Method for preparing PET runner with continuously changing surface contact angle and processing device

Abstract

The application discloses a kind of based on plasma processing's contact angle continuous change's polyethylene terephthalate (PET) surface runner preparation method and processing device, using the PET material obtained by the method and device, and the water contact angle of its surface runner is continuously changed.The processing process is: using anhydrous ethanol and ultrasonic cleaning machine to clean PET matrix sample, then PET matrix sample is installed on the processing device table top, and is closely attached with graphic template;After setting the motion rate of table top and delay time, the processing device is placed into plasma processing equipment to carry out PET material surface treatment, and the surface runner of PET material with locally continuous change of water contact angle is obtained.The method and device disclosed in the application solve the problems of surface structure being damaged during the hydrophilic treatment process of PET material, water contact angle being unable to be accurately controlled, poor biological adaptability and the like, in addition, the process operation disclosed in the application is convenient, low in cost, and batch production can be realized.

Description

Technical Field

[0001] This invention relates to a method and apparatus for preparing PET flow channels with continuously varying surface contact angles, belonging to the field of surface engineering technology and also to the field of micro-nano manufacturing. Background Technology

[0002] Polyethylene terephthalate (PET) is a thermoplastic polyester material with excellent transparency, chemical resistance, temperature resistance, abrasion resistance, and good processing performance. It can achieve rapid molding and manufacturing of high-precision complex structures through hot pressing, injection molding, and other methods. It has a wide range of applications in medical devices, food packaging, solar energy, batteries, electronics, and other fields. In recent years, with the development of microfluidic technology, its application as a matrix material for microfluidic devices has been increasing.

[0003] While PET materials possess advantages such as good surface dimensional stability, high strength-to-weight ratio, and low production cost, the lack of hydrophilic groups in the PET molecular chain results in poor hydrophilicity, printability, and adhesion, as well as low surface energy, limiting their application in biomedical, microfluidic, and flexible circuit device manufacturing. Activating the hydrophilic groups on the PET surface, reducing the water contact angle, and improving hydrophilicity can significantly enhance the practicality of PET materials in microfluidics and flexible circuits.

[0004] Currently, methods for surface modification of PET materials mainly include the fabrication of hydrophilic / superhydrophilic structures, coating with hydrophilic materials, and chemical treatment of hydrophilic groups. By altering the microstructure of the PET surface, creating micro / nano structures such as pores and pits, the water contact angle of the PET surface can be changed, resulting in superhydrophilic or superhydrophobic surfaces; however, the fabrication of these micro / nano structures is difficult. Coating the PET surface with hydrophilic chemical agents is simple, but the preparation and deposition processes are complex. Using keratinase to hydrolyze ester bonds in PET fibers to generate hydrophilic groups can modify the PET surface. All three methods can effectively improve the hydrophilicity of PET materials, but physical methods require expensive equipment and have low production efficiency, chemical methods use complex reagent preparation processes, and biological methods use enzymes with stringent experimental conditions and are prone to inactivation. Some studies have also used lasers, ultraviolet light, and electron beams for surface treatment, but these methods can damage the surface morphology and structure of the material.

[0005] Low-temperature plasma surface treatment utilizes simple equipment, is easy to operate and control, causes no environmental pollution, does not affect the macroscopic properties of materials, and can simultaneously achieve surface superhydrophilicity and oleophobicity. Researchers at Southwest Forestry University used oxygen-based low-temperature plasma treatment technology to modify the surface of PET films. Before treatment, the water contact angle of the PET film surface was 74.1°; under a power of 60W for 120 seconds, the water contact angle decreased to 21.8°. Researchers at Beijing University of Aeronautics and Astronautics used argon-based low-temperature plasma treatment technology to reduce the water contact angle of the PET film surface from 79.8° to 19.8°. The principle behind the improved hydrophilicity of PET materials through low-temperature plasma treatment lies in the formation of hydrophilic groups. Due to the bombardment of PET films by active particles in the plasma, the macromolecular chains on the PET film surface undergo chain breakage or hydrogen extraction, thereby forming active free radicals. These active free radicals, upon contact with oxygen or air, form hydrophilic functional groups such as -OH, CO-, -COOH, and COO- on the film surface. Most current research can only treat large areas of PET material surfaces simultaneously, and cannot selectively treat localized surfaces to achieve special biological, chemical, and fluid functions.

