CN112892619B - PDMS (polydimethylsiloxane) master mold with arc-shaped edge section, micro-fluidic valve and chip and preparation thereof - Google Patents

Abstract

The invention discloses a PDMS master mold with an arc-shaped edge section, a microfluidic valve, a chip and the preparation thereof. A simple, low-cost, and effective method for fabricating PDMS master molds with curved edge cross-sectional structures by combining isotropic etching of printed circuit boards with PDMS surface modification. Microfluidic chips with curved edge cross-section channels can be generated by using prepared PDMS master molds. The present invention further demonstrates that AC can fabricate microfluidic pneumatic valves, called arcuate edge section microfluidic valves, that can be used for multiplex control, compatible large-scale integration, liquid control, single-cell manipulation, and detection.

Description

PDMS master mold, microfluidic valve and chip with curved edge section and their fabrication

technical field

The invention relates to the technical field of microfluidic chips, in particular to a PDMS master mold with an arc-shaped edge section, a microfluidic valve and a chip and preparations thereof.

Background technique

The rapid development of microfluidic technology has made important contributions to the development of chemistry, biology, clinical medicine, bioengineering and other fields. Fabrication of microfluidic devices can be achieved by various methods, such as soft lithography, micro-milling, printed circuit board (PCB) etching, and 3D printing. Various substrate materials such as glass, silicon polymers, plastics, and even paper have been adopted for microfluidic applications. The development of different fabrication techniques and matrix materials has made microfluidics versatile and increasingly accessible in both academia and industry. Low cost and high volume manufacturing processes are very important for mass production.

Direct fabrication of microfluidic chips includes 3D printing, laser micromachining and stereolithography, as well as molding, which is undoubtedly the most suitable and economical method for mass production.

Among the mold manufacturing methods, printed circuit board (PCB) technology has several advantages: (1) the precision machining process is efficient, low cost, and easily accessible without the need for clean room equipment; (2) the copper master mold is durable, Microfluidic structures with heights ranging from several hundred microns to one hundred microns can be fabricated by one-step etching; (3) PDMS microfluidic chips prepared from PCB master molds have been shown to be biocompatible; (4) Usually with photoresist Pre-coated films and can be prepared by commercial service.

Microfluidic valves are becoming more and more indispensable as a key component in microfluidic systems as it is a key component for continuous sample processing, highly parallel analysis, automated fluidic and particle manipulation. Therefore, many efforts have been focused on the fabrication of microfluidic valves using novel materials of different technologies, such as monolithic PDMS valves, flapper-diaphragm valves, microvalves in wax-based microfluidics, 3D-printed microfluidic valves, etc. There is reason to believe that these valves could make PDMS, flaps and paper chips more powerful. However, other than multiple soft lithography, other techniques cannot be used for mass production, depending on the molding method. In addition, monolithic PDMS valves have obvious advantages over other types of valves: (1) functional diversity: solenoid valves, peristaltic pumps, mixers and traps (sieve valves); (2) feasible large-scale integration; (3) Durable and durable drive. Therefore, they are the most widely adopted and reported microvalves in microfluidics.

Herein, the present invention proposes a simple, low-cost, effective and easy-to-obtain method based on the combination of PCB isotropic etching and PDMS surface modification to prepare a PDMS master mold containing an arc-shaped cross-section structure. Using PDMS master molds, microfluidic chips containing arcuate cross-section channels (ACs) can be generated. The present invention further demonstrates that ACs can fabricate monolithic pneumatic valves, termed arcuate section monolithic valves (AMVs). AMVs chips can be used for multiplexed control, compatible with large-scale integration, and used for liquid control, single-cell manipulation and detection. This method of making PDMS molds has 6 advantages: (1) low cost (PCB is much cheaper than SU8); (2) accessibility (UV light, even sunlight can be used for exposure); (3) efficiency (via One-step etching, the height of microchannels ranges from a few microns to a hundred microns); (4) Simple (PCB etching is very easy to learn); (5) Scale-up (PDMS molds can be further scaled up by PCB master); 6) Functional (AMVs chips for liquid and particle manipulation can be fabricated using a one-step PCB etching method).

SUMMARY OF THE INVENTION

A first object of the present invention is to provide a method for fabricating a cross-section with curved edges by combining isotropic etching of printed circuit board (PCB) with PDMS (polydimethylsiloxane) surface modification The method of the PDMS master mold is simple, low-cost and effective.

