CN114798022B - Device and method for portable vacuumizing of PDMS (polydimethylsiloxane) bubbles - Google Patents
Device and method for portable vacuumizing of PDMS (polydimethylsiloxane) bubbles Download PDFInfo
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- CN114798022B CN114798022B CN202210427544.0A CN202210427544A CN114798022B CN 114798022 B CN114798022 B CN 114798022B CN 202210427544 A CN202210427544 A CN 202210427544A CN 114798022 B CN114798022 B CN 114798022B
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- 239000004205 dimethyl polysiloxane Substances 0.000 title claims abstract description 106
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 title claims abstract description 106
- 238000000034 method Methods 0.000 title claims abstract description 31
- -1 polydimethylsiloxane Polymers 0.000 title abstract description 3
- 238000009423 ventilation Methods 0.000 claims abstract description 5
- 239000003292 glue Substances 0.000 claims description 10
- 230000008093 supporting effect Effects 0.000 claims description 8
- 238000003756 stirring Methods 0.000 claims description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 5
- 239000003431 cross linking reagent Substances 0.000 claims description 5
- 239000002243 precursor Substances 0.000 claims description 5
- 229910052710 silicon Inorganic materials 0.000 claims description 5
- 239000010703 silicon Substances 0.000 claims description 5
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- 238000009434 installation Methods 0.000 claims description 3
- 230000000149 penetrating effect Effects 0.000 claims description 2
- 235000013870 dimethyl polysiloxane Nutrition 0.000 claims 4
- CXQXSVUQTKDNFP-UHFFFAOYSA-N octamethyltrisiloxane Chemical compound C[Si](C)(C)O[Si](C)(C)O[Si](C)(C)C CXQXSVUQTKDNFP-UHFFFAOYSA-N 0.000 claims 4
- 238000004987 plasma desorption mass spectroscopy Methods 0.000 claims 4
- 238000010438 heat treatment Methods 0.000 abstract description 8
- 238000005406 washing Methods 0.000 abstract description 8
- 239000007788 liquid Substances 0.000 abstract description 7
- 238000005086 pumping Methods 0.000 abstract description 6
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- 238000001291 vacuum drying Methods 0.000 description 4
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- 238000001723 curing Methods 0.000 description 3
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- 229960000074 biopharmaceutical Drugs 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000740 bleeding effect Effects 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
- B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
- B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
- B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
- B01L3/502707—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by the manufacture of the container or its components
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D19/00—Degasification of liquids
- B01D19/0073—Degasification of liquids by a method not covered by groups B01D19/0005 - B01D19/0042
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D19/00—Degasification of liquids
- B01D19/02—Foam dispersion or prevention
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- Chemical Kinetics & Catalysis (AREA)
- Dispersion Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- General Health & Medical Sciences (AREA)
- Hematology (AREA)
- Clinical Laboratory Science (AREA)
- Sampling And Sample Adjustment (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
The invention discloses a device and a method for carrying out portable vacuum pumping on PDMS (polydimethylsiloxane) bubbles, which are characterized in that a portable vacuum cup is adopted, PDMS is uniformly stirred and poured into a pouring container provided with a micro-channel template, the pouring container is placed into the vacuum cup, a double-layer ventilation cover is covered, a piston at the lower part of the vacuum cup is used for exhausting air outwards, so that a large negative pressure environment is generated in the vacuum cup, at the moment, air bubbles in the PDMS gradually float to the top of a PDMS liquid surface due to the influence of density, when the phenomenon is observed through a cup body, a top cover of the vacuum cup is rotated to align small holes of the top cover with small holes of the ventilation cover, then the internal negative pressure environment is released, the pouring container filled with PDMS solution after the air exhausting is taken out, the small bubbles which float to the top of the PDMS liquid surface are blown by an ear washing ball, the PDMS solution is heated by a heating table, finally, the prepared micro-fluidic channel is subjected to demoulding treatment by a metal tweezer, and finally the portable micro-fluidic channel without any bubbles is prepared.
Description
Technical Field
The invention belongs to the field of preparation of a Polymethylsilane (PDMS) microfluidic chip based on soft lithography, and particularly relates to a method for removing bubbles of a PDMS mixed solution by manually pumping a piston, wherein a large number of bubbles can appear in the PDMS mixed solution prepared in a microchannel pouring process due to dissolution of air.
