A method for regulating surface texture of a flexible substrate based on oxygen plasma etching

Abstract

The application discloses a method for regulating surface texture of a flexible substrate based on oxygen plasma etching. The method comprises the following steps: providing a flexible substrate; and etching the flexible substrate provided with a metal mask by using an oxygen plasma etching technology, wherein the metal mask is arranged directly above the surface of the flexible substrate, so that the surface texture of the flexible substrate is regulated, and a flexible substrate with micro-nano structures is prepared. By precisely controlling the surface texture, the flexible substrate surface can be gradually changed from a hydrophobic state (>120 DEG) to a super-hydrophilic state (<5 DEG), and the prepared flexible substrate with micro-nano structures can realize a tensile property of more than 150%. Meanwhile, the method has the advantages of obtaining a regular and controllable surface nano texture without affecting the intrinsic performance of the flexible substrate, and the wetting state of the flexible substrate surface can be regulated, and the preparation method is simple, so that the method is expected to be applied to the field of flexible wearable electronic devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface texture preparation, and in particular relates to a method for regulating the surface texture of a flexible substrate based on oxygen plasma etching. Background Art

[0002] With technological advancements and the continuous improvement of people's living standards, various smart wearable devices are experiencing rapid development, with the market size continuously expanding. Flexible wearable technology is a key development direction in the field of smart wearable devices. By integrating electronic components into flexible, bendable materials, it achieves a conforming fit to the human body and a comfortable wearing experience. It has been applied in a variety of fields, including health monitoring, sports monitoring, precision medicine, human-computer interaction, and environmental monitoring.

[0003] With the development of bionics, researchers have tried to introduce new textures into flexible wearable sensors and found that the design and application of microstructures can greatly improve the sensitivity, response time and repeatability of devices. One of the core issues restricting related applications is how to achieve large-area and stable regulation of microstructures on the surface of flexible substrates.

[0004] Flexible substrates show significant advantages over traditional silicon-based sensors in terms of mechanical flexibility, cost-effectiveness, biocompatibility, and sensitivity, giving them broad application prospects in wearable devices, health monitoring, flexible electronic skin, and other fields. Flexible substrates such as polydimethylsiloxane films are commonly used in existing research. They have high flexibility, high elasticity, and permanent resilience, and are particularly suitable for electronic skin, as they have good conformability, gas permeability, and biocompatibility. Currently, microstructure control methods such as laser etching and template transfer have been developed for polydimethylsiloxane flexible substrate materials, but they have obvious shortcomings in terms of process complexity, cost, suitability for mass production, microstructure controllability, production efficiency, and maintaining the intrinsic properties of the substrate. For example, the laser etching method is complex, costly, and lacks the conditions for large-scale preparation. The structural accuracy is low, and the high temperature during the preparation process can damage the performance advantages of flexible electronic devices such as high elasticity. Template transfer can prepare smaller-scale surface nanostructures, but it requires the use of photolithography to process the template and then replicate the molding. The process is complex, and the introduction and peeling process of the structure will affect the intrinsic properties of the substrate. At the same time, the surface energy of silicone polymer films is extremely low, making them difficult to combine with other materials. Their surface properties limit their expected application areas. Existing studies have shown that regulating the surface properties of thin film substrates can optimize the preparation process of flexible electronic devices and further achieve sensing performance. However, how to break through the large-area, low-cost surface nanostructure preparation and modification technology of flexible substrates without damaging the intrinsic properties of flexible materials remains a key challenge in this field. Therefore, developing a new method for manufacturing surface nanostructures on flexible substrates that is simple, low-cost, easy to mass-produce, and does not damage the substrate will greatly improve the manufacturing level of advanced flexible sensors and promote related practical applications. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method for regulating the surface texture of a flexible substrate based on oxygen plasma etching, so as to overcome the shortcomings of the prior art.

[0006] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0007] An embodiment of the present invention provides a method for regulating the surface texture of a flexible substrate based on oxygen plasma etching, which includes:

[0008] providing a flexible substrate;

[0009] Oxygen plasma etching technology is used to etch a flexible substrate provided with a metal mask, wherein the metal mask is arranged directly above the surface of the flexible substrate, thereby achieving regulation of the surface texture of the flexible substrate and producing a flexible substrate with a micro-nano structure.

