JP2005125280A - Device and method for manufacturing fine particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for manufacturing fine particles capable of stably and continuously manufacturing the fine particles. <P>SOLUTION: In the device for manufacturing the fine particles, the fine particles are continuously manufactured by making a precursor-containing solution pass through a micro-channel 6. The inner wall of the micro-channel 6, of which the surface is decorated by functional groups or the like, is controlled in the hydrophilicity, the hydrophobicity or the surface electric-charge. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fine particle production apparatus and a fine particle production method for continuously producing fine particles of nanometer order.

  Nanometer-order fine particles (nanoparticles) can be used alone as stable monochromatic fluorescent particles and magnetic particles, as well as building blocks such as wavelength-tunable light-emitting diodes, single-particle transistors, and ultra-high-density magnetic storage media. It attracts attention.

  Recently, the application of fine particles has been spreading especially with technological progress, and the demand has been increasing. So far, as the material of the fine particles, metals such as gold, platinum and nickel; compounds such as platinum iron, titanium oxide, zinc oxide, cadmium selenide and zinc sulfide; have been reported. There are a wide variety of fine particle synthesis methods (manufacturing methods) such as a uniform precipitation method, a hydrothermal synthesis method, and a hot soap method.

  In general, when producing fine particles, it is necessary to generate a large number of nuclei in order to reduce the particle diameter. Therefore, it is necessary to rapidly increase the precursor concentration during production. For this reason, it is inevitable that the temperature and the precursor concentration in the reaction system become non-uniform. However, such non-uniformity greatly affects the particle size distribution of the resulting particles. In particular, when scale-up is performed, such nonuniformity of temperature and precursor concentration is more likely to occur. In general, mass synthesis of fine particles is very difficult, and continuous synthesis is particularly difficult.

  Until now, when producing nanometer-order particles, in order to control the particle size of the generated particles, the type of organic molecules such as raw materials and coexisting surfactants are properly selected, and the reaction temperature and reaction time are controlled. Many methods have been taken to control the decomposition rate of the precursor particles. However, when particles are synthesized by this method using a conventional reactor, precise control of the reaction temperature and reaction time becomes difficult, and it is necessary to intentionally increase the reaction time even for reactions that take a short time. .

On the other hand, the present inventors are able to satisfactorily control the precipitation conditions (reaction conditions) when synthesizing the fine particles, and have a technique for continuously producing fine particles having a controlled particle size (particle diameter). It has been developed (see Patent Document 1). In this technique, a reactor having a micro flow channel capable of accurately controlling conditions such as temperature, concentration, residence time and the like is used as the reaction condition.
JP 2003-225900 A (released on August 12, 2003)

  However, in the reactor described above, due to precipitation and adhesion of the generated fine particles on the wall surface of the microchannel, the yield of the microparticles is decreased, the form controllability of the microparticles is decreased, and the microchannel is blocked. There is a problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a fine particle production apparatus that can stably produce fine particles continuously.

  As a result of continual research, the present inventors, as a result of surface modification of the inner wall of the microchannel when producing microparticles with a reactor having a microchannel, the product is deposited and adhered to the inner wall of the microchannel. The present inventors have found that this can be effectively suppressed and have completed the present invention.

  That is, the fine particle production apparatus according to the present invention is a fine particle production apparatus that continuously produces fine particles by passing a precursor-containing solution composed of a precursor and a solvent through a microchannel in order to solve the above problems. The microchannel is characterized in that the inner wall is surface-modified. The microchannel preferably has a diameter in the range of 1 μm to 5000 μm.

  In the microparticle production apparatus, the inner wall of the microchannel is preferably hydrophobic. In the fine particle production apparatus, it is also preferable that the inner wall of the microchannel has a surface charge having the same sign as the charge of the produced fine particle. In the fine particle production apparatus, the inner wall of the microchannel is surface-modified so that the difference in surface energy between the inner wall and the solvent is smaller than the difference in surface energy between the inner wall and the produced fine particles. It is also preferable. The inner walls of these microchannels may be appropriately selected depending on the properties of the fine particles to be produced and the properties of the solvent. In particular, when the reaction solution is hydrophobic, a small amount of water adsorbed on the inner wall of the microchannel is released and adsorbed on the fine particles, which promotes aggregation. However, the inner wall should be made hydrophobic. Therefore, it becomes possible to suppress the adsorption of moisture to the inner wall, and as a result, aggregation can be suppressed.

