JP5193078B2 - Analysis method and manufacturing method of surface modified substrate - Google Patents

Description

  The present invention relates to a method for analyzing and manufacturing a surface-modified substrate in which an organic compound is immobilized on a substrate.

Various surface chemical modification techniques have been developed in which an organic compound is bonded onto a substrate to modify the substrate surface at the molecular level to give a desired function.
In general, a covalent bond is formed on a surface of a glass plate or a quartz plate and a surface of a metal oxide film by a condensation reaction of a silane-containing organic compound or a sulfonic acid group-containing organic compound, and organics derived therefrom. The compound is allowed to bind. Thereby, the substrate surface can be modified.

Specifically, for example, when a resin film such as an adhesive or a photoresist is formed on a glass substrate, a methyl group is introduced on the surface of the glass substrate in order to improve adhesion to these substrates. This can be achieved, for example, by bonding hexamethyldisilazane to the glass substrate surface.
Further, in a device such as an ink jet, it is necessary to make the discharge side surface of the discharge port water-repellent or oil-repellent, and a perfluoroalkyl group is introduced into the discharge port surface. This can be realized, for example, by bonding a silane-containing organic compound to the discharge port surface (see Patent Document 1).
In addition, when a biomolecule is detected on a solid phase carrier (substrate surface) by a luminescence phenomenon such as a fluorescent signal, a probe that specifically binds to the biomolecule needs to be immobilized on the solid phase carrier. . Similarly to the above, this can be realized by bonding an organic compound having a specific functional group to the surface of the solid phase carrier (see Non-Patent Document 1).

Thus, the technique of immobilizing an organic compound on a substrate for modification is applied in various fields. In such a surface chemical modification technique, it is important to analyze whether the modification state of the substrate surface is a desired one.
Conventionally, electrochemical methods (see Non-Patent Document 2); ellipsometry method; quartz crystal microbalance method; electron microscope (scanning type, transmission type), scanning tunneling microscope or atomic force microscope are used as analysis methods X-ray photoelectron spectroscopy or the like is applied. Furthermore, in order to analyze the structure of the organic compound immobilized on the substrate, infrared spectroscopy and nuclear magnetic resonance are effective (see Non-Patent Documents 2 and 3). Significant knowledge is gained in the development of modification techniques and organic compounds used for modification.

JP-A-10-176139

CHEMBIOCHEM, (2001) 2,686 MRS Bull. , (1993) 18, 45 Langmuir, (1999) 15, 66.

In the field of surface chemical modification, in order to obtain in situ information on the organic compound immobilized on the substrate surface, analyzing the structure of the immobilized organic compound itself is a very important means. is there. In particular, the molecular structure can be analyzed in detail and easily by applying infrared spectroscopy.
However, in the past, there has been no actual development of a method for stably immobilizing an organic compound on a substrate surface and further analyzing the immobilized organic compound by applying infrared spectroscopy. .

  The present invention has been made in view of the above circumstances, a surface-modified substrate capable of analyzing in detail the structure of an organic compound immobilized on the substrate surface and the modification state by the organic compound by infrared spectroscopy, and its It is an object to provide an analysis method.

To solve the above problem,
In the invention described in claim 1, a metal thin film having light reflectivity in the infrared region is formed on a substrate, and the surface of the thin film is an oxide film. A method for analyzing a surface-modified substrate, comprising combining a compound represented by any one of formulas (I) to (III) to form a surface-modified substrate and measuring an infrared light reflection spectrum of the surface-modified substrate. It is.

[Wherein R ¹ is a hydroxyl group or a hydrolyzable group; R ² is a hydrogen atom or a monovalent hydrocarbon group; X ¹ , X ² and X ³ are each independently a monovalent organic group; A plurality of X ² may be the same or different from each other; n is 1, 2 or 3; when n is 2 or 3, n R ¹ may be the same or different from each other When n is 1, two R ^{2 s} may be the same or different from each other; ]

The invention according to claim 2 is the method for analyzing a surface-modified substrate according to claim 1, wherein the metal is titanium, chromium, aluminum, or copper.
The invention according to claim 3 is a method of manufacturing a surface-modified substrate having an organic compound immobilized on a substrate, the step of forming a metal thin film having light reflectivity in the infrared region on the substrate; And a step of forming an oxide film on the surface of the thin film, and a step of bonding an organic compound represented by any one of the following general formulas (I) to (III) to the oxide film. This is a method for producing a surface-modified substrate.