Background
In recent decades, microfluidic technology (Microfluidics) has attracted extensive attention for its potential applications in various fields of drug packaging, material synthesis, crystallization, chemical reactions, etc., and is a technology and science for manipulating nano-liter to picoliter (10 -9-10-12 L) volume fluids in a micron-scale structure. Along with the continuous enhancement of the requirements of the biomedical and high-end manufacturing fields on the miniaturization and integration of novel detection devices, the efficient and convenient preparation technology of the microfluidic chip is expected to solve the pain point in the industry. Current microfluidic fabrication processes generally involve two methods, one based on glass capillary microchannel fabrication and the other based on soft lithography Polymethylsilane (PDMS) microchannel fabrication. The preparation method of the micro-channel of the glass capillary has the advantages of high flexibility, difficult alignment, poor device stability and difficult realization of batch production; the preparation method of the PDMS micro-channel based on soft lithography adopts a mature template for pouring, can rapidly obtain the micro-channel with stability and accurate size according to different templates, and has wide prospect in large-scale mass production. The PDMS prepolymer has outstanding value in the micro-fluidic field, and has more remarkable application advantages in the flexible electronic and biopharmaceutical fields due to the excellent light transmittance, safety, no toxicity, low heat curing temperature, high strength and elastic modulus close to human skin.
When the soft lithography-based Polymethylsilane (PDMS) is adopted to prepare the micro-channel, firstly, the pre-cured PDMS precursor (adhesive A) and the cross-linking agent (adhesive B) are weighed, mixed and stirred according to the mass ratio of 10:1, and usually, only 25 g of PDMS mixed solution is needed when the micro-channel is poured. But the stirring process is accompanied by a dissolution process of air in the PDMS stirring solution. Numerous microbubbles, typically less than 1mm in diameter, are generated after dissolution, and the specific bubble morphology is not directly observed by the human eye, but the clear solution is seen to become milky. If the PDMS prepolymer is not subjected to air extraction treatment, the poured channel can seriously reduce the strength of the channel because bubbles obstruct microscopic observation and generation and control of micro-droplets. When the liquid containing bubbles is in a region with very low absolute pressure, the bubbles can evaporate or dissociate rapidly and float to the surface of the liquid under the action of buoyancy, and finally the bubbles can gather on the surface of the PDMS solution under the action of the liquid level tension, and the bubbles at the liquid level can be blown by the ear washing ball so as to realize the effect of removing the bubbles.
At present, in order to eliminate bubbles in PDMS solution, a vacuum drying oven is mainly used for carrying out air extraction treatment on the prepolymer, but the experimental equipment is often huge in volume and high in price; to above problem, propose a portable evacuation PDMS bubble's device, through manual bleed can realize the function that this instrument possessed, whole device is removable completely moreover, does benefit to washing and equipment, small in size simple structure, satisfies the laboratory to the requirement of bleeding that easily produces a large amount of bubble solution.
Disclosure of Invention
The invention aims to design a portable device for vacuumizing PDMS bubbles, and solves the problem of removing solution bubbles when pouring a micro-fluidic PDMS micro-channel.
The technical scheme adopted by the invention is that the portable device for vacuumizing PDMS bubbles comprises three modules, and each part is obtained through 3D printing or mechanical processing (turning and milling); the first module is a module for assembling the cup body to create a vacuum cavity; the second module is used for assembling a manual air extraction piston and realizing an adjustable positioning function, the top of the piston is provided with a rubber sleeve, so that PDMS solution in the cup body is not exposed, and the sealing effect is good; the third module is used for pouring the microfluidic channel, the pressure gauge ensures that the negative pressure environment meets the requirement of rapid precipitation of bubbles, and the pouring container and the template are used for containing PDMS solution;
The portable device for vacuumizing PDMS bubbles comprises a cup body (3), wherein internal threads are arranged on the inner wall of the top of the cup body (3), and threads are arranged at the upper and lower positions of a through hole cover (2); the lower position of the through hole cover (2) is in threaded connection with the inner wall of the top of the cup body (3); the upper position of the through hole cover (2) is in threaded connection with the top cover (1); through holes are formed in the through hole cover (2) and the top cover (1), and air closing or ventilation is achieved through rotation alignment.
