JPWO2015059766A1 - Electroosmotic pump - Google Patents

Abstract

A novel AC osmotic flow pump capable of AC drive is provided. The electroosmotic pump 2 includes a dielectric porous membrane 21, a first water permeable electrode 22, and a second water permeable electrode 23. The first water permeable electrode 22 is disposed on one side of the dielectric porous film 21. The second water permeable electrode 23 is disposed on the other side of the dielectric porous film 21. The hydrophilicity of the main surface of the dielectric porous membrane 21 on the first water permeable electrode 22 side and the hydrophilicity of the main surface of the second water permeable electrode 23 side are different from each other.

Description

  The present invention relates to an electroosmotic flow pump.

  In recent years, the demand for a micropump, which is a kind of microfluidic device, has increased. There are various uses of the micropump, such as a microreactor, a portable medical device, and a fuel feed for a fuel cell. Conventionally, a mechanical micropump is known as a micropump. However, the mechanical micro pump is composed of precision parts. For this reason, there is a limit to cost reduction and miniaturization in the mechanical micropump. From such a background, an electroosmotic pump is attracting attention as a micro pump that replaces a mechanical pump (see, for example, Patent Document 1).

  The electroosmotic flow is a flow of a liquid that is generated when a voltage is applied to an electric double layer where the liquid and the solid are in contact. Electroosmotic flow was discovered with electrophoresis by physicist Royce in the early 19th century. In contrast to electrophoresis in which solutes and charged particles move in a liquid, solids are fixed in electroosmotic flow. For this reason, the bulk liquid moves when electroosmotic flow occurs. The electroosmotic flow is observed in a liquid or ionic liquid composed of polarizable molecules including a protic solvent such as water or alcohol. A pump for feeding liquid using this electroosmotic flow is an electroosmotic flow pump.

JP 2010-216902 A

  Patent Document 1 describes an example of an electroosmotic flow pump. In order to drive a conventional electroosmotic pump such as the electroosmotic pump described in Patent Document 1, it is necessary to apply a DC voltage.

  When a DC voltage is applied to operate the electroosmotic pump, a liquid electrolysis reaction occurs in parallel. When the electrolysis reaction of the liquid proceeds, there arises a problem that the pH of the liquid changes or bubbles are generated in the liquid. In particular, when water is used as a liquid, hydrogen and oxygen are generated, which is dangerous. Therefore, there is a strong demand for a new electroosmotic flow pump that does not cause these problems.

  The main object of the present invention is to provide a novel AC drive electroosmotic pump.

  The first electroosmotic pump according to the present invention includes a dielectric porous membrane, a first water permeable electrode, and a second water permeable electrode. The first water permeable electrode is disposed on one side of the dielectric porous film. The second water permeable electrode is disposed on the other side of the dielectric porous film. The hydrophilicity of the main surface on the first water permeable electrode side of the dielectric porous membrane is different from the hydrophilicity of the main surface on the second water permeable electrode side.

  In the electroosmotic pump according to the present invention, each of the first water permeable electrode and the second water permeable electrode includes a conductive porous film, a conductive mesh, a conductive fine particle sintered film formed on the surface of the dielectric porous film, Or it is preferable that it is a pattern electrode printed on the porous insulating film.

  In the first electroosmotic pump according to the present invention, the dielectric porous film may have a hydrophilic layer on one main surface.

  The second electroosmotic pump according to the present invention includes a dielectric porous membrane, a first water permeable electrode, and a second water permeable electrode. The first water permeable electrode is disposed on one side of the dielectric porous film. The second water permeable electrode is disposed on the other side of the dielectric porous film. The zeta potential on one side of the dielectric porous film and the zeta potential on the other side are different from each other, or the streaming potential on one side of the dielectric porous film is different from the streaming potential on the other side.

  The third electroosmotic pump according to the present invention includes a dielectric porous membrane, a first water permeable electrode, and a second water permeable electrode. The first water permeable electrode is disposed on one side of the dielectric porous film. The second water permeable electrode is disposed on the other side of the dielectric porous film. The dielectric porous membrane is formed so that when an alternating voltage is applied between the first water permeable electrode and the second water permeable electrode, the liquid in the dielectric porous membrane is changed to the first water permeable electrode side. It is comprised so that the force to selectively move from one side of the 2nd water-permeable electrode side to the other may be provided.