[Wherein R ¹ is a hydroxyl group or a hydrolyzable group; R ² is a hydrogen atom or a monovalent hydrocarbon group; X ¹ , X ² and X ³ are each independently a monovalent organic group; A plurality of X ² may be the same or different from each other; n is 1, 2 or 3; when n is 2 or 3, n R ¹ may be the same or different from each other When n is 1, two R ^{2 s} may be the same or different from each other; ]

  The invention according to claim 4 is the method for producing a surface modified substrate according to claim 3, wherein the metal is titanium, chromium, aluminum or copper.

  According to the present invention, the structure of an organic compound immobilized on the substrate surface and the modification state by these organic compounds can be analyzed in detail by infrared spectroscopy. Even fine modification patterns can be analyzed with high accuracy.

It is a schematic sectional drawing for demonstrating the manufacturing method of the surface modification board | substrate of this invention, (a) is a board | substrate for analysis, (b) is a schematic sectional drawing of a surface modification board | substrate. It is a figure which shows the analysis data in the total reflection measurement method of the infrared spectroscopy of the surface modification board | substrate in Example 2. FIG. 6 is a schematic cross-sectional view showing a surface-modified substrate produced in Example 3. FIG. It is a figure which shows the analysis data in the total reflection measuring method of the infrared spectroscopy of the surface modification board | substrate in Example 4. FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings.
<Method for producing surface-modified substrate>
FIG. 1A is a schematic cross-sectional view illustrating an analysis substrate in the present invention. The analysis substrate is a substrate used for manufacturing a surface-modified substrate.
In the analysis substrate 1, a metal thin film 13 is formed on the surface 11 a of the substrate 11, and an oxide film 14 is formed on the surface of the metal thin film 13.
The material of the substrate 11 may be a commonly used material. Specifically, glass, resin, metal, and ceramics can be exemplified, and glass or silicon resin is particularly preferable. In the present invention, since the analysis substrate is used for measurement of reflected light, the material of the substrate 11 does not necessarily have light transmittance.

What is necessary is just to set the thickness and surface area of the board | substrate 11 suitably according to the objective. For example, considering the operability, the thickness _{T 11} typically is preferably 0.1 to 10 mm, more preferably 0.3 to 1.5 mm. If it is such a range, it will become the thing especially excellent in the fine workability of the board | substrate 11, and the usability of the obtained surface modification board | substrate.

The material of the metal thin film 13 may be any material as long as it has light reflectivity in the infrared region and can be oxidized. Among these, titanium (Ti), chromium (Cr), aluminum (Al), and copper (Cu) can be exemplified as preferable examples.
The thickness _{T 13} of the metal thin film 13 is not particularly limited as long as they do not impair the light reflectivity is preferably 40～600Nm, more preferably from 50 to 400 nm, and particularly preferably 50~300nm . By setting the thickness T ₁₃ equal to or greater than the lower limit, the more uniform thin film is obtained, the modified layer on the substrate can be more clearly confirmed, by more than the upper limit, a substrate for a good analysis handleability It can be.

  If the metal thin film 13 cannot be satisfactorily adhered to the substrate surface due to the material of the metal thin film 13, the substrate surface 11a may be roughened as necessary.

An oxide film 14 is formed on the surface of the metal thin film 13. The oxide film 14 is a film for immobilizing an organic compound that modifies the substrate surface 11a and has reactivity with oxygen atoms on the substrate. That is, the organic compound is indirectly bonded onto the substrate 11 by bonding to the oxide film 14.
The oxide film 14 is a metal oxide formed by oxidizing the surface of the metal thin film 13, and oxygen atoms constituting the metal oxide may be bonded to hydrogen atoms to form a hydroxyl group.

