Process for preparing porous silicon dioxide thin flm by polyvinyl alcohol as molding board

A technology of porous silica and polyvinyl alcohol, which is applied in the field of inorganic porous materials to achieve high thermal stability

Inactive Publication Date: 2005-01-05
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

So far, no reports on the use of polyvinyl alcohol (PVA) as a template for the syn

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Embodiment 1: with a kind of low polymerization degree polyvinyl alcohol LPVA, high polymerization degree polyvinyl alcohol HPVA=0, low polymerization degree polyvinyl alcohol LPVA and SiO 2 The case where the weight ratio is 0.8. Dissolve 1.48g of polyvinyl alcohol PVA (the degree of polymerization is 124) in 50g of deionized water for later use; take 9.25ml of SiO 2 20% SiO 2 Sol (containing 1.85g SiO 2 ), and SiO with oxalic acid 2 The pH value of the sol is adjusted to 3.0, and then the solution is mixed with a low-polymerization degree polyvinyl alcohol LPVA solution, heated at 60°C for 1 hour, and the sol is deposited on the substrate by a gel-spinning process, and heat-treated at 550°C 1 hour.

Embodiment 2

[0019] Embodiment 2: polyvinyl alcohol PVA and SiO 2 The weight ratio is 0.5, and the molar ratio of low polymerization degree polyvinyl alcohol LPVA and high polymerization degree polyvinyl alcohol HPVA is equal to 10. 0.69g low polymerization degree polyvinyl alcohol LPVA (polymerization degree is 500) and 0.24g high polymerization degree polyvinyl alcohol HPVA (polymerization degree is 1750) are respectively dissolved in 25g deionized water, mix two kinds of polyvinyl alcohol PVA solutions, in Heat and stir at 60°C for 20 minutes and set aside; take 18.5ml of SiO 2 10% SiO 2 Sol (containing 1.85g SiO 2 ), and SiO with oxalic acid 2 The pH value of the sol was adjusted to 3.5, the solution was mixed with the polyvinyl alcohol PVA solution, heated and stirred at 80°C for 2 hours, and the sol was deposited on the substrate by the glue-spinning process, and heat-treated at 800°C for 1.5 hours.

Embodiment 3

[0020] Embodiment 3: polyvinyl alcohol PVA and SiO 2 The weight ratio is 1.2, and the molar ratio of the low degree of polymerization polyvinyl alcohol LPVA to the high degree of polymerization polyvinyl alcohol HPVA is equal to 7. 1.64g low polymerization degree polyvinyl alcohol LPVA (polymerization degree is 800) and 0.58g high polymerization degree polyvinyl alcohol HPVA (polymerization degree is 2000) are dissolved in 30g deionized water respectively, two kinds of polyvinyl alcohol PVA solutions are mixed, 60 ℃ under heating and stirring for 30 minutes; take 18.5ml SiO 2 10% SiO 2 Sol (containing 1.85g SiO 2 ), with formic acid to SiO 2 The pH value of the sol was adjusted to 4.0, the solution was mixed with the polyvinyl alcohol PVA solution, heated and stirred at 60°C for 60 minutes, the sol was deposited on the substrate by the gel-spinning process, and heat-treated at 650°C for 2 hours .

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Abstract

The invention relates to a method of preparing multiporous SiO2 film by using polyvinyl alcohol (PVA) as template. It can singly use PVA with arbitrary a degree of polymerization to prepare multiporous SiO2 film, where the aperture size and distribution can be regulated by adding in two kinds of PVA with different degrees of polymeraiztion; the main process course: preparing PVA template solution, then mixing and stirring the PVA template solution with SiO2 sol, heating and synthesizing film precursor. The multiporous SiO2 film has the characters of reguable aperture, high porosity, large specific area, large thickness, and excellent thermal stability and has a wide use in high speed IC, catalysis, separation, heat insulation and preservation, subject and object chemistry, nano composite, etc.

Description

technical field [0001] The invention belongs to the technical field of inorganic porous materials, and in particular relates to a polyvinyl alcohol used as a template for porous silicon dioxide (SiO 2 ) film preparation method. technical background [0002] According to the definition of the International Union of Theoretical and Applied Chemistry (IUPAC), porous substances with a pore diameter of less than 2nm are micropores, larger than 50nm are macropores, and those between 2-50nm are mesopores or mesopores. Porous SiO 2 Due to its low dielectric constant, low thermal conductivity and high specific surface area, thin films are widely used in submicron high-speed integrated circuits, catalysis, separation, heat insulation and heat preservation, host-guest chemistry, and nanocomposites. . However, it is difficult to prepare porous SiO with a porosity greater than 30% and a thickness greater than 1 micron without cracking by the conventional sol-gel (Sol-Gel) method. 2 f...

Claims

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Application Information

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IPC IPC(8): C04B38/08
Inventor 吴小清姚熹汪敏强
Owner XI AN JIAOTONG UNIV
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