The bottom of the manual piston (8) is provided with a mounting hole of the supporting plate (6), and the supporting plate (6) and the manual piston (8) can be connected into a whole through the mounting hole; a piston rod is arranged in the middle of the manual piston (8), and a piston rubber sleeve (5) is arranged at the top of the piston rod; a pouring container (10) is arranged at the upper part of the piston rubber sleeve (5), and a PDMS solution (11) and a micro-channel template (12) are arranged in the pouring container (10);
The piston rod of the manual piston (8) and the supporting plate (6) are provided with a plurality of fixing holes which are arranged in parallel, and the fixing holes are internally provided with positioning square pins (7) for fixing the position of the manual piston (8).
The upper part of the cup body (3), namely the space between the through hole cover (2) and the pouring container (10), is provided with a vacuum chamber (4). The side wall of the upper part of the cup body (3) is provided with a vacuum barometer (9).
Further, the micro-channel template (12) is obtained by processing a round silicon wafer through a photoetching method and is placed in a pouring container (10).
Further, the supporting plate (6) and the manual piston (8) are connected through the mounting hole.
Further, uniformly stirring a pre-cured PDMS precursor, namely an A adhesive and a crosslinking agent, namely a B adhesive through a disposable plastic spoon, taking out a manual piston (8), sleeving a piston rubber sleeve (5) on the top end of the piston, inserting two support plates (6) into two square slotted holes at the bottom disc and fixing the two support plates through the A adhesive and the B adhesive, then inserting the manual piston (8) into a cup body (3) from the lower part, putting a pouring container (10) containing a PDMS solution (11) and a micro-channel template (12) into the cup body (3) from the upper part through tweezers, and taking the top of the manual piston (8) as a support; a vacuum barometer (9) is connected in an internal threaded hole of the side wall of the cup body (3) in a threaded manner; the top of the cup body (3) is connected with the through hole cover (2) through threads, one side of the through hole cover (2) is externally connected with the cup body (3) through threads, the other side of the through hole cover is internally connected with the top cover (1) through threads, and the through hole cover (2) and the vent hole of the top cover (1) are not aligned and sealed through rotating the top cover (1); finally, the manual piston (8) is pulled down, after the negative pressure of the vacuum barometer (9) reaches a preset value, the fixed installation is completed by penetrating the two support plates (6) and the manual piston (8) through the positioning square pins (7), and the vacuum chamber (4) is formed at the upper part of the cup body (3).
The device has a pouring container in the cup body, a micro-channel template to be poured is placed at the bottom of the pouring container, a layer of PDMS prepolymer is covered above the template, a vacuum chamber is generated in the cup body by manually pulling down a piston, internal bubbles of PDMS solution are promoted to float up to the surface, the pulled down piston is clamped by two support plates and a positioning square pin, a pressure gauge is inserted into the wall surface of the vacuum chamber part, so that whether the pressure in internal pressure maintaining meets the requirement or not is ensured, and the degassing process can be realized by maintaining the pressure for 40min normally.
The principle of the portable vacuumizing PDMS bubble device is divided into seven parts: 1) Pouring the PDMS mixed solution into a pouring container with a micro-channel template at the bottom and filling the pouring container into a cup body; 2) Creating a vacuum cavity through piston air extraction and checking whether the pressure gauge meets vacuum requirements; 3) The locating square pin is blocked to ensure that the solution bubbles float to the surface in a continuous negative pressure environment; 4) The vent hole is rotated to release the negative pressure in the cup body and pour the PDMS solution; 5) Taking out the pouring container from the cup body; 6) Blowing open microbubbles on the surface of the PDMS mixed solution in the pouring container through the ear washing ball, and heating the microbubbles at 80 ℃ for 60min to finish curing; 7) And separating the poured PDMS micro-channel from the pouring container and the template by using tweezers.
It should be noted that by rotating the vent cover to align its small aperture with the top cover vent hole, a negative pressure environment and an open environment can be created inside the cup.
Compared with the prior art, the PDMS solution before and after the treatment by the device and the method provided by the invention has the advantages that a large number of bubbles are contained in the untreated PDMS solution and the untreated PDMS solution is milky white, the treatment can see that the light transmission effect of the PDMS cured micro-channel in the pouring container is excellent, the micro-bubbles contained in the untreated PDMS micro-channel can be found to block the channel under the observation of an inverted fluorescence microscope, the preparation of micro-drops and the movement of particles are prevented, and the treated PDMS micro-channel has no micro-bubbles and excellent performance.
