Bionic leaf and preparation method thereof

Abstract

The invention discloses a bionic leaf and a preparation method thereof. Firstly, chlorophyllase is inactivated by a hot water bath, and then the photo-oxidation process of chlorophyll is blocked by making a chlorophyll / PVA film and adding a light stabilizer. This method can improve the stability and weather resistance of natural plant leaves without changing the spectral properties, and prepare a bionic leaf with stable spectral performance.

Description

Technical Field

[0001] The present invention relates to the field of adaptive bionic technology, and in particular to a bionic leaf and a preparation method thereof. Background Art

[0002] Adaptive bionic technology is a new technology that can automatically and continuously respond to changes in environmental background, reconnaissance threats, and other conditions, while maintaining a robust biomimetic effect. Adaptive materials are a key component of this technology. Based on the target's detectable threat band, adaptive bionic technology can be categorized into three main categories: visible light adaptive bionic technology, infrared adaptive bionic technology, and radar adaptive bionic technology. Visible light adaptive bionic technology aims to reduce the brightness and color differences between the target and the background, thereby achieving an adaptive bionic effect. For example, traditional camouflage materials can only achieve "color matching" with green vegetation, but not "spectral matching," making them difficult to counteract against fine-grained spectral reconnaissance. The key to countering hyperspectral detection is to achieve a precise spectral match between the bionic plant target and the background. The development of biomimetic camouflage materials with refined reflectance spectral characteristics is an effective approach to achieving this goal.

[0003] The main component of chloroplast pigments is chlorophyll, which is bound to proteins in living cells. The extracted chlorophyll is very unstable and easily decomposes under light, high temperature, oxidation and other environments. If it is directly used as a biomimetic material, not only will the color change, but the spectral characteristics will also change greatly. Yang Yujie, Hu Biru and others designed and prepared a new type of plant leaf biomimetic material. [1] It contains chlorophyll, water and loose porous structure, the three determining factors of the plant leaf reflectance spectrum. The chlorophyll is encapsulated in a high oxygen-barrier material and the water is encapsulated in a high water-barrier material. However, after three months of sunlight, the spectral performance of the material has decreased and the thickness has decreased.

[0004] References:

[0005] [1] Journal of National University of Defense Technology, Design and Preparation of Plant Leaf Bionic Camouflage Materials, No. 5, 2011, pp. 50-53, Yang Yujie, Hu Biru, Wu Wenjian Summary of the Invention

[0006] In view of the deficiencies in the prior art, the present invention aims to provide a bionic leaf and a preparation method thereof.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing a bionic leaf, the specific process is as follows:

[0009] S1. Collect natural plant leaves and treat them in a hot water bath to inactivate chlorophyllase in the natural plant leaves, thereby blocking photosynthesis and biodegradation reactions in the leaves;

[0010] S2, encapsulating the chlorophyll / PVA film on the outer surface of the leaves treated in step S1 to block the photooxidation reaction of the chlorophyll and ensure the retention of the internal moisture;

[0011] The preparation process of the chlorophyll / PVA film is as follows:

[0012] PVA and water are added to a flask, heated and stirred until the PVA is completely dissolved, and allowed to stand for defoaming to obtain a PVA aqueous solution; the chlorophyll ethanol solution and the PVA aqueous solution are mixed, stirred evenly, poured into a mold, and dried in the dark at room temperature to obtain the chlorophyll / PVA film.

[0013] Furthermore, during the preparation of the chlorophyll / PVA film, the chlorophyll ethanol solution and the PVA aqueous solution are mixed and stirred evenly and poured into a mold, and then an oxygen free radical quencher, a free radical capture substance, an antioxidant and an ultraviolet light absorber are further added and fully stirred, and then dried in the dark at room temperature to obtain the chlorophyll / PVA film.

[0014] Furthermore, the oxygen free radical quenching substance is glutathione, the free radical capturing substance is a hindered amine light stabilizer, the antioxidant is butylated hydroxyanisole, and the ultraviolet light absorber is phenyl salicylate.

[0015] Furthermore, based on the total weight of the chlorophyll / PVA film, the added mass percentage of the oxygen free radical quencher is 0.5%; the added mass percentage of the free radical capture substance is 0.5%; the added mass percentage of the antioxidant is 0.5%; and the added mass percentage of the ultraviolet light absorber is 1%.

[0016] The present invention also provides a bionic leaf prepared by the above preparation method.

[0017] The beneficial effects of the present invention are as follows: the method of the present invention first inactivates chlorophyllase through a hot water bath, and then blocks the photooxidation process of chlorophyll by preparing a chlorophyll / PVA film and adding a light stabilizer, thereby improving the stability and weather resistance of natural plant leaves without changing their spectral properties, thereby producing bionic leaves with stable spectral properties. DETAILED DESCRIPTION

[0018] The present invention is further described below. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment.