[0010] The embodiment of the present invention further provides a flexible substrate having a micro-nano structure manufactured by the aforementioned method.

[0011] The embodiment of the present invention further provides the use of the aforementioned flexible substrate with micro-nano structure in the field of preparing flexible sensors.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) The method provided by the present invention has the advantages of obtaining regular and controllable surface nanotexture without affecting the intrinsic properties of the flexible substrate, and can regulate the surface wetting state of the flexible substrate. The preparation method is simple and is expected to be applied in the field of flexible wearable electronic devices.

[0014] (2) The method provided by the present invention can control the surface texture morphology and distribution of the flexible substrate by controlling process parameters such as etching time, and the texture size is highly correlated with the aperture of the mask. Compared with technical means such as laser etching and template transfer, this process is simple, controllable and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 Schematic diagram of the preparation process of the surface texture of the flexible substrate in an embodiment of the present invention;

[0017] Figure 2 This is a photo of the preparation process of the flexible substrate surface texture in Example 1 of the present invention;

[0018] Figure 3a is a surface image of a substrate prepared in Example 1 of the present invention;

[0019] Figure 3b is a surface image of a substrate prepared in Example 2 of the present invention;

[0020] Figure 3c is a surface image of a substrate prepared in Example 3 of the present invention;

[0021] Figure 4a is a topographic image of the substrate surface texture obtained in Example 7 of the present invention;

[0022] Figure 4b is a topographic image of the substrate surface texture obtained in Example 8 of the present invention;

[0023] Figure 4c is a topographic image of the substrate surface texture obtained in Example 9 of the present invention;

[0024] Figure 5 This is a surface image of a sample after oxygen plasma etching without using a mask in Comparative Example 1 of the present invention;

[0025] Figure 6 This is a surface image of a sample after oxygen plasma etching using a nylon flat screen mask in Comparative Example 2 of the present invention;

[0026] Figure 7 3. This is a comparison diagram of the water contact angle of the substrate surface in Comparative Example 3, Comparative Example 4, Example 4, Example 5, and Example 6 of the present invention;

[0027] Figure 8a This is a tensile performance diagram of an untreated substrate in the present invention subjected to strain testing using a tensile testing machine;

[0028] Figure 8b is a tensile performance diagram of a strain test performed on a flexible substrate having a micro-nano structure using a tensile testing machine in Example 1 of the present invention;

[0029] Figure 9 This is a surface image of a sample etched with oxygen plasma after changing the distance between the mask and the sample in Comparative Example 5 of the present invention;

[0030] Figure 10 This is a surface image of the sample after etching for more than 30 minutes in comparative example 6 of the present invention. DETAILED DESCRIPTION

[0031] In view of the defects of the prior art, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. It mainly adopts an inductively coupled PECVD composite deposition system, introduces a specific metal plane template, and controls the oxygen plasma etching time, the shape, aperture and size of the mask, and the distance between the mask and the substrate surface. It can change the periodicity of the spatial distribution of the oxygen plasma, and realize the preparation of nano-depth structures on the surface of the flexible substrate and the distribution of different regularities of the surface structure. The texture morphology is characterized by a fluorescent metallographic microscope to determine the surface texture morphology of the substrate. Through precise control of the surface texture, the surface of the flexible substrate can be gradually transformed from a hydrophobic state (>120°) to a super-hydrophilic state (<5°). At the same time, the flexible substrate with a micro-nano structure can achieve a tensile property with a strain exceeding 150%.

[0032] The technical solution of the present invention will be described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] Specifically, as one aspect of the technical solution of the present invention, a method for regulating the surface texture of a flexible substrate based on oxygen plasma etching includes:

[0034] providing a flexible substrate;

[0035] Oxygen plasma etching technology is used to etch a flexible substrate provided with a metal mask, wherein the metal mask is arranged directly above the surface of the flexible substrate, thereby achieving regulation of the surface texture of the flexible substrate and producing a flexible substrate with a micro-nano structure.

[0036] In some preferred embodiments, the method specifically includes: using an inductively coupled PECVD composite deposition system, placing a metal mask directly above the surface of a flexible substrate, introducing oxygen, and using a radio frequency power supply to generate an alternating electric field between two plates so that the oxygen is ionized in the electric field to generate oxygen plasma.

