A polymer composite film for skin moisturization and a method of preparing the same

Abstract

A polymer composite film for skin moisturizing and a preparation method thereof, comprising a conical microstructure layer and a porous material layer, wherein the conical microstructure layer is provided with a vertical upward conical microarray on the top surface, and the conical microarray is made of PDMS material; the conical microstructure layer has a plurality of regularly arranged conical arrays, and the conical array is a conical structure; the conical microstructure layer has a small hole, which can transport the water collected by the conical microarray to the porous material layer; the polymer composite film has a hydrophilic porous structure, can store the water absorbed by the super-hydrophobic microarray and the hole structure for a long time, and is attached to the skin to provide persistent moisturizing for the skin.

Description

Technical Field

[0001] This invention belongs to the field of polymer film preparation, and specifically relates to a method for preparing a polymer composite film for skin moisturizing. Background Technology

[0002] Skin is susceptible to damage from environmental pollution, climate change, dryness, and ultraviolet radiation, leading to dryness, roughness, peeling, and wrinkles, severely impacting health and appearance. Currently, skin moisturizing products on the market are mainly in the form of creams, lotions, and masks. These products are primarily cosmetics containing humectants, which work by absorbing, retaining, and reducing evaporation. However, these products are mostly chemically synthesized, requiring frequent application and offering limited long-lasting effects, and may contain harmful chemicals. With increased travel, people frequently encounter low-humidity, high-temperature environments (such as desert travel), causing skin to easily dry out and even crack due to moisture evaporation. This further increases the demand for hydrating and moisturizing products. Therefore, safer, more effective, and longer-lasting skin moisturizing products require further development.

[0003] Given the advantages of micro / nano structures and porous structures in water vapor collection and moisturizing, the development of polymer composite films with micro / nano and porous structures for skin moisturizing has significant application prospects. Currently, common methods for preparing polymer films include in-situ polymerization, sol-gel methods, and extrusion molding. In-situ polymerization prepares polymer films through polymerization reactions on a substrate surface. This method requires reagents to undergo chemical reactions under specific conditions, which are demanding and the preparation process is complex. The sol-gel method involves hydrolyzing metal salts under appropriate conditions to form a sol, followed by solvent removal through evaporation or heat treatment. During the gel drying process, the evaporation of water and solvent can cause the material to shrink, deform, and become brittle. Extrusion molding uses a pre-made mold to extrude polymer materials under heating. This method is only suitable for preparing thermoplastic films. These methods are only applicable to the preparation of single-material films and lack the capability to prepare polymer films with multi-material micro / nano structures. Therefore, methods for preparing composite films with multiple materials and micro / nano structures require further development.

[0004] In light of the above background, this paper provides a method for preparing composite films using various materials and micro / nano structures, and its application is of great significance for the further development of skin moisturizing products. Summary of the Invention

[0005] To address the aforementioned shortcomings, this invention proposes a polymer composite film for skin moisturizing, integrating a microarray and a porous structure. The microarray effectively collects and stores water vapor microdroplets from the air; the porous structure absorbs and locks in moisture, adhering to the skin for moisturizing. This composite film uses a hydrogel composite material, which effectively retains moisture for a long time, meeting the humidity requirements of human skin, and reducing skin surface temperature to prevent sunburn.

[0006] The object of this invention is achieved in the following manner:

[0007] A polymer composite film for skin moisturizing includes a conical microstructure layer and a porous material layer. The upper surface of the conical microstructure layer has multiple conical structures arranged regularly, and small pores are provided between every four adjacent conical structures. The porous material layer has a porous structure.

[0008] Furthermore, the conical structure is a cylindrical conical structure.

[0009] Furthermore, the height of the conical structure is 1.5 mm, the radius of the base of a single cone is 0.13 mm, the apex angle of a single cone is 10°, and the center distance between cones is 0.5 mm.

[0010] Furthermore, the surface of the conical microstructure layer is made of PDMS material, and the porous material layer is made of photosensitive resin material.

