A method for preparing a three-dimensional non-contact sensor based on direct writing and printing

Abstract

The present invention relates to a method for preparing a three-dimensional non-contact sensor based on direct writing and printing, characterized in that the steps of the preparation method are: 1) preparing electronegative friction layer ink; 2) printing electronegative friction layer; 3) preparing aerogel-based electronegative friction layer; 4) assembling non-contact sensor. The present invention uses direct writing and printing to obtain a patterned three-dimensional porous aerogel based on electronegative materials / charge capture materials to form a non-contact sensor based on the principle of friction nano-power generation. The method of the present invention is simple and fast, can effectively save costs, and obtain a patterned three-dimensional structure with a high specific area, effectively improve the charge separation and transmission capacity, thereby increasing the output voltage, reducing the trapped charge and reducing the charge attenuation, and thus improving the electrical performance of the non-contact sensor.

Description

Technical Field

[0001] The invention belongs to the field of nano functional device preparation, relates to a sensor, and particularly relates to a method for preparing a three-dimensional non-contact sensor based on direct writing and printing. Background Art

[0002] With the emergence of the Internet of Things and artificial intelligence, sensors for human-machine interaction have attracted more and more demands and changed the way people communicate with their surroundings. Currently, most sensors need to interact with the environment through physical contact to obtain signals during operation. However, physical contact between surfaces can have some great disadvantages, such as reduced output power due to material wear and the need to replace the device. This need for repeated physical contact may also lead to inevitable mechanical fatigue and bacterial contamination of sensors, which will limit their practical possibilities and versatility.

[0003] The friction nanogenerator based on triboelectric and electrostatic induction coupling can be used for non-contact sensing in somatosensory interaction systems. However, in the non-contact working mode, as the distance between the friction nanogenerator and the detection object becomes farther and farther, the output performance of the device will weaken.

[0004] In order to improve the output performance of non-contact friction nanogenerators, researchers have tried surface patterning, dielectric layer stacking, dielectric constant modulation and ion implantation. The patterned structure can increase the contact area of ​​the friction layer and effectively improve the triboelectric performance. The existing methods are mostly template-assisted methods, photolithography, etc. These methods are complex, time-consuming and expensive. In addition, due to the electrostatic potential induction, the output performance of non-contact friction nanogenerators still has the phenomenon of charge drift, which leads to the loss of friction electrons, rapid charge decay and reduced voltage output.

[0005] Therefore, developing a non-contact sensor that does not require physical contact, can interact with surrounding information, and is simple, fast, cost-effective, and has excellent output performance has always been one of the research hotspots. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a three-dimensional non-contact sensor based on direct writing and printing. The method of the present invention is simple and fast, can effectively save costs, and obtain a patterned three-dimensional structure with a high specific area, effectively improve the charge separation and transmission capacity, increase the output voltage, reduce charge attenuation, and thus improve the electrical performance of the non-contact sensor.

[0007] The present invention solves the technical problem by the following technical solutions:

[0008] A method for preparing a three-dimensional non-contact sensor based on direct writing and printing, characterized in that: the method prints a gel-like ink on a substrate according to pattern information, and obtains a patterned three-dimensional aerogel based on an electronegative material / charge capture material through freeze-drying, and finally assembles it with an electrode layer to form a non-contact sensor based on the principle of friction nano-power generation.

[0009] A method for preparing a three-dimensional non-contact sensor based on direct writing and printing, characterized in that the steps of the method are:

[0010] 1) Preparation of electronegative friction layer ink: uniformly mix electronegative material and charge capture material, the mixing ratio of electronegative material to charge capture material is 100:0-5:1, then add viscosity modifier, the ratio of electronegative material to viscosity modifier is 100:1-100:7, centrifuge the mixture of the above three materials, the centrifugal time is 5-30min, the centrifugal speed is 1000-8000rpm, and obtain electronegative friction layer ink;

[0011] 2) Printing of electronegative friction layer: injecting electronegative friction layer ink into the syringe of the direct writing printer, fixing the printing substrate on the printing platform, adjusting the syringe nozzle so that the printing nozzle directly writes the electronegative friction layer ink on the printing substrate according to the pattern information, and obtaining the electronegative friction layer with a preset pattern structure;

[0012] 3) Preparation of aerogel-based electronegative friction layer: placing the printed electronegative friction layer into a freeze dryer to freeze, thereby obtaining an aerogel-based electronegative friction layer with a 3D preset pattern structure;

[0013] 4) Assembling the non-contact sensor: assembling the aerogel-based electronegative friction layer and the electrode layer obtained in step 3) into a single electrode structure, and performing non-contact reciprocating motion between the hand and the aerogel-based electronegative friction layer to obtain a non-contact sensor.