[0006] In microfluidic chip technology, microchannels play a crucial role in the collection, manipulation, transport, and mixing of microfluidics, especially in PET-based microfluidic structures driven by surface tension. Precise control of the water contact angle on the material surface enables more flexible and precise fluid manipulation. Theoretical calculations and simulations have shown that channel surfaces with continuously varying contact angles can achieve effective microfluidic actuation and velocity control. However, currently, there is no surface plasmon processing method to precisely control the continuous variation of local contact angles on PET surfaces at the microscale.

[0007] This invention proposes a method and apparatus for preparing PET surface flow channels based on plasma treatment and contact angle gradient variation. The PET material surface flow channels obtained using this method and apparatus exhibit a continuously changing water contact angle. The advantages of this method are twofold: firstly, it improves the hydrophilicity of the PET material surface, thereby accelerating fluid flow within the microchannels; secondly, the continuously changing contact angle of the prepared PET surface flow channels drives fluid flow. The proposed method for preparing PET surface flow channels with contact angle gradient variation is characterized by low cost, high efficiency, precise controllable water contact angle, and convenient operation. Summary of the Invention

[0008] This invention proposes a method for fabricating PET channels with continuously varying surface contact angles. This method achieves continuously varying surface contact angles by controlling the exposure time and plasma energy of the target position of the PET substrate sample in the plasma processing chamber. For example... Figure 1 It mainly includes the following steps:

[0009] (1) Clean the PET substrate sample to remove surface impurities;

[0010] (2) Fix the PET substrate sample on the table of the processing device, then connect the graphic template to the top cover fixing surface of the processing device so that the PET substrate sample and the graphic template fit tightly together, and move the PET substrate sample to the initial position.

[0011] (3) Set the movement speed and delay time of the platform;

[0012] (4) Turn on the power of the processing device, and during the delay time, place the processing device into the plasma processing chamber and set the plasma processing equipment voltage and processing time.

[0013] (5) Start the plasma treatment equipment to treat the local surface of the PET matrix sample;

[0014] (6) Remove the processing device, unload the PET substrate sample and graphic template to obtain a PET surface flow channel with continuously changing contact angle.

[0015] This invention proposes a flow channel treatment device for PET surfaces with continuously varying local water contact angles, such as... Figure 4 The processing device 5 comprises a device base plate 51, a lower housing 52, a battery 53, a speed control module 54, a forward / reverse control module 55, an upper housing 56, a motion platform 57, and a graphic template 58. The device base plate 51 is located at the bottom of the processing device 5. The battery 53, speed control module 54, and forward / reverse control module 55 are arranged side-by-side on top of the device base plate 51. The lower housing 52 is connected to the device base plate 51 by screws and encloses the battery 53, speed control module 54, and forward / reverse control module 55 inside the lower housing 52. The motion platform 57 is located on the upper surface of the lower housing 52. A linear motor 572 is connected to the fixed end of the motion platform 57 via a flange, and the circuit wiring of the linear motor 572 is connected to the speed control module 54 and the forward / reverse control module 55. The platform 571 is fixed to the upper surface of the motion platform 57; the upper shell 56 is connected to the lower shell 52 by screws, and the motion platform 57 and the PET substrate sample 4 are wrapped inside the upper shell 56. The upper surface of the upper shell 56 has a window corresponding to the platform 571. The graphic template 58 is fixed on the top cover fixing surface 59 and is located directly above the window.

[0016] The motion platform 57 consists of a table 571, a linear motor 572, a guide rail 573, a lead screw 574, a limit switch 575, and a pulley assembly 576, as shown below. Figure 5The linear motor 572 drives the lead screw 574 to move. The speed control module 54 and the forward and reverse control module 55 control the speed and direction of the linear motor 572, respectively, and control the relative speed and direction of the PET substrate sample 4 and the graphic template 58. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 This is a flow chart of a PET surface flow channel treatment process with continuously varying contact angle provided by the present invention;

[0019] Figure 2 This is a schematic diagram of the PET surface flow channel preparation process with continuously varying contact angle provided by the present invention;

[0020] Figure 3 This is a graph showing the relationship between the PET surface contact angle and the processing time provided by the present invention;

[0021] Figure 4 This is a schematic diagram of the PET surface flow channel treatment device provided by the present invention;

[0022] Figure 5 This is a schematic diagram of the motion platform structure in the PET surface flow channel treatment device provided by the present invention;

[0023] Reference numerals: 1-Plasma processing equipment; 2-Plasma processing chamber; 3-Gas plasma; 4-PET matrix sample; 5-Processing device; 51-Device substrate; 52-Lower housing; 53-Battery; 54-Speed ​​control module; 55-Forward and reverse control module; 56-Upper housing; 57-Motion platform; 58-Graphic template; 59-Top cover fixing surface; 571-Tabletop; 572-Linear motor; 573-Guide rail; 574-Threaded screw; 575-Limit switch; 576-Pulley assembly. Detailed Implementation