[0011] A method for preparing a polymer composite film for skin moisturizing includes the following steps:

[0012] S1. Select a double-sided polished silicon wafer with high flatness as the substrate and clean it;

[0013] S2. Spin-coat SU8-2050 photoresist onto the silicon wafer surface using a spin coater;

[0014] S3. Heat the silicon wafer after spin coating with photoresist to cure the photoresist, and then cool it to room temperature;

[0015] S4. Using a photomask and a photolithography machine, photolithography is performed on the silicon wafer with cured photoresist to cause the photoresist in the light-transmitting part to undergo a cross-linking reaction;

[0016] S5. The silicon wafer is heated a second time to enhance the adhesion between the photoresist and the substrate;

[0017] S6. The silicon wafer with cured photoresist is developed to remove the uncrosslinked photoresist portion, thereby processing multiple regularly arranged conical grooves on the silicon wafer;

[0018] S7. Perform hardening treatment on the developed silicon wafer to obtain a master mold with a tapered microstructure layer having tapered grooves;

[0019] S8. Liquid PDMS is poured onto the master mold of the conical microstructure layer, heated and cured, and then the film is peeled off to obtain the conical microstructure layer 1;

[0020] S9. Use an automatic drilling machine to drill small holes in the tapered microstructure layer;

[0021] S10. Prepare an electronic fluorinated oil containing 0.5% by mass of trichloro(1H,1H,2H,2H-perfluorooctyl)silane, immerse the conical microstructure layer in the electronic fluorinated oil containing 0.5% by mass of trichloro(1H,1H,2H,2H-perfluorooctyl)silane at 50°C for 12 hours, and perform hydrophobic enhancement treatment on the conical microstructure layer to obtain a superhydrophobic conical microstructure layer;

[0022] S11. Prepare photocurable liquid polymer systems by mechanical stirring and crushing;

[0023] S12. Liquid photocurable system liquid polymer foam is poured onto the surface of the obtained conical microstructure layer away from the conical structure;

[0024] S13. Using 365nm wavelength, 1W UV ultraviolet light to irradiate liquid polymer foam, the liquid polymer foam undergoes a cross-linking reaction, forming a porous material layer on the surface of the conical microstructure layer away from the conical structure, thus obtaining a photolithography polymer composite film.

[0025] Furthermore, in step S2, the spin coater is first operated at a low speed of 500 rpm for 10 seconds, and then at a high speed of 2500 rpm for 30 seconds.

[0026] Furthermore, the heating of the silicon wafer after spin coating with photoresist in S3 specifically involves heating at 65°C for 3 minutes, then raising the temperature to 95°C for 20 minutes, and finally turning off the power to the heating stage to allow the photoresist to cool naturally to room temperature along with the heating stage.

[0027] Furthermore, the exposure time used in S4 is 170 seconds;

[0028] Furthermore, the secondary heating of the silicon wafer in S5 specifically involves heating at 65°C for 3 minutes, then raising the temperature to 95°C for 20 minutes, and finally turning off the power to the heating stage to allow the photoresist to cool naturally to room temperature along with the heating stage.

[0029] Further, the specific steps of the development process in S6 are as follows: Place the photolithographically etched silicon wafer into a petri dish containing SU8-2050 special developing solution, and repeatedly move the silicon wafer with tweezers to ensure the surface of the wafer is fully in contact with the developing solution. After 5 minutes, rinse the surface of the silicon wafer with deionized water and observe whether the microchannels are clearly visible. Simultaneously, observe whether the non-channel areas have been thoroughly rinsed. If there is residual photoresist, continue development until the channels are clear and the silicon wafer surface is clean.

[0030] Furthermore, the specific steps of the S7 medium hard film treatment are as follows: baking on a 150°C heating stage to remove residual developer and moisture, and then cooling to room temperature.

[0031] Furthermore, the preparation method of liquid PDMS in S8 is as follows: PDMS and curing agent are mixed evenly at a mass ratio of 10:1, and the gas in the liquid PDMS is extracted using a vacuum box. This process is repeated until the mixed solution is completely transparent and clear to obtain liquid PDMS.

[0032] Furthermore, the liquid polymer in the photocurable system of S11 is composed of 35% polyethylene glycol diacrylate, 1% photoinitiator, 2% surfactant Tween 80, and 62% deionized water by mass.

[0033] Furthermore, the liquid polymer foam in the photocurable system in S11 is prepared by mechanical stirring or microfluidic methods.

[0034] The advantages of this invention compared to existing technologies are as follows:

[0035] (1) This invention proposes a polymer composite film for skin moisturizing, which has a superhydrophobic microarray and porous structure, and can realize the collection and transport of water vapor in the air.

[0036] (2) The polymer composite film proposed in this invention has a hydrophilic porous structure, which can preserve the water absorbed by the superhydrophobic microarray and porous structure for a long time, adhere to the skin, and provide long-lasting moisturization for the skin.

