JP2017096685A - Needle, and injection needle equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a needle that can be easily manipulated without suffering adhesion of oil droplets to its tip or side face when oil droplets are manipulated in water and can discharge oil droplets of an appropriately minute size, and an injection needle equipped with such a needle.SOLUTION: A needle is equipped with a base material and an in-water ultra oil-repellent layer having an oil-contact angle of 150 degrees or more in water, formed at least on the outside surface of a tip part of the base material. As it manifests an in-water ultra oil-repellent property, adhesion of oil droplets to the needle tip can be prevented.SELECTED DRAWING: Figure 6

Description

The present invention relates to a needle used when manipulating oil droplets in water and an injection needle equipped with the needle.

It has been known to impart antifogging and antifouling functions by making a solid surface water-repellent or hydrophilic, and studies on wettability of the solid surface in the atmosphere have been conducted for a long time. On the other hand, recently, in addition to the wettability of water and oil in the atmosphere, interest in the wettability of oil in water has been increasing, and is being recognized as a new research object (for example, Patent Documents) 1). As a measurement sample, in recent years, interest in materials that behave oil-repellently in water (particularly super-oil-repellent surfaces) has increased.

When evaluating the wettability of dynamic oil in water on the surface of a solid sample, a technique for discharging fine oil droplets from the needle tip in water is required. Although much research has been conducted on the wettability evaluation technique for water and oil in the atmosphere, the measurement and evaluation techniques for wettability of oil in water have not been fully established.

FIG. 1 shows the procedure for measuring the contact angle of oil in water on the surface of a solid sample. First, the needle tip is brought close to the sample surface in a state where oil droplets are ejected from the tip (FIG. 1A), and when the oil droplet ejected from the needle tip contacts the sample surface, the needle tip is pulled away from the sample surface (FIG. 1B). The oil droplets are pulled away from the needle tip and land on the sample surface (FIG. 1C). Then, the degree of wetting is evaluated by measuring the contact angle between the deposited droplet and the sample surface.

JP2015-39685A

In the measurement of wettability in water, a tube made of a material having insufficient oil repellency in water (for example, a smooth stainless needle) is used as an existing needle. However, with a conventional stainless steel needle, when an oil droplet formed on the needle tip is operated in water, the oil droplet adheres to the needle tip and the side surface of the needle, making it difficult to operate the oil droplet.

Further, in order to attach oil droplets to a sample surface from a conventional stainless needle, it is necessary to form an extremely large oil droplet and then press the oil droplet strongly against the sample surface. However, when attempting attachment, an oil droplet may adhere to the outer wall of the needle as shown in FIG. In such a case, it is necessary to take out the needle from the water once, wash the side and tip of the needle, and then form an oil drop in the water again, which requires time and effort for the operation.

In addition, as shown in FIG. 3, in order to analyze the wettability of oil on the surface of a solid sample, it is analyzed how the oil droplets that have landed move when the sample surface is inclined. Contact angle measurement: advancing contact angle, receding contact angle, falling angle) is important. However, when it is difficult to deposit oil droplets on the sample surface and the oil droplets are excessively pressed onto the sample surface, the condition is different from the original wetting of the sample surface, and the desired information is obtained. It is thought that it will be impossible. Therefore, it is important to eject oil droplets of moderately small size that are not excessively large from the tip of the needle without strongly pressing the oil droplets adhering to the sample surface on the sample surface in order to adhere naturally to the sample surface. It becomes.

Thus, although it is considered that a small-sized oil droplet can be ejected by reducing the inner diameter of the needle, a needle having a smaller inner diameter has reduced mechanical durability and is expensive to manufacture.

Further, it is desirable that the contact angle measuring needle is not disposable and can be washed and reused after use. However, with a needle having a small inner diameter, the washing operation becomes difficult, and there is a risk of oil adhesion and clogging.

The needle 1 of the present invention is used when manipulating oil droplets in water, and has an oil contact angle in water of 150 degrees formed on the outer surface of the tubular base material 2 and at least the tip of the base material 2. The underwater super oil-repellent layer 3 is provided. As the substrate, commercially available stainless steel or titanium needles can be used. As a material of the underwater super oil repellent layer 3, metal oxides such as silica and titanium oxide can be used. By forming the underwater super-oil-repellent layer 3 on the surface of this base material, when the oil droplet is operated in water, it can be easily operated without the oil droplet adhering to the needle tip or the side surface of the needle.