[0037] In some preferred embodiments, the method specifically includes: using a vacuum pump to evacuate the chamber of the deposition system so that the vacuum degree of the chamber of the deposition system is 2 to 3×10 -5 Torr, oxygen is then introduced to make the chamber pressure of the deposition system 15-20mTorr, and an RF power supply is used to excite the ionization of the oxygen introduced into the deposition system chamber to obtain oxygen plasma; wherein, the oxygen flow rate is 50-100sccm, the applied frequency of the RF power supply is 5N350kHz, the pulse width is 0.4N5.0μs, and the bias voltage is -250V~-500V.

[0038] In some preferred embodiments, the distance between the metal mask and the surface of the flexible substrate is 0 mm to 0.1 mm.

[0039] In some preferred embodiments, the etching treatment time is 1 second to 60 minutes.

[0040] In some preferred embodiments, the material of the flexible substrate includes an organosilicon polymer; the organosilicon polymer includes any one or more combinations of polydimethylsiloxane, Ecoflex, polyethylsiloxane, liquid silicone rubber, high temperature silicone rubber, and room temperature vulcanized silicone rubber, but is not limited thereto.

[0041] In some preferred embodiments, the material of the metal mask includes any one of aluminum, copper, and stainless steel, but is not limited thereto.

[0042] In some preferred embodiments, the metal mask is a planar structure, which includes any one or more combinations of circular, rectangular, diamond, elliptical, polygonal, strip, linear, wire mesh, and array shapes, and is not limited thereto.

[0043] In some preferred embodiments, the metal mask is a planar wire mesh-shaped rectangular structure, the wire thickness of the metal mask is 20 μm to 10,000 μm, and the aperture of the metal mask is 20 μm to 2,000 μm.

[0044] In some preferred embodiments, the water contact angle of the flexible substrate before etching is greater than 120°, and the water contact angle of the flexible substrate having micro-nano structures obtained after etching is less than 5°.

[0045] The present invention is based on a method for etching the surface texture of a flexible substrate using oxygen plasma and regulating its wettability. It adopts an inductively coupled PECVD composite deposition system and introduces a specific metal plane template. By controlling the oxygen plasma etching time, the shape, aperture and size of the mask, and the distance between the mask and the substrate surface, the periodicity of the spatial distribution of the oxygen plasma can be changed, thereby realizing the preparation of nano-depth structures on the surface of the flexible substrate and the distribution of different regularities of the surface structure. The texture morphology is characterized by a fluorescent metallographic microscope to determine the surface texture morphology of the substrate. Through precise control of the surface texture, the surface of the flexible substrate can be gradually transformed from a hydrophobic state (>120°) to a super-hydrophilic state (<5°). At the same time, the flexible substrate with a micro-nano structure can achieve a tensile property with a strain exceeding 150%. The present invention has the advantages of obtaining a regular and controllable surface nanotexture without affecting the intrinsic properties of the flexible substrate, and can regulate the wettability of the flexible substrate surface. The preparation method is simple and is expected to be applied to the field of flexible wearable electronic devices.

[0046] In some preferred embodiments, the method for regulating the surface texture of a flexible substrate based on oxygen plasma etching comprises the following steps:

[0047] S1. Place the flexible substrate in the chamber of the vacuum deposition system, place the mask, introduce oxygen, and use a radio frequency power supply to generate an alternating electric field between the two plates. The oxygen is ionized in the electric field to generate oxygen plasma.

[0048] Furthermore, the material of the flexible substrate includes organic silicon polymers such as polydimethylsiloxane, Ecoflex, polyethylsiloxane, liquid silicone rubber, high temperature silicone rubber, room temperature vulcanized silicone rubber, etc.

[0049] S2. The oxygen plasma in the deposition system chamber selectively etches the substrate surface through the mask to achieve the preparation of regular texture on the substrate surface;

[0050] S3. Use fluorescence metallographic microscopy to characterize substrate surfaces with different textures to determine that a regular surface texture is obtained. The texture morphology can be controlled by changing the etching time, the shape, aperture and size of the mask, and the distance between the mask and the substrate surface.

[0051] Furthermore, the mask is a plane type, with circular, rectangular, diamond, elliptical, polygonal, strip, linear, wire mesh and array structures, and the mask is made of metals such as aluminum, copper, and stainless steel.

