KR20160133946A

KR20160133946A - Microfluidic valve

Info

Publication number: KR20160133946A
Application number: KR1020150067196A
Authority: KR
Inventors: 조영호; 김성진
Original assignee: 한국과학기술원
Priority date: 2015-05-14
Filing date: 2015-05-14
Publication date: 2016-11-23
Also published as: KR101727624B1

Abstract

The present invention relates to a microfluid valve which can maintain opening pressure to be constant and low. The microfluid valve comprises: a channel flow path layer structure having a first opening unit and a second opening unit which communicate with an inlet and an outlet, respectively, and a valve sheet which is extended from the first opening unit and the second opening unit and divides the first and second opening units; a variable membrane which covers the channel flow path layer structure, operates to be able to selectively come in contact with the valve sheet, and defines a first area and a second area with the first opening unit and the second opening unit; and a membrane control layer structure which is arranged on the channel flow path layer structure while the variable membrane is interposed between the same and the channel flow path layer structure and has a third opening unit which forms, with the variable membrane, a third area for pressurizing or depressurizing the variable membrane with the valve sheet. The valve sheet is in a bent shape to make a portion of the valve sheet protrude toward the second area.

Description

MICROFLUIDIC VALVE

The present invention relates to a microfluidic valve, and more particularly, to a microfluidic valve for interrupting a flow of a fluid flowing through a microfluidic channel.

Accurate, low pressure driven microfluidic elements are very important for a variety of biochemical applications. Of these elements, microfluidic valves that control the flow and direction of the fluid are key factors. The microfluidic valve is divided into a normally closed microfluidic valve (NC valve) and a normally open microfluidic valve (NO valve). Among them, NC valve is a very important factor in autonomously operating microfluidic circuit such as digital fluid logic circuit and fluid oscillator. The NC valve (hereinafter referred to as " fine valve ") can perform a valve opening / closing operation by deforming and driving a flexible membrane capable of elastically deforming.

However, the problem of the conventional microvalves is that the opening pressure is as high as about 9 kPa to 83 kPa, and the opening pressure varies depending on the driving conditions. Due to these problems, as the degree of integration of the valve in the microfluidic system increases, the driving pressure of the entire system increases greatly, and the response characteristic becomes non-linear.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a microfluidic valve capable of maintaining a constant and low pressure for opening a microvalve.

It is to be understood, however, that the present invention is not limited to the above-described embodiments and various modifications may be made without departing from the spirit and scope of the invention.

According to an aspect of the present invention, there is provided a microfluidic valve including a first opening and a second opening communicating with an inlet and an outlet, respectively, and a second opening extending between the first opening and the second opening, A channel channel layer structure having a valve seat separating the first and second openings, the channel channel layer structure covering the channel channel layer structure and operable to selectively contact the valve seat, And a third region disposed on the channel channel layer structure with the variable membrane sandwiched therebetween and for pressurizing or depressurizing the variable membrane against the valve seat together with the variable membrane, A membrane control layer structure having a third opening for forming a region, Teuneun has a curved shape that a portion of said valve seat so as to project into the second area.

In exemplary embodiments, the valve seat may have a V-shape, a U-shape, or a combination thereof.

In the exemplary embodiments, the areas of the first opening and the second opening may be determined according to the protruding shape of the valve seat.

In exemplary embodiments, the area of the first opening may be larger than the area of the second opening.

In exemplary embodiments, the microfluidic valve may further include a coating film formed on a surface of at least one of the contact surfaces of the variable membrane and the valve seat.

In exemplary embodiments, the first opening and the second opening are spaced apart from each other in a first direction, the valve seat extends in a second direction transverse to the first direction, and a portion of the valve seat May protrude into the second region in the first direction.

In exemplary embodiments, the variable membrane may comprise a flexible polymeric material.