[0024] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0025] This invention proposes a method for preparing flow channels with continuously varying local water contact angles on the PET surface. This method achieves continuously varying surface contact angles by controlling the exposure time and plasma energy of the target location of the PET sample in the plasma processing chamber. For example... Figure 1 It mainly includes the following steps:

[0026] 1) Clean the PET substrate sample 4 to remove surface impurities;

[0027] 2) Fix the PET substrate sample 4 on the table surface 571 of the motion platform 57 of the processing device, and then connect the graphic template 58 to the top cover fixing surface 59 of the processing device so that the PET substrate sample 4 and the graphic template 58 are tightly attached, and move the PET substrate sample 4 to the initial position.

[0028] 3) Set the motion speed v and delay time T of the motion platform 57;

[0029] 4) Turn on the output switch of the battery 53 of the processing device 5, and within the delay time T, place the processing device 5 into the plasma processing chamber 2 and set the voltage U of the plasma processing equipment 1.

[0030] 5) Start plasma treatment equipment 1 to perform localized surface treatment on PET substrate sample 4, such as... Figure 2 ;

[0031] 6) Remove the processing device 5, unload the PET substrate sample 4 and the graphic template 58 to obtain a PET surface flow channel with continuously changing contact angle.

[0032] As described in step 1) above, the PET matrix sample 4 is characterized by being placed in anhydrous ethanol, ultrasonically washed for 5-10 minutes, preferably 5 minutes, and then air-dried at room temperature for 5-10 minutes, preferably 5 minutes.

[0033] As described in step 2 above, the PET substrate sample 4 is moved repeatedly 5-10 times, and the PET substrate sample 4 and the graphic template 58 rub against each other to generate static electricity, so that the two adhere together. Then the PET substrate sample 4 is moved to the initial position of the microchannel.

[0034] As described in step 2 above, the graphic template 58 has a graphic pattern corresponding to the designed microchannel shape, and the material of the graphic template 58 is selected as a polymer material, such as polyimide, PET, polymethyl methacrylate, etc., preferably polyimide.

[0035] Alternatively, the graphic on graphic template 58 can be manufactured using engraving methods such as laser processing and electron beam processing.

[0036] As described in step 2 above, the graphic template 58 is fixed to the top cover fixing surface 59 of the processing device by screws, and can be disassembled and replaced multiple times.

[0037] Step 3) as described above is characterized by: based on the pre-obtained contact angle-time variation law, such as... Figure 3Analysis of experimental data shows that the contact angle α is a function of the voltage U of plasma processing device 1 and the processing time t as α = 34.7exp[-t / 0.34U] + 49.7. Based on the target contact angle variation range α0-α1, where α0 is the initial contact angle (approximately 85°), the flow channel length is s, the voltage of plasma processing device 1 is set to U, and the movement speed of the platform 571 is set to -s / 0.34U(ln((α1-49.7) / 34.7)).

[0038] As described in step 3 above, the characteristic is that: based on the target's contact angle variation range α1-α2, the flow channel length is s, the voltage of the plasma processing device 1 is set to U, the delay time of the motion platform 57 is set to T+0.34v*ln((α1-49.7) / 34.7), and the motion speed of the platform 571 is -s / 0.34v(ln((α2-49.7) / 34.7)).

[0039] Step 3 as described above is characterized in that: the delay time T of the motion platform 57 is set according to the duration required for operation and the vacuuming time T of the plasma processing equipment 1.

[0040] As described in step 4 above, the characteristic is that: the installed processing device 5 is placed into the plasma processing equipment 1, and the voltage of the plasma processing equipment 1 is set to U.

[0041] Step 5 as described above is characterized by: starting the plasma treatment equipment 1, drawing a vacuum, and performing local surface treatment on the PET substrate sample 4.

[0042] As described in step 6 above, the characteristic is that: the gas pressure in the plasma treatment chamber 2 is balanced with the atmospheric pressure, the door of the plasma treatment equipment 1 is opened to take out the treatment device 5, the PET substrate sample 4 and the graphic template 58 are removed, and a PET surface flow channel with continuously changing contact angle is obtained.

[0043] This invention proposes a flow channel treatment device for PET surfaces with continuously varying local water contact angles, such as... Figure 4 The processing device 5 consists of a device base plate 51, a lower housing 52, a battery 53, a speed control module 54, a forward and reverse rotation control module 55, an upper housing 56, a motion platform 57, and a graphic template 58.