[0037] (3) The polymer composite film proposed in this invention has excellent biocompatibility, is harmless to the skin, and is environmentally friendly and pollution-free in its preparation process. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the polymer composite film of the present invention;

[0039] Figure 2 This is a partially enlarged view of the structure of the polymer composite film of the present invention;

[0040] Figure 3This is a schematic diagram of the porous structure of the polymer composite film of the present invention;

[0041] Figure 4 This is a flowchart illustrating the preparation process of the polymer composite film of the present invention;

[0042] Figure 5 This is a schematic diagram illustrating the water collection principle of the polymer composite film of the present invention. Detailed Implementation

[0043] The present invention discloses a polymer composite film for skin moisturizing, which integrates a microarray and a porous structure to effectively collect and store water vapor in the air; the composite film uses a hydrogel composite material, which can effectively retain moisture, meet the humidity requirements of human skin, and reduce the skin surface temperature.

[0044] The present invention will be further described below with reference to specific embodiments.

[0045] Example 1

[0046] A polymer composite film for skin moisturizing includes a conical microstructure layer 1 and a porous material layer 2. The upper surface of the conical microstructure layer 1 has a plurality of conical structures 1-1 arranged regularly, and small holes 1-2 are provided between every four adjacent conical structures. The porous material layer 2 has a porous structure, which can preserve moisture for a long time.

[0047] The conical structure is a cylindrical structure.

[0048] like Figure 5 As shown, multiple cone-shaped structures 1-1 are regularly arranged on the upper surface of the cone-shaped microstructure layer 1. These cone-shaped structures 1-1 resemble the spines of a cactus. Air containing water vapor is captured and collected by the tips of the cone-shaped structures 1-1, condensing into microdroplets. As the microdroplets gradually increase in size, they are driven by the combined effects of the Plass pressure difference and the surface energy gradient, sliding down the side of the cone-shaped structure 1-1 and entering the pores 1-2, and then into the porous material layer 2 where they are collected. The porous material layer 2 can retain moisture for a long time, adhering to the skin and providing long-lasting hydration.

[0049] The cone structure has a height of 1.5 mm, a base radius of 0.13 mm, a apex angle of 10°, and a center distance of 0.5 mm between cones.

[0050] Furthermore, the conical microstructure layer 1 is made of PDMS material, and the porous material layer 2 is made of photosensitive resin material.

[0051] Example 2

[0052] A method for preparing a polymer composite film for skin moisturizing:

[0053] Among them, S1-S8 is the process of preparing the master mold of the conical microstructure layer 1;

[0054] S1. Select a double-sided polished silicon wafer with high flatness as the substrate and clean it;

[0055] S2. Spin-coat SU8-2050 photoresist onto the silicon wafer surface using a spin coater;

[0056] S3. Heat the silicon wafer after spin coating with photoresist to cure the photoresist, and then cool it to room temperature;

[0057] S4. Using a photomask and a photolithography machine, photolithography is performed on the silicon wafer with cured photoresist to cause the photoresist in the light-transmitting part to undergo a cross-linking reaction;

[0058] S5. The silicon wafer is heated a second time to enhance the adhesion between the photoresist and the substrate;

[0059] S6. The silicon wafer with cured photoresist is developed to remove the uncrosslinked photoresist portion, thereby processing multiple regularly arranged conical grooves on the silicon wafer;

[0060] S7. Perform hard film treatment on the developed silicon wafer to obtain a master mold of the tapered microstructure layer 1 with tapered grooves;

[0061] S8. Liquid PDMS is poured onto the master mold of the conical microstructure layer 1, heated and cured, and then the film is peeled off to obtain the conical microstructure layer 1;

[0062] S9. Use an automatic drilling machine to drill small holes 1-2 on the conical microstructure layer 1;

[0063] S10. Prepare an electronic fluorinated oil containing 0.5% by mass of trichloro(1H,1H,2H,2H-perfluorooctyl)silane, immerse the conical microstructure layer 1 in the electronic fluorinated oil containing 0.5% by mass of trichloro(1H,1H,2H,2H-perfluorooctyl)silane at 50°C for 12 hours, and perform hydrophobic enhancement treatment on the conical microstructure layer 1 to obtain a superhydrophobic conical microstructure layer 1;

[0064] S11. Prepare photocurable liquid polymer systems by mechanical stirring and crushing;

[0065] S12. Liquid photocurable liquid polymer foam is poured onto the surface of the obtained conical microstructure layer 1 away from the conical structure;

[0066] S13. Using 365nm wavelength, 1W UV ultraviolet light to irradiate liquid polymer foam, the liquid polymer foam undergoes a cross-linking reaction, forming a porous material layer 2 on the surface of the conical microstructure layer 1 away from the conical structure, thus obtaining a polymer composite film for skin moisturizing.