The thickness T ₁₄ of the oxide film 14 is not particularly limited as long as they do not impair the binding of the organic compound. For example, the thickness can be made 10 nm or less by appropriately adjusting the oxidation conditions. With such a thickness, it is possible to obtain an analysis substrate that can be stably bonded to the organic compound and has good handleability.
The thickness T ₁₄ can be adjusted by adjusting the oxidation conditions of the metal thin film 13.

The analysis substrate can be manufactured by the following method. Here, the case of the analysis substrate 1 will be described with reference to FIG. 1, but other analysis substrates can be similarly manufactured.
First, the metal thin film 13 is formed on the substrate surface 11a by a known method such as sputtering.
Next, the surface of the metal thin film 13 is oxidized to form an oxide film 14. The oxidation method may be a known method and may be selected in consideration of the material of the metal thin film 13. Specifically, a method of exposing the metal thin film 13 to water vapor or a method of irradiating the metal thin film 13 with plasma can be exemplified. Further, the metal thin film 13 may be oxidized by air.
The oxidation conditions are preferably adjusted as appropriate according to the desired thickness of the oxide film.
When exposed to water vapor, the temperature of the water vapor during the treatment is preferably about 300 to 500 ° C. The treatment time is preferably about 0.5 to 3 hours.
In the case of plasma irradiation, it is preferable that the antenna power is about 600 to 900 W and irradiation is performed for about 10 to 50 minutes. The plasma is preferably oxygen plasma.
After forming the oxide film 14, the substrate 11 may be cleaned. By doing so, the organic compound can be more reliably bonded to the oxide film 14 in the next step. Cleaning method is UV / ozone irradiation; use strong acid such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, 30% hydrogen peroxide / concentrated sulfuric acid = 1/3 (v / v) (pyranha solution) Examples of cleaning are as follows.
Thus, the analysis substrate 1 is obtained.

  The analysis substrate is a surface-modified substrate by bonding an organic compound represented by any one of the following general formulas (I) to (III) having reactivity with oxygen atoms to the oxide film. Can do. The organic compound is presumed to be bonded to the oxide film by reacting with an oxygen atom which forms a hydroxyl group by combining with an oxygen atom or a hydrogen atom constituting the metal oxide on the oxide film. As is apparent from the general formula, the organic compound is a silane-containing organic compound or a sulfonic acid group-containing organic compound.

[Wherein R ¹ is a hydroxyl group or a hydrolyzable group; R ² is a hydrogen atom or a monovalent hydrocarbon group; X ¹ , X ² and X ³ are each independently a monovalent organic group; A plurality of X ² may be the same or different from each other; n is 1, 2 or 3; when n is 2 or 3, n R ¹ may be the same or different from each other When n is 1, two R ^{2 s} may be the same or different from each other; ]

In the formula, R ¹ is a hydroxyl group or a hydrolyzable group. Here, the “group” in the hydrolyzable group may be either a single atom or a group consisting of a plurality of atoms.
Preferred examples of the hydrolyzable group for R ¹ include an alkoxy group having 1 to 6 carbon atoms, an aryloxy group, an aralkyloxy group, an acyloxy group, and a halogen atom.
Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, pentoxy group and hexyloxy. Examples are groups.
Examples of the aryloxy group include a phenoxy group and a naphthoxy group.
Examples of the aralkyloxy group include a benzyloxy group and a phenethyloxy group.
Examples of the acyloxy group include an acetoxy group, a propionyloxy group, a butyryloxy group, a valeryloxy group, a pivaloyloxy group, and a benzoyloxy group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Among these, R ¹ is preferably a hydrolyzable group, more preferably an alkoxy group having 1 to 6 carbon atoms, and particularly preferably a methoxy group or an ethoxy group.

In the formula, R ² is a hydrogen atom or a monovalent hydrocarbon group.
The monovalent hydrocarbon group for R ² is not particularly limited, and may be a chain structure or a cyclic structure, and may be either saturated or unsaturated. In the case of a chain structure, either a straight chain or a branched chain may be used, and in the case of a cyclic structure, either a monocyclic structure or a polycyclic structure may be used.
Of these, preferred are alkyl groups having 1 to 6 carbon atoms, aryl groups and aralkyl groups.
Examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group and hexyl group. It can be illustrated.
Examples of the aryl group include a phenyl group and a naphthyl group.
Examples of the aralkyl group include a benzyl group and a phenethyl group.
Among these, R ² is preferably a monovalent hydrocarbon group, more preferably an alkyl group having 1 to 6 carbon atoms, and a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Particularly preferred is a methyl group, and most preferred is a methyl group.