Drawings
Fig. 1 is a module for assembling a cup to create a vacuum chamber. (a) a top cap: the vent hole is arranged and is in threaded fit with the through hole cover, so that two modes of sealing and opening can be realized; (b) a vent cap (comprising a front side and a back side): the front surface of the through hole cover is in threaded fit with the cup body, and the back surface of the through hole cover is in fit with the top cover; (c) a transparent acrylic cup body: the cup body is designed with a drainage sharp angle, so that the pumped PDMS solution can be poured out and is provided with a hand-held handle, and volume scales can be added on the side wall of the cup body in subsequent productization.
FIG. 2 is a module for assembling a manual bleed piston and implementing an adjustable positioning function. (a) a piston rubber sleeve: the rubber sleeve is matched with the disc at the top of the manual piston to realize the bottom sealing of the cup body; (b) a manual piston: can realize the outward air suction from the cup body; (c) a support plate: when the device is used in pairs, the square holes of the device are matched with the positioning square pins, so that the device can be ensured to continuously maintain a negative pressure state; (d) locating square pins: the square section can ensure the support stability of the cup body.
Fig. 3 is a module for casting microfluidic channels: (a) microfluidic channel templates: preparing a microfluidic channel template on a silicon wafer by adopting soft lithography, and customizing for a laboratory or a mechanism; (b) barometer: taking a pressure vacuum gauge as a main part, inserting the pressure vacuum gauge into the threaded hole in the side wall of the vacuum cup body, ensuring 0.2 atmosphere pressure and maintaining the pressure for 40min optimally; (c) pouring the container: the cylindrical container is made of 304 stainless steel and is used for containing the PDMS mixed solution.
Fig. 4 is an assembled schematic diagram of a portable evacuated PDMS bubble device: a pouring container is arranged in a cup body of the device, a micro-channel template to be poured is arranged at the bottom of the pouring container, a layer of PDMS prepolymer (with a large number of bubbles) is covered above the template, a vacuum chamber (negative pressure environment) is formed in the cup body by manually pulling down a piston, the bubbles in the PDMS solution are promoted to float up to the surface, the pulled down piston is clamped by two support plates and a positioning square pin, a pressure gauge is inserted into the wall surface of the vacuum chamber part, so that whether the pressure in the internal pressure maintaining process meets the requirement or not is ensured, the degassing process can be realized by normally maintaining the pressure, the whole device is small and exquisite and simple, all parts can be cleaned in a detachable mode, and the cost is low.
Fig. 5 is a schematic diagram of a portable vacuum PDMS bubble apparatus: pouring the mixed solution of 1 and PDMS into a pouring container with a micro-channel template at the bottom and filling the pouring container into a cup body; 2. creating a vacuum cavity through piston air extraction and checking whether the pressure gauge meets vacuum requirements; 3. the locating square pin is blocked to ensure that the solution bubbles float to the surface in a continuous negative pressure environment; 4. the vent hole is rotated to release the negative pressure in the cup body and pour the PDMS solution; 5. taking out the pouring container from the cup body; 6. blowing open microbubbles on the surface of the PDMS mixed solution in the pouring container through the ear washing ball, and heating the microbubbles at 80 ℃ for 60min to finish curing; 7. and separating the poured PDMS micro-channel from the pouring container and the template by using tweezers.
Fig. 6 is a schematic view of the closing and opening of the through-hole lid: by rotating the ventilation cover, a closed and open environment in the cup cavity is created.
FIG. 7 is a schematic diagram showing the vacuum pumping of bubbles inside the PDMS mixed solution: a large amount of bubbles are arranged in the solution before vacuumizing and are milky white, the bubbles float to the surface of the solution after vacuumizing, and at the moment, the bubbles are blown by the ear washing balls so as to completely remove the bubbles.
Fig. 8 is a PDMS microchannel observed under an inverted fluorescence microscope: the left and right figures respectively show a micro-channel which is not treated by the device method (the micro-channel is blocked by the air bubbles contained therein) and a micro-channel which is treated by the device method, so that the channel has good visual field and no air bubbles or impurities which obstruct the flow of the micro-fluid.
Fig. 9 is a cross-sectional view (front view and side view) of a portable vacuum-pumping PDMS bubble apparatus, which is compact and novel, easy to realize mass production, and has a detachable integral apparatus, a simple structure, and a low price.