  In the fine particle production apparatus, the inner wall of the microchannel is preferably modified with a functional group. In the fine particle production apparatus, it is preferable that a particle layer modified with a functional group is formed on the inner wall of the microchannel.

  The functional group preferably has a charge having the same sign as that of the fine particles to be produced. The functional group is a group capable of making the difference in surface energy between the inner wall of the microchannel after surface modification and the solvent smaller than the difference in surface energy between the inner wall and the fine particles to be produced. Is also preferable. The functional group is preferably a group having hydrophilicity equivalent to that of the solvent. Examples of the functional group include a hydroxyl group, an alkyl group, a carboxyl group, a thiol group, an amide group, a fluoroalkyl group, silicone, or a group in which these are mixed. Furthermore, it is preferable that the length when the functional group is linearly extended is 0.5 nm or more.

  In the fine particle manufacturing apparatus, a thin film is preferably formed on the inner wall of the microchannel. The thin film is preferably made of a polymer.

  In the microparticle production apparatus, it is preferable to use a capillary tube as the microchannel. The capillary tube is preferably made of glass.

  The fine particle production method according to the present invention is a fine particle production method for continuously producing fine particles in order to solve the above-mentioned problem, and comprises a precursor and a solvent after surface modification of the inner wall of a microchannel. The precursor-containing solution is continuously supplied into the microchannel, and the precursor-containing solution is reacted. The microchannel preferably has a diameter in the range of 1 μm to 5000 μm.

  In the fine particle manufacturing method, it is preferable to make the inner wall of the microchannel hydrophobic by surface modification. It is also preferable to make the inner wall of the microchannel into a surface charge having the same sign as the charge of the manufactured microparticles by surface modification. Furthermore, the inner wall may be modified so that the difference in surface energy between the inner wall of the surface-modified microchannel and the solvent is smaller than the difference in surface energy between the inner wall and the produced microparticles. preferable.

  In the fine particle production apparatus, it is preferable to modify the surface of the inner wall of the microchannel using a coupling agent. The coupling agent preferably has a length of 0.5 nm or more when the molecule is stretched on a straight line. Furthermore, it is also preferable to surface-modify the inner wall of the microchannel using alkoxysilane. It is also preferable to apply a polymer to the inner wall of the microchannel to modify the surface. In addition, examples of the polymer include fluorine-based resin, polyimide, and polypropylene.

  In the fine particle production apparatus, it is also preferable to modify the surface by flowing a solution containing a surfactant through the microchannel. Furthermore, in the fine particle production apparatus, it is also preferable to modify the surface by forming a thin film on the inner wall of the microchannel using a sol-gel method. It is also preferable to modify the surface by forming a surface-modified particle layer on the inner wall of the microchannel.

  According to the fine particle production apparatus and the fine particle production method of the present invention, the inner wall of the microchannel is surface-modified, so that the produced microparticles are difficult to deposit and adhere to the inner wall of the microchannel. Thereby, blockage | closure of a microchannel can be suppressed and microparticles | fine-particles can be manufactured in large quantities continuously. Further, it is possible to prevent a decrease in the yield of fine particles and a decrease in the form controllability of the fine particles.

  A microparticle production apparatus according to an embodiment of the present invention is described below with reference to FIG. Note that the present invention is not limited to this. In the fine particle manufacturing apparatus of the present embodiment, a case where fine particles are formed using a solution (precursor containing solutions A and B) containing two types of particle forming precursors (precursors) will be described as an example.

  The fine particles produced by the fine particle production apparatus of the present invention are not particularly limited as long as they are fine particles (nanoparticles) having a particle size of nanometer order (1 to 1000 nm). The material of the fine particles is not particularly limited. For example, titania (anatase type, etc.), oxides such as zinc oxide; chalcogenite compounds such as cadmium selenide, cadmium sulfide, zinc sulfide; gold, silver, Examples thereof include metals such as platinum, palladium, cobalt, and nickel; semimetals (semiconductors) such as silicon and germanium; polymer compounds such as polystyrene; and the like.

  As shown in FIG. 1, the fine particle production apparatus according to the present embodiment includes syringe pumps (feeders) 1 and 2, a microreactor 3, and a collection container 4, and these are connected by a pipe 5. It is. The microreactor 3 includes a microchannel 6 and a heating unit (temperature adjusting means) 7.

