Preparation method of cellulose-based embedded circuit

Abstract

The invention relates to a preparation method of a cellulose-based embedded circuit. The preparation method comprises the following steps: S1, preparing a cellulose precursor solution; s2, preparing conductive ink; s3, printing the embedded circuit; and S4, forming the cellulose-based embedded circuit. The cellulose-based embedded circuit is prepared through the dissolution and regeneration characteristics of cellulose, an embedded printing method is expanded, a two-dimensional circuit and a three-dimensional circuit can be printed, compared with traditional embedded printing, the requirements for a matrix and printing ink are lowered, printing is easier and more convenient, and the printing efficiency is improved. The method has a wide application prospect in the field of flexible electronics.

Description

Technical Field

[0001] The invention belongs to the technical field of flexible electronics, and in particular relates to a method for preparing a cellulose-based embedded circuit. Background Art

[0002] Flexible electronics is a hot topic in today's research field. It has attracted widespread research attention due to its advantages such as portability, biocompatibility, wear resistance, excellent mechanical stability, high integration and versatility, and has become one of the current frontier interdisciplinary disciplines.

[0003] Flexible electrodes are an indispensable part of flexible electronics, and are mainly used to realize the conductive and electrochemical functions in flexible electronic systems. The preparation of the electrode is to pattern the conductive material (conductive polymer, metal nanomaterial and carbon-based material) onto a flexible substrate. However, the patterned circuit is often subject to scratches, wear, corrosion or oxidation, resulting in unstable performance and affecting the service life.

[0004] In order to prevent the electrodes from being affected by external forces, we currently protect the electrodes through packaging, microfluidics and embedded printing. However, packaging is cumbersome and the substrates are mostly made of petroleum-based polymers. Microfluidics has high requirements for equipment and has certain requirements for ink and substrate. The flexible electrodes produced have poor biocompatibility, are difficult to biodegrade, and are not easy to recycle.

[0005] Embedded printing can solve the above challenges very well. It is easy to operate, and can highly integrate electronic components and circuits to achieve functionalization. It has a wide range of applications and can print not only two-dimensional but also three-dimensional circuits. The supporting matrix is ​​mostly biomass material, which is environmentally friendly and biodegradable.

[0006] Therefore, developing a printing method for embedded circuits that is simple in preparation and environmentally friendly is one of the research hotspots. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing a cellulose-based embedded circuit.

[0008] The present invention solves the technical problem by the following technical solutions:

[0009] A method for preparing a cellulose-based embedded circuit, the method comprising the following steps:

[0010] S1. Preparation of cellulose precursor solution: crushing the pulp dissolving pulp into flocculent cellulose and placing it in an oven to dry, removing water and adding it into a cellulose solvent, and then adding a cross-linking agent and stirring and mixing uniformly to obtain a cellulose precursor solution;

[0011] S2. Preparation of conductive ink: dissolving a conductive material in a solvent to obtain conductive ink;

[0012] S3, printing of embedded circuits: printing the circuits in the cellulose precursor solution of S1 by direct writing the conductive ink of S2;

[0013] S4. Forming of cellulose-based embedded circuits: The cellulose solution of S3 is immersed in a regeneration liquid for overall regeneration and forming to obtain embedded circuits.

[0014] Moreover, the mass fraction of cellulose in the cellulose precursor solution of S1 is 1% to 15%; the dissolving pulp is one or more of coniferous wood dissolving pulp, broadleaf wood dissolving pulp, bamboo dissolving pulp, corn straw dissolving pulp, reed dissolving pulp, wheat straw dissolving pulp, rice straw dissolving pulp, jute dissolving pulp, and willow branch.

[0015] Moreover, the cellulose solvent of S1 is one or more of N-methyl-N-oxide solvent, LiCl / N, N-dimethylacetamide solution, cuprammonia solution, ionic liquid, tetrabutylammonium fluoride / dimethyl sulfoxide solution, organic alkali aqueous solution, alkali / urea solution, and molten inorganic salt hydrate.

[0016] Moreover, the stirring time of S1 is 90 min to 150 min, and the stirring speed is 1000 rpm to 3000 rpm.

[0017] Moreover, the cross-linking agent of S1 is one or more of glutaraldehyde, formaldehyde, epichlorohydrin, polyethylene glycol diglycidyl ether, and silane coupling agent.

