JP4877806B2 - Polymer multi-stage nanowire and starburst type nanoparticle and production method thereof - Google Patents

Description

  The present invention relates to a polymer multistage nanowire composed of two or more different polymer materials, a starburst type (star) nanoparticle in which a plurality of nanowires are radially bonded, and a polymer multistage nanowire and a starburst type. The present invention relates to a method for designing, controlling and producing nanoparticles easily and freely.

  Nanostructured materials that have been rapidly developed in recent years are expected to be applied in a wide range of fields such as the IT field, the medical field, and the environmental field, and nanoscience research is currently being conducted in various countries around the world. Many of them use a bottom-up method such as the use of self-arrangement / organization of atoms / molecules or a top-down method represented by semiconductor lithography as a forming method (see, for example, Non-Patent Document 1).

  Nanowires (nanofibers) and nanotubes that are typical nanostructured materials are produced by electrospinning, supramolecular self-assembly, template polymerization spinning, bio-nanofiber induced formation, and the like. However, it is difficult to arbitrarily control the number of nanowires formed, diameter, length, shape, etc., and mass production is also difficult.

In recent years, techniques for producing nanowires having a radius of several to several tens of nanometers are being researched and provided. However, in these technologies, the manufacturing method using only one kind of substance is still present, and it has not been applied to nanowires composed of a plurality of constituent substances.
Illustrated nanofiber, Tatsuya Motomiya, Nikkan Kogyo Shimbun (2006)

  In this way, the nanowires (nanofibers) and nanotubes formed in the prior art are made from a single type of material, and multiple materials are combined to precisely control length, diameter, etc. The order of connections and the number of connections could not be controlled arbitrarily.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a polymer multistage nanowire made of two or more different polymer materials and a starburst type in which a plurality of nanowires are radially coupled (star Type) to provide nanoparticles.

  Another object of the present invention is to provide a method for designing, controlling and producing polymer multi-stage nanowires and starburst nanoparticles in a simple and free manner.

  The polymer multi-stage nanowire of the present invention has two or more kinds of cylindrical polymer materials having a diameter of 1 nm to 50 nm, connected in series, or a cylindrical polymer material having a diameter of 1 nm to 50 nm. Are characterized in that two or more are connected in a ring shape.

  The starburst type nanoparticles of the present invention are characterized in that cylindrical polymer materials having a diameter of 1 nm to 50 nm are radially connected.

  The method for producing a polymer multi-stage nanowire according to the present invention includes a step of laminating two or more different polymer materials on a substrate to form a polymer multilayer film, and irradiating the polymer multilayer film with an ion beam. A step of forming a cylindrical cross-linked portion in which cylindrical cross-linked portions of two or more polymer materials are connected in series in the direction of irradiation, and other uncross-linked portions; and And a step of removing with a solvent.

  In addition, the method for producing a polymer multi-stage nanowire according to the present invention includes a step of laminating two or more different polymer materials on a substrate to form a polymer multilayer film, and irradiating the polymer multilayer film with an ion beam. A step of forming a cylindrical cross-linked portion in which cylindrical cross-linked portions of two or more kinds of polymer materials are connected in series in the direction of irradiation, and other non-cross-linked portions; And a step of selectively aggregating a specific cross-linked portion and connecting both ends of the cylindrical cross-linked portion in a ring shape.

  By controlling the thickness of the polymer multilayer film, the length of the cylindrical cross-linked portion can be controlled. In addition, the diameter of the cylindrical cross-linked portion can be increased by increasing the molecular weight of the polymer material or increasing the energy application rate of the ion beam.

  The specific cross-linking portion can be selectively aggregated by soaking in a hydrophobic solvent if it is a hydrophilic cross-linking portion, or by immersing it in a hydrophilic solvent if it is a hydrophobic cross-linking portion.

  The method for producing starburst nanoparticles of the present invention comprises a step of forming a polymer multilayer film by laminating two or more different polymer materials on a substrate, and irradiating the polymer multilayer film with an ion beam. A plurality of cylindrical cross-linked portions and other uncross-linked portions in the direction of irradiation, and removing the non-cross-linked portions with a solvent and selectively a specific cross-linked portion. And a step of agglomerating and connecting the plurality of cylindrical cross-linking portions radially.

  By controlling the thickness of the polymer multilayer film, the length of the cylindrical cross-linked portion can be controlled. In addition, the diameter of the cylindrical cross-linked portion can be increased by increasing the molecular weight of the polymer material or increasing the energy application rate of the ion beam. Further, the specific cross-linking portion can be selectively aggregated by immersing in a hydrophobic solvent if it is a hydrophilic cross-linking portion and in a hydrophilic solvent if it is a hydrophobic cross-linking portion. .