  The above particle forming precursor is not a fine particle itself, but a reaction (for example, a reaction that forms a powdered solid by heating or mixing, a reaction that precipitates an insoluble compound from a plurality of solubilized compounds, one kind of soluble compound) A substance in which fine particles are formed by, for example, a reaction in which a powdery compound is generated by thermal decomposition of The particle forming precursor is preferably used as a solution or dispersion obtained by dissolving or dispersing in a solvent. In the present specification, the dispersion is also included in the concept of the solution. Accordingly, the particle forming precursor can be continuously supplied to the microchannel, and mixing can be performed efficiently and smoothly. The solvent used here is not particularly limited, and a known solvent suitable for the reaction of synthesizing fine particles may be appropriately selected. Specific examples include water or aqueous solutions; nonpolar organic solvents such as hexane, cyclohexane, and toluene; polar organic solvents such as dimethylsulfoxide and dimethylformamide, but are not particularly limited. These solvents may be used alone or in combination of two or more.

  The syringe pump 1 is charged with the precursor-containing solution A, and the syringe pump 2 is charged with the precursor-containing solution B. These precursor-containing solutions A and B are continuously supplied to the microreactor 3 through the pipe 5 by the syringe pumps 1 and 2. The precursor-containing solutions A and B are reacted in the microreactor 3 to produce (synthesize) fine particles. The fine particles are collected in the collection container 4 from the microchannel 6 through the pipe 5. In the microreactor 3, the temperature can be controlled by the heating device 7 as necessary.

  In the microreactor 3 to which the precursor-containing solution A / B is supplied, the precursor-containing solution A / B is mixed in the microchannel 6 to react the precursor, or the precursor-containing solution is layered. Fine particles are produced by reacting the precursor as a stream.

  Here, in the microparticle manufacturing apparatus according to the present embodiment, the inner wall of the microchannel 6 is subjected to surface modification (surface treatment). The surface modification includes modification with a functional group, formation of a particle layer modified with a functional group, or formation of a functional material layer. By this surface modification, precipitation and adhesion of the synthesized fine particles to the inner wall of the microchannel are suppressed.

  In addition, the functional group for modifying the inner wall of the microchannel is not particularly limited, and the difference in surface energy between the inner wall of the microchannel and the solvent after the surface modification is determined. Any group that can be made smaller than the difference in surface energy between the fine particles is acceptable. Specifically, functional groups generally used for surface modification, such as hydroxyl group, alkyl group, carboxyl group, thiol group, amide group, fluoroalkyl group, silicone, polyethylene glycol, polyvinyl acetate, polyvinyl alcohol, or Examples include a mixed group. These functional groups may be appropriately selected according to the properties of the fine particles to be produced.

  Furthermore, in the said functional group, when the said functional group is extended linearly, it is preferable that the length is 0.5 nm, More preferably, it is 10 nm, More preferably, it is 100 nm or more. If the molecular size of the functional group that modifies the inner wall is equal to or greater than this lower limit, the effect of modifying the surface properties is improved by manifesting the volume exclusion effect of the molecular chain and more effectively concealing the surface of the tube wall material. In addition, it becomes easier to suppress the adhesion between the particles and the wall surface more effectively. The upper limit is not particularly limited.

  Here, when the produced microparticles are deposited and adhered to the inner wall of the microchannel, the interaction between the microparticles, the inner wall of the microchannel and the solvent becomes a problem.

  For example, when the inner wall of the microchannel is hydrophilic and the generated fine particle surface has metal ions that react with hydroxyl groups, the moisture or hydroxyl group on the inner wall of the microchannel reacts with the generated fine particle surface. Fine particles are likely to deposit and adhere to the inner wall of the microchannel. On the other hand, when the inner wall of the microchannel is hydrophobic, since there is almost no moisture or hydroxyl group on the inner wall of the microchannel, the adhesion of fine particles to the inner wall of the microchannel can be suppressed. Alternatively, when the reaction solution is hydrophobic, it can be seen that a small amount of water adsorbed on the inner wall of the microchannel is liberated and adsorbed on the fine particles to promote aggregation. Therefore, by making the inner wall of the microchannel hydrophobic, it becomes possible to suppress the adsorption of moisture to the inner wall, and as a result, aggregation can be suppressed.