In order to achieve the above object, the microfluidic valve according to exemplary embodiments includes a lower layer structure, an upper layer structure disposed on the lower layer structure and having a valve seat, and a lower layer structure interposed between the lower layer structure and the upper layer structure A variable membrane that covers the upper layer structure and forms a source region and a drain region that communicate with the inlet and the outlet respectively and forms a gate region for covering the lower layer structure to pressurize or depressurize the variable membrane against the valve seat And the valve seat has a shape bent so that a part of the valve seat protrudes into the second region.

The microfluidic valve according to the invention thus constructed is opened at a designed constant pressure without being influenced by a driving environment such as a flow rate change. Also, the critical pressure at which the microfluidic valve is opened can be kept very low. Accordingly, it is possible to provide a microfluidic valve having a linear and low driving pressure.

However, the effects of the present invention are not limited to the above-mentioned effects, and may be variously expanded without departing from the spirit and scope of the present invention.

1 is a plan view showing a microfluidic valve in accordance with exemplary embodiments.
2 is a cross-sectional view taken along line AA 'of FIG.
FIGS. 3A and 3B are cross-sectional views illustrating a process of closing and opening the microfluidic valve of FIG.
Fig. 4 is an optical microscope photograph showing the microfluid valve of Fig. 1; Fig.
5 is a view showing the degree of deformation of the variable membrane in the microfluidic valves in which the I-shaped valve seat and the V-shaped valve seat are respectively used.
6 is a graph showing the opening pressure according to the flow rate of the microfluidic valve of FIG.
7 is a top view showing a microfluidic valve in accordance with exemplary embodiments.
8 is a top view showing a microfluidic valve in accordance with exemplary embodiments.

For the embodiments of the invention disclosed herein, specific structural and functional descriptions are set forth for the purpose of describing an embodiment of the invention only, and it is to be understood that the embodiments of the invention may be practiced in various forms, The present invention should not be construed as limited to the embodiments described in Figs.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms may be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprise", "having", and the like are intended to specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be construed as meaning consistent with meaning in the context of the relevant art and are not to be construed as ideal or overly formal in meaning unless expressly defined in the present application .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

1 is a plan view showing a microfluidic valve in accordance with exemplary embodiments. 2 is a cross-sectional view taken along the line A-A 'in Fig. FIGS. 3A and 3B are cross-sectional views illustrating a process of closing and opening the microfluidic valve of FIG. Fig. 4 is an optical microscope photograph showing the microfluid valve of Fig. 1; Fig.

1 to 4, a microfluidic valve 100 includes a channel channel layer structure 110 having a first opening 112 and a second opening 114 separated by a valve seat 116, A membrane control layer structure 130 that pressurizes the variable membrane 120 and the valve seat 116 to contact the valve seat 116 and the variable membrane 120 that covers the layer structure 110 and selectively contacts the valve seat 116, . &Lt; / RTI >

In the exemplary embodiments, the microfluidic valve 100 may be disposed between the inlet 10 and the outlet 20 of the flow passage. The first opening 112 of the channel channel layer structure 110 communicates with the inlet 10 of the channel and the second opening 114 of the channel channel layer structure 110 can communicate with the outlet 20 of the channel. have.

The channel channel layer structure, the variable membrane, and the membrane control layer structure may be formed by semiconductor manufacturing processes including growth and etching of a crystal structure using photolithography, ion lithography, electronic lithography, and a scanning probe. For example, the channel channel layer structure and the membrane control layer structure may be formed using a polymer material, an inorganic material, or the like. The variable membrane may be formed using a polymer material having flexible characteristics. Examples of the polymer material include PDMS, PMMA, SU-8, and the like. Examples of the inorganic material include glass, quartz, silicon and the like.

2, the microfluidic valve 100 may include a channel flow channel layer structure 110 as a sequentially deposited lower layer structure, a variable membrane 120, and a membrane control layer structure 130 as an upper layer structure. have. The variable membrane 120 may be interposed between the channel channel layer structure 110 and the membrane control layer structure 130.