  In the first to third electroosmotic flow pumps according to the present invention, the dielectric porous film includes the first dielectric porous film and the second dielectric porous film stacked, and one principal surface is It may be configured by the first dielectric porous film, and the other main surface may be configured by the second dielectric porous film.

  The first to third electroosmotic pumps according to the present invention may further include a power source that applies an alternating voltage between the first water permeable electrode and the second water permeable electrode. In that case, the power source preferably applies an AC voltage having a frequency of 1 MHz or less.

  In the first to third electroosmotic pumps according to the present invention, the thickness of the dielectric porous film is preferably in the range of 5 μm to 100 μm.

In the first to third electroosmotic pumps according to the present invention, the ratio of the areas of the first and second permeable electrodes to the square of the thickness of the dielectric porous membrane ((first and second permeable water The area of the conductive electrode) / (thickness of the dielectric porous film) ² ) is preferably larger than 100.

  In the first to third electroosmotic pumps according to the present invention, it is preferable that the average pore diameter in the dielectric porous membrane is in the range of 10 nm to 50 μm.

  In the first to third electroosmotic pumps according to the present invention, it is preferable that each of the first and second water permeable electrodes has a through hole penetrating in the thickness direction.

  In the first to third electroosmotic pumps according to the present invention, the dielectric porous film preferably has a through hole penetrating in the thickness direction.

  In the first to third electroosmotic pumps according to the present invention, the hydrophilicity of the main surface on the first permeable electrode side of the dielectric porous membrane is the hydrophilicity of the main surface on the second permeable electrode side. Is higher, the first permeable electrode preferably has a hydrophilic layer on the surface layer opposite to the dielectric porous membrane.

  ADVANTAGE OF THE INVENTION According to this invention, the novel electroosmotic flow pump which can be driven by alternating current can be provided.

FIG. 1 is a schematic cross-sectional view of a liquid delivery module including an electroosmotic flow pump according to the first embodiment. FIG. 2 is a schematic cross-sectional view of a part of the liquid-feeding film in the first embodiment. FIG. 3 is a schematic cross-sectional view of a part of the liquid feeding film in the second embodiment. FIG. 4 is a schematic diagram of the hydrophilic layer of the liquid-feeding film in the second embodiment. FIG. 5 is a schematic cross-sectional view of a part of the liquid feeding film in the third embodiment. FIG. 6 is a fracture cross-sectional photograph of the track-etched film used in Example 1. FIG. 7 is a graph showing the relationship between the applied voltage and the flow rate in Example 1. FIG. 8 is a graph showing the relationship between the applied voltage and the flow rate in Examples 1 to 3.

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  Moreover, in each drawing referred in embodiment etc., the member which has a substantially the same function shall be referred with the same code | symbol. The drawings referred to in the embodiments and the like are schematically described, and the ratio of the dimensions of the objects drawn in the drawings may be different from the ratio of the dimensions of the actual objects. The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio of the object should be determined in consideration of the following description.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of an electroosmotic flow pump according to the present embodiment. FIG. 2 is a schematic cross-sectional view of a part of the liquid feeding film in the present embodiment.

  The liquid feeding module 1 shown in FIG. 1 includes fixing jigs 10 and 11 and an electroosmotic pump 2 attached to the fixing jigs 10 and 11. The electroosmotic pump 2 includes a liquid feeding film 20 sandwiched between a first water permeable electrode and a second water permeable electrode. The electroosmotic pump 2 is supplied with AC power. The liquid feeding film 20 partitions the first storage unit 12 and the second storage unit 13. A liquid storage tank 30 is connected to the second storage unit 13. Liquid is supplied from the liquid reservoir 30 to the first reservoir 12. The liquid supplied to the first storage unit 12 is supplied to the second storage unit 13 by the liquid transfer film 20 and is discharged from the discharge port 14 provided in the second storage unit 13.

  In addition, the 1st storage part 12 and the 2nd storage part 13 are for guide | inducing a liquid to the one surface and other surface of the electroosmotic flow pump 2, and will become a path | route through which a liquid is conveyed. That's fine. The first and second reservoirs 12 and 13 do not necessarily have a specific volume. The first reservoir 12 and the second reservoir 13 may be part of any channel flow path of the microfluidic device. Moreover, the 1st storage part 12 and the 2nd storage part 13 may each be satisfy | filled with the water-permeable porous body and the gel.