Further, irregularities having an arithmetic average roughness of 100 nm or more may be formed in the underwater super oil repellent layer 3. Furthermore, the needle 1 may be attached to the tip of the injection needle. In the present specification, as in the concept of general terms in the technical field, “super oil repellency in water” refers to a physical property having a contact angle with oil in water of 150 degrees or more. In the present invention, a relatively large contact angle corresponding to “super oil repellency in water” is defined as a value calculated by the tangent method. The measurement of the contact angle by such a method can be performed using a commercially available general contact angle meter (measurement system).

Since the needle 1 of the present invention is coated with the underwater super-oil-repellent layer 3 on the base material 2, when the oil droplet is operated in water, it can be easily operated without the oil droplet adhering to the needle tip or the side surface of the needle.

In addition, with the needle 1 having an appropriate inner diameter, an oil droplet of a desired moderate size is ejected from the tip of the needle without strongly pressing the oil droplet adhering to the needle 1 against the sample surface 3, and the sample surface 3 is ejected. Natural adhesion can be made possible.

Furthermore, by applying an injection needle equipped with the needle 1, it is possible to discharge fine oil droplets without scaling down the size of the needle 1.

FIG. 1 is a diagram illustrating a procedure for measuring an oil contact angle in water on the surface of a solid sample. FIG. 2 is a diagram showing a state in which an oil droplet is pressed against the sample surface with a conventional stainless needle. FIG. 3 is a diagram showing a procedure for measuring a dynamic oil contact angle in water on the surface of a solid sample. FIG. 4 is a SEM observation photograph of the stainless steel plate on which the silica layer is formed. FIG. 5 is a SEM observation photograph of the super oil-repellent needle of the present invention. FIG. 6 is a diagram illustrating a state in which oil droplets are ejected from the super oil repellent needle according to the first embodiment. FIG. 7 is a diagram illustrating a state in which oil droplets are pressed against the sample surface by the super oil repellent needle according to the second embodiment. FIG. 8 is a view showing oil droplets discharged from the super oil repellent needle according to the second embodiment.

First embodiment The super oil-repellent needle 1 of the present embodiment has a tubular shape so that liquid such as oil droplets can be discharged, and is used when manipulating oil droplets in water. . Here, `` operation '' means, for example, discharging oil in water to form oil droplets, moving to an arbitrary position with oil droplets attached, pressing oil droplets on the surface of a solid sample, etc. It means to contact, attach, move, discharge, and form oil droplets.

In the present embodiment, application to an oil droplet forming needle used when measuring the contact angle of oil in water on the solid sample surface 4 is assumed. FIG. 1 is a diagram showing a procedure for measuring the oil contact angle of the solid sample surface 4 in water. As shown in FIG. 1, the oil droplets are brought close to the sample surface 4 with the oil droplets attached to the tip of the super oil repellent needle 1 (FIG. 1A), and the oil droplets discharged from the needle tip are brought into contact with the sample surface 4 ( FIG. 1B). Then, by pulling the needle tip away from the sample surface 4, oil droplets are deposited on the sample surface (FIG. 1C).

In addition, as shown in FIG. 3, analysis is made of how the oil droplets that have landed move when the sample surface 4 is tilted (dynamic contact angle measurement: forward contact angle, backward contact angle, falling) It may also be used when cornering. That is, an oil droplet is discharged from the tip of the needle 1 (FIG. 3A), and the oil droplet is brought into contact with the sample surface 4 (FIG. 3B). Then, with the oil droplets attached, the sample surface is tilted and the oil droplets are moved (FIG. 3C). However, if it is a use which operates an oil drop in water, it can be used for various uses, for example, when forming an emulsion, you may use this super oil-repellent needle 1.

Here, “the contact angle of oil in water” means the angle formed between the oil droplet to be operated and the horizontal plane on which the oil droplet is placed in water at the oil liquid / substrate interface. And is used as a measure of surface wettability. That is, a large value of the oil contact angle indicates that the wettability with respect to the oil liquid on the surface is low and the oil repellency is high. In addition, “underwater super oil repellency” used in the present specification means that the contact angle of oil with a substrate in water is 150 degrees or more, and the oil repellency in water is extremely high.