The channel channel layer structure 110 includes a first opening 112 and a second opening 114 spaced apart in a first direction and a second opening 114 formed between the first opening 112 and the second opening 114, And a valve seat 116 extending in a second direction to separate the first and second openings 112, 114. The first opening 112 and the second opening 114 may be formed in a recessed shape on the lower surface of the channel channel layered structure 110, respectively. The valve seat 116 is formed to protrude from the bottom surfaces of the first and second openings 112 and 114 to separate the first and second openings 112 and 114 from each other. The first opening 112, the second opening 114 and the valve seat 116 may have a square or rectangular shape, but the present invention is not limited thereto. For example, the opening pressure of the valve, the flow rate of the flowing fluid, It will be understood that the present invention can have various shapes in consideration of the shape and the like.

The variable membrane 120 may be coupled to cover the channel channel layer structure 110 at a lower portion of the channel channel layer structure 110. The variable membrane 120 is operable to selectively contact the valve seat 116. The variable membrane 120 defines a first region or source region that is in communication with the inlet 10 to cover the first opening 112 and the variable membrane 120 covers the second opening 114, A second region, i.e., a drain region, which is in communication with the source region 20 can be defined.

The membrane control layer structure 130 is disposed below the channel channel layer structure 110 with the variable membrane 120 interposed therebetween and has a predetermined internal space for pressing or depressurizing the variable membrane 120 against the valve seat 116. [ And a third opening 132 for providing pressure. The third opening 132 may be formed in a recessed shape on the upper surface of the membrane control layer structure 130. The third opening 132 may have a rectangular or square shape corresponding to the first opening 112, the second opening 114, and the valve seat 116 as viewed in a plan view.

The variable membrane 120 may be coupled to cover the membrane control layer structure 130 at the top of the membrane control layer structure 130. The variable membrane 120 may form a third region, i.e., a gate region, as a space for covering the third opening 112 to pressurize or depressurize the variable membrane 120 relative to the valve seat 116. The gate region is in communication with the control pneumatic pressure line 30 and the gate region may be connected to the fluid source (not shown) via the control pneumatic pressure line 30. Accordingly, a fluid such as gas, liquid, or the like is supplied into the gate region, and the gate region has a predetermined internal pressure, so that the variable membrane 120 is pressurized or decompressed against the valve seat 116, May selectively contact the valve seat 116 according to the internal pressure to open or close the flow passage.

3A, when there is a pressure difference less than a predetermined value between the source region and the gate region, the variable membrane 120 contacts the valve seat 116 to keep the microvalve closed have.

3B, when the microfluid flows into the source region and the pressure starts to increase, the variable membrane 120 located below the first opening 112 begins to deform downward, and the pressure of the source region Is greater than a preset value, the variable membrane 120 is separated from the valve seat 116 and the microvalve is opened. As a result, the fluid flows from the source region to the drain region. The difference in pressure between the source region and the gate region when the fine valve is opened will be referred to as a threshold pressure or an opening pressure.

In exemplary embodiments, the valve seat 116 may have a bent shape such that a portion of the valve seat 116 protrudes toward the outlet side 20. The areas of the first opening 112 and the second opening 114 can be determined according to the protruding shape of the valve seat 116. [ When the valve seat 116 has a protruding shape, the area of the first opening 112 may be larger than the area of the second opening 114. Accordingly, the critical pressure can be decreased and the critical pressure can be maintained to have a constant value with respect to the flow rate.

In a plan view, the valve seat 116 can extend in a V-shape. The valve seat 116 may have a bar shape bent so that the central portion of the valve seat 116 protrudes into the source region. The valve seat 116 may extend along the second direction so as to traverse a first direction from the inlet 10 toward the outlet 20. The inside portion 116a of the valve seat 116 toward the inlet 10 and the outside portion 116b of the valve seat 116 toward the outlet 20 can extend in a straight line.

