CN112763106B - High-sensitivity and wide-range composite conductive nanofiber aerogel sensor and preparation method thereof - Google Patents
High-sensitivity and wide-range composite conductive nanofiber aerogel sensor and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a high-sensitivity and wide-range composite conductive nanofiber aerogel sensor and a preparation method thereof, wherein thermoplastic polymer nanofibers and conductive materials are used as raw materials, the dosage ratio is reasonably controlled, a nanofiber aerogel material with a three-dimensional structure is prepared by a freeze drying method, different composite conductive nanofiber aerogels with high sensitivity in different pressure ranges are combined by utilizing the lower density, higher softness, high conductivity and reversible compressibility of the aerogel material, the high-sensitivity detection of the composite conductive nanofiber aerogels at all levels on the pressure in different force value ranges is realized, the high-sensitivity of the sensor in the whole range from small pressure to large pressure range is realized through the ingenious multi-level composite conductive nanofiber aerogel structure distribution, the wide-range is realized, and the contradiction between the sensitivity and the range is solved, the performance of the sensor is greatly improved, and the application scenes of the sensor are enriched.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a high-sensitivity and wide-range composite conductive nanofiber aerogel sensor and a preparation method thereof.
Background
The sensitivity and the measuring range are two important performance parameters of the sensor, and the sensitivity and the measuring range are generally in an opposite relationship of mutual restriction, so that the comprehensive requirements of people on the two aspects cannot be met in many occasions. The patent refers to the field of 'compositions of macromolecular compounds'. Therefore, the magnetorheological elastomer (actually, the conductive composite material) formed by mixing tiny conductive (and/or magnetic conductive) particles with insulating organisms becomes a novel pressure-capacitance/piezoresistive pressure or strain sensitive material, and the principle is that the spatial distribution of the microscopic conductive particles is rearranged under the compression action of pressure/strain, so that the dielectric constant or the conductivity of the sensitive material is remarkably changed, and the pressure/strain sensor manufactured by the method has wide range and better sensitivity. In particular, the conductive composite material prepared under the magnetic field condition can obtain ultrahigh sensitivity which is one to two orders of magnitude higher than that of the traditional sensitive material by establishing a magnetic chain type microstructure on the microstructure, and has wide range due to the increased Young modulus of particle filling. However, the high sensitivity of such conductive composite materials is embodied in a large pressure range, and the sensitivity in a small pressure range in the initial stage is not ideal. The degree of particle rearrangement is a key factor affecting the sensitivity of such conductive composites, i.e., macroscopic pressure effects deform the material by compression, causing the microscopic particle distribution to rearrange such that neighboring particles re-pair into a large number of new microcapacitors or channels, thereby dramatically affecting the macroscopic capacitance or resistance of the sensitive material. Therefore, the large scale of particle rearrangement occurs depending on whether the macroscopic strain of the material is significant under the pressure, which is why the sensitivity in the small pressure range is small in the initial stage.
In order to overcome the above technical drawbacks, researchers have proposed increasing sensitivity by increasing particle volume fraction and using nanoparticle packing (both increasing the number of particles rearranged), employing preparation conditions for magnetic chaining (increasing the local particle volume fraction), but the beneficial sensitivity increase is still mainly in the large pressure range, while sensitivity in the small pressure range remains difficult to meet, especially the method of packing nanoparticles also significantly reduces the range. Therefore, the balance between sensitivity and measuring range is difficult to be considered by simply changing the formula of the material, and the difficulty and the cost in the process are higher. Under the condition of a certain volume fraction of the particles, the sensitive material is easy to deform, so that the particle rearrangement degree is improved (so that the sensitivity is improved), and the difficulty in deformation means that the upper limit of the resistance of the sensitive material to the external pressure is increased (namely the range is increased), and other flexible sensitive materials generally have the characteristic. In response to this fact, a highly sensitive and wide range pressure sensor is needed.
Furthermore, a sensitive material usually has a high sensitivity only in a certain pressure range, below which the sensitivity is lower, above which the sensitivity is also lower or saturation has occurred. Thus, if the combination of sensing units with high sensitivity in different pressure ranges is used, high sensitivity can be achieved in the whole range from low to high pressure and still obtain a wide range, and the key of the structural combination is how to make the different sensing units function by being pressed in a certain order in their effective pressure ranges.
