Ultrathin optical transparent consumable film as well as preparation method and application thereof

Abstract

The invention discloses an ultrathin optical transparent consumable film and a preparation method and application thereof.The preparation method is a multi-physics field coupling auxiliary solution tape casting method, an electrostatic field and thermal field regulation and control mechanism is introduced on the basis of a traditional tape casting method, and the ultrathin optical transparent consumable film which is good in uniformity, free of bubbles and smaller than 3 microns in thickness can be prepared; the preparation method is simple, the preparation cost of the ultrathin optical transparent consumable film can be remarkably reduced, and large-scale industrial production is expected to be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision polymer films, and in particular relates to an ultra-thin optically transparent consumable film and a preparation method and application thereof. Background Art

[0002] As a key technology in the field of life sciences in the 21st century, laser microdissection technology can achieve subcellular precision separation, capture and sample preservation from complex biological tissues, effectively avoiding the risk of heterogeneous contamination in the traditional sample collection process. The core consumables that laser microdissection technology currently relies on, membrane slides and frame slides, have long been monopolized by foreign manufacturers for their preparation technology. Core consumables rely on imports, and key technical links are subject to foreign patent barriers.

[0003] In laser microdissection technology, the thickness of the consumable film has a direct impact on the cutting accuracy and cell / tissue capture efficiency. The film thickness of commercially available consumables is mostly 1 to 4 μm (such as Leica laser microdissection slides), and the film thickness requirement depends on the material's ability to absorb lasers. In industrial production, the melt extrusion stretching method is often used to achieve mass production of ultra-thin polymer films. For example, CN101367266A discloses a method for preparing ultra-thin polymer films by melt extrusion stretching, which can produce films with a thickness of less than 7 μm; CN102582311B produces ultra-thin thermal transfer PET films with a thickness of 3.5 to 5.3 μm through a specific process. However, for some materials with low ultraviolet laser absorption rates, such as PET (the thickness of the PET film in the Leica PET frame slide is 1.4 μm), there are technical challenges in using melting technology to prepare films with a thickness of less than 3 μm, and the related processes are complex, the equipment is expensive, and the preparation cost is high.

[0004] The spin coating process can quickly prepare ultra-thin polymer films ranging from a few nanometers to tens of microns. U.S. Patent US0030031781A1 discloses a thermoplastic EVA film prepared by spin coating process, which is used as an infrared laser microdissection cell tissue transfer membrane; US2010 / 0055759A1 discloses a photoreactive epoxy resin (such as SU-8) transparent laser microdissection film prepared by spin coating process, which is used as a cell tissue support membrane for ultraviolet laser microdissection. However, this method has technical limitations such as high reliance on expensive precision equipment for film uniformity, high raw material loss rate, narrow process window, and insufficient control accuracy for submicron to micron scale film thickness, making it difficult to achieve large-scale industrial production.

[0005] Solution casting is a method for mass-producing ultrathin polymer films by regulating polymer concentration and coating thickness. However, the traditional solution casting method may cause uneven solution spreading due to differences in substrate surface tension distribution, which may easily produce non-uniform thickness areas and local defects. Summary of the invention

[0006] The purpose of the present invention is to provide an ultra-thin optically transparent consumable film and a preparation method and application thereof, wherein the film is prepared by a casting method, and an electrostatic field and a thermal field are used in the coating process to effectively improve the uniformity of the coating and reduce defects such as bubbles and stripes in the film.

[0007] The technical solution of the present invention is as follows:

[0008] A method for preparing an ultra-thin optically transparent consumable film comprises the following steps:

[0009] (1) dissolving a dehydrated polymer powder having a water content of ≤0.3 wt.% in an organic solvent to obtain a homogeneous precursor solution having a solid content of 3 to 30 wt.%;

[0010] (2) coating the homogeneous precursor solution on the surface of the substrate at a speed of 0.5 to 2.0 mm / s using an energized coating device, and obtaining an ultra-thin optically transparent consumable film after drying, wherein the temperature of the substrate is 0 to 250° C., the voltage of the coating device is 0 to 15 kV, and the coating thickness is 1 to 20 μm;

[0011] The dehydrated polymer powder is obtained by dehydrating a soluble thermoplastic polymer powder having ultraviolet light absorption characteristics and a relative molecular weight of 20,000 to 1,000,000 g / mol.

[0012] In the above technical solution, the external electric field can induce the orderly arrangement of polymer molecular chains, enhance the adhesion between the solution and the substrate, improve the coating uniformity, improve the spreading performance of the solvent on the substrate, reduce defects such as bubbles and stripes, and promote the orderly arrangement of polymer molecular chains and improve mechanical or optical properties. At the same time, the volatilization rate of the solvent, the film formation rate and the film crystallinity can be controlled by the thermal field.

[0013] In some preferred embodiments, the preparation method of the dehydrated polymer powder is: vacuum dehydrating the powder of the soluble thermoplastic polymer at 50-80° C. for 1-4 hours.