  The liquid feeding film 20 may have a flat plate shape, or may have a bent structure, a structure having a plurality of irregularities, or a folded structure. In that case, the ratio of the actual surface area to the area of the liquid delivery film 20 in plan view ((actual area of the surface of the liquid delivery film 20) / (area of the liquid delivery film 20 in plan view)) may be increased. it can. Therefore, the liquid feeding capability of the electroosmotic flow pump 2 can be improved.

  The liquid feeding film 20 has a dielectric porous film 21. The dielectric porous film 21 is made of an appropriate dielectric. The dielectric porous film 21 is, for example, a polymer film made of polycarbonate (PC), polyester (PET), polyimide (PI) or the like, ceramic, silicon, glass, aluminum oxide sintered body, aluminum nitride sintered body. Further, it may be composed of an inorganic film made of a mullite sintered body, a silicon carbide sintered body, a silicon nitride sintered body, a glass ceramic sintered body, or the like. The dielectric porous film 21 may be, for example, a monolithic porous body.

  The dielectric porous film 21 is preferably a track-etched film. Here, the track-etched film means a track-etched film. Track etching is chemical etching that forms a linear track by irradiating a film with strong heavy ions.

  When the dielectric porous film 21 is a polymer film or an inorganic film, pores can be formed by laser light irradiation.

  The dielectric porous film 21 is preferably a film having open cells, and is preferably a film having a plurality of through holes penetrating in the thickness direction. Usually, the track-etched film has many through holes penetrating in the thickness direction.

  The thickness of the dielectric porous film 21 is not particularly limited, but is preferably about 5 μm to 100 μm, and more preferably 10 μm to 60 μm. By setting the thickness of the dielectric porous film 21 to such a thickness, it is possible to antagonize the thickness of the dielectric porous film 21 and the thickness of the electric double layer to be formed. Therefore, the operation of the electroosmotic flow pump 2 is suitable.

  The average pore diameter in the dielectric porous film 21 is preferably 10 nm to 50 μm, more preferably 20 nm to 10 μm, and further preferably 50 nm to 2 μm. If the average pore diameter in the dielectric porous film 21 is too small, the flow resistance may be large and the liquid feeding amount may be small. If the average pore size in the dielectric porous film 21 is too large, the water pressure of the liquid feeding is lowered, and the energy efficiency of the electroosmotic flow may be deteriorated.

  The aperture ratio of the dielectric porous film 21 is preferably 1% to 50%, and more preferably 3% to 30%. If the aperture ratio of the dielectric porous film 21 is too high, adjacent holes are likely to be fused, and a problem may occur in the self-supporting property of the film. If the aperture ratio of the dielectric porous film 21 is too low, the liquid feeding amount may be small.

Pore density of the dielectric porous film 21, 4 E2 / c is preferably m is ^{2 ~ 5E 13 / c m 2} , 3E 4 / cm 2 ~ 7.5 E1 0 / cm 2 and it is further preferable. If the pore density of the dielectric porous film 21 is too high, the aperture ratio may be too high or the average pore size may be too small. If the pore density of the dielectric porous film 21 is too low, the energy efficiency of the electroosmotic flow may be deteriorated.

  A first water-permeable electrode 22 is provided on the second reservoir 13 side of the dielectric porous film 21. A second water permeable electrode 23 is provided on the first reservoir 12 side of the dielectric porous film 21. The first and second water permeable electrodes 22 and 23 may be provided so that an electric double layer is formed on the surface of the dielectric porous film 21 when the liquid is supplied. Each of the first and second permeable electrodes 22 and 23 is not necessarily in contact with the dielectric porous film 21. For example, a conductive rubber having a high elastic modulus may be interposed between each of the first and second water permeable electrodes 22 and 23 and the dielectric porous film 21.

  The first and second water permeable electrodes 22 and 23 are provided so that liquid can pass in the thickness direction. Each of the first and second water permeable electrodes 22 and 23 preferably has a through-hole penetrating in the thickness direction. The through holes of the first and second permeable electrodes 22 and 23 and the through holes of the dielectric porous film 21 are preferably connected.