Detailed Description
The invention designs a portable device for vacuumizing PDMS bubbles, which solves the problem of removing solution bubbles in the pouring process of the traditional microfluidic PDMS micro-channel. The device comprises three modules, and each part can be obtained through 3D printing or machining (turning and milling): one is a module for assembling a cup to create a vacuum chamber, as shown in fig. 1; secondly, a module for assembling a manual air extraction piston and realizing an adjustable positioning function is provided, as shown in fig. 2, the top of the piston is provided with a rubber sleeve, so that PDMS solution in the cup body is not exposed, and the sealing effect is good; thirdly, a module for pouring the microfluidic channel, wherein the pressure gauge ensures that the negative pressure environment meets the requirement of rapid precipitation of bubbles, and a pouring container and a template are used for containing PDMS solution, as shown in FIG. 3; the device has a pouring container in the cup body, a micro-channel template to be poured is placed at the bottom of the pouring container, a layer of PDMS prepolymer is covered above the template, a vacuum chamber is generated in the cup body by manually pulling down a piston, internal bubbles of PDMS solution are promoted to float up to the surface, the pulled down piston is clamped by two support plates and a positioning square pin, a pressure gauge is inserted into the wall surface of the position of the vacuum chamber, so that whether the pressure in internal pressure maintaining meets the requirement or not is ensured, the degassing process can be realized after the pressure is maintained for 40min generally, and an assembly schematic diagram of the device is shown in figure 4.
The principle of the portable vacuumizing PDMS bubble device is divided into seven parts: pouring the PDMS mixed solution into a pouring container with a micro-channel template at the bottom, filling the pouring container into a cup body, pumping air through a piston to create a vacuum cavity, checking whether a pressure gauge meets vacuum requirements, locking a positioning square pin to ensure a continuous negative pressure environment so that solution bubbles float up to the surface, rotating a vent hole to release negative pressure in the cup body, pouring the PDMS solution, taking the pouring container out of the cup body, blowing micro-bubbles on the surface of the PDMS mixed solution in the pouring container through an ear washing ball, heating at 80 ℃ for 60min to complete solidification, and separating the poured PDMS micro-channel from the pouring container and the template by using tweezers, wherein the schematic diagram is shown in figure 5. It should be noted that by rotating the vent cover to align its small aperture with the top cover vent hole, a negative pressure environment and an open environment can be created inside the cup, as shown in fig. 6. The PDMS solution before and after the treatment by the apparatus and method is shown in fig. 7, wherein the untreated PDMS solution contains a large amount of bubbles and exhibits milky color, the treatment can see that the cured PDMS in the interior of the casting container has excellent light transmission effect, and the observation under the inverted fluorescence microscope can find that the bubbles contained in the untreated PDMS microchannel block the channel, thus preventing the preparation of microdroplets and the movement of particles, while the treated PDMS microchannel has no bubbles and excellent performance, as shown in fig. 8. Finally, a front cross-sectional view and a side cross-sectional view of the entire device are shown in FIG. 9.
Examples
At present, a vacuum drying oven is mainly used for pumping the prepolymer for removing bubbles in the PDMS solution, but the experimental equipment is often huge in volume, high in price and not easy to carry; aiming at the problems, the portable device for vacuumizing the PDMS bubbles and the improved preparation scheme of the microfluidic chip are provided, the actual requirement of a laboratory on removing a large number of bubbles from a PDMS solution is met, the prepared microfluidic PDMS micro-channel is highly smooth and transparent, no bubble impurity exists, and microfluidic experiments such as liquid drops, cells, particles, liquid metal and the like can be performed.
The connection relation of all parts of the portable device for vacuumizing PDMS bubbles is as follows, a micro-channel template (12) required by experiments is obtained by processing a round silicon wafer through a photoetching method, the micro-channel template is placed into a pouring container (10), a pre-cured PDMS precursor (A glue) and a cross-linking agent (B glue) are stirred and evenly poured on the surface of the micro-channel template through a disposable plastic spoon until the pouring container is completely poured, a manual piston (8) is taken out at the moment, a piston rubber sleeve (5) is sleeved on a disc at the top end of the piston, two support plates (6) are inserted into two square slotted holes at the disc at the bottom of the piston and fixed through AB glue, then the manual piston is inserted into a cup (3) from the bottom, the pouring container containing PDMS solution (11) and the micro-channel template (12) is placed into the cup from the top through tweezers, the manual piston top is used as a support, a vacuum air pressure gauge (9) is connected in an internal threaded hole with the cup side wall with the diameter of 3mm, at the moment, one layer of hole cover (2) is connected through threads at the top of the cup, one side of the through hole cover is connected with the other side of the manual piston through threads, the top cover is fixed through the cap through AB glue, two support plates (1), the manual piston is inserted into the manual piston through the cap through the manual piston, and finally a proper negative pressure effect is achieved through the vacuum piston, and the vacuum piston can not reach the proper value through the vacuum piston and reach the vacuum pressure chamber. The final assembly is schematically shown in fig. 4.