[0044] The device base plate 51 is located at the bottom of the processing device 5 and is used to support and fix other components. The battery 53, speed control module 54, and forward / reverse control module 55 are arranged side by side on the device base plate 51, and the circuit connections between the three are connected according to motor drive logic. The lower housing 52 is connected to the device base plate 51 by screws and encloses the battery 53, speed control module 54, and forward / reverse control module 55 inside the lower housing 52. The motion platform 57 is located on the upper surface of the lower housing 52, and the two are connected by screws. The linear motor 572 is connected to the fixed end of the motion platform 57 through a flange, and the circuit connection of the linear motor 572 is connected to the speed control module 54 and the forward / reverse control module 55. The platform 571 is fixed to the upper surface of the motion platform 57; the upper shell 56 is connected to the lower shell 52 by screws, and the motion platform 57 and the PET substrate sample 4 are wrapped inside the upper shell 56. The upper surface of the upper shell 56 has a window corresponding to the platform 571. The graphic template 58 is fixed on the top cover fixing surface 59 and is located directly above the window, opposite to the position of the PET substrate sample 4 fixed on the platform 571.

[0045] The battery 53 supplies power to the speed control module 54, the forward / reverse control module 55, and the linear motor 572. The graphic template 58 has a graphic window that matches the designed microchannel shape. The graphic template 58 is fixed to the top cover fixing surface 59 and is replaceable. The upper housing 56 and the lower housing 52 are bolted together to protect the speed control module 54, the forward / reverse control module 55, and the linear motor 572 from interference from strong magnetic fields and plasma energy.

[0046] The platform 571 of the motion platform 57 is used to support the PET substrate sample 4. The motion platform 57 moves the PET substrate sample 4, realizing the relative movement between the PET substrate sample 4 and the fixed graphic template 58. The motion platform 57 consists of the platform 571, a linear motor 572, a guide rail 573, a lead screw 574, a limit switch 575, and a pulley assembly 576, as shown below. Figure 5 The linear motor 572 drives the lead screw 574 to move. The speed control module 54 and the forward and reverse control module 55 control the speed and direction of the linear motor 572, respectively, and control the relative speed and direction of the PET substrate sample 4 and the graphic template 58.

[0047] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0048] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0049] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0050] Example

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0052] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0053] A process for fabricating a PET flow channel (10 mm in length) with a gradually increasing contact angle between 55° and 85° is described below:

[0054] 1) Immerse PET substrate sample 4 (45mm*37mm*1.5mm) in a beaker containing anhydrous ethanol solution, then place the beaker in an ultrasonic cleaner and ultrasonically clean for 5 minutes at room temperature to remove impurities from the surface of PET substrate sample 4. After cleaning, remove PET substrate sample 4 from the beaker and dry it at room temperature for 5 minutes before use.

[0055] 2) First, use positioning pins to position and install the PET substrate sample 4 directly above the table 571 of the processing device 5. After the PET substrate sample 4 is installed, use screws to fix the flexible graphic template 58 with a specific graphic ("I-shaped" microchannel, with a specification of 10mm*0.15mm) graphic window to the top cover fixing surface 59. Move the PET substrate sample 4 repeatedly 5 times to make the PET substrate sample 4 and the polyimide flexible graphic template 58 fit tightly together. Then move the PET substrate sample 4 to the initial position of the specific graphic.

[0056] 3) Set the voltage of plasma processing equipment 1 to 550V and the movement speed of the platform 571 to 0.2mm / s.

[0057] 4) Turn on the power of the battery 53 of the processing device 5, set the delay time to 60s, start the timing of the speed control module 54, and close the hatch.

[0058] 5) After setting the parameters, turn on the argon gas source system to introduce argon gas into the plasma processing chamber 2, and adjust the gas flow rate and pressure to achieve suitable plasma generation conditions. Turn on the vacuum pump to extract the gas inside the plasma processing chamber 2. After the plasma processing chamber 2 reaches the set vacuum level, it ignites, and the plasma processing equipment 1 starts working. After the delay time of the waiting device 5 ends, the speed control module 54 controls the motion stage to start moving the PET substrate sample 4 at a speed of 0.2 mm / s, generating relative motion with the flexible graphic template 58 with specific microchannel patterns. The plasma processes the surface of the PET substrate sample 4 below the flexible graphic template 58.

