JP3194010B2 - Modified solid surface with highly reactive active species immobilized on the surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid surface having highly reactive active species immobilized on a surface by a chemical reaction.

[0002]

2. Description of the Related Art Processing of the surface of an organic material typified by a polymer material using an excimer laser that oscillates a high intensity pulse light in the ultraviolet region is performed by a precise surface treatment of the organic material.
The surface processing method is being actively studied from both basic and applied aspects. On the other hand, Miyake et al. Have developed a method for producing high-purity thin films of semiconductors, metals, and dielectrics by performing laser ablation on a low-temperature frozen target of metal or semiconductor raw material and depositing the plasma-converted raw material on a solid substrate. (JP-A-63-177414). In this method, the target is obtained by depositing a raw material gas alone on a low-temperature solid substrate. However, since the target is a solid film containing only a raw material that does not contain a medium, the raw material is irradiated on the atomic order by high-intensity laser irradiation. It is characterized by being decomposed into plasma by the minute. The present inventors have previously found a method of hydrophilizing the surface of a fluoropolymer molded article by irradiating an ultraviolet laser in the presence of hydrazines, and a method of depositing a metal film on the hydrophilized surface (Japanese Patent Publication No. 7-5773 and Japanese Patent Publication No. 7-5776). The hydrophilized surface is obtained by the reaction of hydrazine molecules photo-decomposed in the gas phase by a laser with the surface of the molded product, whereby the F atoms on the surface are extracted, and the H atoms and NH ₂ groups of the photo-decomposed product are replaced. Can be However, since the photolysis reaction occurs in a diffusion atmosphere in the gas phase, the composition and state of the photolysis product could not be precisely controlled.

[0003]

It is an object of the present invention to provide a solid surface in which highly reactive active species are immobilized on the solid surface.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, a solid layer formed of a mixture of a matrix substance and a photoreactive substance formed on a substrate is irradiated with an ultraviolet laser having a wavelength of 400 nm or less, and the emitted highly reactive active species is applied to the solid surface. The modified solid surface is characterized in that the highly reactive active species obtained by contacting the surface is a solid surface fixed to the surface by a chemical reaction.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As the photoreactive substance used in the present invention, any substance can be used as long as it is a compound having an absorption in the ultraviolet region, and a substance which is easily decomposed by irradiation with ultraviolet light is desirable. Examples include azide compounds, azo compounds, carbonyl compounds, acid anhydrides, hydrazines, and organic halogen compounds. These materials can be solid, liquid, or gaseous. The matrix material is preferably a solid, gaseous, or liquid material having no absorption in the ultraviolet region and not easily decomposed by ultraviolet light irradiation. For example, an inert gas such as a rare gas, a nitrogen gas, and carbon dioxide, a fluorinated alkane compound, an alkane compound, ethers, and alcohols are exemplified.

As the substrate, any material having high thermal conductivity and not reacting with the matrix material may be used. For example, a metal substrate such as silver, a sapphire substrate, a cesium iodide substrate and the like are suitable. The substrate temperature may be any temperature at which the matrix material is solidified. Therefore, when using an alkane or the like, the substrate temperature is set to 200 K or less (preferably about the temperature of liquid nitrogen). Or lower (typically 20K or lower).

[0007] As the laser in the present invention, an ultraviolet laser which emits ultraviolet light corresponding to the absorption band of the starting material is suitable. In particular, ArF (wavelength: 193 nm), Kr
F (248 nm), XeCl (308 nm), or
XeF (351 nm) excimer laser is suitable. Nd +: YAG laser, dye laser, K
The fundamental wavelength light of r ion laser, Ar ion laser or copper vapor laser is
Those converted to harmonics in the ultraviolet region of 00 nm or less are also effective. The fluence of the laser varies depending on the type of polymer or hydrazine, but a high-intensity laser having a pulse width of about nanoseconds and about 1 mJ / pulse or more is desirable.

In the present invention, a solid layer (film) composed of a mixture of a matrix substance and a photoreactive substance is formed on a substrate. In this solid layer, the proportion of the photoreactive substance may be 50 mol% or less, preferably in the range of 1 to 0.01 mol%, based on the matrix substance.