The second object of the present invention is to provide a PDMS master mold with an arc-shaped edge section obtained by the preparation method in the first object above.

The third object of the present invention is to provide a preparation method of a microfluidic valve with an arc-shaped edge section; the preparation method uses the PDMS master mold in the above second object to generate a fluid layer with an arc-shaped edge section channel, and then combines with The arc section microfluidic valve (AMV) was prepared by the alignment of the control layer.

The fourth object of the present invention is to provide a microfluidic valve with an arc-shaped edge section obtained by the preparation method in the third object above; the valve can be used for multiplex control, compatible large-scale integration, liquid control, single Cell manipulation and detection.

The fifth object of the present invention is to provide a microfluidic chip including the above arc-shaped edge section microfluidic valve.

In order to realize above first purpose, the present invention adopts following technical scheme:

A first aspect of the present invention provides a method for preparing a PDMS master mold with an arc-shaped edge section, comprising the following steps:

S100, forming a groove with an arc-shaped edge cross-section by patterning on a printed circuit board (PCB) with photoresist to obtain a PCB master mold;

S200, pouring the PDMS prepolymer on the PCB master mold and polymerizing to obtain a PDMS master mold with an arc-shaped edge section.

The preparation method combines isotropic etching of printed circuit board (PCB) with PDMS (polydimethylsiloxane) surface modification, casting and curing PDMS prepolymer on PCB, these PDMS replicas That is, as a PDMS master.

The printed circuit board PCB in this preparation method can be directly purchased commercially, and usually has a photoresist pre-coating film.

In the preparation method of the PDMS master mold with the arc-shaped edge section, the selection and proportion of the base material and the curing agent in the PDMS prepolymer are adjusted as required, which can be purchased directly or configured after purchase; preferably Specifically, the mass ratio of the binder and the curing agent in the PDMS prepolymer is 5:1.

In a preferred solution of the present invention, in the above method for preparing a PDMS master mold with an arc-shaped edge section, the patterning process includes the following steps:

S110, covering a photomask on a printed circuit board with photoresist, and exposing it;

S120, developing, and transferring the pattern to the photoresist;

S130, etch with ferric chloride solution to form a groove on the copper plate in the printed circuit board; the groove is formed by etching, and its edge is arc-shaped, and the cross-section of the groove is an arc-shaped edge section;

S140, removing the photoresist with acetone to obtain a PCB master mold.

In this preferred solution, the exposure can use UV light, or other light sources, such as sunlight; preferably, the exposure uses UV light.

Those skilled in the art can easily understand that the above patterning process is a conventional technical means in the field, and both positive photoresist or reverse photoresist can be used to achieve the purpose of forming grooves by patterning above, and the present invention will no longer be used here. List them one by one.

In a preferred solution of the present invention, in the above preparation method of the PDMS master mold with arc-shaped edge section, the step of S200 specifically includes:

S210, pour the PDMS prepolymer on the PCB master mold,

S220, the PDMS prepolymer on the PCB master mold is polymerized;

S230 , peeling off the polymerized PDMS and treating with poloxamer 407 to obtain a PDMS master mold with an arc-shaped edge section.

In S230, regarding the process of using poloxamer 407 to treat the polymerized PDMS, in a specific embodiment of the present invention, poloxamer 407 (ie, PF127) can be directly soaked for 3 hours.

In order to realize the above second purpose, the present invention adopts the following technical solutions:

A second aspect of the present invention provides a PDMS master mold with an arc-shaped edge section, which is prepared by the method for preparing a PDMS master mold with an arc-shaped edge section provided in the first aspect.

The PDMS master mold with arc-shaped edge section mentioned in the present invention has protrusions corresponding to the grooves on the PCB master mold, and the cross-section of the protrusions has arc-shaped edges. Using this PDMS master mold, a fluidic layer with curved edge cross-section channels can be prepared, which in turn, together with a control layer, can be used to prepare an arcuate edge cross-section microfluidic valve (AMV) and a microfluidic containing the curved edge cross-section microfluidic valve. control chip.

The size of the protrusions in the PDMS master with curved edge section can be controlled by adjusting the size of the pattern in the photomask and the etching time. The size of the protrusion corresponds to the size of the channel with an arc-shaped edge cross-section prepared by using the PDMS master mold. The size of the pattern in the photomask and the etching time can be adjusted according to the size requirements of the channel, which is not the present invention. Do limit.