In the formula, X ¹ , X ² and X ³ are each independently a monovalent organic group. Then, a plurality of X ² may be the same or different from each other. That is, all six X ² in the general formula (II) may be the same, a part of them may be different, or all may be different.
The monovalent organic groups of X ¹ , X ² and X ³ can be arbitrarily selected according to the purpose. Specific examples include linear, branched or cyclic hydrocarbon groups and those in which at least one hydrogen atom or carbon atom of the hydrocarbon group is substituted with a substituent. Here, the “substituent” may be either a single atom or a group consisting of a plurality of atoms.

For example, when the substrate surface is modified with a liquid repellent monomolecular film, X ¹ , X ² and X ³ are each a linear or branched fluoroalkyl group or fluoroalkyl ether having 1 to 16 carbon atoms It is preferably a group. Here, the “fluoroalkyl group” refers to “one or more hydrogen atoms of the alkyl group substituted with fluorine atoms”. The “fluoroalkyl ether group” refers to “a monovalent group in which the fluoroalkyl group is bonded to an oxygen atom”. Furthermore, “liquid repellency” refers to “water repellency” or “oil repellency”.
As the alkyl in the fluoroalkyl group or fluoroalkyl ether group of X ¹ , X ² and X ³ , methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, Examples include heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl and hexadecyl.
The number of carbon atoms in the fluoroalkyl group or fluoroalkyl ether group of X ¹ , X ² and X ³ is preferably 3 to 12, and more preferably 6 to 10.
The fluoroalkyl group or fluoroalkyl ether group is preferably as the number of fluorine atoms substituted with hydrogen atoms increases, and may be a perfluoroalkyl group or a perfluoroalkyl ether group in which all hydrogen atoms are substituted with fluorine atoms. . In X ¹ and X ² , it is preferable that all of the hydrogen atoms at the terminal opposite to the portion bonded to the silicon atom are substituted with fluorine atoms. Similarly, in the X ^3, preferably hydrogen atoms of the opposite end is substituted with any fluorine atom and moiety bonded to a sulfur atom.

Among these, as the fluoroalkyl group or fluoroalkyl ether group of X ¹ , X ² and X ^3, a linear group is preferable, and a linear fluoroalkyl group is more preferable. In particular, when a linear or branched perfluoroalkyl group or perfluoroalkyl ether group is used, the modified layer formed of these organic compounds is more transparent than the conventional layer containing polytetrafluoroethylene or the like. Excellent, suitable for forming a thin single layer thin film, and excellent in fine workability such as patterning and removal. Since the transparency is excellent, for example, when optically detecting a cell or a substance acting on the cell, noise can be greatly reduced, and a biochip capable of highly sensitive analysis can be provided. Moreover, since it is excellent in fine workability, a large number of patterns having a small size can be formed on the substrate, and a biochip capable of analysis with high efficiency can be provided.

When the substrate surface is modified with a monomolecular film, preferred examples of X ¹ , X ² and X ³ include linear or branched alkyl groups. Here, the linear or branched alkyl group preferably has 5 to 30 carbon atoms, more preferably 5 to 25 carbon atoms, and particularly preferably 8 to 20 carbon atoms. And it is preferable that it is a linear alkyl group.

Specific examples of the substituent in which the hydrogen atom of the hydrocarbon group in X ¹ , X ² and X ³ is substituted include an amino group, a nitro group, a cyano group, and a halogen atom excluding a fluorine atom.
Specific examples of the substituent in which the carbon atom of the hydrocarbon group in X ¹ , X ² and X ³ is substituted include an oxygen atom, a sulfur atom, a nitrogen atom, a carbonyl group, an oxycarbonyl group, a carbonyloxy group, an amide A group (—NH—C (═O) —) can be exemplified.