Disclosure of Invention
The invention aims to provide a high-sensitivity and wide-range composite conductive nanofiber aerogel sensor which has high sensitivity in the whole range from small pressure to large pressure and can keep wide pressure range and a preparation method thereof, aiming at the characteristic that the sensitivity of the sensor is improved due to the fact that a sensitive material for a pressure sensor is easy to deform and the measuring range of the sensor is increased due to the fact that the sensitive material is difficult to deform or different sensitive materials with high sensitivity in different pressure ranges are structurally combined in the prior art.
In order to achieve the purpose, the invention adopts the technical scheme that:
the sensor comprises a plurality of layers of composite conductive nanofiber aerogel sequentially stacked from bottom to top, and the content of nanofibers in the multilayer composite conductive nanofiber aerogel is gradually reduced from bottom to top in a gradient manner.
As a further limitation of the above technical solution, the multi-range composite conductive nanofiber aerogel sensor comprises at least two layers of composite conductive nanofiber aerogel.
As a further limitation of the above technical solution, in the process that the external pressure on the multilayer composite conductive nanofiber aerogel is gradually increased, the multilayer composite conductive nanofiber aerogel is sequentially pressed from top to bottom.
As a further limitation of the above technical solution, the young modulus of the composite conductive nanofiber aerogel which is pressed first should be smaller than the young modulus of the composite conductive nanofiber aerogel which is pressed later; and the small pressure sensitivity of the composite conductive nanofiber aerogel which is firstly pressed is higher than that of the composite conductive nanofiber aerogel which is secondly pressed.
As a further limitation of the above technical solution, the filling concentration of the conductive material in the composite conductive nanofiber aerogel which is firstly pressed should be higher than the filling concentration of the conductive material in the composite conductive nanofiber aerogel which is secondly pressed.
As a further limitation of the above technical solution, the high sensitivity pressure range of the composite conductive nanofiber aerogel which is firstly compressed is smaller than the high sensitivity pressure range of the composite conductive nanofiber aerogel which is secondly compressed; and when the sensor is pressed, the pressure borne by at least one layer of the composite conductive nanofiber aerogel is within a high-sensitivity pressure range.
As a further limitation of the above technical solution, the composite conductive nanofiber aerogel is prepared from the following components in percentage by mass: 1-10% of conductive material, 0.1-10% of thermoplastic polymer nano fiber, 1-10% of cross-linking agent and the balance of mixed solvent.
As a further limitation of the above technical solution, the thermoplastic polymer nanofibers are polyvinyl alcohol-ethylene copolymer nanofibers, polyamide nanofibers, polyethylene terephthalate nanofibers or polyurethane nanofibers; the mixed solvent is an alcohol-water mixed solution, and the mass ratio of alcohol to water is 7: 3-3: 7, the alcohol is one of n-propanol, isopropanol, n-butanol or tert-butanol.
As a further limitation of the above technical solution, the conductive material is selected from one of single-walled/multi-walled carbon nanotubes, graphene oxide, carbon black, graphite micro-sheets, metal nanoparticles, metal nanowires/sheets, liquid metal, metal oxide powder, conductive titanium dioxide, ionic liquid, or conductive polymer; the conductive polymer is selected from one or more of polyaniline, polythiophene, polypyrrole, polyacetylene, polyphenylene sulfide, polyparaphenylene, polyaniline derivatives, polythiophene derivatives and polypyrrole derivatives.
As a further limitation of the above technical solution, the cross-linking agent is one or more of glutaraldehyde, formaldehyde or acetaldehyde.
As a further limitation of the technical scheme, the composite conductive nanofiber aerogel further comprises an acid which is added with the mass percentage concentration of 0.1-2% and is used as a catalyst. Preferably, the acid is one or more of hydrochloric acid, sulfuric acid, nitric acid or acetic acid.
The invention also provides a preparation method of the composite conductive nanofiber aerogel sensor with high sensitivity and wide range, which comprises the following steps:
s1, dissolving the thermoplastic polymer nanofiber in an alcohol-water mixed solution to form a suspension with the mass percentage concentration of 0.1-10%, and then sequentially adding a conductive material with the mass percentage concentration of 1-10% and a cross-linking agent with the mass percentage concentration of 1-10% to uniformly mix to obtain an aerogel glue solution;
s2, carrying out freeze drying treatment on the aerogel glue solution prepared in the step S1 by adopting a freeze drying treatment process to prepare the composite conductive nanofiber aerogel;
s3, coating the aerogel glue solution prepared in the step S1 on the composite conductive nanofiber aerogel prepared in the step S2;
s4, performing freeze drying treatment on the composite conductive nanofiber aerogel processed in the step S3 to obtain a multilayer composite conductive nanofiber aerogel;
and S5, repeating the steps S3 and S4 for multiple times to obtain the composite conductive nanofiber aerogel sensor with high sensitivity and wide range.