(Structure of super oil-repellent needle)
The super oil repellent needle 1 according to the first embodiment will be described. The super oil repellent needle 1 of this embodiment includes a base material 2 and an underwater super oil repellent layer 3 formed on the outer surface of at least the tip of the base material 2. The base material 2 is a commercially available stainless steel needle having an outer diameter of 0.6 mm and a wall thickness of 0.13 mm. A silica layer is coated on the surface of the substrate 2 as an underwater super oil repellent layer 3. The underwater super oil-repellent layer 3 may be formed on the surface of the base material 2 as in the present embodiment, or the base material 2 itself may be made of an underwater super oil repellent material.

(Formation of silica layer)
The silica layer is formed by a sol coating method. Specifically, a silica layer is formed by applying a coating liquid containing silicon alkoxide and silica gel fine particles to the surface of a stainless needle and heat-treating it at about 500 degrees for about 30 minutes in a ceramic oven. According to the sol coating method, since there are no restrictions on the equipment depending on the size and shape of the base material, no special equipment is required, and a film can be easily formed on the surface of the base material 2. However, the method for forming the silica layer is not particularly limited, and various methods such as vapor deposition, sputtering, and CVD can be used.

This silica layer makes it possible to exhibit the super-oil repellency in water with an oil contact angle in water of 150 degrees or more. Thereby, when operating an oil drop in water, it can operate simply, without an oil drop adhering to a needle point or a needle side. In addition, the contact angle of the oil in the water of the silica layer of this embodiment was 171.5 degrees.

Further, irregularities derived from the silica particles are formed on the surface of the silica layer. FIG. 4 is a SEM observation photograph in which the surface of the stainless steel plate on which the silica layer is formed is photographed by SEM (scanning electron microscope). It can be seen that irregularities are formed on the surface by the silica particles. The arithmetic average roughness of the unevenness is 100 nm or more, preferably 500 nm or more, and more preferably 1000 nm or more. This arithmetic average roughness can be arbitrarily determined by selecting the size of the silica particles contained in the coating liquid.

FIG. 5 is a SEM observation photograph obtained by photographing the surface of the needle 1 according to the present embodiment and the conventional stainless steel needle with an SEM (scanning electron microscope). FIG. 5A is a surface SEM observation photograph of a conventional stainless needle, and FIG. 5B is a surface SEM observation photograph of the needle 1 on which a silica layer is formed. The photographic magnifications in FIGS. 5A and 5B are the same. The outer diameter of the needle is about 0.6 mm and the wall thickness is about 0.13 mm. The super oil-repellent needle 1 of the present embodiment also had a needle hole that was not crushed by silica particles, and the inner diameter was about 0.34 to 0.35 mm, similar to a conventional stainless steel needle.

(Silica layer underwater super oil repellency)
Hereinafter, the underwater super oil repellency of the silica layer will be described. Whether a solid surface behaves oil-repellently in water and the degree of oil repellency depends on the “chemical properties” of the solid surface and the “microstructure such as surface irregularities”. Here, the fact that silica is suitable as a chemical property is shown by a test using oleic acid, which is one of general-purpose fatty acids as oil. As the solid sample, a relatively smooth silica sample without special irregularities was used. For sample preparation, a stainless steel plate was used as the substrate, and a coating solution containing silicon alkoxide was used for the silica sample.

The coating was performed by a dip coating method, and then the sample was prepared by heat treatment at 500 degrees. As a result of measuring the contact angle of oleic acid in the water of the sample immediately after cleaning the sample surface obtained with the UV-ozone cleaner, the silica sample showed super-oil repellency exceeding 160 degrees. In addition, even when hexadecane, which is a linear alkane, was used in the oil droplets, it exhibited super oil repellency exceeding 160 degrees. From the above results, it can be seen that silica exhibits excellent oil repellency in water depending on the type of oil.

(Experiment related to oil droplet ejection)
Next, the state of the oil droplet when the oil droplet is discharged into water using the super oil-repellent needle 1 of the present embodiment and a conventional stainless steel needle will be described. FIG. 6 shows the results of a discharge experiment of oil droplets (hexadecane) in water. The photographic magnifications are the same in FIGS. 6A, 6B, and 6C.