[0014] In some preferred embodiments, the soluble thermoplastic polymer is at least one of polyethersulfone (PES), polybenzimidazole (PBI), polyethylene terephthalate (PET), and polyimide (PI).

[0015] In some preferred embodiments, the preparation method further includes step (3): keeping the ultra-thin optically transparent consumable film at 50°C for 10 to 30 minutes, then heating it to 100 to 350°C at a heating rate of 2 to 20°C / min, keeping it for 30 to 60 minutes, and finally cooling it to room temperature.

[0016] In some preferred embodiments, the cooling method is natural cooling, annealing or quenching.

[0017] In some preferred embodiments, the specific operation of dissolving is to mix the dehydrated polymer powder with an organic solvent, heat to 40-60° C., and then stir for 2-4 hours.

[0018] In some preferred embodiments, the organic solvent is at least one of N-methylpyrrolidone, dimethylformamide, dimethylacetamide, tetrahydrofuran, hexafluoroisopropanol, trifluoroacetic acid, dichloromethane, ethylene glycol, dimethyl isosorbide and dimethyl sulfoxide.

[0019] In some preferred embodiments, the coating device is a doctor blade, a four-sided preparer, a wire rod, or an automatic coater.

[0020] An ultra-thin optically transparent consumable film is prepared by the above preparation method.

[0021] Application of the above ultra-thin optically transparent consumable film in the preparation of glass slides.

[0022] The application of the above-mentioned ultra-thin optically transparent consumable film in laser microdissection technology.

[0023] The present invention has at least the following beneficial effects:

[0024] The preparation method provided by the present invention is a multi-physical field coupling-assisted solution casting method, which introduces electrostatic field and thermal field control mechanisms on the basis of the traditional casting method, and can produce ultra-thin optically transparent consumable films with good uniformity, no bubbles and a thickness of less than 3μm. The preparation method is simple, does not require sophisticated production equipment, can significantly reduce the preparation cost of ultra-thin optically transparent consumable films, and is expected to realize large-scale industrial production and domestic substitution of ultra-thin optically transparent consumable films. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 An optical photograph of a homemade PET frame glass slide assembled from the optimized ultra-thin optically transparent consumable film prepared in Example 1;

[0026] Figure 2 The optical microscope photos of Example 1 and Comparative Example 1, wherein (a) is Comparative Example 1, and (b) is Example 1;

[0027] Figure 3 It is a force-displacement curve diagram of the puncture resistance test of Example 1 and Comparative Example 2;

[0028] Figure 4 Optical microscope photos of UV laser cutting of Example 1 and Comparative Example 2, where (a) is Comparative Example 2, and (b) is Example 1. From left to right, the laser currents are 3.4 A, 3.3 A, and 3.2 A, respectively. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0030] In the following examples, the water used can be one or more of distilled water, purified water, and deionized water; unless otherwise specified, the detection methods in the following examples are conventional detection methods; unless otherwise specified, the reagents in the following examples are purchased from commercial channels. The Example 1 and Comparative Example 1 mentioned in the performance test and the accompanying drawings refer to the optimized ultra-thin optically transparent consumable film and the optimized comparative consumable film finally prepared.

[0031] Example 1

[0032] (1) dehydrating PET powder with a relative molecular weight of 50,000 g / mol at 65° C. in a vacuum environment for 3 h, and measuring the water content of the PET powder to be ≤0.3 wt.%, to obtain a dehydrated polymer powder;

[0033] (2) mixing the dehydrated polymer powder with a mixed solvent of trifluoroacetic acid (TFA) and dichloromethane (DCM) (volume ratio of 1:1), and then stirring at 40° C. for more than 3 h to obtain a homogeneous precursor solution with a PET content of 20 wt.%;

[0034] (3) using a scraper as a coating device and applying a positive voltage of 5 kV to it, applying a homogeneous precursor solution to the surface of the substrate at a coating speed of 1 mm / s, wherein the substrate is heated to 60° C., the coating thickness is 5 μm, and after drying, an ultra-thin optically transparent consumable film with an average thickness of 2 μm is obtained;

[0035] (4) The ultra-thin optically transparent consumable film is placed in a program temperature control device and a heat treatment program is performed, the temperature is kept at 50°C for 20 minutes, and then the temperature is increased to 200°C at a heating rate of 10°C / min and maintained for 45 minutes. Finally, the film is naturally cooled to room temperature to obtain an optimized ultra-thin optically transparent consumable film.