In order to form a solid layer comprising a mixture of a matrix material and a photoreactive material on a substrate, the matrix material and the photoreactive material are formed on a substrate maintained at a low temperature at which the matrix material solidifies. May be brought into contact with the mixture. For example, when the matrix material is a liquid material at normal temperature, a photoreactive substance may be mixed or dissolved in the liquid matrix material, and the mixed solution or solution may be applied on the low-temperature substrate. As a coating method in this case,
A spray method, a casting method, or the like can be employed. When a liquid matrix material mixed with a photoreactive substance is applied to a low-temperature substrate, the matrix material is cooled and solidified, and a solid layer (film) composed of a mixture of the matrix substance and the photoreactive substance is formed on the substrate. . On the other hand, when the matrix material is in a gaseous state at room temperature, the gas is deposited on the substrate surface cooled to a low temperature at which the matrix material solidifies, for example, in the case of a rare gas, the temperature is lowered to the Debye temperature or lower (20K or lower). A mixture in which a mist-like or gaseous photoreactive substance is mixed and dispersed in a matrix-like matrix substance may be sprayed on the low-temperature substrate surface. The gaseous mixture sprayed on the low-temperature substrate is cooled and solidified, and a solid layer composed of the mixture is formed on the substrate.

In the present invention, an ultraviolet laser is applied to a solid layer formed on a substrate and formed of a mixture of a matrix material and a photoreactive material as described above. When a solid layer is irradiated with an ultraviolet laser, the photoreactive substance in the solid layer absorbs the ultraviolet laser and is converted into a highly reactive active species by ablation. Emitted from the layer upwards. The active species released from the solid layer is a photoreactive substance that has been photolyzed, and is a highly reactive species composed of radical species and ionic species.

The method for modifying a solid surface according to the present invention is a method in which highly reactive active species released from the solid layer as described above are brought into contact with the solid surface. When the highly reactive active species comes into contact with the solid surface, the molecules on the solid surface react with the active species, and the solid surface is modified according to the properties of the active species. For example, when the active species contains an oxygen atom or a nitrogen atom, such an atom is bonded to the solid surface to form a highly hydrophilic surface. On the contrary, when the active species contains a fluorine atom, the fluorine atom is bonded to the solid surface to form a surface having high water repellency.

The solid surface includes various solid surfaces such as an organic solid surface, a ceramic solid surface, and a metal solid surface. Examples of the organic solid surface include a polymer molded product surface, for example, a solid surface of a molded product formed from a thermoplastic resin or a thermosetting resin. These polymer molded product surfaces can be converted into modified surfaces of various properties according to the active species.

Next, the photoreaction in the solid layer will be described in more detail. When a low-temperature solid layer is irradiated with an ultraviolet laser, the photoreactive substance is photolyzed into reactive intermediates (active species) such as radicals, carbene and nitrene. The use of an inert matrix environment in the reaction field suppresses side reactions and chain reactions of photodegradants, so the life of these active species is dramatically extended, and the active species can be converted into a matrix with high purity. Can be held within. At this time, if a matrix environment is not used, the generated active species are close to each other, so that the active species react with each other, and there is a disadvantage that only low-purity active species can be obtained by a side reaction. Therefore, the use of a matrix material is an important aspect of the present invention.

Further, since the ultraviolet laser can irradiate the substrate with high intensity, the above-mentioned photolysis reaction explosively proceeds by the pulse laser, and the solid layer is instantaneously vaporized and evaporated by the generated reaction heat (ablation). ) Is possible. The vaporized substance generated in a pulse by the ablation in such a matrix field has directivity in a scattering direction, and the vaporized substance is composed of a high-purity photodecomposed substance and a matrix substance. Since the matrix substance itself has no reactivity, when a surface of an organic material such as a polymer molded article is irradiated with a beam of a vaporized substance, only a photodecomposition reacts with the surface. By precisely designing the chemical structure of the starting materials and optimizing the laser irradiation, various reactive intermediates (active species) suitable for creating high-performance surfaces are converted into high-purity, high-concentration pulse beams. Obtainable.

In the method of the present invention, the intensity of the ultraviolet laser must be higher than the threshold intensity at which ablation occurs (about 5 mJ / cm ² / pulse or more). However, in the process of generating the active species in the matrix, a low-intensity stationary light source such as a mercury lamp can be used. In addition, the matrix material layer on the low-temperature substrate may be a single layer containing a single-component photoreactive material, but it is also possible to disperse a plurality of photoreactive materials dilutely in the matrix or to form a multilayer structure. It is. By mixing and reacting a plurality of active species on the surface of the base material, a more reactive active species can be generated. When a plurality of photoreactive substances are used, irradiation at a wavelength suitable for each substance is desirable, so that light irradiation at multiple wavelengths is also effective.

