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Smectic aerogel and method for production thereof

外国特許コード F110003548
整理番号 BE05902WO
掲載日 2011年6月29日
出願国 アメリカ合衆国
出願番号 51612807
公報番号 20100047479
公報番号 8323526
出願日 平成19年11月16日(2007.11.16)
公報発行日 平成22年2月25日(2010.2.25)
公報発行日 平成24年12月4日(2012.12.4)
国際出願番号 JP2007072266
国際公開番号 WO2008072445
国際出願日 平成19年11月16日(2007.11.16)
国際公開日 平成20年6月19日(2008.6.19)
優先権データ
  • 特願2006-336120 (2006.12.13) JP
  • 2007JP072266 (2007.11.16) WO
発明の名称 (英語) Smectic aerogel and method for production thereof
発明の概要(英語) The present invention is to provide a high quality smectic aerogel which is not brittle and a method for producing the smectic aerogel by using a host material comprising a mixture of a smectic liquid crystal and a UV-curable material or a host material comprising a smectic UV-curable material and by selecting an appropriate host material.
A smectic aerogel comprising 4-nonyl-4′-cyanobiphenyl (9BC) and air bubbles can be produced, wherein hexagonal or pentagonal air cells are separated from each other by a smectic layer comprising a smectic liquid crystal.
The thickness of the wall of the smectic layer at the boundaries of the air cells is about 24 μm, which corresponds to about 6000 smectic layers.
The thickness of the wall of the smectic layer at the boundaries can be varied.
Particularly, the thickness can be reduced to as thin as several smectic layers.
従来技術、競合技術の概要(英語) BACKGROUND ART
An aerogel is a solid state meso-porous material having open cells which has a porosity of 50% or more in volume.
Typically, the aerogel is composed of 90 to 99.8% of air, with density ranging from 1.1 to about 150 mg/cm3.
At the nanoscale, an aerogel structure resembles a sponge, and comprises a network structure of nanometer-sized voids connected with each other.
The aerogel can be made of various materials such as silica (SiO2), alumina (Al2O3), oxides of transition metal and lanthanide metal, metal chalcogenide including CdS and CdSe, organic and inorganic polymers, carbon, and the like.
An aerogel has, in general, an extremely high rigidity for its density, and can support a weight 2,000 times or more than the weight of itself.
The aerogel also serves as an excellent thermal insulation material since it almost nullifies three factors of heat transmission, i.e. convection, conduction, and radiation.
Furthermore, the aerogel serves as a good material for preventing heat convection, since air cannot circulate throughout the lattice.
The aerogel works as a desiccating agent since it has a hygroscopic property.
Technologies concerning liquid crystals can be referred to Non-Patent Documents 1 and 2 mentioned below.
[Non-Patent Document 1] S. Urban, J. Przedmojski, and J. Czub, Liquid Crystals, Vol. 32, No. 5, pp. 619-624 (2005).
[Non-Patent Document 2] EKISHOUBINRAN (Handbook of liquid crystal), ed. by committee of EKISHOUBINRAN (Handbook of liquid crystal), published by MARUZEN on Oct. 30, 2000.

特許請求の範囲(英語) [claim1]
1. A smectic aerogel having a fixed solid state aerogel structure of individual gas inclusion cells separated by smectic boundary layers, wherein the smectic boundary layers are formed by polymerizing a host material comprising a mixture of a smectic liquid crystal material with a smectic phase and a UV-curable monomer and fixing permanently a solid state aerogel structure after forming the gas inclusion cells.
[claim2]
2. A smectic aerogel having a fixed solid state aerogel structure of individual gas inclusion cells separated by smectic boundary layers, wherein the smectic boundary layers are formed by polymerizing a host material comprising a smectic UV-curable material with a smectic phase and fixing permanently a solid state aerogel structure by UV irradiation after forming the gas inclusion cells.
[claim3]
3. The smectic aerogel according to claim 1, wherein the UV-curable monomer is a monomer having an acrylate or methyl acrylate group.