Based on the device assembly scheme, the specific scheme for manufacturing the PDMS micro-fluidic chip through the invention is as follows:
The first step: microfluidic channel template pretreatment
The micro-channel template required by the experiment is obtained by processing on a smooth silicon wafer through a photoetching method, and if micro-channels with different shapes need to be processed on one template, and the design needs to be carefully carried out, the parting line is left as in the traditional process.
And a second step of: pouring PDMS mixed solution
Placing the processed micro-channel template into a pouring container, and placing a pre-cured PDMS precursor (adhesive A) and a cross-linking agent (adhesive B) into the pouring container through a disposable plastic spoon according to the weight ratio of 10:1, uniformly stirring and pouring the mixture on the surface of the micro-channel template until the pouring container is completely poured, wherein the PDMS solution obtained by stirring is milky white due to the fact that the PDMS solution contains a large number of bubbles. A plurality of clapboards can be arranged in the pouring container (cylindrical container) so as to meet the requirement of pouring micro-channels of different templates at the same time.
And a third step of: assembled manual piston
The manual piston is taken out, a piston rubber sleeve is sleeved on the disc at the top end of the piston, the realization process of generating a vacuum chamber by subsequent air extraction is guaranteed by good adherence sealing performance of rubber products, in addition, two square slotted holes are obtained at the disc at the bottom of the piston through turning, two support plates which are processed in advance can be inserted, three square holes are formed in the support plates so as to adjust the negative pressure of the inner cavity of the cup body, and after the support plates are inserted, glue sealing is carried out at the matched holes through AB glue so as to prevent the support plates from falling in the subsequent installation process.
Fourth step: assembled cup and pressure gauge installation
The manual piston is inserted into the cup body from the lower part, a pouring container containing PDMS solution and a micro-channel template is placed into the cup body from the upper part through tweezers, the top of the manual piston is used as a support, the vacuum barometer is connected in an internal threaded hole with the diameter of 3mm on the side wall of the cup body in a threaded manner, the negative pressure value of the vacuum cavity in the cup body can be directly read by the manometer, and the corresponding pressure maintaining time is selected.
Fifth step: hole cover mounting and sealing
After the cup body is assembled, the internal thread at the top of the cup body is connected with the external thread of the through hole cover, one side of the through hole cover is the external thread, the other side of the through hole cover is the internal thread, the internal thread is connected with the top cover, and the rotatable top cover enables the through hole cover and the top cover vent hole not to achieve sealing effect.
Sixth step: pull-down piston and fixed pressure maintaining
The manual piston is pulled down by the hand, so that the inside of the cup body is in a complete negative pressure state, at the moment, the pointer of the vacuum pressure gauge arranged on the side wall of the cup body deflects, when the pointer points to 0.4 atmosphere, the two support plates and the manual piston penetrate through one square pin, the blocking process is completed, the square pin can play a stable supporting effect on the whole cup body, the negative pressure intensity and the pressure maintaining time show a certain relationship, the part can be provided with different clamping groove positions at the support plates, the negative pressure gear control is realized, the stronger the negative pressure is, the shorter the pressure maintaining time is, when the pressure is 0.4 atmosphere, the micro bubbles in the PDMS solution can be completely floated on the surface by maintaining the pressure for 40min, and the floating effect of the bubbles can be directly observed due to the transparent acrylic material of the cup body.
Seventh step: pressure release and PDMS solution surface micro-bubble treatment
The top cover is rotated to enable the holes to be communicated with the top cover holes, and the pressure release process is completed, and the principle is shown in fig. 6. Then the top cover and the through hole cover are opened, the pouring container is taken out from the inside and placed at the flat desktop by using tweezers, the ear washing ball is pressed by hands, micro bubbles on the surface of the PDMS solution inside the whole pouring container are blown, the process of completely eliminating the bubbles is completed, and at the moment, the whole PDMS solution is observed to be completely transparent under a spotlight, as shown in the right graph of FIG. 7.