Among these, X ¹ , X ² and X ³ are preferably a linear alkyl group or a linear fluoroalkyl group.

In the formula, n is 1, 2 or 3, and when n is 2 or 3, n R ^{1 s} may be the same as or different from each other, and when n is 1, R ² may be the same as or different from each other.

  The said organic compound may be used individually by 1 type, and may use 2 or more types together. When two or more types are used in combination, for example, among the general formulas (I) to (III), two or more types represented by the same general formula may be used in combination, or those represented by different general formulas may be used. Two or more kinds may be used in combination. Furthermore, when using 2 or more types together, the combination and ratio should just be set suitably according to the objective.

FIG. 1B is a schematic cross-sectional view illustrating a surface-modified substrate in the present invention. Here, the analysis substrate 1 described with reference to FIG. 1A is used as the surface modification substrate 2, and the organic compounds are classified into those represented by the general formula (I) 1H, 1H, An example produced using 2H, 2H-perfluorooctyltriethoxysilane is illustrated. However, the organic compound represented by the general formula (I) is not limited thereto, and R ¹ is the organic compound represented by the general formula (II), and the silicon atom is the organic compound represented by the general formula (III). In the organic compound represented, it is presumed that the sulfonic acid group is bonded to the oxide film 14 by being reacted with an oxygen atom and fixed to the substrate. Then, the immobilized organic compound forms a modification layer 15 and the substrate surface is modified. In FIG. 1B, the modification layer 15 is not shown in cross-section in order to show the immobilization state of the organic compound and the oxide film 14 in detail.

The thickness T ₁₅ of the modification layer 15 depends on the molecular length of the organic compound that forms the modification layer 15, and is not particularly limited as long as the bond with the oxide film 14 is not impaired. If the modified layer 15 and the monomolecular film, preferably 10nm thickness T ₁₅ of the modified layer 15 or less, more preferably be a 5nm or less, in such a thickness, stable and oxide film 14 Can be combined.
The thickness T ₁₅ can be measured by a known method using an ellipsometer or the like.

In the present invention, the total thickness (T ₁₄ + T ₁₅ ) of the oxide film 14 and the modification layer 15 depends on the molecular length of the organic compound, but a thickness of 200 nm or less is preferably obtained. And it can also be 10 nm or less by adjusting oxidation conditions suitably. In addition, by setting the total thickness of the oxide film 14 and the modification layer 15 in such a range, for example, various substrates having a particularly fine pattern on the surface can be manufactured with high accuracy.

In the present invention, by fixing the organic compound on the substrate 11 via the oxide film 14, the modification layer 15 can be formed with an extremely thin thickness as described above. This is presumed to be because the organic compound easily forms a monomolecular film with the oxide film 14 interposed, and is uniformly oriented outward from the substrate surface 11a.
On the other hand, if the organic compound is directly fixed to the metal thin film 13 without the oxide film 14 interposed, the modification layer cannot be formed with the thin thickness as described above, and the thickness becomes several thousand nm. Is normal. This is presumably because the reaction of the organic compound cannot be controlled, for example, the organic compound is randomly fixed without being oriented on the metal thin film 13 and a bond is formed between the organic compounds.
Thus, the surface-modified substrate in the present invention is characterized in that the total thickness of the oxide film 14 and the modified layer 15 can be extremely reduced.

The organic compound can be bonded to the oxide film 14 by a generally used method. Specific examples of preferred methods include a method in which a solution of an organic compound having a predetermined concentration is brought into contact with the oxide film 14 in a solution, and a method in which the organic compound is vaporized in a vacuum and brought into contact with the oxide film 14. More specifically, dip coating can be exemplified as a suitable method.
When using a solution of an organic compound, the concentration of the organic compound in the solution is not particularly limited, and is usually 0.03 M or more, as long as the organic compound does not precipitate and does not cause a problem in handling. , 0.06M or more is more preferable, and 0.09M or more is particularly preferable. If it is such a range, an organic compound can be combined more reliably.
The solvent may be selected in consideration of the type of the organic compound, and preferably has no reactivity with the organic compound, and examples thereof include alcohols and halogen solvents. As the alcohol, ethanol or isopropanol is preferable. Moreover, when using alcohol, it is good also as a mixed solvent with aqueous solution. Moreover, as a halogen-type solvent, a fluorine-type solvent and a chlorine-type solvent are preferable. Usually, when an organic compound has a halogen atom, it is preferable to use a halogen-based solvent.

