A super-tough solid-state fluorescent hydrogel composite material, a preparation method and application thereof

Abstract

The application discloses a super-tough solid-state fluorescent hydrogel composite material which is prepared from the following components in mass percentage: amphiphilic polyurethane: 80-99, carbon quantum dots: 1-20. The application also discloses a preparation method of the super-tough solid-state fluorescent hydrogel composite material and application thereof. The application has the following beneficial effects: the used equipment and process are simple, the used carbon quantum dots based on waste biomass are simple to produce and low in cost; the composite technology is simple and easy to operate, and the carbon quantum dot composite material with excellent dispersity can be obtained without special treatment; the prepared solid-state fluorescent composite material has excellent mechanical properties, the elongation at break is above 1000%, and the tensile strength is above 30 MPa, so that the application in different fields can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fluorescent polymer composites and preparation thereof, in particular to a super-tough solid-state fluorescent hydrogel composite material and a preparation method and application thereof, which is a biomass carbon quantum dot / polyurethane hydrogel composite material, the water content, mechanical properties, fluorescent properties and geometric shape of which can be adjusted, and especially a stable and efficient solid-state fluorescent light emitting system can be constructed in an aggregated state. BACKGROUND

[0002] Carbon quantum dots (CDs) as a new type of carbon nanometer (size less than 10 nanometers) fluorescent material have been concerned since they were discovered by Xu et al. in 2004. The fluorescent performance of CDs is adjustable and has good light stability, and CDs also have the advantages of good biocompatibility and low production cost, so they have attracted attention in the fields of sensing detection and biomedical science. However, the prepared CDs mostly exist in the form of aqueous solution, and serious fluorescence quenching occurs in the aggregated state, which limits the application of CDs in solid-state devices, and the development of stable solid-state carbon quantum dot fluorescent light emitting system has become a research hotspot.

[0003] It is extremely attractive to prepare polymer fluorescent materials with solid-state light emitting performance, especially for white or blue light emitting substances, by compounding CDs and polymers, which have wide application prospects in light emitting diodes, fluorescent printing and biomedical science. However, due to the polarity difference between carbon quantum dots and polymers, direct compounding will lead to aggregation of carbon quantum dots and loss of fluorescent properties.

[0004] A Chinese patent application for invention with the publication number CN103382389A discloses a fluorescent carbon quantum dot, a light emitting polymer-based composite material and a preparation method thereof. The carbon quantum dots are formed by the reaction of a polymerizable organosilicon monomer and a small molecule carbon source in one step, and the reaction product can be further reacted to form a carbon quantum dot and organosilicon resin composite material without purification and only by removing the solvent. The organosilicon monomer can promote the formation of carbon quantum dots and stabilize the carbon quantum dots, and can also act as a monomer of the polymer matrix, so that the obtained carbon quantum dot has stable light emitting performance, good compatibility with the polymer matrix and maintains the original light emitting properties. However, the synthesis of this technical solution is relatively complex, and its large-scale application is limited.

[0005] A Chinese invention application with patent application publication number CN113045978A discloses a preparation method of carbon quantum dots-water-soluble polyurethane solution, comprising the following steps: step one: preparing water-soluble carbon quantum dots; step two: fully mixing the prepared water-soluble carbon quantum dots with water-soluble polyurethane to obtain a carbon quantum dots polymer solution; and the prepared carbon quantum dots polymer solution is applied to light-emitting diodes (LEDs) and solar concentrators (LSCs). The method is simple and easy to implement, and has obvious advantages such as green, low cost, and large-scale production. However, the prepared carbon quantum dots-water-soluble polyurethane solution is in a solution state and is only used as a coating material.

[0006] A Chinese invention application with patent application publication number CN115261014A discloses a carbon quantum dots / waterborne polyurethane composite fluorescent powder and a preparation method thereof. The carbon quantum dots / waterborne polyurethane composite fluorescent powder is prepared by using the acidity of the carbon quantum dots solution to make the positive and negative charges of the anionic waterborne polyurethane unbalanced, breaking the emulsion and coagulating, and coagulating and compounding the carbon quantum dots solution and the waterborne polyurethane emulsion based on the coagulation compounding method. The method has a simple operation route and low cost. The prepared carbon quantum dots / waterborne polyurethane composite fluorescent powder has strong light stability and can be uniformly dispersed in the waterborne polyurethane without aggregation quenching and other phenomena. Although the carbon quantum dots / waterborne polyurethane composite fluorescent powder prepared by the technical scheme is a fluorescent powder, it needs to be compounded with other materials to be prepared into a solid block.