  The first and second water permeable electrodes 22 and 23 are each made of, for example, a conductive material such as metal on the dielectric porous film 21 so that the pores of the dielectric porous film 21 are not completely closed. It can be formed by forming a film. Moreover, the 1st and 2nd water-permeable electrodes 22 and 23 may be comprised by patterned electrodes, such as a mesh electrode, a comb-shaped electrode, a staggered electrode, and a fractal pattern electrode, respectively.

  The material of the first and second water permeable electrodes 22 and 23 is not particularly limited as long as it is a conductive material, but the first and second water permeable electrodes 22 and 23 are made of a highly conductive material. Is preferred. Specifically, each of the first and second permeable electrodes 22 and 23 is composed of at least one metal of gold, silver and copper, a composite material mainly composed of carbon such as carbon nanotube, indium tin oxide (ITO). ) Or other transparent conductive oxides or the like.

  The electroosmotic pump 2 includes an AC power supply 40. An AC voltage is applied between the first and second permeable electrodes 22 and 23 by the AC power source 40. The AC power supply 40 preferably applies an AC voltage having a frequency of 1 MHz or less between the first and second permeable electrodes 22 and 23, and more preferably applies an AC voltage of 0.5 Hz to 20 kHz. More preferably, an alternating voltage of 1 Hz to 100 Hz is applied. If the frequency of the AC voltage applied between the first and second permeable electrodes 22 and 23 is too high, the electroosmotic pump 2 may not operate properly.

  As shown in FIG. 2, in the electroosmotic pump 2, the dielectric porous membrane 21 has a hydrophilic layer 21 a on the main surface on the first water permeable electrode 22 side. For example, when the dielectric porous film 21 is a track-etched film, one surface layer of the dielectric porous film 21 is a hydrophilic layer 21a. When the dielectric porous film 21 is not a track-etched film, one surface of the dielectric porous film 21 has a hydrophilic treatment or a hydrophilic functional group typified by plasma treatment such as atmospheric pressure plasma chemical treatment. The hydrophilic layer 21a can be formed by chemically modifying with molecules. As the polymer containing a hydrophilic functional group, a polyurethaneurea containing a phosphorylcholine group is preferably used. Moreover, polylysine, polyallylamine, etc. which have many amino groups in a molecular chain can also be used as a polymer containing a hydrophilic functional group. The method of chemically modifying the surface of the dielectric porous film 21 with a molecule having a hydrophilic functional group is not limited to these, and a chemical modification hydrophilization technique known to those skilled in the art can be applied.

  The hydrophilicity of the surface of the hydrophilic layer 21a is higher than the hydrophilicity of the main surface of the dielectric porous film 21 on the second water permeable electrode 23 side. Therefore, the zeta potential of the main surface of the dielectric porous membrane 21 on the first water permeable electrode 22 side and the zeta potential of the main surface on the second water permeable electrode 23 side are different from each other, or the dielectric The streaming potential of the main surface of the body porous membrane 21 on the first permeable electrode 22 side is different from the streaming potential of the main surface on the second permeable electrode 23 side. Specifically, the magnitude of the zeta potential on the main surface of the dielectric porous film 21 on the first water permeable electrode 22 side is larger than the zeta potential on the main surface on the second water permeable electrode 23 side. Alternatively, the flow potential on the main surface of the dielectric porous membrane 21 on the first water permeable electrode 22 side is larger than the flow potential on the main surface on the second water permeable electrode 23 side. Therefore, when an AC voltage is applied between the first water permeable electrode 22 and the second water permeable electrode 23, the liquid is transferred from the first reservoir 12 to the second reservoir 13. Thereby, the electroosmotic flow pump 2 operates.

  Thus, in this embodiment, when the dielectric porous film 21 is applied with an alternating voltage between the first water permeable electrode 22 and the second water permeable electrode 23, the dielectric porous film 21. A force for moving the liquid from the first water-permeable electrode 22 side to the second water-permeable electrode 23 side is applied to the liquid inside. For this reason, the electroosmotic flow pump 2 can be driven by an alternating voltage. Therefore, unlike the case where a DC voltage is applied to the electroosmotic pump, the liquid is electrolyzed when the electroosmotic pump 2 is driven, and the pH of the liquid is not easily changed and bubbles are not easily changed.