After the organic compound is bonded to the oxide film 14, the surface-modified substrate 2 is obtained by drying the substrate 11 and washing it as necessary.
Examples of the cleaning method include a method in which the same solvent as that used in the organic compound solution is used as the cleaning liquid.

<Method for analyzing surface-modified substrates>
By measuring the infrared light reflection spectrum, the surface-modified substrate can analyze in detail the structure of the organic compound immobilized on the substrate surface and the modification state by these organic compounds.
The infrared light reflection spectrum is preferably measured by an infrared spectroscopy (FT-IR) total reflection measurement method (ATR method) or a highly sensitive reflection method (RAS method). For example, when the substrate surface 11a of the surface-modified substrate 2 shown in FIG. 1A is relatively smooth, both the total reflection measurement method and the high-sensitivity reflection method can be applied, and the substrate surface 11a is roughened. If it is, it is preferable to apply the total reflection measurement method.

  According to the present invention, the structure of an organic compound immobilized on the substrate surface and the modification state by these organic compounds can be analyzed in detail by infrared spectroscopy. Even fine modification patterns can be analyzed with high accuracy. As described above, since the surface-modified substrate can be analyzed in detail and with high precision, a substrate having a desired function can be selected and used. In addition, useful information can be obtained for the development of a surface-modified substrate with a new function added.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.
[Example 1]
(Preparation of analysis substrate)
An analysis substrate was prepared by the method described in FIG.
That is, a silicon substrate (thickness: 0.5 mm) was used as the substrate 11, and a 200 nm thick chromium thin film was formed as the metal thin film 13 on the entire surface 11a by sputtering using argon plasma.
Next, the chromium thin film 13 was treated with water vapor at 400 ° C. for 1 hour to form a chromium oxide film as an oxide film 14 on the surface thereof.
Next, the substrate for analysis was obtained by washing the substrate on which the chromium oxide film was formed by ultraviolet / ozone irradiation for 20 minutes. As a result of measuring the contact angle with respect to the surface of the chromium oxide film of the analysis substrate, both the contact angle with water and the contact angle with hexadecane were 5 ° or less.

Fluorine-based solvent (0.02 mol / L of _{CF 3 - (CF 2) 7} - (CH 2) 2 -SiCl 3) is Novec HFE (TM, manufactured by Sumitomo 3M Limited) using a concentration of 0. A 5 M solution of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane was prepared. This solution is dip coated on the analysis substrate, dried overnight, and then washed with Novec HFE to bind 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane to the substrate, A modified layer having a thickness of about 0.9 nm was formed.
As described above, a surface-modified substrate in which 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane was bonded as an organic compound having reactivity with oxygen atoms and the surface was modified was obtained.
The obtained surface-modified substrate was further washed by ultraviolet / ozone irradiation, and the contact angle was measured on the surface of the modified layer. As a result, the contact angle with water was 118 ° and the contact angle with hexadecane was 71 °. That is, by forming the modification layer, the substrate has liquid repellency.

[Example 2]
As a result of analyzing the surface modification substrate produced in Example 1 from the surface side of the modification layer by a total reflection measurement method (ATR method) of infrared spectroscopy (FT-IR), a C—F bond, a C—C bond, Signals derived from each of the C—H bonds could be detected with high sensitivity. As analysis data at this time, detection data of CF bond is shown in FIG.

