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Free-standing periodic mesoporous organosilica (PMO) films were grown at the interface of an ethylene-bridged organosilica and surfactant template via a self-assembly process. After the pyrolysis of the PMO films with ethylene-bridged organosilica moieties in the pore walls under an Ar flow at temperatures ranging from 400 to 900 °C, free-standing mesoporous silica/carbon composite films were obtained. The composite films had a highly ordered periodic mesostructure with a hexagonal closed-packed arrangement of channels running parallel to the surface. The mesopore walls of the films pyrolyzed above 700 °C in the presence of alkali metal ions had a cristobalite structure at the pore walls. When the pyrolysis temperature was between 400 and 900 °C, the pore diameter, surface area, and pore volume of the silica/carbon composite films were 18.2−30.5 A, 172−690 m2 g−1, and 0.18−0.64 cm3 g−1, respectively.

We report the effect of the amount of the mesoporous material, SBA-15, on the basic traits of fully aliphatic polyimides (API). For this purpose, water soluble, fully aliphatic poly(amic acid) triethyl amine salts (PAA(s)) were prepared and mixed with various amounts of SBA-15. Fully aliphatic polyimide hybrid composites containing the SBA 15-type mesoporous silica were synthesized successfully from bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and alicyclic diamine, 4,4′-methylene bis(2-methylcyclohexylamine). The structure of the hybrid composites was confirmed by IR spectroscopic analysis. Scanning electron microscopy revealed the morphology of the compounds. The hybrid composites exhibited good thermal stability, reasonable transparency, and a low dielectric constant.

Recently, mesoporous silica was blended with polyimide to develop low dielectric constant (k) materials with improving mechanical and thermal properties of polyimide by utilizing both the nanoporous structure and silica framework. However, even the use of mesoporous silica did not show a significant decrease of k due to the phase segregation in between polyimide and the mesoporous silica materials. In this work, we attempted to prepare polyimide/mesoporous silica hybrid nanocomposites having relatively good phase mixing behavior by utilizing polyimide synthesized from a water soluble poly(amic acid) ammonium salt, which lead to low k up to 2.45. The thermal properties of polyimide were improved by adding mesoporous silicas. For this work, we have fabricated mesoporous silicas through surfactant-templated condensation of tetraethyl orthosilicate (TEOS). Pyromellitic dianhydride (PMDA)-4,4′-oxydianiline (ODA) polyimide was prepared from poly(amic acid) ammonium salt, which had been obtained by incorporating triethylamine (TEA) into PMDA-ODA poly(amic acid) in dimethylacetamide (DMAc), followed by thermal imidization.

Highly ordered mesoporous silica, SBA-15 was synthesized using triblock copolymer (P123) as template and tetraethyl orthosilicate (TEOS) as silica source. Through the post-synthesis treatment, pore surface of the mesoporous silica was modified with aminosilane and then Eu3+ ions were incorporated in the modified mesoporous silica for the formation of Eu complex. Mesoporous silica with the hexagonal mesostructure was characterized by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The successful modification of the mesoporous silica was verified by FT-IR spectra and nitrogen adsorption/desorption isotherms. Eu incorporated mesoporous silicas showed different photoluminescent intensities depending on the pH of acidic and basic aqueous solutions.