  Furthermore, for example, if particles precipitated in the solution have a charge different from the surface charge of the inner wall of the microchannel, they attract each other, and therefore easily adhere to the microchannel. On the other hand, if the fine particles precipitated in the solution have the same sign as the inner wall of the microchannel, they repel each other, so that the adhesion of the particles to the inner wall of the microchannel can be suppressed. Therefore, the functional group preferably has a charge having the same sign as that of the fine particles to be produced.

  Still further, for example, the fine particles precipitated in the solution have intermediate hydrophilicity between the inner wall of the microchannel and the solvent (medium), that is, the hydrophilicity of the microparticle is close to the hydrophilicity of the inner wall of the microchannel. , Easy to adhere in the microchannel. On the other hand, when the inner wall of the microchannel and the solvent have almost the same hydrophilicity, the surface energy between the inner wall / solvent is the surface energy between the inner wall / fine particles, that is, the hydrophilicity of the fine particles precipitated in the solution. Since the inner wall of the microchannel is separated from the hydrophilicity (since the microparticles are deposited from the solvent, the hydrophilicity between the solvent and the microparticles is separated), the fine particles deposited in the solution adhere to the inner wall of the microchannel Can be suppressed.

  The point of suppressing the adhesion of the fine particles to the inner wall can be explained by the difference in surface energy before and after the fine particles adhere, that is, the difference in interface energy. That is, if the inner wall is surface-modified so that the difference in surface energy between the inner wall and the solvent is smaller than the difference in surface energy between the inner wall and the fine particles, adhesion of fine particles to the inner wall is suppressed. be able to.

  More specifically, for example, when the inner wall is W, the solvent is M, and the fine particles are P and the interfacial energy (the difference in surface energy) between them is shown, the interfacial energy between the inner wall and the solvent is γ (W / M), the interfacial energy between the solvent and the fine particles can be represented by γ (M / P), and the interfacial energy between the inner wall and the fine particles can be represented by γ (W / P). At this time, when the relationship between these interfacial energies is as shown in the following equation (1), it is ideally possible to suppress adhesion of fine particles to the interface.

γ (W / M) + γ (M / P) <γ (W / P) (1)
That is, when the sum of the interfacial energy between the inner wall / solvent and the interfacial energy between the solvent / fine particles is smaller than the interfacial energy between the inner wall / fine particles, it is possible to suppress adhesion of the fine particles. Here, since the fine particles are precipitated from the solvent as described above, the interface energy between the solvent and the fine particles can be substantially ignored. Therefore, the inner wall surface is such that the interfacial energy between the inner wall / solvent (the difference in surface energy between the inner wall and the solvent) is smaller than the interfacial energy between the inner wall / fine particles (the difference in surface energy between the inner wall and the fine particles). If it is modified, adhesion of fine particles to the inner wall can be suppressed.

  The surface modification to the inner wall of the microchannel 6 is not particularly limited as long as the hydrophilicity, hydrophobicity, or surface charge of the inner wall of the microchannel can be adjusted. Can be done in a quality way. For example, a silane coupling agent containing an alkoxysilane such as octadecyltrimethoxysilane, a method using a coupling agent such as a titanium coupling agent, a method using a bond between a thiol and a noble metal, or a sol-gel method to coat a thin film on the surface A method, a method of applying a polymer film such as polyimide or polypropylene, a method of spreading the surface-modified particles on the wall surface in the capillary tube, a method of treating with a surfactant, and the like can be used. Further, for example, a capillary tube in which the surface of the capillary tube is previously modified may be used.

  When the surface of the inner wall of the microchannel is modified using a coupling agent, the coupling agent used should have a length of 0.5 nm or more when the molecules are stretched on a straight line. Is preferred. This is because, as described above, in the functional group for modifying the inner wall, the length when the functional group is linearly extended is preferably 0.5 nm or more.

  The microchannel 6 is a main component of the microreactor 3 and can be regarded as the microreactor itself. The microchannel is not particularly limited as long as the fluid flow maintains a laminar flow, but preferably has a diameter in the range of 1 to 5000 μm, more preferably in the range of 50 to 1000 μm. .