FIG. 6A shows oil droplets ejected from a stainless needle. As shown in FIG. 6A, it can be seen that the oil droplets discharged from the conventional stainless needle have a large diameter of about 3.4 mm. In order to attach such a large oil droplet to the sample surface 4 from the needle, the oil droplet adhering to the needle must be strongly pressed against the sample surface 4, and what is the original wetting of the sample surface 4? There is a possibility that the target information cannot be obtained because of different states. Therefore, it is considered that a small-sized oil droplet can be ejected by reducing the inner diameter of the needle. However, a needle having a smaller inner diameter has a problem that the mechanical durability is lowered and the production is expensive. is there.

FIG. 6B shows oil droplets ejected from the super oil-repellent needle 1 on which the silica layer according to the present embodiment is formed. As shown in FIG. 6B, it can be seen that the oil droplets ejected from the super oil repellent needle 1 are very small, about 0.5 mm. This is because oil droplets are smoothly ejected from the super oil repellent needle 1 as a result of the reduced wettability of the oil droplets of the super oil repellent needle 1. As described above, if oil droplets of an appropriate minute size can be ejected, the oil droplets adhering to the super oil-repellent needle 1 are adhered to the sample surface 4 in a natural state without strongly pressing the sample surface 4. It becomes possible.

FIG. 6C shows oil droplets ejected from a needle on which the silica layer is formed and the surface of the super oil-repellent needle 1 is subjected to contamination treatment. Oleic acid is used as an oily soil for contamination treatment. As shown in FIG. 6C, the oil droplets ejected from the needle whose surface of the silica layer of the needle had been subjected to contamination treatment were about 2.0 mm, which was sufficiently small compared to a conventional stainless steel needle, and oleic acid (oil-based stain) It was found that small oil droplets can be ejected even when a contamination treatment using) is performed.

This result shows that not only a relatively clean state immediately after the silica treatment but also fine oil droplets can be ejected by the surface unevenness effect of the silica particles even after the needle is stored in the atmosphere for a predetermined period. In other words, when stored in the air, oily soil components floating in the air are attached to the needle surface even though a very small amount, and the wettability of the surface changes from hydrophilic to oleophilic, repelling in water. It is thought that oiliness will be impaired. However, on a fine uneven surface, water is effectively bited between the oil and the needle surface in water, so that it exhibits oil repellency and the formation of fine oil droplets can be achieved.

Second Embodiment (Configuration of Super Oil-Repellent Needle)
Next, the super oil repellent needle 1 according to the second embodiment will be described. The description will focus on the differences from the first embodiment, and the description of the overlapping points will be omitted. The super oil repellent needle 1 of the present embodiment also includes a base material 2 and an underwater super oil repellent layer 3 as in the first embodiment. A commercially available titanium needle is used for the base material 2, and a titanium oxide layer is coated on the surface as an underwater super oil repellent layer 3.

(Formation of titanium oxide layer)
The titanium oxide layer is formed on the substrate surface by firing at 400 to 1000 degrees. Titanium oxide is used because it has high hydrophilicity and reacts by irradiation with ultraviolet light having a relatively long wavelength. In addition to titanium oxide, various metal oxides such as zinc oxide, niobium oxide, and tungsten oxide are used. Can be used.

Before the needle 1 is used, the titanium oxide layer is irradiated with ultraviolet light. By irradiating the titanium oxide layer having a photocatalytic function with ultraviolet light, it exhibits super oil repellency with an oil contact angle of 150 degrees or more in water. Thereby, when operating an oil droplet in water, it can operate simply, without an oil droplet adhering to the needle tip and the side surface of a needle.

In this embodiment, the titanium oxide layer is formed on the surface by firing a titanium needle, but the method for forming the titanium oxide layer is not particularly limited. For example, a titanium oxide layer may be coated on a commercially available stainless steel needle by a sol coating method. Specifically, a titanium oxide layer can be formed by applying a coating liquid containing titanium alkoxide and titania fine particles to the surface of a stainless needle and heat-treating it at about 500 degrees for about 30 minutes in a ceramic oven.