Preferably, the freezing temperature in the freeze drying treatment is-55 ℃ to-30 ℃, and the drying time is 12-48 h.
Preferably, in step S3, the composite conductive nanofiber aerogel can be coated by dip coating, drop coating, pulling or spin coating.
Preferably, the density of the composite conductive nanofiber aerogel material prepared by the method is 5-10 mg/cm, the specific surface area is 300-800 m/g, and the average pore diameter is 1-3 mu m.
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention takes the thermoplastic polymer nano fiber and the conductive material as the raw materials, reasonably controls the dosage ratio of the thermoplastic polymer nano fiber and the conductive material, prepares the nano fiber aerogel material with the three-dimensional structure by a freeze drying method, combines different composite conductive nano fiber aerogels with high sensitivity in different pressure ranges by utilizing the lower density, the high specific surface area and the void fraction of the aerogel material, and the nano fiber aerogel material with the three-dimensional structure is very soft and has high conductivity and reversible compressibility, realizes the high sensitivity of the composite conductive nano fiber aerogels at all levels to the pressure in different force value ranges, thereby obtaining the high sensitivity of the sensor in the whole range from small pressure to large pressure, still keeping the wide pressure range, and realizing the high sensitivity of the sensor in the whole range from small pressure to large pressure range by the ingenious multi-level composite conductive nano fiber aerogel structure distribution, the wide-range sensor has the advantages that the contradictory contradiction between sensitivity and range is solved, the performance of the sensor is greatly improved, and the application scenes of the sensor are enriched.
(2) The invention provides a high-sensitivity and wide-range composite conductive nanofiber aerogel sensor, which is simple in integral process and convenient to operate, can be used for preparing composite conductive nanofiber aerogel with high sensitivity in different pressure ranges only by reasonably adjusting the mass percentage concentration of thermoplastic polymer nanofibers in aerogel glue solution and performing freeze drying and coating steps, has good controllability in the whole preparation process, and is suitable for preparing three-dimensional structure nanofiber aerogel materials with different compactness degrees and fiber thicknesses.
Drawings
FIG. 1 is a scanning electron micrograph of sample 1 prepared in example 1 of the present invention.
FIG. 2 is a scanning electron micrograph of sample 2 prepared in example 1 of the present invention.
FIG. 3 is a scanning electron micrograph of sample 3 prepared in example 1 of the present invention.
FIG. 4 is a scanning electron micrograph of sample 4 prepared in example 1 of the present invention.
FIG. 5 is a graph of the pressure-resistance versus rate of change of sample 1 prepared in example 1 of the present invention.
FIG. 6 is a graph of the pressure-resistance versus rate of change for sample 2 made in example 1 of the present invention.
FIG. 7 is a graph of the pressure-resistance versus rate of change for sample 3 made in example 1 of the present invention.
FIG. 8 is a graph of the pressure-resistance versus rate of change of sample 4 prepared in example 1 of the present invention.
FIG. 9 is a graph of the pressure-resistance versus rate of change of sample 5 prepared in example 2 of the present invention.
FIG. 10 is a graph of the pressure-resistance versus rate of change for sample 6 made in example 2 of the present invention.
FIG. 11 is a graph of the pressure-resistance versus rate of change for sample 7 made in example 2 of the present invention.
FIG. 12 is a graph of the pressure-resistance versus rate of change for sample 8 made in example 3 of the present invention.
FIG. 13 is a graph of the pressure-resistance versus rate of change for sample 9 made in example 3 of the present invention.
FIG. 14 is a graph of the pressure-resistance versus rate of change of sample 10 made in comparative example 1 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly apparent, the present invention is further described in detail with reference to the following embodiments; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.
The present invention will be described in further detail below with reference to specific embodiments and with reference to the attached drawings.
Example 1
The embodiment provides a high sensitivity and wide range's compound electrically conductive nanofiber aerogel sensor, the sensor includes the four layers of compound electrically conductive nanofiber aerogel of establishing of stacking in proper order from bottom to top, just nanofiber's content in the four layers of compound electrically conductive nanofiber aerogel is the gradient from bottom to top and descends.