Ratio of the area of the first and second permeable electrodes 22, 23 to the square of the thickness of the dielectric porous film 21 ((area of the first and second permeable electrodes 22, 23) / (dielectric) The thickness ( ² ) of the porous membrane 21 is preferably greater than 100. If the ratio ((area of the first and second permeable electrodes 22 and 23) / (thickness of the dielectric porous film 21) ² ) is too small, the efficiency of liquid feeding becomes poor. There is no restriction for this large ratio.

  The hydrophilicity can be measured with an automatic contact angle meter (Kyowa Interface Science Co., Ltd., DM-300).

  Zeta potential: A solid or liquid interface in contact with a protic solvent typified by an aqueous solution is charged except in special cases. The electric field due to this electric charge attracts ions (counter ions) of opposite signs from the solution side to form an ion atmosphere (electric double layer) near the surface. There is a counter ion which is a particularly strongly adsorbed ion on the surface of the solid, a stern layer in which the counter ion hardly moves, and a structure in which the counter ion diffuses in a state where it becomes thin enough to move away from the solid surface and can move. A diffusion electric double layer is present. The zeta potential is a potential at a “sliding surface” (also referred to as a shear surface) at the boundary between the Stern layer and the diffusion electric double layer. The zeta potential on the surface of the membrane can be measured, for example, with a membrane zeta potential measuring device (Otsuka Electronics ELSZ-1). The zeta potential in the pores can be measured by, for example, a solid zeta potential measuring device (Anton Paar Japan, SurPASS).

  The streaming potential can be measured with a solid zeta potential measuring device (Anton Paar Japan, SurPASS).

  In addition, although the electroosmotic flow pump of this invention operate | moves when an alternating voltage is applied, it does not necessarily need to be a thing which does not operate | move when a direct voltage is applied. Usually, the electroosmotic pump of the present invention operates not only when an AC voltage is applied but also when a DC voltage is applied.

  Hereinafter, other examples of preferred embodiments of the present invention will be described. In the following description, members having substantially the same functions as those of the first embodiment are referred to by the same reference numerals, and description thereof is omitted.

(Second Embodiment)
FIG. 3 is a schematic cross-sectional view of a part of the liquid feeding film in the second embodiment.

  The electroosmotic pump according to the present embodiment is different from the electroosmotic flow pump according to the first embodiment in that the first water permeable electrode 22 has a hydrophilic layer 22a on the surface layer opposite to the dielectric porous membrane 21. Different from pump 2.

  By providing the hydrophilic layer 22a as in the present embodiment, the liquid feeding performance can be improved.

The hydrophilic layer 22a can be formed, for example, by performing a surface treatment with a self-assembling reagent capable of gold-thiol bonding when the first permeable electrode 22 contains gold. The self-assembling reagent preferably used is a molecule having a main chain including one terminal constituted by a sulfur atom and another terminal constituted by a hydrophilic group. As a specific example of such a self-assembling reagent, for example,
_{HS- (CH 2) n -COOH .........} (1)
_{HOOC- (CH 2) n -S-} S- (CH 2) n-COOH ......... (2)
HS- (CH ₂ ) _n —OH (3)
_{HS- (CH 2) n - (} OCH 2 -CH 2) 6 - (CH 2) n -OCH 2 -COOH ......... (4)
_{HS- (CH 2) n -NH 3} Cl ......... (5)
_{HS- (CH 2) n - (} OCH 2 -CH 2) 6 -NH 3 Cl ......... (6)
Etc.

  FIG. 4 shows a schematic diagram of the hydrophilic layer 22a formed using the self-assembling reagent as described above (specifically, 1,1-mercaptodecanoic acid).

Note that degreasing treatment, supercritical CO ₂ cleaning, plasma treatment, corona discharge treatment, and the like may be additionally performed before the hydrophilic treatment with the self-assembling reagent.

