A self-adhesive photocuring polycarbonate film with one-way liquid guiding function and a preparation method thereof

Abstract

The application discloses a self-adhesive photocuring polycarbonate film with one-way liquid guiding function and a preparation method thereof, and belongs to the technical field of medical dressings. The film comprises a film body, the film body has oppositely arranged first and second surfaces, a plurality of large holes are distributed on the first surface, a plurality of small holes are distributed on the second surface, the large holes and the small holes are communicated through asymmetric conical channels penetrating through the film body, the large hole diameter is 300-500 microns, the small hole diameter is 50-150 microns, and the film body has self-adhesion. The preparation method comprises the following steps: preparing a photocuring precursor, pouring the photocuring precursor into a PDMS mold, and performing scraping coating forming; and demolding after ultraviolet light curing. The film of the application realizes directional transmission of liquid through the asymmetric conical channels in a single film layer and in cooperation with a hydrophilic layer to form a capillary liquid absorption gradient, and meanwhile, no additional fixing material is needed.

Description

Technical Field

[0001] This invention relates to the field of medical dressing technology, and in particular to a self-adhesive photocurable polycarbonate film with one-way liquid guiding function and its preparation method. Background Technology

[0002] One-way fluid-guiding membrane materials allow liquids to preferentially pass through the membrane layer in a specific direction, showing potential applications in wound exudate management, medical dressing interface layers, and flexible adhesive materials. Existing one-way fluid-guiding membranes mostly employ Janus hydrophilic-hydrophobic gradient structures, electrospun nanofiber structures, or multilayer composite structures to achieve directional liquid transport. However, multilayer composite structures suffer from insufficient interlayer bonding and are prone to delamination after long-term wet use; electrospun nanofiber membranes have drawbacks such as wide pore size distribution and insufficient mechanical stability. Furthermore, some materials utilize post-processing methods such as fabric perforation or laser drilling to create conical channels, but the pore morphology is easily affected by factors such as substrate softness and processing pressure, making consistency and stability difficult to guarantee. Regarding material systems, existing fluid-guiding membranes typically lack self-adhesion capabilities, requiring medical tape or additional adhesive layers for fixation, increasing structural complexity. Photocuring processes offer advantages such as fast curing speed, room temperature operation, and low energy consumption, and can precisely replicate microstructure patterns using mold methods. Photocurable polycarbonate materials possess advantages such as strong structural designability, adjustable mechanical properties, and mild molding conditions. However, there is currently no record of combining a photocurable polycarbonate system with a tapered through-hole structure to create a bird's beak-like geometric gradient liquid-guiding channel in a single film layer using a molding method, thereby giving the resulting film both unidirectional liquid-guiding and self-adhesive functions.

[0003] Therefore, providing a thin film material that can stably form a unidirectional liquid guiding structure in a single film layer and also has self-adhesive function has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] This invention provides a self-adhesive photocurable polycarbonate film with unidirectional liquid guiding function, comprising a film body formed of photocurable polycarbonate material. The film body has a first surface and a second surface disposed opposite to each other. A plurality of macropores are distributed on the first surface, and a plurality of micropores are distributed on the second surface. The macropores and micropores in the same axial direction are connected by an asymmetric conical channel penetrating the thickness direction of the film body. The macropore diameter is 300 to 500 micrometers, and the micropore diameter is 50 to 150 micrometers. The film body has self-adhesive properties.

[0005] Furthermore, the macropore diameter is 400 micrometers, and the micropore diameter is 100 micrometers.

[0006] Furthermore, the film body is formed by UV curing and crosslinking a photocurable precursor comprising methacrylic anhydride-modified polytrimethylene carbonate, a hydrophilic active monomer, an adhesion-related active monomer, and a photoinitiator. The hydrophilic active monomer is N,N-dimethylacrylamide, and the adhesion-related active monomer includes a first adhesion-related active monomer and a second adhesion-related active monomer. The first adhesion-related active monomer is an acrylate monomer containing a C18 long-chain alkyl group, and the second adhesion-related active monomer is a methacrylate monomer containing a C12 long-chain alkyl group. The mass ratio of the methacrylic anhydride-modified polytrimethylene carbonate, N,N-dimethylacrylamide, the acrylate monomer containing a C18 long-chain alkyl group, and the methacrylate monomer containing a C12 long-chain alkyl group is 3–6:1–3:1–3:1–3, preferably 4:2:2:2.