The degree of protrusion of the valve seat 116 can be expressed by the protrusion index L / W. Here, the reference width W is half the total width Wvalve of the microfluidic valve 100, and the protruding length L is the width of the valve seat 116 at the start position of the outer side 116b of the valve seat 116 To the outermost portion (117). As the protrusion index (L / W) increases, the degree to which the valve seat 116 is relatively protruded increases.

For example, the total width (Wvalve) of the microfluidic valve 100 may be in the range of 0.5 to 1 mm. The width Wseat of the valve seat 116 may be in the range of about 100 to 200 占 퐉. The projection length L of the outermost portion 117 of the valve seat 116 may be 200 占 퐉 or less.

5 is a view showing the degree of deformation of the variable membrane in the microfluidic valves in which the I-shaped valve seat and the V-shaped valve seat are respectively used.

Referring to FIG. 5, deformation of the variable membrane 120 into the second opening 114 can be effectively suppressed according to the degree of protrusion of the valve seat 116.

When the microfluidic fluid flows into the microfluidic valve, when the I-shaped valve seat 216 is used, the variable membrane 220 is deformed by a considerable depth into the drain region, while the V- The deformation of the variable membrane 120 into the drain region can be reduced. The greater the degree to which the variable membrane 120 is deformed into the second opening 114, the more the opening of the microvalve is disturbed and the opening pressure can be increased. Accordingly, when the valve seat has a protruding shape, the degree of deformation into the second opening 114 can be reduced, so that the change in the critical pressure can be reduced and the critical pressure can be kept constant regardless of the change in pressure .

6 is a graph showing the opening pressure according to the flow rate of the microfluidic valve of FIG.

6, when the protrusion index L / W is 0, the valve seat 116 does not protrude, and when the protrusion index L / W is 0.87, the outermost protrusion 117 ) Is almost at the end of the valve. When the protrusion index (L / W) is 0, the critical pressure is 2 to 6 times higher than the protrusion index (L / W) of 0.87, and the critical pressure is greatly affected by the flow rate change . Therefore, the projected shape of the valve seat 116 can effectively reduce the critical pressure, and the critical pressure value can be kept constant.

In the exemplary embodiments, the microfluidic valve 100 may further include a coating 122 formed on the surface of at least one of the contact surfaces of the variable membrane 120 and the valve seat 116. The variable membrane 120 may be formed using PDMS (Polydimethylsiloxane) having adhesive force. The coating film 122 may be formed using a cell culture solution, a protein solution such as serum and albumin, a surfactant such as pluronic, and the like. For example, when the coating film 122 is formed using a cell culture solution, the critical pressure is reduced by about 30%. Particularly, when the fine valve is formed using a substance having an adhesive force such as PDMS, by using a cell culture liquid as a coating solution for a microvalve, various protein substances are adsorbed on the microvalve surface, have.

As described above, the microfluidic valve is composed of two lower flow passages, and a flexible membrane capable of elastic deformation may be interposed between the two flow passages. In addition, a valve seat for dividing the input portion and the output portion is formed in the upper flow path so that the flow of the flow in the upper flow path is stopped when the membrane is deformed upward and comes into contact with the valve seat. Conversely, when the membrane is deformed downward, a flow flow in the upper flow path is possible. At this time, the valve seat has a protruding shape, and a coating film may be formed on the contact surface between the valve seat and the membrane.

Accordingly, the microfluidic valve is opened at a designed constant pressure without being influenced by a driving environment such as a flow rate change. Also, the critical pressure at which the microfluidic valve is opened can be kept very low. Accordingly, it is possible to provide a microfluidic valve having a linear and low driving pressure.

7 is a top view showing a microfluidic valve in accordance with exemplary embodiments. The microfluidic valve is substantially the same as or similar to the microfluidic valve of Fig. 1 except for the shape of the valve seat. Accordingly, the same constituent elements will be denoted by the same reference numerals, and repetitive description of the same constituent elements will be omitted.