[0059] 6) When the gas pressure in the plasma treatment chamber 2 is balanced with the atmospheric pressure, open the chamber door treatment device 5 of the plasma treatment equipment 1, remove the PET substrate sample 4 and the graphic template 58, and obtain the PET surface flow channel with continuously changing contact angle.

[0060] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for preparing PET microchannels with continuously varying surface contact angles, comprising the following steps: (1) Controlling the exposure time of a target position of a PET sample in a plasma processing chamber and adjusting the energy to obtain PET surface microchannels with continuously varying local water contact angles. S1 Clean the PET substrate sample to remove impurities from the surface of the PET substrate sample; S2 Fix the PET substrate sample on the table of the processing device, then connect the graphic template to the top cover fixing surface of the processing device, so that the PET substrate sample and the graphic template fit tightly together, and move the PET substrate sample to the initial position. S3 sets the movement speed and delay time of the processing unit table; S4 Turn on the power of the processing device, and within the delay time, place the processing device into the plasma processing chamber, and set the voltage and processing time of the plasma processing equipment; S5 activates the plasma treatment equipment to treat localized surfaces of the PET matrix sample; S6 Remove the processing device, unload the PET substrate sample and pattern template to obtain PET surface microchannels with continuously varying contact angles; Step S1 as described above, characterized in that Place the PET matrix sample in anhydrous ethanol, ultrasonically vibrate and wash for 5-10 minutes, and then air dry for 5-10 minutes. As described in step S2 above, the PET substrate sample is repeatedly moved so that the PET substrate sample and the pattern template rub against each other to generate static electricity and make the two adhere tightly. Then the PET substrate sample is moved to the initial position of the microchannel. As described in step S3 above, based on the target's contact angle variation range α0−α1, where α0 is the initial contact angle and the flow channel length is s, the voltage of the plasma processing device is set to... U The movement speed of the platform is set to -s / 0.

34. U *(ln((α1-49.7) / 34.7)); Step S3 as described above is characterized in that: based on the target's contact angle variation range α1−α2 and the flow channel length s, the voltage of the plasma processing device is set to... U Set the delay time of the motion platform to T -0.34 U *ln((α1-49.7) / 34.7), T The time required to place the processing device into the plasma processing chamber is given by the movement speed of the stage, which is -s / 0.

34. U (ln((α2-49.7) / 34.7)); As described in step S4 above, during the delay time, the assembled experimental setup is placed into the plasma processing equipment, and the processing voltage is set. U And during the processing time, close the hatch; As described in step S5 above, the plasma processing equipment is started, a vacuum is drawn, and local surface treatment of the PET substrate sample is performed. The processing device described above comprises a device base plate, a lower housing, a battery, a speed control module, a forward / reverse control module, an upper housing, a motion platform, and a template. The device base plate is located at the bottom of the processing device and is used to support and fix the other components. The battery, speed control module, and forward / reverse control module are arranged side-by-side on top of the device base plate, and their circuit connections follow motor drive logic. The lower housing is connected to the device base plate by screws and encloses the battery, speed control module, and forward / reverse control module inside the lower housing. The motion platform is located above the lower housing. Within the motion platform, the motor... The motor is connected to the fixed end of the motion platform, and the motor's circuit wiring is connected to the speed control module and the forward / reverse control module. The platform is fixed to the upper surface of the motion platform. The upper shell is connected to the lower shell by screws, and the battery, speed control module, and forward / reverse control module are enclosed inside the upper shell. The upper surface of the upper shell has a window corresponding to the platform. The flexible template is fixed on the upper shell and located directly above the window, opposite to the position of the PET substrate sample fixed on the platform. The upper and lower shells are made of metal. The flexible template has a graphic window that matches the designed microchannel shape and can be replaced.

2. The method for preparing a PET flow channel with continuously varying surface contact angle as described in claim 1, wherein step S2 is characterized in that: The graphic template has a graphic pattern corresponding to the shape of the microchannel, and the material of the graphic template is a polymer material.

3. The method for preparing a PET flow channel with continuously varying surface contact angle as described in claim 1, wherein in step S2, the material of the pattern template is polyimide.

4. The method for preparing a PET flow channel with continuously varying surface contact angle as described in claim 1, characterized in that... The motion platform consists of a table, a linear motor, a guide rail, a lead screw, a limit switch, and a pulley assembly. The table is used to support the PET matrix sample and move the PET matrix sample to achieve relative movement with the fixed template. The motion platform is driven by a linear motor, and the speed regulation module and the forward and reverse rotation control module control the speed and direction of the motor, respectively, and control the relative movement speed and direction between the PET matrix sample and the template.

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