[0007] Furthermore, the photoinitiator is an acylphosphine oxide photoinitiator TMO, and the amount of photoinitiator is 1% to 3% of the total mass of the photocurable precursor.

[0008] Furthermore, the unidirectional liquid guiding function of the film is achieved in conjunction with the hydrophilic layer, which provides the driving force for capillary action. The hydrophilic layer can be any one of medical gauze, non-woven fabric, cotton pad, hydrophilic hydrogel or sponge.

[0009] The present invention also provides a method for preparing the above-mentioned self-adhesive photocurable polycarbonate film with unidirectional liquid guiding function, comprising the following steps:

[0010] Step S100: Preparation of photocurable precursor: Mix methacrylic anhydride modified polytrimethylene carbonate, hydrophilic active monomer, adhesion-related active monomer and photoinitiator evenly to obtain photocurable precursor;

[0011] Step S200, mold preparation and casting: a polydimethylsiloxane mold is provided, the surface of which has an asymmetric array of conical micropillars that complements the conical channel structure, and the photocurable precursor obtained in step S100 is cast onto the surface of the mold.

[0012] Step S300, Scraping and forming: Using a scraper, the precursor is evenly scraped along the surface of the mold to fill the gaps between the conical micropillar array and form a precursor film layer of uniform thickness.

[0013] Step S400, UV curing, the precursor film obtained in step S300 is cured by UV irradiation;

[0014] Step S500: Demolding. The film cured in step S400 is removed from the mold surface to obtain a self-adhesive photocurable polycarbonate film with asymmetric conical through-holes.

[0015] Further, in step S200, the diameter of the large end of the micropillar is 300 to 500 micrometers, the diameter of the small end of the micropillar is 50 to 150 micrometers, and the pore size of the micropillar gradually changes along the axial direction. In step S300, the film thickness is 400 micrometers. In step S400, the ultraviolet light wavelength is 365 nanometers, and the ultraviolet light irradiation time is 20 to 60 seconds.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) This invention uses a single photocurable polycarbonate film layer to construct a directional liquid-conducting key structure. The asymmetric conical through-holes within the film body form a geometric gradient structure. The different radii of curvature at the two ends of the channels generate a capillary pressure difference, making it easier for liquid to enter from the larger end and be transported to the smaller end. When the smaller end contacts the hydrophilic layer, the hydrophilic layer further provides capillary absorption, promoting the transfer of liquid towards the hydrophilic layer. Compared with existing materials that rely on multiple hydrophilic and hydrophobic film layers to form liquid-conducting channels, the liquid-conducting key structure of this invention is located inside the film body, and the hydrophilic layer mainly plays the role of liquid absorption and conduction. Therefore, the structure is simpler and the morphology of the liquid-conducting channel is more stable.

[0018] (2) This invention replicates and forms conical through-holes in one step using a mold method and ultraviolet curing process. The hole structure is continuous and the morphology is clear, avoiding problems such as uneven hole shape, hole edge damage, or structural springback that may be caused by post-processing methods such as fabric perforation and laser drilling. The photocuring process has the advantages of fast curing speed, room temperature operation, and low energy consumption. Moreover, the mold method can accurately replicate microstructure patterns, which is conducive to forming asymmetric conical through-holes with clear structure and good hole consistency. The photoinitiator is an acylphosphine oxide photoinitiator TMO, which can initiate photocuring crosslinking reaction under 365nm ultraviolet light irradiation.

[0019] (3) When the film of the present invention is used in conjunction with the hydrophilic layer, it exhibits directional liquid-guiding properties. The hydrophilic layer can be any of the following: medical gauze, non-woven fabric, cotton pad, hydrophilic hydrogel, or sponge, with a wide range of choices to suit different application scenarios. The directional liquid-guiding properties are derived from the combined effects of the Laplace pressure difference generated by the asymmetric conical channels, the geometric gradient of the channels, and the capillary liquid absorption effect of the hydrophilic layer, resulting in clear and reliable liquid guidance.

