阅读说明：本技术 一种pdms薄膜的便捷制作方法 (Convenient manufacturing method of PDMS film ) 是由 刘赵淼 赵思宇 李梦麒 逄燕 于 2019-09-30 设计创作，主要内容包括：本发明公开了一种PDMS薄膜的便捷制作方法,属于微流控技术应用领域。本发明方法涵盖了两大关键技术：薄膜悬浮制作技术、PDMS水面均匀铺展技术。其中薄膜悬浮技术是利用PDMS和水的基本物理特性,PDMS因密度较大而浮在水面,同时PDMS所受重力与水面对PDMS的表面张力使得PDMS完全铺展成规则的圆形,制作完成的PMDS薄膜悬浮在水面可以方便的取下同时不破坏薄膜完整性。PDMS水面均匀铺展技术为PDMS薄膜的表面光滑性以及平整性提供了保障。因为薄膜制作容器大小可调整,因此本方法为PDMS工业化大批量制作提供了解决方案。(The invention discloses a convenient manufacturing method of a PDMS film, belonging to the field of microfluidic technology application. The method of the invention covers two key technologies: a film suspension manufacturing technology and a PDMS water surface uniform spreading technology. The thin film suspension technology utilizes the basic physical characteristics of PDMS and water, the PDMS floats on the water surface due to high density, meanwhile, the PDMS is completely spread into a regular circle by the gravity borne by the PDMS and the surface tension of the water surface to the PDMS, and the manufactured PMDS thin film is suspended on the water surface and can be conveniently taken down without damaging the integrity of the thin film. The PDMS water surface uniform spreading technology provides guarantee for the surface smoothness and the smoothness of the PDMS film. Because the size of the film manufacturing container can be adjusted, the method provides a solution for the industrial mass manufacturing of PDMS.)

1. A convenient manufacturing method of a PDMS film is characterized by comprising the following steps: the method comprises the following steps of,

firstly, pouring half of water (3) into a polytetrafluoroethylene container (1), and adding a proper amount of surfactant SDS into the water (3) to adjust the surface tension of the water surface;

secondly, mixing a mixed solution of a PDMS presetting agent and a curing agent in a ratio of 10:1, fully stirring, placing the mixed solution in a vacuum box for vacuumizing operation, and removing residual bubbles in the solution;

thirdly, tightly attaching the container opening filled with the bubble-removing PDMS solution to the water surface, and slowly moving the container filled with the PDMS solution clockwise to pour a proper amount of the PDMS solution on the water surface; in the pouring process, the density of the PDMS solution is higher than that of the water (3) and the surface tension of the water (3) facing the PDMS solution, so that the PDMS solution can float on the water surface to form a PDMS film (2), and the pouring of the PDMS film (2) is stopped when the edge of the PDMS film (2) is 3cm away from the edge of the polytetrafluoroethylene container (1); after the pouring process is finished, irradiating the water surface by using a light source to check the integrity of the PDMS film (2), and filling gaps in time if so;

fourthly, the PDMS film (2) is stood for one day and solidified at normal temperature, and the PDMS film (2) in the standing stage continuously expands and collapses to finally form the PDMS film (2) with uniform thickness and smooth surface;

finally, the formed PMDS film (2) can be conveniently taken down after being suspended on the water surface without damaging the integrity of the film.

2. The method of claim 1, wherein the PDMS film is prepared by a method comprising: the size of the polytetrafluoroethylene container for manufacturing the PDMS film is adjusted according to the size requirement of the film, but the PDMS film is prevented from completely filling the container so as to prevent bubbles in water from damaging the integrity of the film.

3. The method of claim 1, wherein the PDMS film is prepared by a method comprising: the thickness of the PDMS film is controlled by adjusting the surface tension of the aqueous solution; testing 0.6% SDS water solution as supporting liquid can produce PDMS film with thickness of 500 nm.

4. The method of claim 1, wherein the PDMS film is prepared by a method comprising: the PDMS solution is poured in one direction, the PDMS solution continuously poured on the water surface is required to form a seamless liquid film, and gaps can be filled before the liquid film is not solidified.

5. The method of claim 1, wherein the PDMS film is prepared by a method comprising: the PDMS liquid film does not fill the whole plane on the water surface, and the edge of the PDMS film is 3cm away from the edge of the container.

Technical Field

The invention relates to a PDMS film manufacturing method, and belongs to the field of microfluidic technology application.