In order to realize the above third purpose, the present invention adopts the following technical solutions:

A third aspect of the present invention provides a preparation method of an arc-shaped edge section microfluidic valve, the preparation method comprising the following steps:

S300, forming a convex edge cross-section on a printed circuit board (PCB) with photoresist by patterning to obtain a PCB control layer master mold;

S400, spin coating PDMS prepolymer on the master mold of the PCB control layer, and obtain a control layer with control channels after polymerization;

S500, using the PDMS master mold with the arc-shaped edge section of the second aspect above to prepare a fluid layer with an arc-shaped edge section channel;

S600. Align the control layer and the fluid layer, and use a flat PDMS layer for sealing to obtain the arc-shaped edge section microfluidic valve.

The arc-shaped edge section microfluidic valve includes a fluid layer and a control layer, and correspondingly includes an arc-shaped edge section channel and a control channel.

The printed circuit board PCB in the preparation method is the same as the printed circuit board PCB in the preparation method of the first aspect of the present invention, which can be directly purchased commercially, and usually has a photoresist pre-coating film.

In the preparation method of the PDMS master mold with the arc-shaped edge section, the ratio of the base material and the curing agent in the PDMS prepolymer is adjusted as required, and can be purchased directly or configured after purchase; preferably, The mass ratio of the binder and the curing agent in the PDMS prepolymer is 20:1.

In a preferred solution of the present invention, in the above method for preparing a microfluidic valve with an arc-shaped edge section, the patterning process described in S300 includes the following steps:

S310, covering a photomask on a printed circuit board with photoresist, and exposing it;

S320, developing, and transferring the pattern to the photoresist;

S330, etching with ferric chloride solution to form bumps on the copper plate in the printed circuit board; because the bumps are formed by etching, the edges of the bumps are inwardly concave arcs, and the cross-sections of the bumps are Inwardly concave arc edge section;

S340, removing the photoresist with acetone to obtain a master mold of the PCB control layer.

In this preferred solution, the exposure can use UV light, or other light sources, such as sunlight; preferably, the exposure uses UV light.

Those skilled in the art can easily understand that the above patterning process is a conventional technical means in the field, and both positive photoresist or reverse photoresist can be used to achieve the purpose of forming protrusions by the above patterning, and the present invention will no longer be used here. List them one by one.

In the above method for preparing a microfluidic valve with curved edge section, the preparation process of the fluid layer in S500 specifically includes: pouring the PDMS prepolymer onto the PDMS master mold provided in the second aspect of the present invention, and peeling off after curing The fluid layer is obtained.

During the preparation of the fluid layer, the ratio of the base material and the curing agent in the PDMS prepolymer can be adjusted as needed, which can be purchased directly or configured after purchase; preferably, in the PDMS prepolymer The mass ratio of binder and curing agent is 5:1. In a specific embodiment of the present invention, the fluid layer is consistent with the PDMS prepolymer used in the PDMS master mold.

In the above preparation method of the arc-shaped edge section microfluidic valve, the flat PDMS layer described in S600 is partially cured, and cured after being sealed.

Above, the specific conditions of polymerization, curing, partial curing, etc. mentioned in the preparation method of the present invention can be optimized and selected by those skilled in the art according to the specific types and proportions of the binder and the curing agent in the specific prepolymer; The present invention is not limited herein.

In order to realize the above fourth purpose, the present invention adopts the following technical solutions:

A fourth aspect of the present invention provides an arc-shaped edge section microfluidic valve, which is prepared by the preparation method of the arc-shaped edge section microfluidic valve provided in the third aspect above.

The size of the control channel in the arc-shaped edge section microfluidic valve corresponds to the size of the protrusion in the master mold of the PCB control layer, which can be controlled by adjusting the size of the pattern in the photomask and the etching time; those skilled in the art The size of the pattern in the photomask and the etching time may be adjusted according to the size requirements of the control channel, which are not limited in the present invention.

In order to realize the above fifth purpose, the present invention adopts the following technical solutions:

A fifth aspect of the present invention provides a microfluidic chip including the arc-shaped edge section microfluidic valve provided in the fourth aspect.

Further, the microfluidic chip includes a self-made controller, and the self-made controller includes 8 solenoid valves for driving the control channel.