[0020] (4) This invention introduces adhesion-related active monomers containing long-chain alkyl groups into the photocurable polycarbonate system, giving the film body self-adhesive properties. Tests show that the film has a peel strength of 116 millinewtons and a shear strength of 53 kPa, significantly higher than pure PTMCMA films and close to the adhesion levels of routine clinical dressings. The film can be adhered to the substrate surface without additional medical tape or external fixation materials, helping to simplify the dressing structure and improve ease of use.

[0021] (5) The film of the present invention has good flexibility and mechanical stability. Tests show that the tensile strength of the film is 2.38 MPa, the elastic modulus is 3.14 MPa, and the elongation at break is 379%, which can meet the requirements of flexible interface adhesion and maintain structural integrity under bending, adhesion, or slight tension conditions. The film surface also has a certain degree of wettability, which can promote the contact and spreading of liquid with the film surface, facilitating the entry of liquid into the asymmetric conical channels and providing a good interfacial basis for the liquid conduction process.

[0022] The present invention will now be further described with reference to the accompanying drawings. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the preparation process of the self-adhesive photocurable polycarbonate film of the present invention.

[0024] Figure 2 This is a scanning electron microscope image of the pores in the thin film. Detailed Implementation

[0025] Reference Figure 1 , Figure 1 This is a schematic diagram illustrating the preparation process of the self-adhesive photocurable polycarbonate film of the present invention. The film of the present invention includes a film body formed of photocurable polycarbonate material. The film body has a first surface and a second surface arranged opposite to each other. A plurality of asymmetric conical channels penetrating the thickness direction are provided in the film body. The conical channels form large-aperture ends on the first surface and small-aperture ends on the second surface. The large-aperture ends and the small-aperture ends are connected, thereby forming a geometric gradient liquid guiding channel within a single film layer.

[0026] The pore size at the macropore end is 300 to 500 micrometers, and the pore size at the micropore end is 50 to 150 micrometers. Preferably, the pore size at the macropore end is 400 micrometers, and the pore size at the micropore end is 100 micrometers. The different radii of curvature at the two ends of the tapered channel can create a capillary pressure difference, making it easier for liquid to enter from the macropore end and be transported to the micropore end. When the micropore end comes into contact with the hydrophilic layer, the capillary action of the hydrophilic layer further promotes the transfer of liquid to the hydrophilic layer, thereby achieving directional liquid conduction.

[0027] The film bulk is formed by UV curing and crosslinking a photocurable precursor comprising methacrylic anhydride-modified polytrimethylene carbonate, hydrophilic reactive monomers, adhesion-related reactive monomers, and a photoinitiator. The methacrylic anhydride-modified polytrimethylene carbonate serves as the photocurable polycarbonate matrix, providing the film with a crosslinkable structure, flexibility, and film-forming properties. The hydrophilic reactive monomers are used to adjust the polarity, flexibility, and wetting properties of the film. The adhesion-related reactive monomers are long-chain alkyl monomers used to impart self-adhesive properties to the film bulk, enabling it to adhere to skin, dressing absorbent layers, or other flexible substrate surfaces without the need for additional adhesive layers. The photoinitiator is an acylphosphine oxide photoinitiator, TMO. As a new generation of environmentally friendly photoinitiators, TMO is non-reproductive, highly reactive, and benzene-free, making it suitable for the preparation of medical materials. The amount of photoinitiator used is 1% to 3% of the total mass of the photocurable precursor.

[0028] Preferably, the hydrophilic active monomer is N,N-dimethylacrylamide, which contains polar structures such as amide groups, and can participate in photocuring crosslinking and be introduced into the polycarbonate network, thereby improving the polarity of the film surface and the liquid interface. The first adhesion-related active monomer is an acrylate monomer containing C18 long-chain alkyl groups, and the second adhesion-related active monomer is a methacrylate monomer containing C12 long-chain alkyl groups. The mass ratio of methacrylic anhydride-modified polytrimethylene carbonate, N,N-dimethylacrylamide, acrylate monomer containing C18 long-chain alkyl groups, and methacrylate monomer containing C12 long-chain alkyl groups is 3-6:1-3:1-3:1-3. Preferably, the mass ratio of the four is 4:2:2:2.