(Third embodiment)
FIG. 5 is a schematic cross-sectional view of a part of the liquid feeding film in the third embodiment. As shown in FIG. 5, in the present embodiment, the dielectric porous film 21 includes a first dielectric porous film 21A and a second dielectric porous film 21B. The first dielectric porous film 21A and the second dielectric porous film 21B are laminated. The first dielectric porous film 21A is located on the first water permeable electrode 22 side, and the second dielectric porous film 21B is located on the second water permeable electrode 23 side. The first dielectric porous film 21A is made of a material having higher hydrophilicity than the second dielectric porous film 21B. For this reason, also in this embodiment, the hydrophilicity of the surface of the dielectric porous membrane 21 on the first water permeable electrode 22 side is higher than the hydrophilicity of the surface on the second water permeable electrode 23 side. Therefore, the electroosmotic pump of this embodiment also operates by applying an alternating voltage.

  Note that the ratio between the thickness of the first dielectric porous film 21A and the thickness of the second dielectric porous film 21B (the thickness of the first dielectric porous film 21A: the second dielectric) The film thickness with the porous membrane 21B) is preferably 1: 100 to 100: 1, and more preferably 1:10 to 10: 1.

  Hereinafter, the present invention will be described in more detail on the basis of specific examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented without departing from the scope of the present invention. Is possible.

Example 1
An electroosmotic pump having a configuration substantially similar to that of the electroosmotic pump 2 according to the first embodiment was produced in the following manner. A gold film having a thickness of 20 nm using a magnetron sputtering apparatus (vacuum device, MSP-1S) on both sides of a track-etched film (Millipore, isopore membrane filters HTTP04700) having a thickness of 20 μm and an average pore diameter of 400 nm. Was deposited to form a liquid delivery film. At this time, it was confirmed that the front and back of the film were electrically insulated. The first and second permeable electrodes made of gold were connected to an AC power source via a conductive rubber electrode. The distance between the first water permeable electrode and the second water permeable electrode was 20 μm, which is equal to the thickness of the track etched film. FIG. 6 shows a fracture cross-sectional photograph of the track-etched film used in Example 1.

The zeta potential on the surface of the track-etched film was measured using a film zeta potential measuring device (Otsuka Electronics ELSZ-1). Specifically, the velocity of electroosmotic flow induced by applying an electric field in parallel to the track-etched film was observed as the motion velocity of polystyrene latex (500 nm) that was not charged by modification of hydroxypropylcellulose. The zeta potential was measured from the movement speed. As the liquid, a 10 mM NaCl aqueous solution was used. The results are shown in Table 1 below.

The zeta potential in the pores of the track-etched membrane was measured by the streaming potential method using a solid zeta potential measuring device (Anton Paar Japan, SurPASS). As a result of calculating the zeta potential from the streaming potential generated by the application of water pressure,
The zeta potential calculated from the flow potential from the first permeable electrode side to the second permeable electrode side is −36.01 mV,
The zeta potential calculated from the flow potential from the second water permeable electrode side to the first water permeable electrode side was −40.11 mV. The zeta potential inside the pores was much lower than the zeta potential on the membrane surface.

  An AC voltage of 25 Hz was applied to the produced electroosmotic flow pump while keeping the back pressure of the liquid (deionized water) at zero. The results are shown in FIG.

  In this example, bubbles were not substantially generated even when the AC voltage was continuously applied for 10 minutes.

  From the results shown in FIG. 7, it can be seen that the electroosmotic pump produced in this example is driven when an AC voltage is applied. It can also be seen that the flow rate can be increased by increasing the applied voltage.

(Experimental example 2)
The electroosmotic flow in the same manner as in Example 1 except that the surface of the first water permeable electrode opposite to the dielectric porous membrane was treated with 1,1-mercaptodecanoic acid to form a hydrophilic layer. A pump was made.

(Experimental example 3)
An electroosmotic pump was prepared in the same manner as in Example 1 except that the surface of the first porous electrode on the dielectric porous membrane side was treated with 1,1-mercaptodecanoic acid to form a hydrophilic layer. did.

  An AC voltage of 25 Hz was applied to the electroosmotic flow pumps produced in Examples 2 and 3 while keeping the back pressure of the liquid (water) at zero. The results are shown in FIG. 8 together with the results of Example 1.

  From the results shown in FIG. 8, it can be seen that the liquid feeding ability can be improved by forming a hydrophilic layer on the surface of the first water permeable electrode opposite to the dielectric porous film.