(Experiment on oil droplet operability)
Next, a description will be given of the results of an experiment in which oil droplets are pressed against the sample surface 4 and deposited using the super oil-repellent needle 1 of the present embodiment and a conventional stainless needle. FIG. 7 is a diagram showing a state in which oil droplets (hexadecane) are pressed against the sample surface 4 in water. FIG. 7A shows a state in which an oil droplet is pressed against the sample surface 4 with a needle tip of a conventional stainless needle, and FIG. 7B shows a state in which the oil droplet is pressed against the sample surface 4 with the super oil repellent needle 1 of the present embodiment. Is shown. The sample surface 4 has super oil repellency.

As shown in FIG. 7A, the oil-in-water contact angle of the conventional stainless steel needle is 144.3 degrees. When the oil droplet is pressed against the sample surface 4 with the needle tip of this stainless steel needle and the needle tip is moved away from the sample surface 4, it can be seen that the oil droplet does not leave the needle tip and is attached to the side surface. In order to adhere to the sample surface, the oil droplets must be excessively pressed against the sample surface, resulting in a state different from the original wetting of the sample surface, and the target information may not be obtained. is there.

On the other hand, as shown in FIG. 7B, the oil-in-water contact angle of the super oil-repellent needle 1 is 165.5 degrees. Even if the oil droplet is pressed against the super-oil-repellent surface with the needle tip, the oil droplet does not leave the needle tip smoothly and adhere to the side surface of the needle. Therefore, the oil droplet can be easily attached to an arbitrary position on the sample surface 4 without excessively pressing the oil droplet against the sample surface 4.

(Injection needle experiment)
Next, the state of the oil droplets discharged from the injection needle equipped with the super oil repellent needle 1 of this embodiment was observed. FIG. 8 is a diagram illustrating a state in which oil droplets (hexadecane) are ejected from the tip of a stainless needle and a super-oil-repellent needle in water. In FIG. 8, only the tip of the needle 1 to which the injection needle is attached is shown, and the injection needle body to which the super oil-repellent needle 1 is attached is not shown. The outer diameter of the needle tip is 1.0 mm, and the wall thickness is 0.1 mm.

FIG. 8A shows a state in which oil droplets are ejected from an injection needle equipped with a conventional stainless needle. The oil droplet contact angle of hexadecane in water of a conventional stainless steel needle is 144.3 degrees. As shown in FIG. 8A, oil droplets discharged from a conventional stainless steel needle are unlikely to be separated from the needle tip, and are discharged to a certain size. The volume of the oil droplet when separated from the needle tip was as large as 28 μL.

FIG. 8B shows a state in which oil droplets are ejected from the injection needle equipped with the super oil repellent needle 1 of the present embodiment. The oil contact angle of hexadecane in water of the super oil repellent needle of this embodiment is 165.5 degrees. As shown in FIG. 8B, the super oil-repellent needle 1 of the present embodiment exhibits super oil repellency in water, so that fine oil droplets can be ejected. The oil droplet volume was 2 μL. As described above, according to the injection needle equipped with the super oil-repellent needle 1 of the present embodiment, it is possible to discharge a small oil droplet in water without down-scaling the injection needle itself.

As described above, according to the super oil-repellent needle of the present embodiment, the underwater super oil-repellent layer is formed, so that when the oil droplet is operated in water, the oil droplet does not adhere to the needle tip or the side surface of the needle. Can be operated. Moreover, it is possible to discharge a desired moderately sized oil droplet from the tip of the needle and allow natural adhesion to the sample surface. Furthermore, by applying an injection needle equipped with a super-oil-repellent needle, it is possible to discharge a micro-sized oil droplet without scaling down the needle size.

1 Super oil repellent needle 2 Base material 3 Super oil repellent layer 4 Sample surface

Claims (6)

A needle used when manipulating oil droplets in water,
A tubular substrate;
An underwater super oil repellent layer having an oil contact angle in water of 150 degrees or more, formed on the outer surface of at least the tip of the substrate;
With a needle. The needle according to claim 1, wherein the underwater super oil repellent layer has irregularities having an arithmetic average roughness of 100 nm or more. The needle according to claim 1 or 2, wherein the underwater super oil-repellent layer contains one or more metal oxides. The needle according to any one of claims 1 to 3, wherein the metal oxide contains silica. The needle according to any one of claims 1 to 3, wherein the metal oxide includes a photocatalyst selected from the group consisting of titanium oxide, zinc oxide, niobium oxide, and tungsten oxide. An injection needle provided with the needle according to claim 1.