[0007] There is no report on the use of amphiphilic polyurethane for the preparation of hydrogels and the preparation of fluorescent composite materials based on the hydrogels. It is difficult to adjust the fluorescence quantum yield by using the solution coating or solid-phase mixing method, because once the carbon quantum dots are introduced into the polyurethane, the fluorescence quantum yield is not easy to adjust.

[0008] Chitosan / carbon quantum dots (reference: Konwar, et al., Carbohydrate Polymers, 2015.) and agarose / carbon quantum dots hydrogel systems (reference: Gogoi, et al., ACS Applied Materials & Interfaces, 2015.) have been successfully prepared. However, the mechanical properties of such hydrogels after drying are poor, which limits their application in solid-state light-emitting devices. SUMMARY

[0009] The present application aims to overcome the deficiencies of the prior art and provides an ultra-tough solid-state fluorescent hydrogel composite material that can be prepared on a large scale and has adjustable performance, which has excellent mechanical properties and fluorescence quantum yield and can be used in the fields of sensing and solid-state devices.

[0010] Another object of the present application is to provide a preparation method of the super-tough solid fluorescent hydrogel composite, which has the advantages of simple production, low cost, simple composite technology and easy operation.

[0011] In order to achieve the above-mentioned objects of the present application, the technical scheme adopted by the present application is as follows: a super-tough solid fluorescent hydrogel composite is prepared from the following mass fractions: amphiphilic polyurethane: 80-99, carbon quantum dots: 1-20.

[0012] The super-tough solid fluorescent hydrogel composite of the present application is a solid hydrogel, film or fiber fluorescent material with excellent mechanical properties and quantum yield. The amphiphilic polyurethane provides a matrix for the fluorescent material, and the hydrogel form ensures excellent dispersion of water-soluble carbon quantum dots in the composite material. The carbon quantum dots based on waste biomass provide a point with adjustable fluorescent properties for the material. The geometry, mechanical properties and fluorescent properties of the material can be further adjusted by controlling the water content.

[0013] The carbon quantum dots are prepared by a hydrothermal method at a temperature of 180-300℃ in an air atmosphere using waste biomass. The carbon quantum dots are in a granular form, and the waste biomass includes but is not limited to miscanthus, straw, wood chips or waste coconut shells, etc.

[0014] The amphiphilic polyurethane is a type of copolymerized block polymer composed of hydrophilic and hydrophobic segments, including but not limited to amphiphilic polyurethane or natural carrageenan, etc. Preferably, it is a PUR-ether with the trademark HydroMed D6 (HydroMed D6) of the American AdvanSource Biomaterials company. TM D6) of the American AdvanSource Biomaterials company.

[0015] The preparation method of the super-tough solid fluorescent hydrogel composite includes the following steps:

[0016] (1) preparing a carbon quantum dot aqueous solution with adjustable fluorescent properties from waste biomass as raw material;

[0017] (2) dissolving the carbon quantum dot aqueous solution and the amphiphilic polyurethane in an ethanol aqueous solution, and then evaporating the ethanol to obtain a super-tough solid fluorescent hydrogel composite;

[0018] (3) removing the water content in the super-tough solid fluorescent hydrogel composite by further thermal evaporation or natural volatilization to prepare super-tough solid fluorescent hydrogel composites with different water contents.

[0019] Preferably, the (1) step carbon quantum dot aqueous solution is prepared by a hydrothermal method with a temperature range of 180-220℃.

[0020] Preferably, in the (2) step, after dissolving in the ethanol aqueous solution, stirring at room temperature for more than 24 hours or ultrasonic dispersion for 5-10 min, finally pouring the transparent emulsion solution into a mold, slowly evaporating ethanol in the solution,

[0021] Preferably, the volume ratio of ethanol to water in the ethanol aqueous solution is 1:9 to 4:6.

[0022] Preferably, the water content of the super-tough solid-state fluorescent hydrogel composite material is adjustable in the range of 0-85%.

[0023] The super-tough solid-state fluorescent hydrogel composite material has excellent mechanical properties and fluorescent properties, and can be used in the fields of 3D printing, heavy metal detection or display devices, but not limited thereto.

[0024] The super-tough solid-state fluorescent hydrogel composite material has an elongation at break of more than 1000% and a tensile strength of more than 25MPa.