Eighth step: heating, curing and demolding
The whole pouring container is placed on a heating table to be heated at a constant temperature, the temperature is usually 80 ℃ and the heating is most suitable for 60min, after the heating is completed, the PDMS mixed solution with bubbles removed is completely solidified, at the moment, the PDMS micro-channel, the micro-channel template and the pouring container are separated through the tips of tweezers to realize the demoulding process, and the pouring container is preserved by adopting traceless adhesive to prevent dust pollution.
Ninth step: bottom plate pouring and bonding
The bottom plate pouring process is similar to the micro-channel pouring process, and only the micro-channel template is not placed in the pouring container, so that pouring is directly performed. After the PDMS micro-channel and the bottom plate are obtained, an ultraviolet plasma bonding machine is adopted to bond the PDMS micro-channel and the bottom plate, and after bonding, the smooth transparent micro-fluidic channel without any bubble can be obtained.
Tenth step: microscopic observation
According to the microfluidic experiment requirement, the prepared microfluidic channel is placed under an inverted fluorescent microscope for observation, a high-precision micro-injection pump is adopted to inject the micro-fluidic channel into each phase channel of the PDMS micro-channel through a PTEF pipe, whether a plurality of high-precision micro-injection pumps are needed or not can be determined according to the actual experiment requirement, and in the scheme of FIG. 8, a single injection pump is adopted to introduce the polystyrene microsphere with the size of 5 micrometers into the PDMS micro-channel for observation, wherein the micro-channel which is not prepared by adopting the scheme has more bubbles and influences shooting and particle movement tracks.
Compared with the prior art, the device directly improves the traditional bubble removing method of the vacuum drying oven adopted by the existing PDMS micro-channel processing, and the prepared PDMS micro-channel has no micro-bubbles, so that the stability and experimental observation of the micro-fluidic device are easy to ensure. Compared with the traditional vacuum drying oven, the device has the advantages of simple structure, easy disassembly and cleaning, and easy mass production and popularization. The materials and the appliances adopted by the device and the scheme are common materials in daily life, and the device and the scheme are low in cost and easy to prepare.
Claims (1)
1. A method for portable vacuuming of PDMS bubbles, characterized by: the device for realizing the method comprises a cup body (3), wherein the inner wall of the top of the cup body (3) is provided with internal threads, and the upper and lower positions of a through hole cover (2) are respectively provided with threads; the lower position of the through hole cover (2) is in threaded connection with the inner wall of the top of the cup body (3); the upper position of the through hole cover (2) is in threaded connection with the top cover (1); the through hole cover (2) and the top cover (1) are respectively provided with a through hole, and air-tight or ventilation is realized through rotary alignment;
The bottom of the manual piston (8) is provided with a mounting hole of the supporting plate (6), and the supporting plate (6) is connected with the manual piston (8) into a whole through the mounting hole; a piston rod is arranged in the middle of the manual piston (8), and a piston rubber sleeve (5) is arranged at the top of the piston rod; a pouring container (10) is arranged at the upper part of the piston rubber sleeve (5), and a PDMS solution (11) and a micro-channel template (12) are arranged in the pouring container (10);
the piston rod of the manual piston (8) and the supporting plate (6) are provided with a plurality of fixing holes which are arranged in parallel, and the fixing holes are internally provided with positioning square pins (7) for fixing the position of the manual piston (8);
the upper part of the cup body (3), namely the space between the through hole cover (2) and the pouring container (10), is provided with a vacuum chamber (4); a vacuum barometer (9) is arranged on the side wall of the upper part of the cup body (3);
The microfluidic channel template (12) is obtained by processing a round silicon wafer through a photoetching method and is placed in a pouring container (10);