On a sapphire substrate at a temperature of 85 K in a vacuum vessel, perfluorohexane (1) as a matrix material and pentafluorophenyl azide (2) as a photoreactive material are mixed at a molar ratio of about 100: 1 to form a solid layer. When deposited and irradiated with a KrF excimer laser (wavelength: 248 nm) having an optimum wavelength at 25 mJ / cm ² / pulse, ablation was observed. When the emission spectrum of the vaporized substance emitted from the solid layer was measured, light emission from perfluorophenyl nitrene (3) was detected and its presence was confirmed (FIG. 1). By the way, when the solid layer of only (2) was ablated without using (1), no light emission from (3) was detected. It was found to have occurred. When the laser intensity was reduced to ² mJ / cm ² / pulse and only photodecomposition was performed in the matrix material, the formation of (3) was confirmed from the ultraviolet / visible absorption spectrum, It was found to be stable. Therefore, the photoreactive substance dispersed in the matrix substance is subjected to photolysis with a laser, whereby active species can be generated with high efficiency.

When a beam of the active species generated by the above method was irradiated on polyethylene terephthalate (PET), no change was observed on the surface by visual observation.
When elemental analysis of the surface was performed by X-ray photoelectron spectroscopy, only peaks of carbon and oxygen were observed before the treatment, but peaks of carbon, nitrogen, oxygen, and fluorine were detected after the treatment (FIG. 2 and FIG. 2). (Fig. 3). This indicates that (3) was immobilized on the PET surface via a chemical bond, and it was found that (3) having high chemical reactivity reacted with the PET surface.

Organic materials such as polymer molded products whose surfaces have been modified by irradiation with these active species are highly functional only in their surface layers while maintaining various bulk properties. Taking advantage of its advantages, improve water / oil repellency and hydrophilicity / lipophilicity, surface adhesion, dye adsorption, nonlinear optical properties, light reflection / refraction properties, optical waveguide properties, medical materials, and cell proliferation The range of application to substrates and the like can be expanded. In addition, by performing the treatment with such active species in multiple stages, a highly functional multilayer thin film can be formed.

The present invention also provides a method of irradiating an active seed beam which has passed through a mask (a metal plate pattern or the like) corresponding to a portion of a polymer film to be modified, so that only a desired irradiated portion is surface-treated. Can be performed. On the other hand, excimer laser beams are helium-neon laser, argon and krypton ion laser, and Nd.
+: Compared with other laser beams such as a YAG laser, the beam shape is large and active species can be generated in a large amount, so that it can easily cope with large area processing. In particular, in the present invention, active species can be generated by a non-thermal photochemical reaction using an ultraviolet laser, so that the surface treatment can be performed very effectively.

The polymer molded article includes various materials such as films, sheets, fibers, fiber reinforced resins, resin molded articles, etc., and does not necessarily need to be a final molded article, There is no limitation. The target resin may be amorphous, crystalline, aromatic, or non-aromatic, and may be any of a hydrocarbon resin or a fluororesin, a copolycondensate thereof, or A synthetic resin consisting of a mixture of The surface of the copolymer of a fluororesin and a hydrocarbon monomer can be similarly functionalized.

[0021]

Next, the present invention will be described in more detail with reference to examples. Example 1 On a sapphire substrate at a temperature of 85 K in a vacuum vessel, perfluorohexane (1) as a matrix material and pentafluorophenylazide (2) as a photoreactive material were mixed at a mixing ratio (molar ratio) of about 100: 1. When deposited as a solid layer and irradiated with a KrF excimer laser at 25 mJ / cm ² / pulse, ablation was observed. When the emission spectrum of the vaporized substance released from the solid layer was measured, light emission from perfluorophenyl nitrene (3) was detected, and the presence of (3) was confirmed (FIG. 1). Further, when the generated active species beam was irradiated on polyethylene terephthalate (PET),
No change was observed by visual observation, but when elemental analysis of the surface was performed by X-ray photoelectron spectroscopy, only peaks of carbon and oxygen were observed before the treatment, but after the treatment, carbon, nitrogen, oxygen, A fluorine peak was detected (FIGS. 2 and 3). From the above results, it was found that (3) was generated from (2) with high efficiency by laser irradiation, and reacted with the PET surface, thereby being immobilized via a chemical bond. Also, the contact angle of PET surface with water changes from 70 degrees to 110 degrees due to the active species irradiation treatment,
It was confirmed that water repellency was achieved.