[0014] Moreover, the electrode layer is composed of a conductive layer or a combined layer of a conductive layer and a printing substrate; the material of the conductive layer is metal, metal oxide or carbon material; the metal is iron, zinc, copper or aluminum; the metal oxide is indium tin oxide; the carbon material is fullerene, carbon black or MXene; the printing substrate is polyethylene terephthalate, epoxy resin, polyamide, nylon 6, polyurethane, polyester, polyoxymethylene, polystyrene or glass.

[0015] Moreover, the electronegative material is an easily available electron material, such as polytetrafluoroethylene, polychlorotrifluoroethylene, polydimethylsiloxane, cellulose or polyvinylidene fluoride.

[0016] Moreover, the charge capture material is MXene, graphene, C60 or silver nanowire.

[0017] Moreover, the viscosity regulator is chitosan, methyl cellulose, sodium carboxymethyl cellulose, gelatin, paraffin or high molecular resin products.

[0018] Furthermore, the air pressure for direct writing and printing in step 2) is 10-50 psi, and the printing speed is 0.01-50 mm s -1 .

[0019] Moreover, the freeze-drying conditions of step 3) are: temperature of -60 to 10° C., and freeze-drying time of more than 12 hours.

[0020] The advantages and beneficial effects of the present invention are:

[0021] The present invention utilizes direct writing and printing to obtain a patterned three-dimensional porous aerogel based on electronegative materials / charge capture materials, thereby forming a non-contact sensor based on the principle of friction nano-power generation. The method of the present invention is simple and rapid, can effectively save costs, and obtain a patterned three-dimensional structure with a high specific area, effectively improving the charge separation and transmission capacity, increasing the output voltage, reducing charge attenuation, and thus improving the electrical performance of the non-contact sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the method of the present invention;

[0023] Figure 2 This is a physical picture of the electronegative friction layer prepared by the present invention;

[0024] Figure 3 This is an electron microscope image of the electronegative friction layer obtained by the present invention;

[0025] Figure 4 A charge density diagram of a non-contact sensor made for the present invention;

[0026] Figure 5 The output voltage diagram of the non-contact sensor at different sensing distances is obtained for the present invention. DETAILED DESCRIPTION

[0027] 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.

[0028] The direct writing printer used in this embodiment is an Ultimus I pneumatic fluid dispensing system controlled by a 2400 multi-axis mobile platform of Nordson EFD, USA.

[0029] A method for preparing a three-dimensional non-contact sensor based on direct writing and printing, the innovation of which lies in: the steps of the preparation method are:

[0030] 1) Preparation of electronegative friction layer ink:

[0031] The pulp was prepared by 2,2,6,6-tetramethylpiperidinium oxide peroxidation method to obtain cellulose nanofibers, the cellulose nanofibers were mixed with a charge capture material, stirred at 1200 r / min for 1 hour to be uniformly mixed, and then a viscosity modifier methyl cellulose was added, and the mixture was centrifuged at a speed of 5000 r / min for 10 minutes in a centrifuge to remove bubbles, thereby obtaining an electronegative friction layer ink that can be used for printing;

[0032] 2) Printing of electronegative friction layer: 3 g of electronegative friction layer ink was injected into the syringe of the direct writing printer, the substrate was fixed on the printing platform, polyethylene terephthalate was used as the printing substrate, and the size of the substrate was 5 cm*5 cm; the distance between the syringe nozzle diameter and the substrate surface was adjusted to 10 μm, and a nozzle with a diameter of 840 μm was selected so that the printing nozzle directly wrote the friction layer ink on the substrate at a speed of 10 mm / s under an air pressure of 25 psi according to a preset program, and a vertical cross-net structure electronegative friction layer was obtained;

[0033] 3) Preparation of aerogel-based electronegative friction layer: The printed electronegative friction layer was placed in a freeze dryer and frozen at a temperature of -55°C for a period of more than 12 hours to obtain an aerogel-based electronegative friction layer with a 3D vertical cross structure pattern of 4 cm*4 cm;

[0034] 4) Non-contact sensor assembly: The obtained aerogel-based electronegative friction layer and the electrode layer are assembled into a single electrode structure, and the hand and the friction layer are moved back and forth without contact to obtain a non-contact sensor.