[0018] Moreover, the solvent of S2 is one or more of 1-butyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium diimide, tetrabutylphosphine hexafluorophosphate, and N-methylpyrrolidine hexafluorophosphate.

[0019] Moreover, the conductive material of S2 is one or two of graphene, carbon nanotubes, C60, MXene, and silver nanowires.

[0020] Moreover, the regeneration liquid in S4 is one or more of ethylene glycol, ethanol, water, glycerol, butanol, octanol, and octyl acetate; and the immersion time of S4 is more than 1 minute.

[0021] The advantages and beneficial effects of the present invention are:

[0022] The present invention prepares cellulose-based embedded circuits through the dissolution and regeneration characteristics of cellulose, expands the method of embedded printing, and can print not only two-dimensional circuits but also three-dimensional circuits. Compared with traditional embedded printing, it reduces the demand for matrix and ink, making its printing easier and having broad application prospects in the field of flexible electronics. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a preparation flow chart of the present invention;

[0024] Figure 2 This is a physical picture of the conductive ink printing process prepared in Example 1;

[0025] Figure 3 The viscosity and modulus diagram of the conductive ink prepared in Example 1 before and after regeneration;

[0026] Figure 4 This is a physical picture of the embedded circuit prepared in Example 1;

[0027] Figure 5 A scanning electron microscope image of the embedded circuit prepared in Example 1;

[0028] Figure 6 This is a diagram of a light bulb lighting up the embedded circuit prepared in Example 1. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0030] Example 1

[0031] like Figure 1 As shown, a method for preparing a cellulose-based embedded circuit is innovative in that the steps of the preparation method are:

[0032] (1) A LiOH (4.5 wt%) / urea (15 wt%) aqueous solution was precooled to -12°C; the absolutely dried cellulose was ground into a cotton-like state by a grinder; 2.5 g of the dried cellulose was added to 100 g of the LiOH / urea aqueous solution, and epichlorohydrin (ECH) was added, wherein the molar ratio of epichlorohydrin to cellulose anhydroglucose unit AGU was 0.32, and the mixture was stirred at 2000 r / min for 2 h under ice bath conditions to mix evenly and remove bubbles, thereby obtaining a transparent cellulose solution with a concentration of 2.5 wt%.

[0033] (2) 3 wt % of multi-walled carbon nanotube conductive material and 5 g of 1-butyl-3-methylimidazolium chloride were mixed and stirred to prepare a conductive ink;

[0034] (3) Printing a circuit with conductive ink in a 2.5 wt% cellulose solution by direct writing, then regenerate the cellulose solution in ethanol for 24 hours, and then rinse with deionized water to obtain an integrated packaged embedded circuit.

[0035] Example 2

[0036] A method for preparing a cellulose-based embedded circuit, the innovation of which lies in the following steps:

[0037] (1) A LiOH (4.5 wt%) / urea (15 wt%) aqueous solution was precooled to -12°C; the absolutely dry cellulose was ground into a cotton-like state by a grinder; 2.5 g of the dried cellulose was added to 100 g of the LiOH / urea aqueous solution and ECH (ECH:AGU=0.6), and stirred at 2000 r / min for 2 h under ice bath conditions to uniformly mix and remove bubbles, thereby obtaining a transparent cellulose solution with a concentration of 2.5 wt%.

[0038] (2) 3 wt % of multi-walled carbon nanotube conductive material and 5 g of 1-butyl-3-methylimidazolium chloride were mixed and stirred to prepare conductive ink.

[0039] (3) Printing a circuit with conductive ink in a 2.5 wt% cellulose solution by direct writing, then regenerate the cellulose solution in ethanol for 24 hours, and then rinse with deionized water to obtain an integrated packaged embedded circuit.

[0040] Example 3

[0041] A method for preparing a cellulose-based embedded circuit, the innovation of which lies in the following steps:

[0042] (1) A LiOH (4.5 wt%) / urea (15 wt%) aqueous solution was precooled to -12°C; the absolutely dry cellulose was ground into a cotton-like state by a grinder; 2.5 g of the dried cellulose was added to 100 g of the LiOH / urea aqueous solution and ECH (ECH:AGU=0.32), and stirred at 2000 r / min for 2 h under ice bath conditions to mix evenly and remove bubbles, thereby obtaining a transparent cellulose solution with a concentration of 2.5 wt%.

[0043] (2) 5 wt % of multi-walled carbon nanotube conductive material and 5 g of 1-butyl-3-methylimidazolium chloride were mixed and stirred to prepare conductive ink.