[0029] The unidirectional liquid-guiding function of the membrane requires the cooperation of a hydrophilic layer. The hydrophilic layer provides a continuous capillary driving force for the liquid, rapidly absorbing and discharging the liquid transported through the conical channels. The hydrophilic layer can be any of the following: medical gauze, non-woven fabric, cotton pads, hydrophilic hydrogel, or sponge. The hydrophilic layer has a porous liquid-absorbing structure, which absorbs and discharging the liquid transported by the conical channels through capillary action, thus creating a directional liquid-guiding effect together with the asymmetric conical channels.

[0030] The present invention will be further illustrated below through specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Any equivalent substitutions or adjustments made by those skilled in the art to the types of materials, material ratios, mold dimensions, curing conditions, or testing methods without departing from the concept of the present invention should fall within the scope of protection of the present invention.

[0031] Example 1: Preparation of methacrylic anhydride-modified polytrimethylene carbonate;

[0032] A certain amount of trimethylene carbonate monomer was weighed and added to a polymerization tube, along with stannous octoate catalyst and 1,3-propanediol initiator in proportion. The system was evacuated and nitrogen was introduced, repeated three times to remove oxygen and moisture, ensuring the reaction was under vacuum-nitrogen protection. The polymerization tube was then sealed with a high-temperature spray gun and placed in an oil bath at 130°C for 24 hours. After the reaction, the product was dissolved in dichloromethane, and anhydrous ethanol and anhydrous diethyl ether were added sequentially for precipitation and purification to remove unreacted monomers and small molecule impurities. The resulting polymer was vacuum dried at 40°C to constant weight to obtain polytrimethylene carbonate.

[0033] Five grams of dried polytrimethylene carbonate were dissolved in dichloromethane. Triethylamine and methacrylic anhydride were added under nitrogen purging, and the mixture was stirred in the dark for 24 hours. After the reaction was completed, the product was precipitated with anhydrous ethanol, filtered, and dried under vacuum to remove residual solvent, yielding methacrylic anhydride-modified polytrimethylene carbonate, i.e., PTMCMA.

[0034] Example 2: Preparation of self-adhesive photocurable polycarbonate film;

[0035] The preparation method of this embodiment includes the following steps:

[0036] Step S100: Preparation of the photocurable precursor.

[0037] The methacrylic anhydride-modified polytrimethylene carbonate obtained in Example 1 was mixed uniformly with N,N-dimethylacrylamide, acrylate monomers containing C18 long-chain alkyl groups, methacrylate monomers containing C12 long-chain alkyl groups, and photoinitiator TMO to obtain a photocurable precursor. The mass ratio of the four components was 4:2:2:2, and the amount of TMO was 1% to 3% of the total mass of the photocurable precursor.

[0038] Step S200: Mold preparation and pouring.

[0039] A polydimethylsiloxane mold is provided, the surface of which has an asymmetric array of conical micropillars complementary to the conical channel structure, the large end diameter of the micropillars being 300 to 500 micrometers and the small end diameter being 50 to 150 micrometers. The photocurable precursor obtained in step S100 is cast onto the surface of the mold.

[0040] Step S300: Scrape coating to form the shape.

[0041] A scraper is used to uniformly coat the precursor along the surface of the mold, so that the photocurable precursor fills the gaps between the conical micropillar array and forms a precursor film layer of uniform thickness. The film thickness is 400 micrometers.

[0042] Step S400: UV curing.

[0043] The precursor film obtained in step S300 is cured by ultraviolet light irradiation. The ultraviolet light wavelength is 365 nm, and the ultraviolet light irradiation time is 20 to 60 seconds.

[0044] Step S500: Demolding.

[0045] The cured film in step S400 is detached from the mold surface to obtain a self-adhesive photocurable polycarbonate film with asymmetric conical through-holes.

[0046] Preferably, in step S200, the diameter of the bottom end of the micropillar is 400 micrometers, and the diameter of the top end of the micropillar is 100 micrometers. Preferably, in step S400, the ultraviolet light irradiation time is 30 seconds.

[0047] Using the aforementioned mold method and UV curing process, the asymmetric conical micropillar array on the mold surface is replicated in a single step into conical through-holes within the film body, thereby forming a liquid transport channel with geometric gradients in a single photocurable polycarbonate film layer. The photocuring process offers advantages such as fast curing speed, room temperature operation, and low energy consumption. Furthermore, the mold method allows for precise replication of microstructure patterns, which is beneficial for forming asymmetric conical through-holes with well-defined structures and good channel consistency.