[0052] S4. Use a contact angle meter to characterize the contact angle between the flexible substrate surface and water.

[0053] Furthermore, the contact angle between the substrate surface and water gradually changes from a hydrophobic state of 124.86° to a superhydrophilic state of less than 5°.

[0054] S5. The flexible substrate with micro-nano structure is strain tested using a tensile testing machine, which has a strain performance of over 200%.

[0055] Furthermore, step S1 is specifically as follows:

[0056] The deposition system chamber is evacuated by a vacuum pump, and the vacuum degree of the deposition system chamber reaches 2-3×10 -5 After 100 mTorr, oxygen gas was introduced with a flow rate of 100 sccm to make the pressure in the deposition system chamber reach 20 mTorr;

[0057] A -500V bias voltage with a frequency of 350kHz and a pulse width of 1.1μs is applied by a radio frequency power supply to provide high-frequency energy, which stimulates the ionization of oxygen introduced into the deposition system chamber, thereby generating oxygen plasma;

[0058] During oxygen plasma etching, the distance between the mask and the sample is 0 mm to 0.1 mm.

[0059] Furthermore, the etching time in step S2 is specifically 1s to 60min.

[0060] In some more specific embodiments, the method for regulating the surface texture of a flexible substrate based on oxygen plasma etching comprises the following steps:

[0061] S1. Select polydimethylsiloxane as the flexible substrate, place the sample in the chamber of the vacuum deposition system, place a metal wire mesh plane mask, introduce oxygen, and use a radio frequency power supply to generate an alternating electric field between the two plates. The oxygen is ionized in the electric field to generate oxygen plasma; Figure 1 As shown;

[0062] The deposition system chamber is evacuated by a vacuum pump, and the vacuum degree of the deposition system chamber reaches 2-3×10 -5 After 100 mTorr, oxygen gas was introduced with a flow rate of 100 sccm to make the pressure in the deposition system chamber reach 20 mTorr;

[0063] A -500V bias voltage with a frequency of 350kHz and a pulse width of 1.1μs is applied by a radio frequency power supply to provide high-frequency energy, thereby exciting the ionization of oxygen introduced into the deposition system chamber to obtain oxygen plasma.

[0064] S2. The oxygen plasma in the deposition system chamber selectively etches the substrate surface through the mask to achieve the preparation of regular texture on the substrate surface. The etching time is 30s to 30min.

[0065] S3. Use fluorescence metallographic microscopy to characterize substrate surfaces with varying textures. The mask is a flat, rectangular mesh with a wire thickness ranging from 20 μm to 10,000 μm and an aperture ranging from 20 μm to 2,000 μm. The mask is made of metals such as aluminum, copper, and stainless steel. During oxygen plasma etching, conductive tape is used to maintain a distance between the mask and the sample of 0 mm to 0.1 mm.

[0066] S4. Use a contact angle meter to characterize the contact angle between the flexible substrate surface and water.

[0067] Another aspect of the embodiments of the present invention further provides a flexible substrate having a micro-nano structure manufactured by the aforementioned method.

[0068] Another aspect of the embodiments of the present invention further provides use of the aforementioned flexible substrate having a micro-nano structure in the field of preparing flexible sensors.

[0069] The present invention provides a method for texturing the surface of a flexible substrate based on oxygen plasma etching and regulating its wettability. An inductively coupled PECVD composite deposition system is used to introduce a specific metal plane template. By controlling the oxygen plasma etching time, the shape, aperture and size of the mask, and the distance between the mask and the substrate surface, the periodicity of the spatial distribution of the oxygen plasma can be changed, thereby realizing the preparation of nano-depth structures on the surface of the flexible substrate and the distribution of different regularities of the surface structure. The texture morphology is characterized by a fluorescent metallographic microscope to determine the surface texture morphology of the substrate. Through precise control of the surface texture, the surface of the flexible substrate can be gradually transformed from a hydrophobic state (>120°) to a super-hydrophilic state (<5°). At the same time, the flexible substrate with a micro-nano structure can achieve a tensile property with a strain exceeding 150%. The present invention has the advantages of obtaining regular and controllable surface nanotexture without affecting the intrinsic properties of the flexible substrate, and can regulate the wettability of the flexible substrate surface. The preparation method is simple and is expected to be applied to the field of flexible wearable electronic devices.