The present invention provides a PDMS master mold with a curved edge cross-sectional structure by combining isotropic etching of printed circuit boards (PCB) with PDMS (polydimethylsiloxane) surface modification The method is simple, low-cost and effective. Microfluidic chips with arc section microchannels (AC) can be generated by using prepared PDMS master molds. The present invention further demonstrates that AC can fabricate microfluidic pneumatic valves, termed arcuate edge section microfluidic valves (AMVs), which can be used for multiplex control, compatible large-scale integration, liquid control, single-cell manipulation, and detection .

The present invention has the following beneficial effects:

1) Low cost: PCB is much cheaper than SU8;

2) Ease of use: UV light, even sunlight can be used for exposure;

3) Efficiency: one-step etching, the height of the microchannel ranges from a few microns to 100 microns;

4) Simple: PCB etching is very easy to learn;

5) Expand production: PDMS molds can be further manufactured by PCB master molds;

6) Function: AMV chips for liquid and particle manipulation can be fabricated by a one-step PCB etching method.

Description of drawings

1 is a schematic diagram of S110 in the preparation method of the PDMS master mold in Example 1.

FIG. 2 is a schematic diagram of S120 in the preparation method of the PDMS master mold in Example 1. FIG.

3 is a schematic diagram of S130 in the preparation method of the PDMS master mold in Example 1.

4 is a schematic diagram of S140 in the preparation method of the PDMS master mold in Example 1.

5 is a schematic diagram of S210 in the preparation method of the PDMS master mold in Example 1.

6 is a schematic diagram of S220 in the preparation method of the PDMS master mold in Example 1.

7 is a schematic diagram of S230 in the preparation method of the PDMS master mold in Example 1.

8 is a schematic diagram of S240 in the preparation method of the PDMS master mold in Example 1.

FIG. 9a shows the PDMS master mold obtained after etching for 25 minutes using a photomask with a 35 μm wide pattern in Example 2. FIG.

FIG. 9b shows the PDMS master mold obtained after etching for 25 minutes using a photomask with a 70 μm wide pattern in Example 2. FIG.

FIG. 9c shows the PDMS master mold obtained after etching for 25 minutes using a photomask with a pattern of 140 μm wide in Example 2. FIG.

Figure 9d is a curved edge cross-sectional channel (AC) fabricated using the PDMS master of Figure 9a.

Figure 9e is a curved edge cross-sectional channel (AC) fabricated using the PDMS master in Figure 9b.

Figure 9f is a curved edge cross-sectional channel (AC) fabricated using the PDMS master of Figure 9c.

FIG. 10a shows the PDMS master after etching for 10 min using a photomask with a 35 μm wide pattern in Example 3. FIG.

FIG. 10b shows the PDMS master after etching for 25 min using a photomask with a 35 μm wide pattern in Example 3. FIG.

FIG. 10c shows the PDMS master after etching for 50 min using a photomask with a 35 μm wide pattern in Example 3. FIG.

FIG. 10d shows the PDMS master after etching for 75 min using a photomask with a 35 μm wide pattern in Example 3. FIG.

Figure 10e is a curved edge cross-sectional channel (AC) fabricated using the PDMS master of Figure 10a.

Figure 10f is a curved edge cross-sectional channel (AC) prepared using the PDMS master of Figure 10b.

Figure 10g is a curved edge cross-sectional channel (AC) prepared using the PDMS master of Figure 10c.

Figure 10h is a curved edge cross-sectional channel (AC) prepared using the PDMS master of Figure 10d.

FIG. 11 shows grooves with a depth of 40 μm obtained by using the PDMS master mold in Example 4, scale bar: 20 μm.

FIG. 12 shows grooves with a depth of 100 μm obtained by using a PDMS master mold in Example 4, scale bar: 20 μm.

13 is a schematic diagram of S310 in the preparation method of the arc-shaped edge section microfluidic valve in Example 5. FIG.

14 is a schematic diagram of S320 in the preparation method of the arc-shaped edge section microfluidic valve in Example 5. FIG.

15 is a schematic diagram of S330 in the preparation method of the arc-shaped edge section microfluidic valve in Example 5. FIG.

16 is a schematic diagram of S340 and S400 in the preparation method of the arc-shaped edge section microfluidic valve in Example 5.