[0048] Example 3, Characterization of thin film microstructure;

[0049] Example 3 was used to verify whether asymmetric conical through-holes were formed in the self-adhesive photocurable polycarbonate film prepared in Example 2, and the morphology of the macropore surface, micropore surface, and cross-section of the film was observed. Scanning electron microscopy was used to observe the surface and cross-sectional structure of the film, demonstrating that the film of the present invention can form a conical channel structure with the macropore end connected to the micropore end within a single film layer.

[0050] Reference Figure 2 , Figure 2 In the image, a is a scanning electron microscope (SEM) image of the macropore surface of the thin film; b is a scanning electron microscope (SEM) image of the micropore surface of the thin film; c is a scanning electron microscope (SEM) image of the cross-section of the thin film; d is a magnified view of a portion of the macropore surface, showing that the macropore diameter is approximately 400 μm; e is a magnified view of a portion of the micropore surface, showing that the micropore diameter is approximately 100 μm; and f is a magnified view of a portion of the cross-section of the tapered through-hole, showing that the through-hole gradually narrows along the thickness direction of the thin film and penetrates the entire thin film.

[0051] The self-adhesive photocurable polycarbonate film prepared in Example 2 was cut to an appropriate size, exposing the macropore surface, micropore surface, and cross-section of the film. After drying, the sample was fixed on the scanning electron microscope stage and subjected to gold sputtering. Subsequently, the macropore surface, micropore surface, and cross-sectional morphology of the film were observed using a scanning electron microscope.

[0052] Among them, the large-hole surface is used to observe the morphology of the large-hole opening on the first surface of the film, the small-hole surface is used to observe the morphology of the small-hole opening on the second surface of the film, and the cross section is used to observe the continuity of the channel in the thickness direction of the film and the tapered change characteristics.

[0053] Scanning electron microscopy results as follows Figure 2 As shown, multiple large pores are regularly arranged on the first surface of the thin film, with relatively intact pore edges and a pore diameter of approximately 400 μm. Figure 2 a, Figure 2 d). Small pore openings corresponding to the locations of the macropores are visible on the second surface of the film. The pore diameter is significantly smaller than that of the macropores, approximately 100 μm, and the pore openings are relatively uniformly distributed. Figure 2 b、 Figure 2 e).

[0054] The cross-sectional view of the thin film shows that the pores penetrate the film body along the thickness direction and gradually narrow from the large pore end to the small pore end, exhibiting a distinct asymmetric conical structure. Figure 2 c. Figure 2 f). The magnified view further shows that the conical channel structure is intact and the pore walls are continuous, indicating that the asymmetric conical micropillar array in the PDMS microstructure mold can be effectively replicated into the photocurable polycarbonate film.

[0055] The above results demonstrate that, after replication using a PDMS microstructure mold and UV curing, the photocurable precursor can form asymmetrical conical through-channels with complete structure, regular arrangement, and continuous pores within a single film layer. This structure differs from ordinary straight-pore or random porous membranes; its channels have different pore diameters and radii of curvature at both ends, which facilitates the formation of capillary pressure differences when the liquid contacts the channels, thus providing a structural basis for the directional transport of liquid from the larger pore end to the smaller pore end.

[0056] Example 4: Test of the directional liquid conductivity of the film after it is combined with the hydrophilic layer;

[0057] The film obtained in Example 2 was brought into contact with the hydrophilic layer in different directions, and a test liquid was dropped onto the side of the film away from the hydrophilic layer to observe the liquid transport behavior. The hydrophilic layer was medical gauze.

[0058] When liquid is dripped onto the macropore side of the membrane and the micropore side contacts the hydrophilic layer, the liquid can enter the conical channel from the macropore end and be transported to the hydrophilic layer through the micropore end under the capillary action of the hydrophilic layer. When liquid is dripped onto the macropore side of the membrane and the micropore side contacts the hydrophilic layer, the liquid entry into the channel from the micropore end is restricted, making it difficult to effectively pass through the membrane. The above results indicate that the membrane of the present invention, when combined with the hydrophilic layer, exhibits directional liquid-conducting properties. In this embodiment, the hydrophilic layer is medical gauze; in performance testing, filter paper can also be used as the hydrophilic absorption layer for verification. The aforementioned directional liquid-conducting properties mainly originate from the combined effects of the Laplace pressure difference generated by the asymmetric conical channel, the channel geometric gradient, and the capillary action of the hydrophilic layer.