[0070] The high-energy oxygen ions formed by the PECVD low-temperature plasma discharge used in the present invention are highly active and can only form etching and chemical reactions on the surface of the substrate material at room temperature. The surface micro-nanostructure will not affect the intrinsic performance of the substrate, and the high elasticity advantage of the substrate is maintained. At the same time, by controlling the oxygen plasma etching time, the shape, aperture and size of the mask, and the distance between the mask and the substrate surface, the plasma characteristics can be changed to achieve the periodicity of the spatial distribution of the oxygen plasma, realize the controllable modulation of different nano-textures on the substrate surface, improve the sensitivity and response speed of subsequent devices, and realize different transformations of the wetting characteristics of the substrate surface. This technology can control the surface texture morphology and distribution of flexible substrates by combining the control of process parameters such as etching time, and the texture size is highly correlated with the aperture of the mask. Compared with technical means such as laser etching and template transfer, this process is simple, controllable and low-cost.

[0071] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0072] Unless otherwise specified, the experimental materials used in the following examples can be purchased from conventional biochemical reagent companies.

[0073] Example 1

[0074] A 200 μm thick polydimethylsiloxane film was placed on the chamber frame, and a stainless steel flat screen mask with a wire thickness of 80 μm and an aperture of 180 μm was attached to the film surface at a distance of 0.1 mm. The chamber was evacuated to 3×10 -5 Torr, 100 sccm of oxygen was introduced into the vacuum chamber, the bias voltage of the RF power supply was set to -500 V, the pulse width was 1.1 μs, the frequency was 350 kHz, the chamber pressure was 20 mTorr, and the substrate was etched with ionized oxygen plasma for 10 minutes. The prepared surface texture had a pore size of 180 μm, which was the same as the pore size of the mask. Figure 2 This is a photo of the preparation process of the flexible substrate surface texture in this embodiment. Figure 3a is the surface image of the prepared substrate. Figure 8a This is a tensile performance diagram of the untreated sample in the present invention using a tensile testing machine to perform strain testing. Figure 8b This is a tensile performance diagram of a flexible substrate with micro-nano structure subjected to strain testing using a tensile testing machine. It can be seen that the invented solution will not damage the substrate and will not affect the intrinsic performance of the substrate.

[0075] Example 2

[0076] A 200 μm thick polydimethylsiloxane film was placed on the chamber frame, and a stainless steel flat screen mask with a wire thickness of 50 μm and an aperture of 80 μm was attached to the film surface at a distance of 0.1 mm. The chamber was evacuated to 3×10 -5 Torr, 100 sccm of oxygen was introduced into the vacuum chamber, the bias voltage of the RF power supply was set to -500 V, the pulse width was 1.1 μs, the frequency was 350 kHz, the chamber pressure was 20 mTorr, and the substrate was etched with ionized oxygen plasma for 10 minutes. The prepared surface texture had an aperture of 80 μm, which was the same as the aperture of the mask. Figure 3b is the surface image of the prepared substrate.

[0077] The difference between the textures obtained in this embodiment and in embodiment 1 is that the pore size of the surface texture in this embodiment is 80 μm.

[0078] Example 3

[0079] A 200 μm thick polydimethylsiloxane film was placed on the chamber frame, and a stainless steel flat screen mask with a wire thickness of 40 μm and an aperture of 50 μm was attached to the film surface at a distance of 0.1 mm. The chamber was evacuated to 3×10 -5 Torr, 100 sccm of oxygen was introduced into the vacuum chamber, the bias voltage of the RF power supply was set to -500 V, the pulse width was 1.1 μs, the frequency was 350 kHz, the chamber pressure was 20 mTorr, and the substrate was etched with ionized oxygen plasma for 10 minutes. The prepared surface texture had a pore size of 50 μm, which was the same as the pore size of the mask. Figure 3c is the surface image of the prepared substrate;

[0080] The difference between the textures obtained in this embodiment and in embodiment 1 is that the pore size of the surface texture in this embodiment is 50 μm.

[0081] Example 4

[0082] The only difference between this embodiment and embodiment 1 is that the etching time is 30 minutes.