Example 2 Perfluorohexane (1) as a matrix material and pentafluorophenyl azide (2) as a photoreactive material were placed on a sapphire substrate at a temperature of 85 K in a vacuum vessel for about 1 hour.
When deposited as a solid layer at a mixing ratio of 00: 1 and irradiated with a KrF excimer laser at 25 mJ / cm ² / pulse, ablation was observed. Furthermore, when a beam of the generated active species was irradiated on a hexadecylthiol monomolecular film on a gold substrate, no change was observed on the surface by visual observation, but elemental analysis of the surface was performed by X-ray photoelectron spectroscopy. As a result, only peaks of carbon and sulfur were observed before the treatment, but new peaks of nitrogen and fluorine were detected after the treatment. In addition, a peak of an aromatic ring (1525 cm ⁻¹ ) was detected in the treated film from reflection infrared absorption measurement, and it was found that perfluorophenylnitrene was fixed on the surface while maintaining the aromatic ring structure. The contact angle of water on the surface of the hexadecylthiol monomolecular film can be increased from 90 degrees to 130 degrees by the irradiation of the active species.
It changed every time, and it was confirmed that water repellency was achieved.

Example 3 Perfluorohexane (1) as a matrix material and perfluoroacetic anhydride (4) as a photoreactive material were placed on a sapphire substrate at a temperature of 85 K in a vacuum vessel at a ratio of about 100: 1.
When a KrF excimer laser was irradiated at 25 mJ / cm ² / pulse, ablation was observed. Further, when the beam of the generated active species was irradiated to the hexadecylthiol monomolecular film on the gold substrate, no change was observed by visual observation, but the elemental analysis of the surface by X-ray photoelectron spectroscopy was performed. Before the treatment, only peaks of carbon and sulfur were observed, but after the treatment, peaks of oxygen and fluorine were newly detected. Therefore, it was found that a trifluoromethyl group or a trifluoroacetyl group was immobilized on the surface. Further, the contact angle of the surface with water changed from 70 degrees to 120 degrees due to the irradiation treatment of the active species, and it was confirmed that the surface became water-repellent.

Example 4 Perfluorohexane as a matrix material and hydrazine as a photoreactive material were deposited as a solid layer at a mixing ratio of about 100: 1 on a sapphire substrate at a temperature of 85 K in a vacuum vessel, and an ArF excimer laser was applied at 25 mJ. / Cm ²
When irradiation was performed with a pulse, ablation was observed. Further, when the beam of the generated active species was irradiated to polytetrafluoroethylene (PTFE), no change was observed by visual observation. However, when the elemental analysis of the surface was performed by X-ray photoelectron spectroscopy, the surface before the treatment was observed. Although only the peaks of carbon and fluorine were observed, a new nitrogen peak was detected after the treatment, and the intensity of fluorine decreased. In addition, since the surface is hydrophilic, P
It was found that the F atom was removed from the TFE surface and replaced by a hydrophilic group containing a nitrogen atom instead.

[0025]

According to the present invention, the solid layer is irradiated with an ultraviolet laser, whereby the solid surface is modified with highly reactive active species. Can be obtained.

[Brief description of the drawings]

FIG. 1 is an emission spectrum of a vaporized substance released from a mixed solid layer in Example 1.

FIG. 2 is a diagram showing a P before irradiation with a vaporized substance in Example 1.
It is an XPS spectrum of an ET film.

FIG. 3 shows P after irradiation with a vaporized substance in Example 1.
It is an XPS spectrum of an ET film.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-42769 (JP, A) JP-A-7-188437 (JP, A) JP-A-5-339396 (JP, A) 507965 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08J ^7/ 00-7/18 B29C 71/00-71/04 C23C 14/28

Claims (5)

(57) [Claims] 1. A solid layer comprising a mixture of a matrix substance and a photoreactive substance formed on a substrate, having a wavelength of 400 nm.
m or less, and the highly reactive active species obtained by contacting the emitted highly reactive active species with the solid surface is a solid surface fixed to the surface by a chemical reaction. Modified solid surface. 2. As an ultraviolet laser, an argon fluorine excimer laser, a krypton fluorine excimer laser,
The solid surface according to claim 1, wherein a xenon chlorine excimer laser or a xenon fluorine excimer laser is used. 3. The solid surface according to claim 1, wherein an azide compound, an azo compound, a carbonyl compound, an acid anhydride, a hydrazine or an organic halogen compound is used as the photoreactive substance. 4. The solid surface according to claim 1, wherein a rare gas, nitrogen gas, carbon dioxide, fluorinated alkane compound, alkane compound, ether or alcohol is used as the matrix material. 5. The solid surface according to claim 1, wherein the solid surface is a polymer surface.