The implementation process of the device is as follows: uniformly stirring a pre-cured PDMS precursor, namely glue A and a cross-linking agent, namely glue B through a disposable plastic spoon, taking out a manual piston (8), sleeving a piston rubber sleeve (5) on the top end of the piston, inserting two support plates (6) into two square slotted holes at the bottom disc and fixing the two support plates through the glue A and the glue B, then inserting the manual piston (8) into the cup body (3) from the lower part, putting a pouring container (10) containing a PDMS solution (11) and a micro-channel template (12) into the cup body (3) from the upper part through tweezers, and taking the top of the manual piston (8) as a support; a vacuum barometer (9) is connected in an internal threaded hole on the side wall of the cup body (3) in a threaded manner; the top of the cup body (3) is connected with the through hole cover (2) through threads, one side of the through hole cover (2) is externally connected with the cup body (3) through threads, the other side of the through hole cover is internally connected with the top cover (1) through threads, and the through hole cover (2) and the vent hole of the top cover (1) are not aligned and sealed through rotating the top cover (1); finally, the manual piston (8) is pulled down, after the negative pressure of the vacuum barometer (9) reaches a preset value, the fixed installation is completed by penetrating the two support plates (6) and the manual piston (8) through the positioning square pins (7), and the vacuum chamber (4) is formed at the upper part of the cup body (3).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210427544.0A CN114798022B (en) | 2022-04-21 | 2022-04-21 | Device and method for portable vacuumizing of PDMS (polydimethylsiloxane) bubbles |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210427544.0A CN114798022B (en) | 2022-04-21 | 2022-04-21 | Device and method for portable vacuumizing of PDMS (polydimethylsiloxane) bubbles |
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103068308A (en) * | 2010-07-16 | 2013-04-24 | 第七感生物系统有限公司 | Low-pressure environment for fluid transfer devices |
| CN104549583A (en) * | 2014-12-26 | 2015-04-29 | 华南师范大学 | Manufacturing method of microfluidic chips |
| CN105779699A (en) * | 2016-03-28 | 2016-07-20 | 上海大学 | Method for removing metallic inclusions through dissolved gas float process and pressurizing vacuum induction furnace refining device |
| CN206068526U (en) * | 2016-10-12 | 2017-04-05 | 胡琪 | Evacuation bowl cover |
| CN106660045A (en) * | 2014-02-05 | 2017-05-10 | 斯利普奇普公司 | Sample preparation module with stepwise pressurization mechanism |
| CN209080623U (en) * | 2018-09-04 | 2019-07-09 | 乐美益 | Vacuum cup and its vacuumize cup lid |
| CN110227566A (en) * | 2019-07-15 | 2019-09-13 | 重庆大学 | A kind of PDMS Micro-fluidic chip die clone method |
| CN110921109A (en) * | 2019-12-31 | 2020-03-27 | 佛山市梵美科技有限公司 | Portable vacuum-pumping cup and vacuum-pumping cup cover |
| CN110975954A (en) * | 2019-12-23 | 2020-04-10 | 北京工业大学 | Device is pour to PDMS micro-fluidic chip secondary |
| CN214085715U (en) * | 2020-12-28 | 2021-08-31 | 杨明祥 | Electric vacuum-pumping device |
-
2022
- 2022-04-21 CN CN202210427544.0A patent/CN114798022B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103068308A (en) * | 2010-07-16 | 2013-04-24 | 第七感生物系统有限公司 | Low-pressure environment for fluid transfer devices |
| CN106660045A (en) * | 2014-02-05 | 2017-05-10 | 斯利普奇普公司 | Sample preparation module with stepwise pressurization mechanism |
| CN104549583A (en) * | 2014-12-26 | 2015-04-29 | 华南师范大学 | Manufacturing method of microfluidic chips |
| CN105779699A (en) * | 2016-03-28 | 2016-07-20 | 上海大学 | Method for removing metallic inclusions through dissolved gas float process and pressurizing vacuum induction furnace refining device |
| CN206068526U (en) * | 2016-10-12 | 2017-04-05 | 胡琪 | Evacuation bowl cover |
| CN209080623U (en) * | 2018-09-04 | 2019-07-09 | 乐美益 | Vacuum cup and its vacuumize cup lid |
| CN110227566A (en) * | 2019-07-15 | 2019-09-13 | 重庆大学 | A kind of PDMS Micro-fluidic chip die clone method |
| CN110975954A (en) * | 2019-12-23 | 2020-04-10 | 北京工业大学 | Device is pour to PDMS micro-fluidic chip secondary |
| CN110921109A (en) * | 2019-12-31 | 2020-03-27 | 佛山市梵美科技有限公司 | Portable vacuum-pumping cup and vacuum-pumping cup cover |
| CN214085715U (en) * | 2020-12-28 | 2021-08-31 | 杨明祥 | Electric vacuum-pumping device |
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| CN114798022A (en) | 2022-07-29 |
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