Background

Microfluidics is a technology for accurately controlling and controlling microscale fluid, has the characteristics of precision, trace, integration and the like, and provides a wide prospect for application of miniaturized microfluidic chips in numerous fields such as biomedical research, drug synthesis screening, environmental monitoring and protection, health quarantine, judicial identification, detection of biological reagents and the like. Polydimethylsiloxane (PDMS) is the most widely used material in the current microfluidic chip due to the characteristics of air permeability, easy processing and the like, and as the microfluidic chip is continuously developed towards miniaturization and precision, PDMS films become research hotspots, but the manufacture of PDMS films still has the following problems:

(1) the most common method is to use a film throwing machine to manufacture the PDMS film, but the use of the film throwing machine in the manufacturing process has strict requirements on the viscosity of the PDMS, the rotating speed and the time of the film throwing machine, and if parameters are not properly processed, the problems of nonuniform film throwing, stripes on the surface, hard blocks condensed and the like are easily caused. The diameter of the manufactured finished product is about 10cm, the large-scale manufacturing is difficult to realize, and the integrity of the film is easy to damage when the film is stripped. When a motor of the film throwing machine works in the using process of the machine, a large amount of oil smoke is generated to pollute air greatly.

(2) Although the method for manufacturing the PDMS film by using the sacrificial layer mold reduces the difficulty of film peeling, the operation process is complex, and meanwhile, the manufacturing method needs various auxiliary tool materials, so that the manufacturing cost of the PDMS film is increased. The method adopts a spin coating process, equipment similar to a spin coater is also needed, and the spin coating method has certain parameter requirements on the viscosity of the PDMS solution and the rotating speed of a machine. The method only solves the problem of difficult peeling of PDMS in the last step, but does not have a simple and early manufacturing process.

The invention mainly aims at the problems of high demand of the film manufacturing technology, difficult film peeling, high manufacturing cost and the like, and designs the PDMS film manufacturing method which covers the film suspension manufacturing technology and the PDMS water surface uniform spreading technology. The thin film suspension technology utilizes the basic physical characteristics of PDMS and water, the PDMS floats on the water surface due to high density, meanwhile, the PDMS is completely spread into a regular circle by the gravity borne by the PDMS and the surface tension of the water surface to the PDMS, and the manufactured PMDS thin film is suspended on the water surface and can be conveniently taken down without damaging the integrity of the thin film. The PDMS water surface uniform spreading technology provides guarantee for the surface smoothness and the smoothness of the PDMS film. Because the size of the film manufacturing container can be adjusted, the method provides a solution for the industrial mass manufacturing of PDMS.

Disclosure of Invention

The invention mainly aims at the problems of high technical requirements for film manufacturing, difficult film peeling, high manufacturing cost and the like, and designs a novel PDMS film manufacturing method. The method comprises two key technologies: thin film suspension technology and PDMS water surface uniform spreading technology.

The film suspension technology utilizes the physical characteristics of water (3) and the PDMS solution (2), and the PDMS solution (2) floats on the support water surface (3) in the whole manufacturing process. The spreading of the PDMS solution (2) on the water surface is influenced by the gravity of the PDMS solution and the surface tension given by the water surface, so that a key step of the thin film suspension technology is to manufacture PDMS thin films (2) with different thicknesses by adjusting the surface tension of the supporting water layer (3).

In addition, the PDMS solution (2) may be slightly cured at normal temperature, and the PDMS (2) that is continuously cured with time may have problems of blocking, weakening of ductility, and the like. Therefore, the effective time after the preparation of the PDMS (2) and the effective discrimination method are also another key steps of the thin film suspension technology.

The PDMS water surface uniform spreading technology provides guarantee for the smoothness and the integrity of the film plane. The technology comprises three steps of pouring liquid level height, pouring direction and liquid film forming judgment of PDMS solution (2). And in the pouring process of the PDMS solution (2) after vacuum pumping, if the distance between the liquid level and the water surface (3) is too large, the PDMS solution (2) can absorb gas in the air in the pouring process, and bubbles can appear on the film. To ensure that the PDMS solution (2) on the water surface (3) is compact and has no gap, the PDMS solution (2) should be poured in one direction. In order to ensure the integrity of the film, after the pouring step is finished, the liquid film is timely illuminated to check whether the liquid film is compact and is properly filled.

Compared with the prior film manufacturing method, the invention has the following technical effects,

1. compared with the common spin-coating method, the method has the advantages of simple device, no need of additional complex driving equipment and no oil smoke pollution to the air due to the work of an engine.