17 is one of the schematic diagrams of S600 in the preparation method of the arc-shaped edge section microfluidic valve in Example 5. FIG.

FIG. 18 is the second schematic diagram of S600 in the preparation method of the arc-shaped edge section microfluidic valve in Example 5. FIG.

Figure 19a is an arcuate edge cross-sectional microfluidic valve (AMV) of the control layer fabricated in Example 6, scale bar: 50 μm.

Figure 19b shows the flow of liquid when the arcuate edge cross-section monolithic valve (AMV) is not closed.

Figure 19c shows that in Example 6, the PDMS prepolymer was spin-coated onto the control layer master mold at 2000 rpm, and the resulting arcuate edge cross-sectional monolithic valve (AMV) was not fully closed.

Fig. 19d shows that in Example 6, the PDMS prepolymer was spin-coated onto the control layer master mold at 3000 rpm, and the resulting curved edge cross-section monolithic valve (AMV) was completely closed.

FIG. 20a is a curved edge cross-sectional channel (AC) produced in Example 7 using a 25 min etch.

Figure 20b shows the curved edge cross-sectional channel (AC) produced in Example 7 using a 50 min etch.

20c is a fluorescence image of the 110 μm wide control channel produced by spin coating at 3000 rpm (20 μm thick) in Example 7. FIG.

FIG. 20d is a fluorescence image of the 110 μm wide control channel produced by spin coating at 4000 rpm (20 μm thick) in Example 7. FIG.

Description of reference numbers:

10-Printed Circuit Board, 11-Substrate, 12-Copper Board, 13-Photoresist, 20-Photomask, 30-UV Lighting, 40-Pattern, 50-Groove, 51-Groove Edge, 60-PDMS Master Mold, 61-Pluronic F-127, 62-PDMS after polymerization, 70-Arc edge section channel (AC);

100 - fluid layer, 200 - control layer, 300 - partially cured planar PDMS.

Detailed ways

In order to illustrate the present invention more clearly, the present invention will be further described below with reference to the preferred embodiments. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

Example 1

This embodiment provides a preparation method of a typical PDMS master mold:

S110 , as shown in FIG. 1 , the printed circuit board 10 with the photoresist 13 is covered with a photomask 20 and exposed by UV light 30 . The printed circuit board 10 is commercially purchased, and includes a substrate 11 , a copper plate 12 and a photoresist 13 .

S120, developing, and transferring the pattern 40 to the photoresist 13; as shown in FIG. 2 .

S130, etching with FeCl ₃ solution to form a groove 50 on the copper plate 12 in the printed circuit board; since the groove 50 is formed by etching, its edge 51 is arc-shaped, and the cross-section of the groove is an arc-shaped edge Section; as shown in Figure 3.

S140 , removing the photoresist 13 with acetone to obtain a PCB master mold, as shown in FIG. 4 .

S210. Pour the PDMS prepolymer (binder:curing agent=5:1, w.t.; Sylgard 184, Dow Corning, Midland, MI) on the PCB master mold, as shown in FIG. 5 .

S220, the PDMS prepolymer on the PCB master mold is polymerized; as shown in FIG. 6 . Exemplarily, cure at 65°C for 30 minutes.

S230, the polymerized PDMS 62 is obtained by peeling off, and the surface is treated with 2% Pluronic F-127 (PF127) 61 for 3 hours. After drying the surface (about 30 minutes), these PDMS replicas served as PDMS masters 60; as shown in FIG. 7 .

S240. Pour the PDMS prepolymer (base material: curing agent=5:1, w.t.) onto the PDMS master mold 60, and peel off after curing to obtain an arc-shaped edge section channel (AC) 70; as shown in FIG. 8 . The polymerized PDMS replica with AC features was easily peeled off the PDMS master.

Example 2

Using the typical preparation process in Example 1, using photomasks patterned with widths of 35 μm, 70 μm, and 140 μm, respectively, after etching for 25 minutes, PDMS master molds were prepared. The resulting PDMS master molds are shown in Figures 9a-9c.

Correspondingly, the curved edge cross-section channels (AC) fabricated using the resulting PDMS master are shown in Figures 9d-9f.

The width of the protrusions in the PDMS master mold with the arc-shaped edge section can be controlled by adjusting the width of the pattern in the photomask under the condition of a certain etching time. The width of the protrusion corresponds to the width of the channel AC with the arc-shaped edge section prepared by using the PDMS master mold, and the width of the pattern in the photomask can be adjusted according to the width requirement of the channel.