  ADVANTAGE OF THE INVENTION According to this invention, the starburst type | mold (star-shaped) nanoparticle which the polymer multistage nanowire which consists of two or more types of different polymer materials, and several nanowire couple | bonded radially can be provided.

  In addition, according to the present invention, by using a multilayer film in which two or more different polymer materials are laminated, interaction with a solvent is used, and from the selective aggregation property of a specific cross-linked portion, the polymer multi-stage nano It is possible to manufacture while designing and controlling the shape of the starburst nanoparticle in which a wire and a plurality of nanowires are radially bonded.

The present inventors have found that when an ion beam is irradiated on the polymer monolayer thin film, polymer crosslinking reaction is caused in the cylindrical realm of energy of the ions has been applied along its track, cylindrical Since it becomes a bridge | crosslinking part and becomes insoluble in a solvent, it has already discovered that nanowire with uniform length and a diameter is formed by isolate | separating an unbridged part with a solvent.

  As a result of further research, the present inventors have produced a polymer multilayer film by alternately laminating a hydrophilic polymer material and a hydrophobic polymer material and irradiating with an ion beam. Multi-stage nanowires in which cylindrical bridges are alternately connected in series can be formed, and by agglomerating them in a specific solvent, a star shape (starburst nanowires) in which multiple nanowires are connected radially It has been found that it is also possible to form particles).

  At this time, by appropriately selecting the order of the polymer layers to be laminated and the number of laminated layers, any number of cylindrical cross-linking portions can be connected in series, and by selecting the type of polymer material to be laminated, It turned out that it becomes possible to produce the polymer multistage nanowire which connected the cylindrical bridge | crosslinking part which has a function peculiar to molecular material in series.

  The present inventors have also found that the diameter of the cylindrical cross-linking portion increases as the molecular weight of the polymer material increases or as the cross-linking efficiency for the ion beam increases. By utilizing this, it becomes possible to control the diameter of each cylindrical cross-linked portion of the polymer multistage nanowire. Furthermore, it becomes possible to control the length of each cylindrical bridge portion of the multi-stage nanowire by the thickness of each polymer thin film.

  That is, since the polymer multistage nanowires are formed corresponding to individual ions, the number is proportional to the ion beam dose (number of irradiated particles), and the number of nanowires formed per unit area is It has been found that the average distance between the wires decreases as the number increases, and the number of polymer multi-stage nanowires connected by aggregation increases. Therefore, it is possible to control the number of nanowires that are radially connected to the starburst nanoparticles according to the irradiation amount of the ion beam.

  Nanowires are generally characterized by (1) the structure itself, like carbon nanotubes, and (2) the surface area is several hundred times larger than thin films, etc. (3) Because it has features such as removal of particles from 100 nm to 1 μm that cannot be removed by conventional microfilters, IT fields such as microelectrodes and electronic paper, DDS, bacteria protection filters, etc. It can be widely applied to environmental fields such as biotechnology fields and harmful substance removal filters.

  In the present invention, in a multistage and starburst structure, the nanowire can be composed of a plurality of substances having different functions, so that a plurality of the above characteristics can be satisfied at the same time, such as a filter function + a catalyst function. It becomes possible to synthesize nanowires having a simple manufacturing method.

(Manufacturing method of polymer multi-stage nanowire)
With reference to FIG.1 and FIG.2, an example of the manufacturing method of the polymeric multistage nanowire which concerns on this invention is demonstrated.

  First, a smooth substrate 1 made of Si or the like is prepared (FIG. 1, step a, FIG. 2a), and a multilayer polymer thin film is formed on the smooth substrate 1. The multilayer polymer thin film is formed by first applying a solvent in which the polymer material A is dissolved onto the smooth substrate 1 such as Si by using a technique such as spin coating or dipping, and then forming the first layer of the polymer thin film A. 3 is produced. Next, in the same manner as described above, the second layer polymer material B is dissolved in a solvent that does not dissolve the first layer 3, and the second layer of the polymer thin film B is formed on the surface of the first layer 3 in the same manner. Layer 5 is produced. Further, a solvent that dissolves the polymer material C is selected, and the third layer 7 of the polymer thin film C is laminated in the same manner (see step b and FIG. 2a in FIG. 1).

  In addition, when trying to fix one end of the nanowire on the substrate, the thickness of the polymer multilayer is made smaller than the range of the ion beam so that the ion beam completely penetrates the polymer multilayer thin film and reaches the substrate. Control to be.