[0025] The super-tough solid-state fluorescent hydrogel composite material has a tensile recovery rate of 100% under a strain of 100%.

[0026] The super-tough solid-state fluorescent hydrogel composite material has a fluorescence quantum yield of more than 3.18%.

[0027] The super-tough solid-state fluorescent hydrogel composite material has a fluorescence effect under UV and controllable fluorescence color, including but not limited to blue, red, etc.

[0028] The super-tough solid-state fluorescent hydrogel composite material has a fluorescence effect under UV and controllable fluorescence color, including but not limited to blue, red, etc.

[0029] The preparation method utilizes the three-dimensional structure characteristics of the polymer hydrogel to construct the super-tough solid-state fluorescent hydrogel composite material which has good dispersion performance, adjustable fluorescent performance and excellent mechanical performance, and the maximum elongation at break can reach 1647%, and the maximum tensile strength can reach 31.6 MPa. The process is simple, the cost is low, and the super-tough solid-state fluorescent hydrogel composite material can be prepared on a large scale, and has good application prospect in the fields of display, anti-counterfeiting and intelligent fiber.

[0030] Compared with the prior art, the application has the following advantages: the used equipment has simple process, the used waste biomass-based carbon quantum dots are simple to produce and low in cost, the composite technology is simple and easy to operate, and the carbon quantum dot composite material with excellent dispersion can be obtained without special treatment, and the prepared solid-state fluorescent composite material has excellent mechanical performance, the elongation at break is more than 1000%, and the tensile strength is more than 30 MPa, so that the application in different fields can be met. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description are briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0032] Figure 1 The fluorescence photos of the super-tough solid-state fluorescent hydrogel composite material prepared in Example 1 of the application under different water contents;

[0033] Figure 2 The fluorescence emission spectrum graphs of the super-tough solid-state fluorescent hydrogel composite materials prepared in Example 1 and Example 4 of the application under different water contents;

[0034] Figure 3 The fluorescence photos of the super-tough solid-state fluorescent hydrogel composite material prepared in Example 4 of the application under different proportions;

[0035] Figure 4 The fluorescence photos of the solid-state fluorescent hydrogel composite material prepared by compounding the red fluorescent carbon quantum dots with polyurethane in Example 5;

[0036] Figure 5 The practical photos of the blue light-emitting diode prepared by using the material in Example 5;

[0037] Figure 6 The mechanical performance test photos and curve graphs of the super-tough solid-state fluorescent hydrogel composite material prepared in Example 1 of the application with 0 water content. DETAILED DESCRIPTION

[0038] The technical solutions of the present application are described in detail below with the help of the accompanying drawings and specific examples. The following examples are further illustrations of the present application, but not limitations of the scope of the present application. All the examples are the preparation of solid-state fluorescent composite materials, and the adjustable parameters include the preparation temperature of carbon quantum dots, reaction time and other conditions, the content of carbon quantum dots, and the water content of solid-state fluorescent composite materials.

[0039] Example 1

[0040] A preparation method of a super-tough solid-state fluorescent hydrogel composite material includes the following steps:

[0041] Put 1.5 g of wheat bran and 0.45 g of polyethylene glycol with a molecular weight of 2000 into a 100 ml polytetrafluoroethylene liner, and add 50 ml of deionized water, stir uniformly; put into an oven with a temperature of 180℃ for 3 hours; then naturally cool to room temperature, open the reaction kettle to obtain a water solution containing carbon quantum dots. The filtrate obtained after centrifugation and filtration of the above water solution containing carbon quantum dots is the carbon quantum dot aqueous solution; the carbon quantum dot aqueous solution is further dried to obtain carbon quantum dot solid particles.

[0042] Take 2.5 g of the above carbon quantum dot solid particles and 10 g of amphiphilic polyurethane (HydroMed TM D6, the polyurethane used in the following examples is selected from this product), mix the carbon quantum dots and polyurethane in a mass ratio of 1:4 in an ethanol solution with a volume ratio of ethanol to water of 1:9, uniformly mix to prepare a polyurethane / carbon quantum dot composite solution, and obtain a super-tough solid-state fluorescent hydrogel composite material after volatilization at room temperature for 48 hours; further dry to remove water to obtain a super-tough solid-state fluorescent hydrogel film with a water content of 0.