  When the diameter of the micro flow path 6 is reduced, the capacity of the micro flow path with respect to the surface area is reduced, and the representative length of the channel itself is also reduced. Therefore, the reaction conditions when synthesizing the fine particles can be accurately controlled. For example, the accuracy of controlling the reaction temperature derived from a small heat capacity and the accuracy of controlling the precursor concentration depending on a short diffusion distance can be made very excellent.

  In this way, by setting the diameter of the microchannel within the range of 1 to 5000 μm, the above reaction conditions can be excellently controlled, so that it is possible to synthesize fine particles even if the reaction time is shortened. . Therefore, when manufacturing microparticles using a microchannel, the productivity can be improved.

  However, if the diameter of the microchannel is less than 1 μm, the pressure loss in the microchannel during synthesis increases. As a result, the productivity of the fine particles is lowered, and the operation relating to the synthesis becomes difficult. On the other hand, when the reaction is carried out by heating, if the diameter of the microchannel exceeds 5000 μm, the surface area of the microchannel with respect to the capacity (volume) of the microchannel is reduced. Therefore, accurate control of the reaction temperature becomes difficult. Therefore, the diameter of the microchannel is preferably in the range of 1 to 5000 μm.

  The specific configuration of the microchannel is not particularly limited except for the above diameter. For example, as long as the length of the microchannel is within a range of 1 cm to 100 m, more preferably within a range of 4 cm to 30 m, the reaction conditions are more easily controlled, but are not particularly limited.

  A microcapillary can be used as the microchannel. In this case, it is preferable that the wall of the microcapillary, that is, the tube wall of the capillary tube is thin. Specifically, for example, a material within the range of 10 μm to 3 mm can be desirably used, but is not particularly limited. If the tube wall is within the above range, temperature control can be made more precise.

  Moreover, the structure and material of the specific member used as a microchannel are not specifically limited. For example, when a capillary tube is used as a microchannel, the material of the capillary tube is not particularly limited as long as it can be surface-modified, various glasses; various metals (including alloys); polyolefin And resins such as polyvinyl chloride, polyamide, polyester, and fluororesin.

  In the above example, a syringe pump is used as the feeder. However, the present invention is not limited to this, and a general pump can be used. It is desirable to use a pump with less pulsation such as a non-pulsating pump.

  Moreover, although the case where the precursor containing solution was mixed using the syringe pumps 1 and 2 was described above, the mixed solution obtained by mixing the precursor containing solution in advance is supplied to the microreactor using one syringe pump. May be. Moreover, you may supply 3 or more types of precursor containing solutions to a micro reactor with a syringe pump, respectively. In this case, in order to keep the reaction time and the concentration of the precursor in the microchannel uniform, especially when the precursor-containing solution is mixed after heating to the reaction temperature, the mixed precursor-containing solution can be supplied. It must be done as quickly and uniformly as possible. Therefore, you may mix with the mixing means which mixes the said 3 or more types of precursor containing solution, and you may supply to a micro reactor. A more specific configuration of the mixer is not particularly limited, but a micromixer having a small mixing volume, a mixing tube, a mixer using ultrasonic waves, or the like can be used.

  In addition, the specific configuration of the heating unit 6 is not particularly limited. For example, a general heating device such as an oil bath, a heating block, an electric furnace, an infrared heating device, a laser beam, a xenon lamp, or the like is preferably used. Can be used. Further, the cooling after heating by the heating unit 6 may be performed by providing some cooling unit. Although the specific structure of a cooling part is not specifically limited, For example, common cooling devices, such as an air cooling, a water cooling, and an oil cooling device, can be used suitably. Further, as the heating unit 6 and the cooling unit, those having a configuration capable of partially heating and cooling the inside of the microchannel 6 may be used. Specifically, for example, a configuration in which a small heating element, a Peltier element, or the like is arranged around the flow path or an electromagnetic wave is irradiated from the outside can be given.

  Hereinafter, an embodiment of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

[Example 1: Production of CdSe fine particles]
A microparticle production apparatus using the following capillary tubes 1) to 4) (using a glass capillary tube having an inner diameter of 200 μm and a length of 1 m) was prepared.
1) Capillary tube whose inner wall is treated with a silane coupling agent (octadecyltrimethoxysilane) 2) Capillary tube whose inner wall is treated with a fluorine-based coating agent (heptadecafluorodecyltrimethoxysilane) Activated capillary tube (GL Science, fused silica capillary tube (inactive tube))
4) Untreated capillary tube not subjected to surface treatment First, the contact angle to water in the air on the inner wall of the capillary tube of 1) to 4) was examined. The results are shown in Table 1.