Next, the cylindrical cross-linking portions 3a, 5a, and 7a and the non-cross-linking portions 3b, 5b, and 7b other than the cylindrical cross-linking portion are formed by ion beam irradiation from above the third layer 7 (step c and FIG. 2b in FIG. 1). The amount of irradiation is unclear because it is related to the diameter of the wire, but is preferably 1 × 10 ¹² ions / cm ² or less. If it exceeds 1 × 10 ¹² ions / cm ² , the wires themselves overlap and cannot be separated one by one. After irradiation, the non-crosslinked portions 3b, 5b, 7b other than the cylindrical crosslinked portions are washed with the solvent 9 and removed as the solutes 3c, 5c, 7c in the solvent 9, thereby removing a cylindrical polymer having a diameter of 1 nm to 50 nm. A polymer multi-stage nanowire in which two or more kinds of materials are connected in series is obtained (FIG. 1, step d, FIG. 2c). As this solvent, a nonpolar solvent such as tetrahydrofuran, toluene, benzene, cyclohexane, normal hexane, xylene and a polar solvent such as mecanol or isopropyl alcohol can be used alone or in combination.

  When the cylindrical cross-linking portion 5a is hydrophilic, it is agglomerated as an aggregate 5d by soaking in a hydrophilic solvent if the cylindrical cross-linking portion 5a is hydrophilic, or is immersed in a hydrophilic solvent if hydrophobic. 3a and the cylindrical bridge portion 7a can be connected (FIG. 1, step e, FIG. 2d).

(Production method of starburst type nanoparticles)
Next, with reference to FIG. 3 and FIG. 4, an example of the manufacturing method of the polymeric multistage nanowire which concerns on this invention is demonstrated.

  First, a smooth substrate 11 made of Si or the like is prepared (FIG. 3, steps a and 4a), and a multilayer polymer thin film is formed on the smooth substrate 11. The multilayer polymer thin film is formed by first applying a solvent in which the polymer material A is dissolved onto the smooth substrate 11 such as Si by using a method such as spin coating or dipping, and then forming the first layer of the polymer thin film A. 13 is produced. Next, in the same manner as described above, the second layer polymer material B is dissolved in a solvent that does not dissolve the first layer 13, and the second layer of the polymer thin film B is formed on the surface of the first layer 13 in the same manner. Layer 15 is produced. Further, a solvent for dissolving the polymer material C is selected, and the third layer 17 of the polymer thin film C is laminated in the same manner (see step b and FIG. 4a in FIG. 3).

  In addition, when trying to fix one end of the nanowire on the substrate, the thickness of the polymer multilayer is made smaller than the range of the ion beam so that the ion beam completely penetrates the polymer multilayer thin film and reaches the substrate. Control to be.

Next, the cylindrical cross-linking portions 13a, 15a, 17a and the non-cross-linking portions 13b, 15b, 17b other than the cylindrical cross-linking portion are formed by ion beam irradiation from above the third layer 17 (FIG. 3, step c, FIG. 4b). The irradiation amount is preferably 5 × 10 ⁹ ions / cm ² or more in order to form starburst nanoparticles. After irradiation, uncrosslinked portions 13b, 15b and 17b other than the cylindrical crosslinked portion are washed with the solvent 19 and removed as the solutes 13c, 15c and 17c in the solvent 19 (step d and FIG. 4c in FIG. 3). As the solvent, tetrahydrofuran, toluene, benzene, cyclohexane, normal hexane, a nonpolar solvent and meta Nord xylene, or alone polar solvent such as isopropyl alcohol, a mixture can be applied.

When the cylindrical cross-linking portion 15a is hydrophilic, it is aggregated as an aggregate 15d by immersing it in a hydrophilic solvent if it is hydrophilic, or in a hydrophilic solvent if it is hydrophobic. Starburst nanoparticles in which cylindrical polymer materials of 1 nm to 50 nm are radially connected are obtained (step e and FIG. 4 d in FIG. 3).
When the irradiation is less than 5 × 10 ⁹ ions / cm ^2, a polymer multi-stage nanowire in which two or more cylindrical polymer materials having a diameter of 1 nm to 50 nm are connected in a ring shape can be obtained. By taking time for aggregation, it is also possible to obtain starburst type nanoparticles composed of about three cylindrical polymer materials.

(Production of polymer multi-stage nanowires)
First, polymethylphenylsilane (PMPS), which is an organosilicon polymer material, is used as the polymer thin film A, polycarbosilane (PCS), which is a carbon / silicon polymer material, is used as the polymer thin film B, and side chains are used as the polymer thin film C. Polyhydroxystyrene (PHS), a carbon skeleton polymer having a hydroxyl group, was used, and PMPS and PCS were dissolved in toluene and PHS was dissolved in isopropyl alcohol to obtain a 5 wt% solution.