[0036] Comparative Example 1

[0037] (1) dehydrating PET powder with a relative molecular weight of 50,000 g / mol at 65° C. in a vacuum environment for 3 hours, and measuring the water content of the PET powder to be ≤0.3 wt.%, to obtain a dehydrated polymer powder;

[0038] (2) mixing the dehydrated polymer powder with a mixed solvent of trifluoroacetic acid (TFA) and dichloromethane (DCM) (volume ratio of 1:1), and then stirring at 40° C. for more than 3 h to obtain a homogeneous precursor solution with a PET solid content of 20 wt.%;

[0039] (3) Using a doctor blade as a coating device, a homogeneous precursor solution is applied to the substrate surface at a coating speed of 1 mm / s, with a coating thickness of 5 μm. After drying, a comparative consumable film with an average thickness of 2 μm is obtained;

[0040] (4) The ultra-thin optically transparent consumable film was placed in a programmable temperature control device and a heat treatment program was performed, the temperature was kept at 50°C for 20 minutes, and then the temperature was increased to 200°C at a rate of 10°C / min and kept for 45 minutes. Finally, the film was naturally cooled to room temperature to obtain an optimized comparative consumable film.

[0041] Comparative Example 2

[0042] Comparative Example 2 is a commercially available Leica 11505151 microdissection slide (or Leica PET frame slide).

[0043] Performance Testing

[0044] (1) Example 1 was assembled to obtain a homemade PET frame slide, and it can be seen that Example 1 has good visible light transmittance.

[0045] (2) Example 1 and Comparative Example 1 were placed under an optical microscope to observe their film-forming states. The results are as follows: Figure 2 As shown, it can be seen that there are no bubbles in Example 1 while there are multiple obvious bubble defects in Comparative Example 1.

[0046] (3) According to GB / T37841-2019, the PET frame slide assembled in Example 1 and Comparative Example 2 were tested for puncture resistance at a puncture speed of 50 mm / min. The results are as follows: Figure 3 It can be seen that under the same force, the displacement of Example 1 is slightly greater than that of Comparative Example 2, but the puncture resistance of the two is basically the same.

[0047] (4) The homemade PET frame slide and comparative example 2 were cut using ultraviolet laser at a cutting speed of 100 μm / s and laser currents of 3.4 A, 3.3 A, and 3.2 A. The results were observed under an optical microscope. Figure 4 As shown, it can be seen that in Example 1, 3.4A and 3.3A can be cut by ultraviolet laser to form a preset pattern.

[0048] In summary, Example 1 has better film-forming performance and significantly reduces bubble defects by adding multi-physical field coupling auxiliary preparation on the basis of the casting method, compared with Comparative Example 1 prepared only by the casting method. The performance of the PET frame slide assembled in Example 1 basically reaches the commercial level, and it is expected to achieve domestic substitution of existing commercial products.

[0049] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A method for preparing an ultra-thin optically transparent consumable film, characterized in that: The steps include: (1) dissolving a dehydrated polymer powder having a water content of ≤0.3 wt.% in an organic solvent to obtain a homogeneous precursor solution having a solid content of 3 to 30 wt.%; (2) coating the homogeneous precursor solution on the surface of the substrate at a speed of 0.5 to 2.0 mm / s using an energized coating device, and obtaining the ultra-thin optically transparent consumable film after drying, wherein the temperature of the substrate is 0 to 250° C., the voltage of the coating device is 0 to 15 kV, and the coating thickness is 1 to 20 μm; The dehydrated polymer powder is obtained by dehydrating a soluble thermoplastic polymer powder having ultraviolet light absorption characteristics and a relative molecular weight of 20,000 to 1,000,000 g / mol.

2. The preparation method according to claim 1, characterized in that The preparation method of the dehydrated polymer powder is as follows: vacuum dehydrating the powder of the soluble thermoplastic high molecular polymer at 50-80° C. for 1-4 hours.

3. The preparation method according to claim 1 or 2, characterized in that: The soluble thermoplastic high molecular polymer is at least one of polyethersulfone, polybenzimidazole, polyethylene terephthalate and polyimide.

4. The preparation method according to claim 1, characterized in that: The method further comprises step (3): keeping the ultra-thin optically transparent consumable film at 50° C. for 10 to 30 minutes, then heating the film to 100 to 350° C. at a heating rate of 2 to 20° C. / min, keeping the temperature for 30 to 60 minutes, and finally cooling the film to room temperature.

5. The preparation method according to claim 4, characterized in that: The cooling method is natural cooling, annealing or quenching.

6. The preparation method according to claim 1, characterized in that: The specific operation of the dissolution is to mix the dehydrated polymer powder with the organic solvent, heat to 40-100° C. and then stir for 2-4 hours.

7. The preparation method according to claim 1 or 6, characterized in that: The organic solvent is at least one of N-methylpyrrolidone, dimethylformamide, dimethylacetamide, tetrahydrofuran, hexafluoroisopropanol, dichloromethane and dimethyl sulfoxide.

8. An ultra-thin optically transparent consumable film, characterized in that: The method is prepared according to any one of claims 1 to 7.

9. Use of the ultra-thin optically transparent consumable film according to claim 8 in preparing a glass slide.

10. Use of the ultra-thin optically transparent consumable film according to claim 8 in laser microdissection technology.

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