Example 3

The PDMS master mold was prepared after etching for 10 min, 25 min, 50 min and 75 min respectively using the typical preparation process in Example 1, using a photomask with a pattern width of 35 μm. The resulting PDMS master molds are shown in Figures 10a-10d.

Correspondingly, arcuate edge cross-section channels (AC) fabricated using the resulting PDMS master are shown in Figures 10e-10h.

The size of the protrusions in the PDMS master mold with the arc-shaped edge section can be controlled by adjusting the etching time under the condition that the pattern width is constant. The size of the protrusion corresponds to the size of the channel AC with arc-shaped edge cross-section prepared by using the PDMS master mold, and the etching time can be adjusted according to the size requirements of the channel.

Example 4

Using the typical preparation process in Example 1, different PCBs were used to prepare a PDMS master mold; and the bumps in the PDMS master mold were arranged in parallel. Among them, the thickness of the copper plate in different PCBs is different, which are 40 μm and 100 μm respectively.

PDMS replicas with multiple grooves were then prepared separately using the prepared PDMS master. As shown in Figure 11 and Figure 12, respectively.

As can be seen from the figure, the depth of the groove depends on the thickness of the copper layer.

Example 5

This embodiment provides a preparation method of a typical PDMS master mold:

S310 , the photomask 20 is covered on the printed circuit board with the photoresist, and exposed by UV; as shown in FIG. 13 .

S320 , developing, and transferring the pattern to the photoresist; as shown in FIG. 14 .

S330, etching with FeCl ₃ solution to form bumps on the copper plate in the printed circuit board; because the bumps are formed by etching, the edges of the bumps are inwardly concave arcs, and the cross-sections of the bumps are inwardly concave The curved edge section of ; as shown in Figure 15.

S340, removing the photoresist with acetone to obtain a master mold of the PCB control layer.

S400. On the obtained master mold of the PCB control layer, spin coat PDMS prepolymer (matrix: curing agent=20:1, w.t.) using a glue spinner (KW-4A, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, China). , and a control layer 200 with a control channel is obtained after polymerization; as shown in FIG. 16 . Exemplarily, the polymerization curing conditions herein are partial curing at 65°C for 40 minutes.

S600 , align the control layer 200 and the fluid layer 100 , as shown in FIG. 17 , and cure the fluid layer and the control layer in a 65° C. oven for another 50 minutes. The assembly was sealed with partially cured planar PDMS 300 on glass as shown in Figure 18. Finally, the microfluidic device was incubated at 65°C overnight; the microfluidic valve with curved edge section was obtained.

Example 6

Using the typical preparation process in Example 5, the control layer obtained by spin coating with different etching times and different rotational speeds (3000 rpm and 2000 rpm) was sealed, and subjected to fluorescent irradiation to test its tightness.

Figure 19a is an arcuate edge cross-sectional microfluidic valve (AMV) of the control layer fabricated in Example 6, scale bar: 50 μm.

Figure 19b shows the flow of liquid when the arcuate edge cross-section monolithic valve (AMV) is not closed.

Figure 19c shows that in Example 6, the PDMS prepolymer was spin-coated onto the control layer master mold at 2000 rpm, and the resulting arcuate edge cross-sectional monolithic valve (AMV) was not fully closed.

Figure 19d shows that in Example 6, the PDMS prepolymer was spin-coated onto the control layer master mold at 3000 rpm, and the resulting curved edge cross-section monolithic valve (AMV) was completely closed.

As shown in Figure 20a, the curved edge cross-sectional channel (AC) was produced using a 25 min etch. Scale bar: 50 μm.

As shown in Figure 20b, the curved edge cross-sectional channel (AC) was produced using a 50 min etch. Scale bar: 50 μm.

As shown in Figure 20c, a fluorescence image of a 110 μm wide control channel produced by spin coating at 3000 rpm (20 μm thick). As can be seen from the image, a small amount of liquid seeps into the channel. Scale bar: 50 μm.

Fluorescence image of a 110 μm wide control channel generated for spin coating at 4000 rpm (20 μm thick) as shown in Figure 20d. As can be seen from the image, there is no liquid flowing into the channel at all. Scale bar: 50 μm.

