| 摘要 |
#CMT# #/CMT# A novel surface-modified structure (I) comprises (a) a substrate, (b) a silicate primary coating and (c) a secondary coating and/or particles containing element(s) other than silica and oxygen. The chemical composition of (b) differs from that of (a) and (c). Either (b) is located between (a) and (c); or (b) and (c) together form a gradient coating, having the compositions of (b) and (c) on the sides facing towards and away from (a) respectively. #CMT# : #/CMT# Independent claims are included for: (1) a surface-modified structure (II) comprising (a) a substrate and (b) a silicate primary coating, where the chemical composition of (b) differs from that of (a); and (2) the production of (I), by simultaneously applying the coatings (b) and (c) to the substrate (a). #CMT#USE : #/CMT# The use of (I) is claimed: (i) for carrying out catalytic reactions, for separation procedures or in shaping, guiding, focusing and reinforcing electromagnetic waves; or (ii) for preparing nanoparticles for medicinal, cosmetic, nanomechanical or optical applications. Disclosed more specific applications are e.g. as catalysts in microreactors for carrying out gas phase reactions (e.g. C-C bond coupling, oligomerization or oxidation reactions); as membranes, separators, molecular sieves or molecular filters for separations; as microcontainers; in modulating electromagnetic waves (e.g. microwave, visible, UV, laser or X-ray radiation) or particle beams (e.g. neutron beams), in applications such as X-ray or UV-lithography (e.g. in mask illumination during semiconductor production) or X-ray microscopy; and production of nanoparticles (including nanotubes, rods or wires) such as contrast agents, stents, cosmetic UV-filters (of titanium dioxide) or non-linear optical components. #CMT#ADVANTAGE : #/CMT# The coated substrates have adjustable properties and high quality. In particular the properties and morphologies of the secondary coating are controllable independently of those of the primary coating, and the two coatings may have inverted surface morphologies. The coatings are readily applicable to glass or other substrates with special or complex geometries (e.g. fibrous, hollow cylindrical or hollow elliptical glass structures). The coatings include even, smooth, cavity-free surface modifying coatings for optical applications; and structured surfaces of high contact area for catalytic applications. The coatings show good adhesion (even under thermal or mechanical stress). When used for modulating radiation (I) show good long-term stability, and the substrates (e.g. of lead glass) are effectively protected against radiation-induced damage. #CMT#CERAMICS AND GLASS : #/CMT# Preferred Substrates: The substrate (a) has a cavity structure, preferably a capillary or a multichannel structure (especially consisting of polycapillaries, photonic crystals or monolithic integral microlenses). (a) is of glass, preferably having a processing temperature below 2000 (especially below 1000)[deg] C. Preferred Primary Coatings: The primary coating (b) has a silicon dioxide (SiO 2) content of more than 90 (especially more than 99) wt. %. (b) is free of barium and Group II and VI non-transition elements (other than oxygen), and is preferably almost or completely free of elements other than silicon, oxygen, carbon and hydrogen. (b) has a carbon content of at least 1 (especially at least 10) wt. %. (b) has a thickness of 1-10000 (especially 0.1-10) nm and a root mean square surface roughness of less than 5 (especially less than 0.5) nm. Preferred Process: The secondary coating (c) is applied by chemical vapor deposition (CVD), chemical vapor infiltration (CVI), physical vapor deposition (PVD) or chemical liquid deposition (CVL). The silicate primary coating (b) is applied to the substrate (a) using CVD, CVI, PVD or CLD methods, preferably by localized energy supply to an organosilicon compound precursor material, especially tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), tetrabutoxysilane, triethoxy-phenylsilane, methyl-tripropoxysilane, 1,2-bis(trimethoxysilyl)-ethane, 1,2-bis-(triethoxysilyl)-ethane, phenethyl-trimethoxysilane, isobutyl-triethoxysilane, tris-(2-methoxyethoxy)-vinylsilane, octyl-trimethoxysilane, phenyl-triethoxysilane or octyl-triethoxysilane (or their derivatives or mixture), particularly TEOS and/or TMOS. #CMT#INORGANIC CHEMISTRY : #/CMT# Preferred Secondary Coatings: The secondary coatings and/or particles (c) contain a Group II-V non-transition or transition element (other than carbon and silicon), specifically one or more of beryllium, zirconium, vanadium, chromium, molybdenum, tungsten, nickel, copper, palladium, platinum, gold, iron, aluminum, rhenium, rhodium, ruthenium, iridium, silver, osmium, lead, bismuth and/or uranium, especially nickel, chromium, molybdenum, copper, palladium, platinum, rhodium, ruthenium, iridium, silver, gold, tungsten, lead, bismuth and/or uranium. (c) is specifically in the form of (preferably amorphous) metal layers and/or particles; or (preferably crystalline) metal layers and/or particles. #CMT#EXAMPLE : #/CMT# A substrate to be coated consisted of a monocapillary of alkali resistant (AR) glass, having a processing temperature of 1040[deg] C and the following composition (by weight): 69% SiO 2, 1% B 2O 3, 13% Na 2O, 3% K 2O, 4% Al 2O 3, 2% BaO and 5% CaO. The capillary was connected to a vacuum system in gas-tight manner and internally cleaned by passage of oxygen (100 mbar) while heating to 733 K. Tetraethyl orthosilicate (TEOS; as precursor) was passed through the capillary while maintaining a pressure gradient of 0.001 mbar to 0.00001 mbar, followed by adjusting localized regions of the capillary to a temperature of 673 K for 2 hours using a moving furnace system. Tungsten hexacarbonyl (as precursor) was passed through the capillary while maintaining a pressure gradient of 0.001 mbar to 0.00001 mbar, followed by adjusting localized regions of the capillary to a temperature of 673 K for 2 hours using a moving furnace system. The obtained tungsten coating had excellent optical properties; in particular the coated glass structure showed high reflectivity. Scanning electron microscopic studies showed that the coating was a homogeneous layer of low roughness on the glass surface (Franck-van der Merve growth). The average particle size was 2-3 nm. |
