zirconio, etc. (12)(13)(14).…”

Section: Introductionunclassified

“…(13)(14)(15)(16). Así las reacciones entre TEOS-PDMS o TEOS-DMDES (dimetil-dietoxisilano) y alcóxidos de titanio se ha estudiado con gran profundidad mediante 29 Si RMN (17).…”

Section: Introductionunclassified

Seguimiento por espectroscopia infrarroja (FT-IR) de la copolimerización de TEOS (tetraetilortosilicato) y PDMS (polidimetilsiloxano) en presencia de tbt (tetrabutiltitanio)

Téllez¹,

Rubio²,

Peña-Alonso³

et al. 2004

Bol. Soc. Esp. Ceram. Vidr.

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Se han preparado materiales híbridos por medio de reacciones de hidrólisis y condensación de alcóxidos de Si y Ti (TEOS y TBT, respectivamente) y de reacciones de copolimerización de éstos con polidimetilsiloxano (PDMS). Se han estudiado las citadas reacciones mediante espectroscopia FT-IR, desde el mismo comienzo hasta la obtención del material final. La hidrólisis del TEOS así como la autocondensación del os grupos Si-OH generados tanto para formar cadenas entrecruzadas como lineales se han seguido mediante las bandas situadas a 880, 1180 y 1150 cm -1 , respectivamente. La policondensación de dichos grupos con PDMS se ha seguido por la banda a 850 cm -1 . Por otro lado, la hidrólisis del TBT y la autocondensación de grupos Ti-OH se han seguido por la banda situada a 1130 y por la variación de la absorbancia en la región espectral 770-510 cm -1 , respectivamente. La formación de enlaces Si-O-Ti por condensación de grupos Si-OH y Ti-OH se ha seguido mediante la banda a 936 cm -1 . Los resultados obtenidos han mostrado que las reacciones de hidrólisis y policondensación dependen de la concentración de TBT en el medio de reacción. La formación de estructuras entrecruzadas de enlaces Si-O-Si se ve favorecida por el TBT, si bien por el contrario éste impide la reacción de copolimerización TEOS-PDMS. La autocondensación de grupos Si-OH y Ti-OH es muy rápida dando lugar a enlaces Si-O-Si y Ti-O-Ti, respectivamente. También se forman enlaces Si-O-Ti en los comienzos de la reacción, sin embargo éstos tienden a desaparecer en el transcurso de la misma. Finalmente se ha estudiado la variación de la concentración de cadenas cíclicas y lineales de PDMS durante toda la reacción. Palabras Clave: Ormosil, sol-gel, hidrólisis, condensación, FT-IR. FT-IR spectroscopy study of the reaction of obtention of hybrid materialsHybrid materials have been prepared in this work through the reactions of Si and Ti alkoxides (TEOS and TBT, respectively) and polydimethil siloxane (PDMS). These reactions have been studied by means of FT-IR spectroscopy during the whole reaction time. The hydrolysis of TEOS molecule has been followed by the 880 cm -1 band, and the self-condensation reactions through the 1180 and 1150 cm -1 bands. Polycondesation reaction between Si-OH groups and PDMS molecules has been followed by the 850 cm -1 band. On the other hand, the hydrolysis reaction of TBT and the self-condensation of Ti-OH groups have been followed by the 1130 and 770-510 cm -1 bands, respectively. Finally the condensation reaction between Si-OH and Ti-OH groups have been studied by the 936 cm -1 band. Results have shown that hydrolysis and condensation reactions are depending on TBT concentration. The formation of Si-O-Si cross-linked structures increases with the TBT concentrations in the reaction. The selfcondensation reaction of Si-OH grups or Ti-OH grous is very reapid forming Si-O-Si and Ti-O-Ti bonds, respectively. However, the Si-O-Ti bonds which are formed during the first moments of reaction are also rapidly broken due to H 2 O molecules or...

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Siloxane Modified Sio₂-TiO₂ Glasses Via Sol-Gel

Cited by 28 publications

References 4 publications

New insights on organosilane oligomerization mechanisms using ESI-MS and 29Si NMR

New insights on organosilane oligomerization mechanisms using ESI-MS and 29Si NMR

In situ Synthesis of High Refractive Index PDMS/Metal Oxide Nanocomposites

Seguimiento por espectroscopia infrarroja (FT-IR) de la copolimerización de TEOS (tetraetilortosilicato) y PDMS (polidimetilsiloxano) en presencia de tbt (tetrabutiltitanio)

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Siloxane Modified Sio2-TiO2 Glasses Via Sol-Gel

Cited by 28 publications

References 4 publications

New insights on organosilane oligomerization mechanisms using ESI-MS and 29Si NMR

New insights on organosilane oligomerization mechanisms using ESI-MS and 29Si NMR

In situ Synthesis of High Refractive Index PDMS/Metal Oxide Nanocomposites

Seguimiento por espectroscopia infrarroja (FT-IR) de la copolimerización de TEOS (tetraetilortosilicato) y PDMS (polidimetilsiloxano) en presencia de tbt (tetrabutiltitanio)

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Siloxane Modified Sio₂-TiO₂ Glasses Via Sol-Gel