[0067] In step S2, the spin coater first operates at a low speed of 500 rpm for 10 seconds, then at a high speed of 2500 rpm for 30 seconds. In step S3, the silicon wafer coated with photoresist is heated at 65°C for 3 minutes, then the temperature is increased to 95°C for 20 minutes, and finally the heating stage power is turned off, allowing the photoresist to cool naturally to room temperature. In step S4, the photolithography machine used has an exposure time of 170 seconds.

[0068] The secondary heating of the silicon wafer in S5 is specifically performed as follows: heating at 65°C for 3 minutes, then raising the temperature to 95°C for 20 minutes, and finally turning off the power to the heating stage to allow the photoresist to cool naturally to room temperature along with the heating stage.

[0069] Furthermore, the exposure time used in S4 is 170 seconds;

[0070] Furthermore, the secondary heating of the silicon wafer in S5 specifically involves heating at 65°C for 3 minutes, then raising the temperature to 95°C and heating for 20 minutes, and finally turning off the power to the heating stage to allow the photoresist to cool naturally to room temperature along with the heating stage.

[0071] Furthermore, the specific steps of the development process in S6 are as follows: Place the photolithographically etched silicon wafer into a petri dish containing SU8-2050 special developing solution, and repeatedly move the silicon wafer with tweezers to ensure the surface of the wafer is fully in contact with the developing solution. After 5 minutes, rinse the surface of the silicon wafer with deionized water and observe whether the microchannels are clearly visible. Simultaneously, observe whether the non-channel areas have been thoroughly rinsed. If there is residual photoresist, continue development until the channels are clear and the silicon wafer surface is clean.

[0072] Furthermore, the specific steps of the S7 medium hard film treatment are as follows: baking on a 150°C heating stage to remove residual developer and moisture, and then cooling to room temperature.

[0073] Furthermore, the preparation method of liquid PDMS in S8 is as follows: PDMS and curing agent are mixed evenly at a mass ratio of 10:1, and the gas in the liquid PDMS is extracted using a vacuum box. This process is repeated until the mixed solution is completely transparent and clear to obtain liquid PDMS.

[0074] Furthermore, the liquid polymer in the photocurable system of S11 consists of 35% polyethylene glycol diacrylate, 1% photoinitiator, 2% surfactant Tween 80, and 62% deionized water by mass.

[0075] Furthermore, the liquid polymer foam in the photocurable system in S11 is prepared by mechanical stirring or microfluidic methods.

[0076] The above embodiments are only used to illustrate the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of the present invention, and the patent protection scope of the embodiments of the present invention should be defined by the claims.

Claims

1. A polymer composite film for skin moisturization, characterized by, The super-hydrophobic polymer composite film comprises a conical microstructure layer (1) and a porous material layer (2), the conical microstructure layer (1) is provided with a plurality of conical structures (1-1) arranged regularly on the upper surface, and a small hole (1-2) is arranged between every four adjacent conical structures; the porous material layer (2) is provided with a porous structure. The preparation steps of the polymer composite film are as follows: S1. Selecting a double-side polished silicon wafer with high flatness as the substrate and cleaning it; S2. Using a spin coater to spin SU8-2050 photoresist on the surface of the silicon wafer; S3. Heating the silicon wafer with the spin-coated photoresist to solidify the photoresist, and then cooling it to room temperature; S4. Using a mask and a photoetching machine to photoetch the silicon wafer with the solidified photoresist, so that the photoresist in the light-transmitting part undergoes cross-linking reaction; S5. Secondary heating of the silicon wafer to enhance the adhesion of the photoresist to the substrate; S6. Developing the silicon wafer with the solidified photoresist to remove the uncross-linked photoresist part, so as to process a plurality of regularly arranged conical grooves on the silicon wafer; S7. Hardening the developed silicon wafer to obtain a master mold of the conical microstructure layer (1) with conical grooves; S8. Pouring liquid PDMS on the master mold of the conical microstructure layer (1), heating and solidifying it, and then removing the film to obtain the conical microstructure layer (1); S9. Using an automatic puncher to punch small holes (1-2) on the conical microstructure layer (1); S10. Configuring electronic fluorinated oil containing 0.5% by mass of trichloro(1H, 1H, 2H, 2H-perfluorooctyl) silane, and immersing the conical microstructure layer (1) in the electronic fluorinated oil containing 0.5% by mass of trichloro(1H, 1H, 2H, 2H-perfluorooctyl) silane at 50 °C for 12 hours to perform hydrophobic enhancement treatment on the conical microstructure layer (1) and obtain a super-hydrophobic conical microstructure layer (1); S11. Preparing a light-curing system liquid polymer by mechanical stirring and crushing; S12. Pouring the prepared light-curing system liquid polymer foam on the surface of the conical microstructure layer (1) away from the conical structures; S13. Using a 365 nm wavelength, 1 W UV light to irradiate the liquid polymer foam, so that the liquid polymer foam undergoes cross-linking reaction to form a porous material layer (2) on the surface of the conical microstructure layer (1) away from the conical structures, and a polymer composite film for skin moisturizing is prepared. The light-curing system liquid polymer in S11 is composed of 35% by mass of polyethylene glycol diacrylate, 1% of a photoinitiator, 2% of a surfactant Tween 80 and 62% of deionized water; the liquid light-curing system liquid polymer foam in S12 is prepared by mechanical stirring or microfluidic method.