[0044] (3) Printing a circuit with conductive ink in a 2.5 wt% cellulose solution by direct writing, then regenerate the cellulose solution in ethanol for 24 hours, and then rinse with deionized water to obtain an integrated packaged embedded circuit.

[0045] The cellulose-based embedded circuits prepared by the above examples are slightly different, so Example 1 is used for analysis.

[0046] Figure 2 and Figure 3This is a real picture of the conductive ink printing process prepared by Example 1 of the present invention and a viscosity modulus diagram of the conductive ink before and after regeneration. The changes in viscosity and modulus before and after the ink regeneration can clearly verify that the integrity of the embedded circuit morphology is achieved through the cellulose dissolution and regeneration characteristics, and the preparation is simple.

[0047] pass Figures 4 to 6 It can be found that the morphology of the embedded circuit prepared by the present invention remains intact, and the lighting of the bulb proves the integrity of the conductive path inside. Compared with traditional embedded printing, the support matrix of the present method does not need to have the characteristics of a yield stress fluid to deposit the ink printing structure, and the ink does not need a certain storage modulus to resist the extrusion of the matrix on the ink to prevent the ink from deforming.

[0048] In summary, the cellulose-based embedded circuit prepared by the present invention expands the method of embedded printing, and can print not only two-dimensional circuits but also three-dimensional circuits. Compared with traditional embedded printing, it reduces the demand for matrix and ink, making its printing simpler, low-cost, and biocompatible, and has broad application prospects in the field of flexible electronics.

[0049] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A method for preparing a cellulose-based embedded circuit, characterized in that: The steps of the method are: S1. Preparation of cellulose precursor solution: crushing the pulp dissolving pulp into flocculent cellulose and placing it in an oven to dry, removing water and adding it into a cellulose solvent, and then adding a cross-linking agent and stirring and mixing uniformly to obtain a cellulose precursor solution; S2. Preparation of conductive ink: dissolving a conductive material in a solvent to obtain conductive ink; S3, printing of embedded circuits: printing the circuits in the cellulose precursor solution of S1 by direct writing the conductive ink of S2; S4. Forming of cellulose-based embedded circuits: The cellulose solution of S3 is immersed in a regeneration liquid for overall regeneration and forming to obtain embedded circuits.

2. The method for preparing a cellulose-based embedded circuit according to claim 1, characterized in that: The mass fraction of cellulose in the cellulose precursor solution of S1 is 1% to 15%; the dissolving pulp is one or more of coniferous wood dissolving pulp, broadleaf wood dissolving pulp, bamboo dissolving pulp, corn straw dissolving pulp, reed dissolving pulp, wheat straw dissolving pulp, rice straw dissolving pulp, jute dissolving pulp, and willow branch.

3. The method for preparing a cellulose-based embedded circuit according to claim 1, characterized in that: The cellulose solvent of S1 is one or more of N-methyl-N-oxide solvent, LiCl / N, N-dimethylacetamide solution, cuprammonia solution, ionic liquid, tetrabutylammonium fluoride / dimethyl sulfoxide solution, organic alkali aqueous solution, alkali / urea solution, and molten inorganic salt hydrate.

4. The method for preparing a cellulose-based embedded circuit according to claim 1, characterized in that: The stirring time of S1 is 90 min to 150 min, and the stirring speed is 1000 rpm to 3000 rpm.

5. The method for preparing a cellulose-based embedded circuit according to claim 1, characterized in that: The cross-linking agent of S1 is one or more of glutaraldehyde, formaldehyde, epichlorohydrin, polyethylene glycol diglycidyl ether, and a silane coupling agent.

6. The method for preparing a cellulose-based embedded circuit according to claim 1, characterized in that: The solvent of S2 is one or more of 1-butyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium diimide, tetrabutylphosphine hexafluorophosphate, and N-methylpyrrolidine hexafluorophosphate.

7. The method for preparing a cellulose-based embedded circuit according to claim 1, characterized in that: The conductive material of S2 is one or two of graphene, carbon nanotubes, C60, MXene, and silver nanowires.

8. The method for preparing a cellulose-based embedded circuit according to claim 1, characterized in that: The regeneration liquid in S4 is one or more of ethylene glycol, ethanol, water, glycerol, butanol, octanol, and octyl acetate; and the immersion time of S4 is more than 1 minute.

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