  Next, a silicon wafer is used as the smoothing substrate 1 shown in FIG. 2, and the first layer 3 is formed by applying PMPS to the surface by spin coating to form a thin film, and then the second layer 5 made of PHS is formed thereon. Further, the third layer 7 made of PCS was similarly thinned and laminated to form a three-layer film having a thickness of ˜1000 nm. The obtained polymer multilayer film substrate was placed in a vacuum irradiation chamber and irradiated with an ion beam from the cyclotron while scanning uniformly to form cylindrical bridge portions 3a, 5a, and 7a along the through track of the ion beam. . Further, the uncrosslinked portions 3b, 5b and 7b other than the cylindrical crosslinked portion are removed using a 2: 1 mixed solvent of toluene and isopropyl alcohol, and at the same time, only the cylindrical crosslinked portion 5a made of PHS is aggregated, and FIG. As shown in d), a multistage nanowire in which only the intermediate cylindrical bridge portion was aggregated was obtained.

(Production of starburst type nanoparticles)
Next, PMPS, PCS, and PHS are prepared in the same manner as in Example 1. A silicon wafer is used as the smooth substrate 11 shown in FIG. 4, and PMPS is applied to the surface by spin coating to form a thin film. After that, the second layer 15 made of PHS and the third layer 17 made of PCS were similarly thinned and laminated thereon to form a three-layer film having a thickness of ˜1000 nm. The obtained polymer multilayer film substrate was placed in a vacuum irradiation chamber, and irradiated with an ion beam from the cyclotron while scanning uniformly to form cylindrical bridge portions 13a, 15a, and 17a along the through track of the ion beam. . Further, the uncrosslinked portions 13b, 15b, 17b other than the cylindrical crosslinked portion were removed using a 2: 1 mixed solvent of toluene and isopropyl alcohol, and at the same time, only the cylindrical crosslinked portion 15a made of PHS was aggregated.

  In this case, since the multistage nanowires are close to each other, the adjacent multistage nanowires are connected to each other by aggregation, and a plurality of nanowires are connected radially around the aggregated portion as shown in FIG. Starburst nanoparticles were formed.

(Relationship between ion beam dose and number of multi-stage polymer nanowires formed)
The relationship between the dose of irradiated ion beam (number of irradiated particles) and the number of multistage polymer nanowires formed was investigated.

In FIG. 5, the dose of the ion beam to irradiate is low dose (1.1 × 10 ⁹ ions / cm ² ), medium dose (5.3 × 10 ⁹ ions / cm ² ), high dose (1.0 × 10 10 ¹⁰ ions / cm ² ) and the relationship with the shape of the nanoparticles when changed.

  As shown in FIG. 5, it can be seen that the higher the dose, the more the starburst nanoparticles in which a large number of nanowires are radially connected can be formed.

  In other words, multi-stage nanowires formed from cylindrical bridges by ion irradiation are formed corresponding to individual ions, the number of which is proportional to the ion beam dose (number of irradiated particles), and the unit of nanowires formed As the number of formations per area increases, the average distance between each wire decreases, the number of polymer multi-stage nanowires connected by aggregation increases, and a star with more cylindrical bridges connected It was found to be burst type nanoparticles.

  In addition, in the case of a low dose, as shown by the arrow in FIG. 5, it was also found that ring-shaped nanoparticles in which the cylindrical bridge portions are connected in a ring shape are formed.

(Relationship between molecular weight and energy application rate and nanowire diameter)
Regarding PCS, which is one of the constituent materials of multi-stage nanowires, the relationship between molecular weight and energy application rate and nanowire diameter was investigated.
The results are shown in Table 1 and FIG.

  From the results of Table 1 and FIG. 1 and No. In No. 2, the energy application rate is large. No. 1 has a different molecular weight. 2 and No. In No. 3, No. having a large molecular weight. No. 3 was found to have a larger nanowire diameter.

Industrial applicability

  Nanowires are generally characterized by (1) the structure itself, like carbon nanotubes, and (2) the surface area is several hundred times larger than thin films, etc. (3) Because it has features such as removal of particles from 100 nm to 1 μm that cannot be removed by conventional microfilters, IT fields such as microelectrodes and electronic paper, DDS, bacteria protection filters, etc. It can be widely applied to environmental fields such as biotechnology fields and harmful substance removal filters.

  In the present invention, in a multistage and starburst structure, the nanowire can be composed of a plurality of substances having different functions, so that a plurality of the above characteristics can be satisfied at the same time, such as a filter function + a catalyst function. Can be synthesized by a simple manufacturing method.