[0083] The above Example 4 was tested using a contact angle meter, and the contact angle between the film and water was 33.40°.

[0084] Example 5

[0085] The only difference between this embodiment and embodiment 2 is that the etching time is 30 minutes.

[0086] The above Example 5 was tested using a contact angle meter, and the contact angle between the film and water was 17.94°.

[0087] Example 6

[0088] The only difference between this embodiment and embodiment 3 is that the etching time is 30 minutes.

[0089] The above Example 6 was tested using a contact angle meter, and the contact angle between the film and water was 4.3°.

[0090] Example 7

[0091] A 300 μm thick polydimethylsiloxane film was placed on the chamber frame, and a stainless steel flat screen mask with a wire thickness of 80 μm and an aperture of 180 μm was attached to the film surface at a distance of 0.1 mm. The chamber was evacuated to 3×10 -5 Torr, 100 sccm of oxygen was introduced into the vacuum chamber, the bias voltage of the RF power supply was set to -500 V, the pulse width was 1.1 μs, the frequency was 350 kHz, the chamber pressure was 20 mTorr, and the substrate was etched with ionized oxygen plasma for 30 seconds. The prepared surface texture had a pore size of 180 μm, which was the same as the aperture of the mask. Figure 4a This is the obtained substrate surface texture morphology.

[0092] Example 8

[0093] The only difference between this embodiment and embodiment 7 is that the etching time is 1 minute. Figure 4b This is the obtained substrate surface texture morphology.

[0094] Example 9

[0095] The only difference between this embodiment and embodiment 7 is that the etching time is 10 minutes. Figure 4c This is the obtained substrate surface texture morphology.

[0096] Comparative Example 1

[0097] A 200 μm thick polydimethylsiloxane film was placed on the chamber rack and the chamber was evacuated to 3×10 - 5 Torr, 100 sccm of oxygen was introduced into the vacuum chamber, the bias voltage of the RF power supply was set to -500 V, the pulse width was 1.1 μs, the frequency was 350 kHz, the chamber pressure was 20 mTorr, and the substrate was etched using ionized oxygen plasma for 10 minutes.

[0098] The comparative example 1 was tested by means of a fluorescence metallographic microscope. Figure 5 In comparative example 1, irregular surface texture is generated after etching.

[0099] Comparative Example 2

[0100] A 200 μm thick polydimethylsiloxane film was placed on the chamber frame, and a nylon flat screen mask with an aperture of 100 μm was attached at a distance of 0.1 mm from the film surface. The chamber was evacuated to 3×10 -5 Torr, 100 sccm of oxygen was introduced into the vacuum chamber, the bias voltage of the RF power supply was set to -500 V, the pulse width was 1.1 μs, the frequency was 350 kHz, the chamber pressure was 20 mTorr, and the substrate was etched using ionized oxygen plasma for 10 minutes.

[0101] The comparative example 2 was tested by means of a fluorescence metallographic microscope. Figure 6 Comparative Example 2 shows a smooth surface after etching, with no regular surface texture.

[0102] Comparative Example 3

[0103] A 200 μm thick polydimethylsiloxane film was attached to a glass plate, and the contact angle between the film and water was 124.86°.

[0104] Comparative Example 4

[0105] A 200 μm thick polydimethylsiloxane film was placed on the chamber rack and the chamber was evacuated to 3×10 - 5 Torr, 100 sccm of oxygen was introduced into the vacuum chamber, the bias voltage of the RF power supply was set to -500 V, the pulse width was 1.1 μs, the frequency was 350 kHz, the chamber pressure was 20 mTorr, and the substrate was etched using ionized oxygen plasma for 30 minutes.

[0106] The comparative example 4 was tested using a contact angle meter, and the contact angle between the film and water was 64.26°.

[0107] Figure 3a-3c The surface images of the samples etched by oxygen plasma under different aperture masks in Examples 1-3 are shown. When observing the etched substrate surface under a fluorescent metallographic microscope, a clear and regular surface texture can be observed. The texture is a rectangular texture. Figure 3a The pore size of the medium texture is 180 μm; Figure 3b The pore size of the medium texture is 80 μm; Figure 3c The medium texture aperture is 50 μm; the texture is arranged regularly and neatly, the texture aperture is the same as the mask aperture, and the substrate surface is not damaged.