[0043] Example 2

[0044] A preparation method of a super-tough solid-state fluorescent hydrogel composite material includes the following steps:

[0045] Put 1.5 g of wheat bran and 0.45 g of polyethylene glycol with a molecular weight of 2000 into a 100 ml polytetrafluoroethylene liner, and add 50 ml of deionized water, stir uniformly; put into an oven with a temperature of 180℃ for 3 hours; then naturally cool to room temperature, open the reaction kettle to obtain a water solution containing carbon quantum dots; centrifuge and filter the above water solution containing carbon quantum dots to obtain a filtrate, which is a carbon quantum dot aqueous solution; further dry the carbon quantum dot aqueous solution to obtain carbon quantum dot solid particles.

[0046] Take 0.5 g of the above carbon quantum dots solid particles and 50.0 g of amphiphilic polyurethane (carbon quantum dots: polyurethane mass ratio of 1:100) mixed in an ethanol solution with a volume ratio of ethanol to water of 4:6, mix uniformly to prepare a polyurethane / carbon quantum dot composite solution, and after evaporation at room temperature for 48 hours, an ultra-tough solid fluorescent hydrogel composite material is obtained. Further drying to remove water to obtain an ultra-tough solid fluorescent hydrogel film with a water content of 0.

[0047] Example 3

[0048] A method for preparing an ultra-tough solid fluorescent hydrogel composite material, comprising the following steps:

[0049] Put 1.5 g of wheat bran, 0.54 g of phenylenediamine, and 0.45 g of polyethylene glycol with a molecular weight of 2000 g into a 100 ml polytetrafluoroethylene liner, add 50 ml of deionized water, stir uniformly, and then put into an oven at a temperature of 220°C for 3 hours; then naturally cool to room temperature, open the reaction kettle to obtain a water solution containing carbon quantum dots; centrifuge and filter the above water solution containing carbon quantum dots, and the filtrate obtained is a red fluorescent carbon quantum dot aqueous solution; further drying the red fluorescent carbon quantum dot aqueous solution to obtain carbon quantum dot solid particles.

[0050] Take 10 mg of the above carbon quantum dot solid particles and 10 g of amphiphilic polyurethane (carbon quantum dots: polyurethane mass ratio of 1:1000) mixed in an ethanol solution with a volume ratio of ethanol to water of 1:9, mix uniformly to prepare a polyurethane / carbon quantum dot composite solution, and after evaporation at room temperature for 48 hours, an ultra-tough solid fluorescent hydrogel composite material is obtained. Further drying to remove water to obtain an ultra-tough solid fluorescent hydrogel film with a water content of 0.

[0051] Example 4

[0052] A method for preparing an ultra-tough solid fluorescent hydrogel composite material, comprising the following steps:

[0053] This example is based on the water content control of the solid composite hydrogel material in Example 1.

[0054] Put 1.5 g of wheat bran and 0.45 g of polyethylene glycol with a molecular weight of 2000 g into a 100 ml polytetrafluoroethylene liner, add 50 ml of deionized water, stir uniformly, and then put into an oven at a temperature of 180°C for 3 hours; then naturally cool to room temperature, open the reaction kettle to obtain a water solution containing carbon quantum dots; centrifuge and filter the above water solution containing carbon quantum dots, and the filtrate obtained is a carbon quantum dot aqueous solution. Further drying the carbon quantum dot aqueous solution to obtain carbon quantum dot solid particles.

[0055] Take 2.5 g of the above carbon quantum dots solid particles and 10 g of polyurethane (carbon quantum dots: polyurethane mass ratio of 1:4) mixed in an ethanol solution with a volume ratio of ethanol to water of 1:9, mix evenly to prepare a polyurethane / carbon quantum dot composite solution, and then evaporate at room temperature to obtain a super-tough solid fluorescent hydrogel film with water content of 30% and 60%, respectively.

[0056] Example 5

[0057] A method for preparing a blue fluorescent light-emitting diode, based on Example 1, includes the following steps:

[0058] Put 1.5 g of wheat bran and 0.45 g of polyethylene glycol with a molecular weight of 2000 into a 100 ml polytetrafluoroethylene liner, add 50 ml of deionized water, and stir evenly; put it into an oven at a temperature of 180°C for 3 hours; then naturally cool to room temperature, open the reaction kettle to obtain a water solution containing carbon quantum dots; the filtrate obtained after centrifugation and filtration of the above water solution containing carbon quantum dots is the carbon quantum dot aqueous solution; the carbon quantum dot aqueous solution is further dried to obtain carbon quantum dot solid particles.