It is a flowchart which shows the manufacturing process of the polymeric multistage nanowire which concerns on this embodiment. It is a schematic diagram explaining the manufacturing process of the polymeric multistage nanowire which concerns on this embodiment. It is a flowchart which shows the manufacturing process of the starburst type nanoparticle which concerns on this embodiment. It is a schematic diagram explaining the manufacturing process of the starburst type nanoparticle concerning this embodiment. It is a microscope picture which shows the relationship between an ion beam dose and the number of formation of multistage polymer nanowires. It is a microscope picture which shows the relationship between molecular weight and an energy provision rate, and a nanowire diameter.

Explanation of symbols

11 Smooth substrate 3,13 1st layer 5,15 2nd layer 7,17 3rd layer 3a, 5a, 7a Cylindrical bridge part 3b, 5b, 7b Uncrosslinked part 3c, 5c, 7c Solute 5d Aggregate 9 Solvent 13a , 15a, 17a Cylindrical bridge portion 13b, 15b, 17b Unbridged portion 13c, 15c, 17c Solute 15d Aggregate 19 Solvent

Claims (12)

Two or more types of cylindrical polymer materials having a diameter of 1 nm to 50 nm made of two or more polymer materials selected from polymethylphenylene, polycarbosilane, and polyhydroxystyrene are connected in series. A feature of polymer multi-stage nanowires. Two or more cylindrical polymer materials having a diameter of 1 nm to 50 nm made of two or more polymer materials selected from polymethylphenylene, polycarbosilane, and polyhydroxystyrene are connected in a ring shape. Polymer multi-stage nanowires characterized by A cylindrical polymer material having a diameter of 1 nm to 50 nm composed of two or more kinds of polymer materials selected from polymethylphenylene, polycarbosilane, and polyhydroxystyrene is radially connected. Burst type nanoparticles. Forming a polymer multilayer film by laminating two or more different polymer materials selected from polymethylphenylene, polycarbosilane , and polyhydroxystyrene on a substrate;
By irradiating the polymer multilayer film with an ion beam, a cylindrical cross-linked portion in which two or more kinds of polymer cross-linked cylindrical cross-linked portions are connected in series in the irradiation direction, and other uncrosslinked portions Forming a portion;
And a step of removing the uncrosslinked portion with a solvent. Forming a polymer multilayer film by laminating two or more different polymer materials selected from polymethylphenylene, polycarbosilane , and polyhydroxystyrene on a substrate;
By irradiating the polymer multilayer film with an ion beam of less than 5 × 10 ⁹ ions / cm ² , a cylinder in which cylindrical bridge portions of two or more polymer materials are connected in series in the irradiation direction A step of forming a cross-linked portion and a non-cross-linked portion other than that,
Removing the uncrosslinked portion with a solvent, and selectively aggregating a specific crosslinked portion to connect both ends of the cylindrical crosslinked portion in a ring shape. Manufacturing method of wire. 6. The method for producing a polymer multi-stage nanowire according to claim 4, wherein the length of the cylindrical cross-linked portion is controlled by controlling the thickness of the polymer multilayer film. 6. The method for producing a polymer multi-stage nanowire according to claim 4, wherein the diameter of the cylindrical cross-linked portion is increased by increasing the molecular weight of the polymer material. 6. The method for producing a polymer multi-stage nanowire according to claim 5, wherein the specific aggregating portion is selectively aggregated by immersing in a mixed solvent of a nonpolar solvent and a polar solvent . Forming a polymer multilayer film by laminating two or more different polymer materials selected from polymethylphenylene, polycarbosilane , and polyhydroxystyrene on a substrate;
Irradiating the polymer multilayer film with an ion beam to form a plurality of cylindrical cross-linked portions and other non-cross-linked portions in the irradiation direction;
Removing the uncrosslinked portion with a solvent, and selectively aggregating a specific crosslinked portion to connect the plurality of cylindrical crosslinked portions in a radial manner. Manufacturing method. The method for producing a starburst nanoparticle according to claim 9, wherein the length of the cylindrical cross-linked portion is controlled by controlling the thickness of the polymer multilayer film. 10. The starburst nanostructure according to claim 9, wherein the diameter of the cylindrical bridge portion is increased by increasing the molecular weight of the polymer material or increasing the energy application rate of the ion beam. Particle production method. The method for producing starburst nanoparticles according to claim 9, wherein the specific agglomeration is selectively agglomerated by immersing in a mixed solvent of a nonpolar solvent and a polar solvent .

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