  As shown in Table 1, the contact angle with water was 1)> 2)> 3)> 4). That is, it was found that the hydrophobicity of the inner wall was also in the order of 1)> 2)> 3)> 4).

  Furthermore, CdSe particles were produced in the fine particle production apparatus using each of the microchannels described above, and the precipitation / adhesion of CdSe fine particles in each capillary tube was examined.

  Specifically, in each microparticle production apparatus, the microchannel was adjusted to 300 ° C. with an oil bath as a heating unit, and the precursor-containing solution was allowed to pass through the microchannel for 1 hour using a syringe pump.

  Examples of the precursor-containing solution include 0.68 g of cadmium stearate, 20 g of trioctylphosphine oxide (TOPO), 2.25 g of trioctylphosphine selenide (TOP-Se), 20 g of stearic acid, and 20 g of trioctylphosphine. A mixed solution was used.

  Thereafter, air was immediately injected from the syringe pump into the microchannel, and the reaction solution was removed from the microchannel. Then, the capillary tube was taken out, and the length of the blackened portion in the microchannel resulting from the deposition and adhesion of CdSe to the microchannel was measured. The measurement results are shown in Table 1. As shown in Table 1, the length of the blackened portion due to the deposition and adhesion of CdSe fine particles becomes shorter as the contact angle between the inner wall of the capillary tube and water becomes larger. In particular, when treated with octadecyltrimethoxysilane, No abnormalities were seen. Therefore, as described above, it was found that precipitation and adhesion of CdSe fine particles to the capillary tube can be prevented by making the inner wall of the capillary tube hydrophobic or adjusting the hydrophilicity. That is, it was found that the surface modification of the inner wall of the capillary tube can prevent the CdSe fine particles from depositing and adhering to the capillary tube.

  When the degree of precipitation of CdSe fine particles in the capillary tube became severe, the CdSe concentration obtained from the tube outlet decreased, and the proportion of particles having a large particle diameter also increased in the obtained CdSe fine particles, thereby widening the particle size distribution.

[Example 2: Production of gold fine particles]
A microparticle production apparatus using the following 1) to 2) capillary tube (using a glass capillary tube having an inner diameter of 200 μm and a length of 1 m) was prepared.
1) After the inner wall is washed with H ₂ O ₂ .NH ₃ water, the surface is treated with aminopropyltrimethoxysilane to make the surface charge positive. 2) The inner wall of the capillary tube of 1) is further treated with caribodiimide. Capillary tube with surface treatment and negative surface charge In the fine particle production apparatus using the capillary tube of 1) and 2) above, the microchannel is adjusted to 60 ° C. with a water bath as a heating unit, and a syringe pump is used. The precursor-containing solution was passed through the microchannel to produce gold fine particles. As the precursor-containing solution, an aqueous solution in which citric acid and chloroauric acid were dissolved was used.

  As a result of the production, in the fine particle production apparatus using the capillary tube of 2), the surface of the inner wall of the capillary tube has the same charge as that of the produced gold fine particles. As a result, gold fine particles could be produced satisfactorily. In contrast, in the fine particle production apparatus using the capillary tube of 1), since the inner wall of the capillary tube has a different charge from the produced gold fine particles, a large amount of gold fine particles are deposited on the inner wall of the capillary tube. As a result, the gold fine particles could not be produced with high yield.

  As described above, according to the present invention, high-quality fine particles can be efficiently produced. Therefore, the present invention relates to various nanotechnology industries that manufacture or use nanoparticles, such as materials and chemical industries that manufacture nanoparticles, wavelength-tunable light-emitting diodes that use nanoparticles, single-particle transistors, The present invention can be suitably used in electronic parts / electronic equipment industries for manufacturing high-density magnetic recording media and the like.

It is a specific example of the fine particle manufacturing apparatus which concerns on embodiment of this invention, and is a schematic diagram which shows the manufacturing apparatus used in the Example.