2. By utilizing the properties of the material, the PDMS solution (2) is influenced by the gravity of the PDMS solution and the surface tension of the water surface (3) to the PDMS solution, the thickness of the manufactured PMDS film (2) is uniform, and the problems of unsmooth surface, particulate matters and the like can be avoided.

3. By adjusting the size of the polytetrafluoroethylene container, the PDMS film with any size can be manufactured at a time, and the method is suitable for industrial mass production.

4. The surface tension of the water surface can be adjusted by adding an appropriate amount of SDS powder to water (3) and preparing SDS aqueous solutions (3) of different concentrations, thereby producing PDMS films (2) of different thicknesses.

5. Because the method is used for manufacturing the PDMS film (2) based on the material property, the film can present a regular and complete round shape under the combined action of gravity and surface tension

Drawings

FIG. 1 is a schematic of the present invention.

In the figure: 1. polytetrafluoroethylene container, 2, PDMS film, 3, water

Detailed Description

How to fabricate the PDMS film is further described in detail below with reference to the drawings. FIG. 1 is a schematic diagram of the present invention. The invention mainly aims at the problems of high technical requirements for film manufacturing, difficult film peeling, high manufacturing cost and the like, and designs a novel PDMS film manufacturing method.

The invention adopts the technical scheme that the method for conveniently manufacturing the PDMS film comprises the following steps:

firstly, pouring half of water (3) into a polytetrafluoroethylene container (1), and adding a proper amount of surfactant SDS into the water (3) to adjust the surface tension of the water surface.

And secondly, mixing a mixed solution of a PDMS presetting agent (A glue) and a curing agent (B glue) in a ratio of 10:1, fully stirring, placing in a vacuum box for vacuumizing operation, and removing residual bubbles in the solution.

And thirdly, tightly attaching the container opening filled with the bubble-removing PDMS solution to the water surface, and slowly moving the container filled with the PDMS solution clockwise to pour a proper amount of the PDMS solution on the water surface. In the pouring process, the density of the PDMS solution is higher than that of the water (3) and the surface tension of the water (3) facing the PDMS solution, so that the PDMS solution can float on the water surface to form a PDMS film (2), and the pouring of the PDMS film (2) is stopped when the edge of the PDMS film (2) is 3cm away from the edge of the polytetrafluoroethylene container (1). And after the pouring process is finished, irradiating the water surface by using a light source to check the integrity of the PDMS film (2), and filling gaps in time if so.

And fourthly, standing the PDMS film (2) for one day, solidifying at normal temperature, and continuously expanding and collapsing the PDMS film (2) in the standing stage to finally form the PDMS film (2) with uniform thickness and smooth surface.

Finally, the formed PMDS film (2) can be conveniently taken down after being suspended on the water surface without damaging the integrity of the film.

Processing requirements are as follows:

A) the size of the polytetrafluoroethylene container for manufacturing the PDMS film is adjusted according to the size requirement of the film, but the film is prevented from being completely filled in the container so as to prevent bubbles in water from damaging the integrity of the film.

B) The thickness of the film is controlled by adjusting the surface tension of the aqueous solution. Testing 0.6% SDS water solution as supporting liquid can produce PDMS film with thickness of 500 nm.

C) And (3) PDMS configuration: and (3) mixing the PDMS presetting agent (A glue) and the curing agent (B glue) in a ratio of 10:1, fully stirring, placing in a vacuum box, and vacuumizing to remove residual bubbles in the solution.

D) Although the prepared PDMS can be kept in a liquid state for a long time, the PDMS solution left for a long time becomes viscous, and a smooth liquid film surface is not easily formed. The next step should be performed in time after configuration. And stirring the PDMS solution after the PDMS solution is placed for a period of time, and pulling the PDMS solution, wherein the PDMS solution is not suitable for film manufacturing if the liquid is not smooth and the wire drawing problem is remained.

E) And in the process of pouring the PDMS solution, keeping the PDMS in direct contact with the water surface to prevent air from entering in the pouring process, and finally, ensuring that the surface of the film is uneven.

F) The PDMS solution should be poured in one direction, the PDMS solution continuously poured on the water surface should form a seamless liquid film, and the gap can be properly filled before the liquid film is not solidified.

G) The PDMS liquid film is not suitable for filling the whole plane on the water surface, and the distance between the edge of the PDMS film and the edge of the container is preferably 3 cm.