[0035] The non-contact sensor prepared by the present invention was tested for non-contact separation power generation. When the separation distance during the test was 1 cm, the maximum charge density of the friction nanogenerator with charge capture material added reached 900mC / cm 3 , which is 1.8 times that of the friction nanogenerator of cellulose nanofibers. The charge density can be kept at 600mC / cm even after 900 seconds. 3 Maintains high charge density and maintains excellent charge retention over time.

[0036] The working mode of the non-contact sensor prepared by the present invention is a single-electrode mode. The electrode layer and the electronegative friction layer in its structure are interconnected as the electron-gaining part. The electron-gaining part is perpendicular to the human body and non-contacts. The charge distribution of the friction layer is changed due to electrostatic induction, giving the device dynamic non-contact sensing characteristics, and the voltage of the device can be detected under different working displacements.

[0037] 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 three-dimensional non-contact sensor based on direct writing and printing, characterized in that: The method prints electronegative friction layer ink on a substrate according to pattern information, freeze-dries it to obtain an aerogel-based electronegative friction layer based on electronegative material / charge capture material, and finally assembles it with an electrode layer to form a non-contact sensor based on the principle of friction nano-power generation; The steps of the method are: 1) Preparation of electronegative friction layer ink: electronegative material and charge capture material are uniformly mixed, the mixing ratio of electronegative material to charge capture material is 100:0~5:1, and then viscosity modifier is added, the ratio of electronegative material to viscosity modifier is 100:1~100:7, the mixture of the above three materials is centrifuged, the centrifugal time is 5~30min, the centrifugal speed is 1000~8000rpm, and the electronegative friction layer ink is obtained; 2) Printing of electronegative friction layer: injecting electronegative friction layer ink into the syringe of the direct writing printer, fixing the printing substrate on the printing platform, adjusting the syringe nozzle so that the printing nozzle directly writes the electronegative friction layer ink on the printing substrate according to the pattern information, and obtaining the electronegative friction layer with a preset pattern structure; 3) Preparation of aerogel-based electronegative friction layer: The printed electronegative friction layer is placed in a freeze dryer to obtain an aerogel-based electronegative friction layer with a 3D vertical cross-net structure pattern; 4) Assembling the non-contact sensor: assembling the aerogel-based electronegative friction layer and the electrode layer obtained in step 3) into a single electrode structure, and performing non-contact reciprocating motion between the hand and the aerogel-based electronegative friction layer to obtain a non-contact sensor; The electronegative material is an easily available electron material, such as polytetrafluoroethylene, polychlorotrifluoroethylene, polydimethylsiloxane, cellulose or polyvinylidene fluoride; The charge capture material is MXene, graphene, C60 or silver nanowire.

2. The method for preparing a three-dimensional non-contact sensor based on direct writing and printing according to claim 1, characterized in that: The electrode layer is composed of a conductive layer or a combined layer of a conductive layer and a printing substrate; the material of the conductive layer is metal, metal oxide or carbon material; the metal is iron, zinc, copper or aluminum; the metal oxide is indium tin oxide; the carbon material is fullerene, carbon black or MXene; the printing substrate is polyethylene terephthalate, epoxy resin, polyamide, nylon 6, polyurethane, polyester, polyoxymethylene, polystyrene or glass.

3. The method for preparing a three-dimensional non-contact sensor based on direct writing and printing according to claim 1, characterized in that: The viscosity regulator is chitosan, methyl cellulose, sodium carboxymethyl cellulose, gelatin, paraffin or high molecular resin products.

4. The method for preparing a three-dimensional non-contact sensor based on direct writing and printing according to claim 1, characterized in that: The air pressure for direct writing printing in step 2) is 10-50 psi, and the printing speed is 0.01-50 mm s -1 .

5. The method for preparing a three-dimensional non-contact sensor based on direct writing and printing according to claim 1, characterized in that: The freeze-drying conditions of step 3) are: temperature of -60 to 10° C., and freeze-drying time of more than 12 hours.

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