[0059] Take 2.5 g of the above carbon quantum dots solid particles and 10 g of polyurethane mixed in an ethanol solution with a volume ratio of ethanol to water of 1:9, mix evenly to prepare a polyurethane / carbon quantum dot composite solution, and then drop coat the polyurethane / carbon quantum dot composite solution on a light-emitting diode chip with an excitation of 395 nm, dry in an oven at 60°C for 120 min to obtain a blue fluorescent light-emitting diode.

[0060] The super-tough solid fluorescent hydrogel composite material prepared in the above examples was subjected to fluorescence performance and mechanical property detection, and all showed blue fluorescence under UV light, as shown in Figures 1-5 The fluorescence spectrum performance test found that the fluorescence intensity of the polymer increased with the decrease of water content, as shown in Figure 6 The mechanical property test results of the solid fluorescent composite material showed that the material had excellent mechanical properties and could be adjusted, with a maximum elongation at break of 1647% and a maximum tensile strength of 31.6 MPa, and the tensile recovery rate of the solid fluorescent material with a water content of 85% reached 100% under a strain of 100%; the mechanical properties and quantum yield are shown in Table 1.

[0061] Table 1 Mechanical properties and fluorescence quantum yield of super-tough solid fluorescent hydrogel composite materials with different water contents

[0062]

[0063] The application takes an amphiphilic polyurethane hydrogel with excellent mechanical properties as a carrier, introduces carbon quantum dots based on waste biomass, and prepares a composite hydrogel material with fluorescence performance. The material has the characteristics of excellent fluorescence performance and mechanical performance. Further, a solid thin film material with fluorescence performance is prepared by water content control. The shape of the material is controllable, and a fiber material with fluorescence performance and high mechanical strength can be prepared, and the fluorescence is adjustable.

[0064] The above is only a preferred embodiment of the application, and cannot limit the scope of the application. Any simple equivalent changes and modifications made according to the scope of the application and the content of the application description are still within the scope of the application.

Claims

1. A super-tough solid fluorescent hydrogel composite material, characterized in that, It is made from the following components by mass fraction: amphiphilic polyurethane: 80-99, carbon quantum dots: 1-20; The method for preparing carbon quantum dots includes the following steps: placing 1.5g of wheat bran and 0.45g of polyethylene glycol with a molecular weight of 2000 into a 100ml polytetrafluoroethylene liner, adding 50ml of deionized water, and stirring until homogeneous; placing the mixture in an oven at 180℃ for 3 hours; then allowing it to cool naturally to room temperature to obtain an aqueous solution containing carbon quantum dots; centrifuging and filtering the aqueous solution containing carbon quantum dots to obtain a carbon quantum dot aqueous solution; and finally drying the carbon quantum dot aqueous solution.

2. The ultra-tough solid fluorescent hydrogel composite material according to claim 1, characterized in that, The amphiphilic polyurethane is a PUR-ether with the trademark name HydroMedD6 from AdvanSource Biomaterials, Inc., USA.

3. The method for preparing an ultra-tough solid fluorescent hydrogel composite material according to any one of claims 1-2, characterized in that, The steps involved are as follows: (1) Prepare an aqueous solution of carbon quantum dots with tunable fluorescence properties using wheat bran as raw material; (2) Using carbon quantum dot aqueous solution and amphiphilic polyurethane as raw materials, after dissolving them in ethanol aqueous solution, the ethanol was evaporated to remove the ethanol and obtain an ultra-tough solid fluorescent hydrogel composite material. (3) The water content of the ultra-tough solid fluorescent hydrogel composite material is removed by further thermal evaporation or natural evaporation to prepare ultra-tough solid fluorescent hydrogel composite materials with different water contents.

4. The preparation method of the ultra-tough solid fluorescent hydrogel composite material according to claim 3, characterized in that, The volume ratio of ethanol to water in the ethanol-water solution is 1:9 to 4:

6.

5. The method for preparing an ultra-tough solid fluorescent hydrogel composite material according to claim 3, characterized in that, The ultra-tough solid fluorescent hydrogel composite material has an elongation at break of over 1000% and a tensile strength of over 25 MPa.

6. The method for preparing an ultra-tough solid fluorescent hydrogel composite material according to claim 3, characterized in that, The ultra-tough solid fluorescent hydrogel composite material exhibits a tensile recovery rate of 100% below 100% strain and a fluorescence quantum yield of over 3.18%.

7. The ultra-tough solid fluorescent hydrogel composite material according to claim 1, characterized in that, Used in 3D printing, heavy metal detection, or display device applications.

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