Referring to Fig. 7, the valve seat 118 may extend in a U-shape. The valve seat 118, when viewed in plan view, may have an arcuate curved rod shape. The inner portion 118a of the valve seat 118 toward the inlet 10 and the outer portion 118b of the valve seat 118 toward the outlet 20 may extend in a curved shape. The inner portion 118a and the outer portion 118b may have a radius of curvature of about 200 to 600 占 퐉.

The valve seat 116 has a curved shape such that a portion of the valve seat 116 protrudes toward the outlet side 20 to reduce the critical pressure (opening pressure) and maintain the critical pressure at a constant value relative to the flow rate. have.

8 is a top view showing a microfluidic valve in accordance with exemplary embodiments. The microfluidic valve is substantially the same as or similar to the microfluidic valve of Fig. 1 except for the shape of the valve seat. Accordingly, the same constituent elements will be denoted by the same reference numerals, and repetitive description of the same constituent elements will be omitted.

Referring to Fig. 8, the valve seat 118 may extend in a combination of V-shape and U-shape. The inside portion 119a of the valve seat 119 facing the inlet 10 may extend in a straight line and the outside portion 119b of the valve seat 119 facing the outlet 20 may extend in a curved shape. The outer portion 119b may have a radius of curvature of about 200 to 600 mu m. The valve seat 119 having a protruding shape can provide a microfluidic valve that is linear and driven at a low driving pressure.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the following claims. It can be understood that it is possible.

10: entrance 20: exit
30: control hydraulic pressure line 100: microfluid valve
100: micro fluid valve 110: channel channel layer structure
112: first opening portion 114: second opening portion
116, 118, 119: valve seat 117: outermost portion
120: Variable membrane 122: Coating film
130: membrane control layer structure 132: third opening

Claims

A channel channel layer structure having a first opening and a second opening communicating with an inlet and an outlet, respectively, and a valve seat extending between the first and second openings to define the first and second openings;
A variable membrane covering the channel channel layer structure and operable to be selectively in contact with the valve seat, defining a first region and a second region together with the first and second openings; And
And a third opening for forming a third region for pressing or depressurizing the variable membrane with the variable membrane, the membrane being disposed on the channel channel layer structure with the variable membrane interposed therebetween, Layer structure,
Wherein the valve seat has a shape bent so that a part of the valve seat protrudes into the second region.

The microfluidic valve according to claim 1, wherein the valve seat has a V-shape, a U-shape, or a combination thereof.

The microfluidic valve according to claim 1, wherein the areas of the first opening and the second opening are determined according to the protruding shape of the valve seat.

The microfluidic valve according to claim 3, wherein the area of the second opening is larger than the area of the first opening.

The microfluidic valve according to claim 1, further comprising a coating film formed on a surface of at least one of the contact surfaces of the variable membrane and the valve seat.

2. The valve seat according to claim 1, wherein the first opening and the second opening are spaced apart from each other in a first direction, the valve seat extends in a second direction transverse to the first direction, And protrudes into the second region in a first direction.

The microfluidic valve of claim 1, wherein the variable membrane comprises a flexible polymeric material.

A lower layer structure;
An upper layer structure disposed on the lower layer structure and having a valve seat; And
Forming a source region and a drain region that are interposed between the lower layer structure and the upper layer structure to communicate with the upper layer structure and communicate with the inlet and the outlet, respectively, and cover the lower layer structure to press the variable membrane against the valve sheet Or a variable membrane forming a gate region for depressurization,
Wherein the valve seat has a shape bent so that a part of the valve seat protrudes into the drain region.

The microfluidic valve according to claim 8, wherein the valve seat has a V-shape, a U-shape or a combination thereof.

The microfluidic valve according to claim 8, further comprising a coating film formed on a surface of at least one of the contact surfaces of the variable membrane and the valve seat.