2. The polymer composite film for skin moisturization according to claim 1, wherein The height of the conical structure is 1.5 mm, the radius of the bottom surface of a single cone is 0.13 mm, and the center distance between the cones is 0.5 mm.

3. The polymer composite film for skin moisturization according to claim 2, wherein The S2 uniform glue machine first low speed 500 revolutions per second for 10 seconds, and then high speed 2500 revolutions per second for 30 seconds; the S3 heating the spin-coated photoresist silicon wafer specifically is: heating at 65 °C for 3 min, then increasing the temperature to 95 °C for 20 min, finally turning off the heating platform power, and allowing the photoresist to cool naturally to room temperature with the heating platform; the S4 exposure time of the photoetching machine used is 170 seconds.

4. The polymer composite film for skin moisturization according to claim 3, wherein The S5 secondary heating of the silicon wafer specifically is: heating at 65 °C for 3 min, then increasing the temperature to 95 °C for 20 min, finally turning off the heating platform power, and allowing the photoresist to cool naturally to room temperature with the heating platform.

5. The polymer composite film for skin moisturization according to claim 4, wherein The S6 developing process specifically is: placing the photoetched silicon wafer into a petri dish containing SU8-2050 special developing solution, repeatedly stirring the silicon wafer with tweezers to allow the silicon wafer surface to fully contact the developing solution, rinsing the silicon wafer surface with deionized water after 5 min, observing whether the microfluid channel is clearly visible, and observing whether the non-fluid channel part is clean, if there is residual photoresist, then continue developing until the fluid channel is clear and the silicon wafer surface is clean.

6. The polymer composite film for skin moisturization according to claim 5, wherein The S7 hardening film treatment specifically is: baking on a 150 °C heating platform to remove residual developing solution and moisture, and then cooling to room temperature; the S8 preparation method of liquid PDMS is: stirring PDMS and curing agent uniformly according to a mass fraction of 10:1, using a vacuum box to extract gas from the liquid PDMS, and repeating the process until the mixed solution is completely transparent and clear, to obtain the liquid PDMS. The S5 secondary heating of the silicon wafer specifically is: heating at 65 °C for 3 min, then increasing the temperature to 95 °C for 20 min, finally turning off the heating platform power, and allowing the photoresist to cool naturally to room temperature with the heating platform. The S6 developing process specifically is: placing the photoetched silicon wafer into a petri dish containing SU8-2050 special developing solution, repeatedly stirring the silicon wafer with tweezers to allow the silicon wafer surface to fully contact the developing solution, rinsing the silicon wafer surface with deionized water after 5 min, observing whether the microfluid channel is clearly visible, and observing whether the non-fluid channel part is clean, if there is residual photoresist, then continue developing until the fluid channel is clear and the silicon wafer surface is clean. The S7 hardening film treatment specifically is: baking on a 150 °C heating platform to remove residual developing solution and moisture, and then cooling to room temperature; the S8 preparation method of liquid PDMS is: stirring PDMS and curing agent uniformly according to a mass fraction of 10:1, using a vacuum box to extract gas from the liquid PDMS, and repeating the process until the mixed solution is completely transparent and clear, to obtain the liquid PDMS.

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