Example 4
A liquid prepared by dissolving a pH indicator in deionized water was supplied to the apparatus prepared in Example 1, and an AC voltage of 9.34 Vrms at 25 Hz was applied between the first and second permeable electrodes for 15 minutes. Then, when the color tone of the 1st and 2nd storage part was observed, the color tone of the 1st and 2nd storage part was the same as that before voltage application, pH did not change, and the gas by electrolysis did not generate | occur | produce. . In addition, even when a 0.9 mass% NaCl aqueous solution was used as the solvent, the first and second reservoirs did not show pH change, and no gas was generated due to electrolysis.

  On the other hand, when a DC voltage of 9.34 V is applied between the first and second permeable electrodes for 15 minutes, the color of the first reservoir changes to an acidic color, and the second reservoir changes to an alkaline color. Then, gas was generated by electrolysis. Moreover, when 0.9 mass% NaCl aqueous solution is used as a solvent, the color tone of the 1st storage part changes to a strongly acidic color, the 2nd storage part changes to a strong alkaline color, and the gas by electrolysis has changed. Occurred.

1: Liquid feeding module 2: Electroosmotic flow pump 10: Fixing jig 11: Fixing jig 12: First reservoir 13: Second reservoir 14: Discharge port 20: Liquid feeding membrane 21: Dielectric porous Membrane 21A: first dielectric porous membrane 21B: second dielectric porous membrane 21a: hydrophilic layer 22: first water permeable electrode 22a: hydrophilic layer 23: second water permeable electrode 30: liquid reservoir 40: AC power supply

Claims (12)

A dielectric porous membrane;
A first water permeable electrode disposed on one side of the dielectric porous membrane;
A second water permeable electrode disposed on the other side of the dielectric porous membrane;
With
The electroosmotic pump, wherein the hydrophilic property of the main surface of the dielectric porous membrane on the first permeable electrode side and the hydrophilic property of the main surface of the second permeable electrode side are different from each other.   The electroosmotic pump according to claim 1, wherein the dielectric porous film has a hydrophilic layer on one main surface. A dielectric porous membrane;
A first water permeable electrode disposed on one side of the dielectric porous membrane;
A second water permeable electrode disposed on the other side of the dielectric porous membrane;
With
The zeta potential on one side of the dielectric porous membrane is different from the zeta potential on the other side, or the streaming potential on one side of the dielectric porous membrane is different from the streaming potential on the other side. Different, electroosmotic flow pump. A dielectric porous membrane;
A first water permeable electrode disposed on one side of the dielectric porous membrane;
A second water permeable electrode disposed on the other side of the dielectric porous membrane;
With
The dielectric porous film is formed in the liquid in the dielectric porous film when the AC voltage is applied between the first water permeable electrode and the second water permeable electrode. An electroosmotic flow pump configured to be provided with a force to selectively move from one of the permeable electrode side and the second permeable electrode side to the other. The dielectric porous film includes a laminated first dielectric porous film and second dielectric porous film,
The one principal surface is constituted by the first dielectric porous film;
The electroosmotic pump according to any one of claims 1 to 4, wherein the other main surface is constituted by the second dielectric porous film. A power source for applying an alternating voltage between the first permeable electrode and the second permeable electrode;
The electroosmotic pump according to any one of claims 1 to 5, wherein the power source applies an AC voltage having a frequency of 1 MHz or less.   The electroosmotic pump according to any one of claims 1 to 6, wherein a thickness of the dielectric porous film is in a range of 5 µm to 100 µm. The ratio of the area of the water permeable electrode to the square of the thickness of the dielectric porous film ((area of the water permeable electrode) / (thickness of the dielectric porous film) ² ) is greater than 100. The electroosmotic pump according to any one of Items 1 to 7.   The electroosmotic pump according to any one of claims 1 to 8, wherein an average pore diameter in the dielectric porous membrane is in a range of 10 nm to 50 µm.   The electroosmotic pump according to any one of claims 1 to 9, wherein each of the first and second permeable electrodes has a through hole penetrating in a thickness direction.   11. The electroosmotic pump according to claim 1, wherein the dielectric porous film has a through hole penetrating in a thickness direction. The hydrophilicity of the main surface of the dielectric porous membrane on the first water permeable electrode side is higher than the hydrophilicity of the main surface of the second water permeable electrode side,
The electroosmotic pump according to any one of claims 1 to 11, wherein the first water-permeable electrode has a hydrophilic layer on a surface layer opposite to the dielectric porous membrane.

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