[Example 3]
The surface modified substrate shown in FIG. 3 was produced by the method described in FIG. FIG. 3 is a schematic cross-sectional view showing the surface-modified substrate produced in this example. Note that, in FIG. 3, the modification layer is not shown in cross section in order to show the immobilization state of the organic compound and the oxide film in detail.
That is, a glass substrate 31 (thickness: 1.1 mm) of Pyrex (registered trademark) (code 7059, manufactured by Corning International Co., Ltd.) is used, and a metal thin film is formed on the entire surface 31a by sputtering using argon plasma. A titanium thin film 33 having a thickness of 50 nm was formed.
Next, the titanium thin film 33 was irradiated with oxygen plasma at an antenna power of 800 W for 30 minutes to form a titanium oxide film 34 as an oxide film on the surface thereof.
Thus, the analysis substrate 3 was obtained. As a result of measuring the contact angle on the surface of the titanium oxide film 34 of the analysis substrate 3, the contact angle with respect to water was 5 ° or less.

A solution of methoxy (dimethyl) octadecylsilane having a concentration of 0.1 M was prepared using a solution obtained by diluting a 20% aqueous acetic acid solution 100 times with isopropyl alcohol. This solution is dip-coated on the above-mentioned analysis substrate, dried for 24 hours, and then washed with isopropyl alcohol to bond methoxy (dimethyl) octadecylsilane to the substrate so that a modification layer having a thickness of about 0.9 nm is obtained. 35 was formed.
As described above, methoxy (dimethyl) octadecylsilane was bonded as an organic compound having reactivity with oxygen atoms, and the surface-modified substrate 3 whose surface was modified was obtained.
As a result of measuring the contact angle on the surface of the modification layer 35, the contact angle with respect to water was 15.6 °. That is, by forming the modification layer, the substrate has liquid repellency.

[Example 4]
As a result of analyzing the surface modification substrate produced in Example 3 from the surface side of the modification layer by the total reflection measurement method (ATR method) of infrared spectroscopy (FT-IR), methyl group (—CH ₃ ), C— Signals derived from each of the C bonds could be detected with high sensitivity. As analysis data at this time, detection data of a methyl group (—CH ₃ ) is shown in FIG.

  The present invention can be used in various fields such as medicine, pharmaceuticals, and foods for analyzing trace components. It can also be used in the field of instrument analysis for developing surface-modified substrates.

DESCRIPTION OF SYMBOLS 1 ... Analytical substrate, 2 ... Surface modification substrate, 11 ... Substrate, 11a ... Substrate surface, 13 ... Metal thin film, 14, 34 ... Oxide film, 15, 35 ...・ Modification layer, 31 ... Silicone substrate, 31a ... Silicone substrate surface, 33 ... Titanium thin film

Claims (4)

A metal thin film having light reflectivity in the infrared region is formed on the substrate, and the surface of the thin film is an oxide film. The oxide film of the analysis substrate has the following general formulas (I) to (III): A surface-modified substrate is formed by binding an organic compound represented by either
A method for analyzing a surface-modified substrate, comprising measuring an infrared light reflection spectrum of the surface-modified substrate.

[Wherein R ¹ is a hydroxyl group or a hydrolyzable group; R ² is a hydrogen atom or a monovalent hydrocarbon group; X ¹ , X ² and X ³ are each independently a monovalent organic group; A plurality of X ² may be the same or different from each other; n is 1, 2 or 3; when n is 2 or 3, n R ¹ may be the same or different from each other When n is 1, two R ^{2 s} may be the same or different from each other; ]   The method for analyzing a surface-modified substrate according to claim 1, wherein the metal is titanium, chromium, aluminum, or copper. A method for producing a surface-modified substrate in which an organic compound is immobilized on a substrate,
Forming a metal thin film having light reflectivity in the infrared region on the substrate;
Forming an oxide film on the surface of the thin film;
A step of bonding an organic compound represented by any one of the following general formulas (I) to (III) to the oxide film;
A method for producing a surface-modified substrate, comprising:

[Wherein R ¹ is a hydroxyl group or a hydrolyzable group; R ² is a hydrogen atom or a monovalent hydrocarbon group; X ¹ , X ² and X ³ are each independently a monovalent organic group; A plurality of X ² may be the same or different from each other; n is 1, 2 or 3; when n is 2 or 3, n R ¹ may be the same or different from each other When n is 1, two R ^{2 s} may be the same or different from each other; ]   The said metal is titanium, chromium, aluminum, or copper, The manufacturing method of the surface modification board | substrate of Claim 3 characterized by the above-mentioned.

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