[0059] Example 5, Thin film wetting performance test;

[0060] Dynamic water contact angle tests were performed on the film obtained in Example 2. A certain volume of deionized water droplets was added to the film surface, and the spreading state and contact angle changes of the droplets at different time points were recorded using a contact angle measuring instrument. At zero seconds after the droplets were added to the film surface, the water contact angle was 63.8 degrees. As the contact time increased, the droplets gradually spread on the film surface, decreasing to 56.5 degrees at 10 seconds and further decreasing to 54.1 degrees at 20 seconds. These results indicate that the film surface of the present invention has a certain degree of wettability, which can promote the contact and spreading of liquids with the film surface.

[0061] Example 6, Thin film mechanical property testing;

[0062] Tensile properties were tested on the film obtained in Example 2. The film was cut into rectangular specimens of 1 cm x 3 cm and subjected to uniaxial tensile testing using a universal testing machine. Each end of the specimen was clamped for 1 cm, resulting in an effective tensile length of 1 cm and a film thickness of approximately 0.4 mm. Force and displacement data were recorded during the test, and stress was calculated based on the specimen's cross-sectional area, while strain was calculated based on the effective tensile length. The tested tensile strength of the film was 2.38 MPa, the elastic modulus was 3.14 MPa, and the elongation at break was 379%. These results indicate that the polycarbonate elastic network formed by photocuring and crosslinking methacrylic anhydride-modified polytrimethylene carbonate, N,N-dimethylacrylamide, acrylate monomers containing C18 long-chain alkyl groups, and methacrylate monomers containing C12 long-chain alkyl groups can impart good flexibility and mechanical stability to the film.

[0063] Example 7, Film shear adhesion and peel adhesion tests;

[0064] Using an aminated glass plate as the test substrate, the film obtained in Example 2 was subjected to shear adhesion and peel adhesion tests, and compared with pure PTMCMA film and routine clinical dressings. The pure PTMCMA film was a control group containing only methacrylic anhydride-modified polytrimethylene carbonate matrix and photoinitiator TMO, without N,N-dimethylacrylamide, containing C18 long-chain alkyl acrylate monomers, and containing C12 long-chain alkyl methacrylate monomers.

[0065] In the shear adhesion test, the film is brought into contact with an ammonia glass plate and a certain pressure is applied to ensure full adhesion between the film and the substrate. Then, it is stretched along a direction parallel to the interface using a mechanical testing device, and the shear adhesion strength is recorded. In the peel adhesion test, the film is attached to the surface of the ammonia glass plate to ensure full contact between the film and the substrate. Then, it is peeled off at a certain angle, and the peel adhesion strength is recorded.

[0066] Testing revealed that the peel strength of the film of this invention is 116 mN / mm and the shear strength is 53 kPa, significantly higher than those of pure PTMCMA film, and approaching the adhesion levels of routine clinical dressings. These results indicate that long-chain alkyl-containing adhesive-related active monomers, such as acrylate monomers containing C18 long-chain alkyl groups and methacrylate monomers containing C12 long-chain alkyl groups, can enhance the interfacial interaction between the film and the substrate, thereby endowing the film with self-adhesive properties. This self-adhesive property allows the film of this invention to adhere to the substrate surface without the need for additional medical tape or external fixation materials, helping to simplify dressing structure.

[0067] As can be seen from the above embodiments, the film of the present invention forms asymmetric conical through-holes in a single film layer through a photocuring molding method. The macropore diameter is 400 micrometers and the micropore diameter is 100 micrometers, and the pore structure is complete and continuous. After being combined with a hydrophilic layer, the film exhibits directional liquid-conducting properties, with moderate wettability, good flexibility, and mechanical stability. Simultaneously, the film has self-adhesive properties, with adhesion performance significantly better than pure PTMCMA film and approaching the level of routine clinical dressings.