Explanation of symbols

1 Syringe pump (supplier)
2 Syringe pump (supplier)
3 Reactor 4 Recovery container 5 Piping 6 Micro flow path 7 Heating part (temperature adjusting means)
A, B precursor-containing solution

Claims (29)

A microparticle production apparatus for continuously producing microparticles by passing a precursor-containing solution composed of a precursor and a solvent through a microchannel,
An apparatus for producing fine particles, wherein the microchannel has a modified inner wall surface.   2. The fine particle manufacturing apparatus according to claim 1, wherein the microchannel has a diameter in a range of 1 [mu] m to 5000 [mu] m.   The microparticle production apparatus according to claim 1 or 2, wherein the inner wall of the microchannel is hydrophobic.   The fine particle manufacturing apparatus according to any one of claims 1 to 3, wherein the inner wall of the microchannel has a surface charge having the same sign as that of the fine particles to be manufactured.   The inner wall of the microchannel is modified so that the difference in surface energy between the inner wall and the solvent is smaller than the difference in surface energy between the inner wall and the fine particles to be produced. Item 5. The fine particle production apparatus according to Item 1, 2 or 4.   The microparticle production apparatus according to claim 1 or 2, wherein an inner wall of the microchannel is modified with a functional group.   The fine particle manufacturing apparatus according to claim 1 or 2, wherein a particle layer modified with a functional group is formed on an inner wall of the microchannel.   The fine particle production apparatus according to claim 6 or 7, wherein the functional group has a charge having the same sign as that of the fine particles to be produced.   9. The fine particle production apparatus according to claim 6, wherein the functional group is a hydrophobic group.   The functional group is a group capable of making the difference in surface energy between the inner wall of the microchannel after surface modification and the solvent smaller than the difference in surface energy between the inner wall and the fine particles to be produced. The fine particle manufacturing apparatus according to any one of claims 6 to 8.   11. The functional group according to claim 6, wherein the functional group is selected from a hydroxyl group, an alkyl group, a carboxyl group, a thiol group, an amide group, a fluoroalkyl group, a silicone, or a group in which they are mixed. The fine particle production apparatus according to the item.   The fine particle manufacturing apparatus according to claim 11, wherein a length when the functional group is linearly extended is 0.5 nm or more.   The fine particle manufacturing apparatus according to claim 1, wherein a thin film is formed on an inner wall of the microchannel.   14. The fine particle manufacturing apparatus according to claim 13, wherein the thin film is made of a polymer.   15. The microparticle production apparatus according to claim 1, wherein a capillary tube is used as the microchannel.   The microparticle manufacturing apparatus according to claim 15, wherein the capillary tube is made of glass. A fine particle production method for continuously producing fine particles,
After surface modification of the inner wall of the microchannel,
A method for producing fine particles, characterized in that a precursor-containing solution comprising a precursor and a solvent is continuously supplied into the microchannel to cause the precursor-containing solution to react.   The method according to claim 17, wherein the microchannel has a diameter in a range of 1 μm to 5000 μm.   The method for producing fine particles according to claim 17 or 18, wherein the inner wall of the microchannel is made hydrophobic by surface modification.   20. The method for producing fine particles according to any one of claims 17 to 19, wherein the inner wall of the microchannel is made to have a surface charge having the same sign as the charge of the produced fine particles by surface modification.   The inner wall is surface-modified so that the difference in surface energy between the inner wall of the surface-modified microchannel and the solvent is smaller than the difference in surface energy between the inner wall and the produced microparticles. The method for producing fine particles according to claim 17, 18 or 20.   The method for producing fine particles according to any one of claims 17 to 21, wherein the inner wall of the microchannel is surface-modified using a coupling agent.   The method for producing fine particles according to claim 22, wherein the inner wall of the microchannel is surface-modified using alkoxysilane.   The method for producing fine particles according to claim 22 or 23, wherein the coupling agent has a length of 0.5 nm or more when the molecules are stretched on a straight line.   The method for producing fine particles according to any one of claims 17 to 21, wherein the polymer is applied to the inner wall of the microchannel to modify the surface.   26. The method for producing fine particles according to claim 25, wherein a fluorine-based resin, polyimide, or polypropylene is used as the polymer.   The method for producing fine particles according to any one of claims 17 to 21, wherein the surface modification is performed by flowing a solution containing a surfactant through the microchannel.   The method for producing fine particles according to any one of claims 17 to 21, wherein the surface is modified by forming a thin film on the inner wall of the microchannel using a sol-gel method.   The method for producing fine particles according to any one of claims 17 to 21, wherein the surface modification is performed by forming a surface-modified particle layer on the inner wall of the microchannel.

Images