[0108] Figure 4a-4c The substrate surface texture morphology images obtained at different etching times in Examples 7-9 are shown in FIG. Figure 4a Etching time 30s; Figure 4b Etching time: 1 min; Figure 4cThe etching time is 10 min. When observing the surface of the etched substrate under a fluorescence metallographic microscope, it can be seen that the texture becomes clearer and more regular as the etching time increases.

[0109] Figure 7 This is a comparison of the water contact angles on the substrate surfaces in Comparative Example 3, Comparative Example 4, Example 4, Example 5, and Example 6. Figure 7 It can be seen that the contact angle of Comparative Example 3 is greater than 90°, indicating a hydrophobic state, while the contact angles of the Examples are all less than 90°, indicating a hydrophilic state. In particular, Example 6 has the smallest contact angle, which is 4.30°.

[0110] Comparative Example 5

[0111] The method is the same as that of Example 1, except that: a stainless steel flat screen mask is attached at a distance of 0.5 mm from the film surface;

[0112] The comparative example 5 was tested by means of a fluorescence metallographic microscope. Figure 9 The surface of comparative example 5 is smooth after etching, but irregular surface texture is generated.

[0113] Comparative Example 6

[0114] The method is the same as that of Example 1, except that the etching time is 60 minutes.

[0115] The comparative example 6 was tested by fluorescence metallographic microscope. Figure 10 In comparative example 6, cracks appeared on the surface of the substrate after etching, affecting the micro-nano texture of the substrate surface.

[0116] Comparative Example 7

[0117] The method is the same as Example 1, except that the bias voltage of the RF power supply is set to -100 V, the pulse width is 6.0 μs, and the frequency is 400 kHz. In this case, oxygen plasma cannot be generated, and thus etching cannot be performed.

[0118] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments using other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0119] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical variations made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the scope of protection of the present invention.

Claims

1. A method for regulating the surface texture of a flexible substrate based on oxygen plasma etching, characterized in that: include: Providing a flexible substrate; wherein the flexible substrate is made of an organic silicon polymer; An inductively coupled PECVD composite deposition system is used. A metal mask is placed directly above the surface of a flexible substrate. Oxygen is introduced, and an RF power supply is used to generate an alternating electric field between two electrodes, ionizing the oxygen in the electric field to generate oxygen plasma. The oxygen flow rate is 50-100 sccm, the RF power supply frequency is 5-350 kHz, the pulse width is 0.4-5.0 μs, and the bias voltage is -250 V to -500 V. The flexible substrate with the metal mask placed directly above the surface of the flexible substrate is then etched using oxygen plasma etching technology. The metal mask is placed directly above the surface of the flexible substrate, thereby achieving control over the surface texture of the flexible substrate and producing a flexible substrate with micro-nano structures. The etching processing time is 1s~30min, the distance between the metal mask and the surface of the flexible substrate is greater than 0mm and less than or equal to 0.1mm; the metal mask is a planar wire mesh rectangular structure, the wire thickness of the metal mask is 20μm~10000μm, and the aperture of the metal mask is 20μm~2000μm.

2. The method according to claim 1, characterized in that Specifically include: The chamber of the deposition system is evacuated by a vacuum pump to a vacuum degree of 2~3×10 -5 Torr, oxygen is then introduced to make the chamber pressure of the deposition system 15~20mTorr, and a radio frequency power supply is used to excite the oxygen introduced into the deposition system chamber to ionize, thereby obtaining oxygen plasma.

3. The method according to claim 1, wherein: The organic silicon polymer is selected from any one or more combinations of polydimethylsiloxane, polyethylsiloxane, liquid silicone rubber, high temperature silicone rubber, and room temperature vulcanized silicone rubber.

4. The method according to claim 1, wherein: The material of the metal mask is selected from any one of aluminum, copper and stainless steel.

5. The method according to claim 1, wherein: The water contact angle of the flexible substrate before etching is greater than 120°, and the water contact angle of the flexible substrate with micro-nano structure obtained after etching is less than 5°.

6. A flexible substrate with micro-nano structure obtained by the method according to any one of claims 1 to 5.

7. Use of the flexible substrate with micro-nano structure according to claim 6 in the field of preparing flexible sensors.

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