[0068] The above results demonstrate that the film of the present invention, through the synergistic design of asymmetric conical through-holes and a self-adhesive photocurable polycarbonate network, simultaneously achieves directional liquid conduction, moderate wetting, flexible support, and self-adhesion functions in a single film. This structure differs from existing liquid-conducting materials that rely on multilayer composites, post-processing perforations, or the addition of external adhesive layers, and is characterized by its simple structure, convenient preparation, and ease of use.

Claims

1. A self-adhesive photocurable polycarbonate film with unidirectional liquid guiding function, characterized in that, Including the thin film body, The film body is formed of photocurable polycarbonate material and has a first surface and a second surface arranged opposite each other. Multiple large pores are distributed on the first surface, and multiple small pores are distributed on the second surface. The large and small pores in the same axial direction are connected by asymmetric tapered channels penetrating the thickness direction of the film body. The large pore diameter is 300 to 500 micrometers, and the small pore diameter is 50 to 150 micrometers. The film body has self-adhesive properties. The film body is formed by UV curing and crosslinking of a photocurable precursor containing methacrylic anhydride-modified polytrimethylene carbonate, hydrophilic active monomers, adhesion-related active monomers and photoinitiators; The hydrophilic active monomer is N,N-dimethylacrylamide, and the adhesion-related active monomers include a first adhesion-related active monomer and a second adhesion-related active monomer. The first adhesion-related active monomer is an acrylate monomer containing a C18 long-chain alkyl group, and the second adhesion-related active monomer is a methacrylate monomer containing a C12 long-chain alkyl group. The mass ratio of methacrylic anhydride-modified polytrimethylene carbonate, N,N-dimethylacrylamide, acrylate monomers containing C18 long-chain alkyl groups to methacrylate monomers containing C12 long-chain alkyl groups is 3-6:1-3:1-3:1-3; The photoinitiator is an acylphosphine oxide photoinitiator TMO, and the amount of photoinitiator used is 1% to 3% of the total mass of the photocurable precursor.

2. The self-adhesive photocurable polycarbonate film with unidirectional liquid guiding function according to claim 1, characterized in that, The macropore diameter is 400 micrometers, and the micropore diameter is 100 micrometers.

3. The self-adhesive photocurable polycarbonate film with unidirectional liquid guiding function according to claim 1, characterized in that, The mass ratio of methacrylic anhydride-modified polytrimethylene carbonate, N,N-dimethylacrylamide, acrylate monomers containing C18 long-chain alkyl groups, and methacrylate monomers containing C12 long-chain alkyl groups is 4:2:2:

2.

4. The self-adhesive photocurable polycarbonate film with unidirectional liquid guiding function according to claim 1, characterized in that, The unidirectional liquid guiding function of the film is achieved in conjunction with the hydrophilic layer, which provides the driving force for capillary action. The hydrophilic layer can be any one of medical gauze, non-woven fabric, cotton pad, hydrophilic hydrogel or sponge.

5. A method for preparing a self-adhesive photocurable polycarbonate film with unidirectional liquid guiding function as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Step S100: Preparation of photocurable precursor: Mix methacrylic anhydride modified polytrimethylene carbonate, hydrophilic active monomer, adhesion-related active monomer and photoinitiator evenly to obtain photocurable precursor; Step S200, mold preparation and casting: a polydimethylsiloxane mold is provided, the surface of which has an asymmetric array of conical micropillars that complements the conical channel structure, and the photocurable precursor obtained in step S100 is cast onto the surface of the mold. Step S300, Scraping and forming: Using a scraper, the precursor is evenly scraped along the surface of the mold to fill the gaps between the conical micropillar array and form a precursor film layer of uniform thickness. Step S400, UV curing, the precursor film obtained in step S300 is cured by UV irradiation; Step S500: Demolding. The film cured in step S400 is removed from the mold surface to obtain a self-adhesive photocurable polycarbonate film with asymmetric conical through-holes.

6. The preparation method according to claim 5, characterized in that, In step S200, the diameter of the large end of the micropillar is 300 to 500 micrometers, the diameter of the small end of the micropillar is 50 to 150 micrometers, and the pore size of the micropillar gradually changes along the axial direction. In step S300, the film thickness is 400 micrometers. In step S400, the ultraviolet light wavelength is 365 nanometers, and the ultraviolet light irradiation time is 20 to 60 seconds.

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