[0019] This embodiment provides a method for preparing a bionic leaf, and the specific process is as follows:

[0020] S1. Collect natural plant leaves and treat them in a hot water bath to inactivate chlorophyllase in the natural plant leaves, thereby blocking photosynthesis and biodegradation reactions in the leaves;

[0021] S2, encapsulating the chlorophyll / PVA film on the outer surface of the leaves treated in step S1 to block the photooxidation reaction of the chlorophyll and ensure the retention of the internal moisture;

[0022] The preparation process of the chlorophyll / PVA film is as follows:

[0023] PVA and water were added to a flask at a mass ratio of 1:9, stirred at a constant temperature of 90°C until the PVA was completely dissolved, and then allowed to stand at 60°C for 2 hours to defoam to obtain a PVA aqueous solution with a mass concentration of 10%; a chlorophyll ethanol solution with a concentration of 25 mg / 100 ml was mixed with the PVA aqueous solution in a mass ratio of 1:10, stirred evenly, poured into a mold, and dried in the dark at room temperature to obtain the chlorophyll / PVA film.

[0024] In this embodiment, during the preparation process of the above-mentioned chlorophyll / PVA film, the chlorophyll ethanol solution and the PVA aqueous solution are mixed and stirred evenly and poured into a mold, and then an oxygen free radical quencher, a free radical capture substance, an antioxidant and an ultraviolet light absorber are further added and fully stirred, and then dried in the dark at room temperature to obtain the chlorophyll / PVA film.

[0025] Specifically, the oxygen free radical quencher is glutathione, the free radical capture substance is a hindered amine light stabilizer (HALS) tetramethylpiperidine derivative, the antioxidant is butylated hydroxyanisole (BHA), and the ultraviolet light absorber is phenyl salicylate (phenyl o-hydroxybenzoate).

[0026] More specifically, based on the total weight of the chlorophyll / PVA film, the added mass percentage of the oxygen free radical quencher is 0.5%; the added mass percentage of the free radical capture substance is 0.5%; the added mass percentage of the antioxidant is 0.5%; and the added mass percentage of the ultraviolet light absorber is 1%.

[0027] It should be noted that the optimal reaction temperature for chlorophyllase in natural plant leaves is between 60 and 80°C. Its activity decreases above 80°C, and it is completely inactivated at 100°C. Therefore, a simple short-term hot water bath treatment can inactivate chlorophyllase and halt its enzymatic degradation process.

[0028] Light shielding and oxygen isolation are effective measures to reduce the rate of photooxidation and improve chlorophyll stability. Bionic leaves are used in open-air environments, so a transparent oxygen-isolating coating that shields or absorbs UV light while having no effect on visible light is necessary to reduce UV-induced chlorophyll degradation, thereby reducing the overall rate of chlorophyll degradation under sunlight.

[0029] PVA does not react with chlorophyll, uses water as a solvent, can form a standalone film, and can be prepared at room temperature. Therefore, it provides oxygen barrier properties while protecting chlorophyll during processing. Therefore, PVA was selected as the high-oxygen barrier material for chlorophyll protection in this example. PVA is a homopolymer of vinyl alcohol, obtained by alcoholysis of polyvinyl acetate. The oxygen barrier properties of dried PVA film are superior to those of PVDC-coated films and EVOH five-layer coextruded films, and are comparable to those of aluminum foil, glass, aluminum oxide-coated films, and silicon oxide-coated films.

[0030] Furthermore, light and oxygen degradation of chlorophyll occurs by generating excited oxygen, which in turn induces free radicals. Therefore, in this embodiment, the addition of an oxygen free radical quencher and a free radical scavenger (both referred to as photostabilizers) to the chlorophyll / PVA film, along with suitable antioxidants and UV absorbers (collectively referred to as anti-photooxidation agents), can, to a certain extent, block the photooxidation of chlorophyll and improve its stability.

[0031] Those skilled in the art can make various corresponding changes and modifications based on the above technical solutions and concepts, and all of these changes and modifications should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a bionic leaf, characterized in that: The specific process is: S1. Collect natural plant leaves and treat them in a hot water bath to inactivate chlorophyllase in the natural plant leaves and block photosynthesis and biodegradation reactions in the leaves; S2, encapsulating the chlorophyll / PVA film on the outer surface of the leaves treated in step S1 to block the photo-oxidation reaction of the chlorophyll and ensure the retention of the water content; The preparation process of the chlorophyll / PVA film is as follows: PVA and water are added into a flask, heated and stirred until PVA is completely dissolved, and the PVA aqueous solution is obtained after standing and defoaming; the chlorophyll ethanol solution is mixed with the PVA aqueous solution, stirred evenly, poured into a mold, and dried in the dark at room temperature to obtain the chlorophyll / PVA film; During the preparation of the chlorophyll / PVA film, the chlorophyll ethanol solution and the PVA aqueous solution are mixed and stirred evenly and poured into a mold, and then oxygen free radical quenchers, free radical capture substances, antioxidants and ultraviolet light absorbers are further added and fully stirred, and then dried at room temperature away from light to obtain the chlorophyll / PVA film.

2. The method for preparing a bionic leaf according to claim 1, characterized in that: The oxygen free radical quenching substance is glutathione, the free radical capturing substance is a hindered amine light stabilizer, the antioxidant is butylated hydroxyanisole, and the ultraviolet light absorber is phenyl salicylate.

3. The method for preparing a bionic leaf according to claim 1 or 2, characterized in that: Based on the total weight of the chlorophyll / PVA film, the added mass percentage of the oxygen free radical quencher is 0.5%; the added mass percentage of the free radical capture substance is 0.5%; the added mass percentage of the antioxidant is 0.5%; and the added mass percentage of the ultraviolet light absorber is 1%.

4. A bionic leaf prepared by the preparation method according to any one of claims 1 to 3.