[claim4]
4. The smectic aerogel according to claim 1, wherein the gas inclusion cells are formed by injecting a spherical gas inclusion into the host material before curing.
[claim5]
5. The smectic aerogel according to claim 4, wherein the gas in the gas inclusion is selected from air, inert gas, and mixtures thereof.
[claim6]
6. The smectic aerogel according to claim 4, wherein the wall thickness of the smectic boundary layers between the gas cells is from about 4 nanometers to about 24 mu m.
[claim7]
7. The smectic aerogel according to claim 4, wherein the gas inclusion is arranged orderly and the gas inclusion cells have a hexagonal or a pentagonal shape.
[claim8]
8. The smectic aerogel according to claim 1, wherein the host material is fixed permanently by UV irradiation.
[claim9]
9. The smectic aerogel according to claim 1, wherein the density of the smectic aerogel is between 1.3 kg/m3 and 400 kg/m3.
[claim10]
10. The smectic aerogel according to claim 1, wherein the fixed solid state structure is formed in a bulk shape, and is cut from the bulk into a desired shape.
[claim11]
11. A method of producing a solid state smectic aerogel, comprising: (a) providing a smectic liquid crystal;
(b) mixing the smectic liquid crystal with an ultra-violet (UV)-curable material to form an ultra-violet (UV)-curable mixture;
(c) injecting a gas inclusion into the mixture; and
(d) curing the mixture by UV irradiation to fix a solid state structure of the smectic aerogel permanently.
[claim12]
12. The method according to claim 11, wherein the smectic liquid crystal is 4-octyl-4'-cyanobiphenyl (8CB) or 4-nonyl-4'-cyanobiphenyl (9CB).
[claim13]
13. A method of producing a solid state smectic aerogel, comprising: (a) providing a smectic UV-curable material;
(b) injecting a gas inclusion into the material; and
(c) curing the material by UV irradiation to fix a solid state structure of the smectic aerogel permanently.
[claim14]
14. The method according to claim 11, wherein a spherical gas inclusion is injected into the mixture.
[claim15]
15. The method according to claim 11, wherein the mixture and the gas inclusion are placed under a hydrostatic pressure which is lower than the pressure during the injection of gas.
[claim16]
16. The method according to claim 15, wherein the thickness of a wall at the boundary of the gas inclusion in the cured mixture is from about 4 nanometers to about 24 mu m.
[claim17]
17. The method according to claim 14, wherein the gas inclusion is arranged orderly in gas inclusion cells having a hexagonal or a pentagonal shape.
[claim18]
18. The method according to claim 11, wherein the solid state smectic aerogel formed has a density between 1.3 kg/m3 and 400 kg/m3.
[claim19]
19. The method according to claim 11, wherein the solid state smectic aerogel is initially formed in a bulk shape, and is then cut from the bulk into a desired shape.
[claim20]
20. The method according to claim 11, wherein the gas inclusion is injected into the mixture of the smectic liquid crystal with an ultra-violet (UV)-curable material while the smectic liquid crystal is in a nematic phase and the nematic phase is thereafter cooled down to the smectic phase.
[claim21]
21. The smectic aerogel according to claim 9, wherein the refractive index of the smectic aerogel is 1.2 or less.
[claim22]
22. The smectic aerogel according to claim 1, wherein the smectic liquid crystal is 4-octyl-4'-cyanobiphenyl (8CB) or 4-nonyl-4'-cyanobiphenyl (9CB).
  • 発明者/出願人(英語)
  • VOELTZ CAMILLA OLIVIA
  • MAEDA YOJI
  • TABE YUKA
  • YOKOYAMA HIROSHI
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
国際特許分類(IPC)
米国特許分類/主・副
  • 252/299.01
  • 252/299.6
  • 349/182
  • 349/184
  • 428/1.1
  • 428/1.2
  • 428/1.3
参考情報 (研究プロジェクト等) ERATO/SORST Liquid Crystal Nanosystem AREA
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