The photoresists in the PCB used in the above embodiments of the present invention are all positive photoresists, and those skilled in the art can easily understand that the use of negative photoresists can also achieve the purpose, and the photomask can be adjusted accordingly. . In addition, the above PCB patterning processes are all conventional technical means in the art, and only one more general one is listed in the present invention, which will not be listed one by one here.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the embodiments of the present invention. Changes or changes in other different forms cannot be exhausted here, and all obvious changes or changes derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims (11)

1. A preparation method of a PDMS master model with an arc-shaped edge section is characterized by comprising the following steps:

s100, forming a groove with an arc-shaped edge section on the printed circuit board with the photoresist through patterning to obtain a PCB female die;

s200, pouring the PDMS prepolymer on the PCB master model and polymerizing to obtain the PDMS master model with the arc-shaped edge section;

wherein the patterning process in S100 includes the steps of:

s110, covering a photomask on the printed circuit board with the photoresist, and exposing;

s120, developing is carried out, and the pattern is transferred to the photoresist;

s130, etching by using a ferric trichloride solution to form a groove on a copper plate in the printed circuit board; the groove is formed by etching, the edge of the groove is arc-shaped, and the cross section of the groove is an arc-shaped edge section;

s140, removing the photoresist by using acetone to obtain a PCB female die;

the step S200 specifically includes:

s210, pouring the PDMS prepolymer on the PCB master model,

s220, polymerizing the PDMS prepolymer on the PCB master model;

and S230, peeling the polymerized PDMS, and treating the PDMS by using poloxamer 407 to obtain a PDMS master model with an arc-shaped edge section.

2. The method of preparing a PDMS master mold having an arc-shaped edge section according to claim 1, wherein the mass ratio of the binder and the curing agent in the PDMS prepolymer is 5: 1.

3. A PDMS master model having an arc-shaped edge section, which is prepared by the method of preparing the PDMS master model having an arc-shaped edge section of claim 1 or 2.

4. A preparation method of a micro-fluidic valve with an arc-shaped edge section is characterized by comprising the following steps:

s300, forming bulges with arc-shaped edge sections on the printed circuit board with the photoresist through patterning to obtain a PCB control layer female die;

s400, rotationally coating PDMS prepolymer on the PCB control layer female die, and polymerizing to obtain a control layer with a control channel;

s500, preparing a fluid layer with an arc-shaped edge section channel by using the PDMS master model with the arc-shaped edge section, which is disclosed in claim 3;

s600, aligning the control layer and the fluid layer, and sealing by using a flat PDMS layer to obtain the micro-fluidic valve with the arc-shaped edge section;

wherein, the patterning process in S300 includes the steps of:

s310, covering a photomask on the printed circuit board with the photoresist, and exposing;

s320, developing, and transferring the pattern to the photoresist;

s330, etching by using a ferric trichloride solution to form a bulge on a copper plate in the printed circuit board; the bulge is formed by etching, the edge of the bulge is an inwards-concave arc shape, and the cross section of the bulge is an inwards-concave arc edge section;

and S340, removing the photoresist by using acetone to obtain a PCB control layer female die.

5. The method for preparing the microfluidic valve with the arc-shaped edge section according to claim 4, wherein the mass ratio of the base material to the curing agent in the PDMS prepolymer is 20: 1.

6. The method for preparing a microfluidic valve with an arc-shaped edge section according to claim 4, wherein the step S500 of preparing the fluid layer specifically comprises the steps of: pouring a PDMS prepolymer onto the PDMS master model with the arc-shaped edge cross section of claim 3, and peeling off after curing to obtain the fluid layer.

7. The method for preparing a microfluidic valve with an arc-shaped edge section according to claim 6, wherein the ratio of the base material to the curing agent in the PDMS prepolymer used in S500 is 5: 1.

8. The method for preparing a microfluidic valve with an arc-shaped edge section according to claim 4, wherein the flat PDMS layer in S600 is partially cured and then cured after sealing.

9. An arc-shaped edge cross-section microfluidic valve, characterized by being prepared by the method for preparing the arc-shaped edge cross-section microfluidic valve as claimed in any one of the preceding claims 4 to 8.

10. A microfluidic chip comprising the arc-shaped edge cross-section microfluidic valve of claim 9.

11. The microfluidic chip according to claim 10, wherein the microfluidic chip comprises a home-made controller, and the home-made controller comprises 8 electromagnetic valves.

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