The preparation method of the composite conductive nanofiber aerogel sensor with high sensitivity and wide range comprises the following steps:
s1, dissolving polyvinyl alcohol-ethylene copolymer nanofibers (PVA-CO-PE) in an alcohol-water mixed solution to form thermoplastic polymer nanofiber suspensions with the mass percentage concentrations of 2%, 5%, 8% and 10%, and then sequentially adding PEDOT, PSS conductive materials and glutaraldehyde crosslinking agents to enable the mass percentage concentrations of the PEDOT, PSS conductive materials and HCl with the mass percentage concentration of 1% to be uniformly mixed to obtain aerogel glue solution; the mass ratio of the alcohol to the water is 5: 5;
s2, carrying out freeze drying treatment on the aerogel glue solution with the mass percentage concentration of 10% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 by adopting a freeze drying treatment process to prepare the composite conductive nanofiber aerogel, and marking the composite conductive nanofiber aerogel as a sample 1;
s3, coating the aerogel glue solution with the mass percentage concentration of 8% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 on the composite conductive nanofiber aerogel prepared in the step S2;
s4, performing freeze drying treatment on the composite conductive nanofiber aerogel processed in the step S3 to obtain two layers of composite conductive nanofiber aerogel, and marking as a sample 2;
s5, coating an aerogel glue solution with the mass percentage concentration of 5% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 on the two-layer composite conductive nanofiber aerogel prepared in the step S4, and marking as a sample 3;
s6, performing freeze drying treatment on the composite conductive nanofiber aerogel processed in the step S5 to obtain a three-layer composite conductive nanofiber aerogel;
s7, coating aerogel glue solution with the mass percentage concentration of 2% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 on the three-layer composite conductive nanofiber aerogel prepared in the step S6;
and S8, performing freeze drying treatment on the composite conductive nanofiber aerogel processed in the step S7 to obtain a four-layer composite conductive nanofiber aerogel sensor, and marking as a sample 4.
Adopt scanning electron microscope to observe the surface morphology of sample 1, sample 2, sample 3, sample 4 that this embodiment made, the result is shown as figure 1 ~ 4 respectively, can see from the picture, the porosity of different density conductive nanofiber aerogel is different, and along with the increase of polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) mass percentage concentration, the porosity of the conductive nanofiber aerogel that makes reduces, thereby demonstrate different electric conductive property, can form a high sensitivity and wide range's compound conductive nanofiber aerogel sensor after the conductive fiber aerogel through different porosities is compound.
The graphs of the pressure-resistance relative change rate of the samples 1, 2, 3 and 4 prepared in this example are shown in fig. 5 to 8, respectively, and it can be seen from the graphs that the sensitivity of the sensor becomes higher as the number of the composite layers increases.
Example 2
The embodiment provides a high sensitivity and wide range's compound electrically conductive nanofiber aerogel sensor, the sensor includes the compound electrically conductive nanofiber aerogel of three-layer that stacks gradually from bottom to top, just nanofiber's content in the compound electrically conductive nanofiber aerogel of three-layer is the gradient from bottom to top and descends.
The preparation method of the composite conductive nanofiber aerogel sensor with high sensitivity and wide range comprises the following steps:
s1, dissolving polyvinyl alcohol-ethylene copolymer nanofibers (PVA-CO-PE) in an alcohol-water mixed solution to form thermoplastic polymer nanofiber suspensions with the mass percentage concentrations of 2%, 5% and 8%, and then sequentially adding PEDOT, a PSS conductive material and glutaraldehyde crosslinking agent to ensure that the mass percentage concentrations of the PEDOT, the PSS conductive material and the glutaraldehyde crosslinking agent are respectively 6% and 1% to uniformly mix to prepare aerogel glue solution; the mass ratio of the alcohol to the water is 5: 5;
s2, carrying out freeze drying treatment on the aerogel glue solution with the mass percentage concentration of 8% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 by adopting a freeze drying treatment process to prepare the composite conductive nanofiber aerogel, and marking the composite conductive nanofiber aerogel as a sample 5;
s3, coating the aerogel glue solution with the mass percentage concentration of 5% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 on the composite conductive nanofiber aerogel prepared in the step S2;
s4, performing freeze drying treatment on the composite conductive nanofiber aerogel processed in the step S3 to obtain two layers of composite conductive nanofiber aerogel, and marking as a sample 6;
s5, coating aerogel glue solution with the mass percentage concentration of 2% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 on the two-layer composite conductive nanofiber aerogel prepared in the step S4, and marking as a sample 3;
and S6, performing freeze drying treatment on the composite conductive nanofiber aerogel processed in the step S5 to obtain a three-layer composite conductive nanofiber aerogel sensor, and recording as a sample 7.
Fig. 9 to 11 are graphs showing the pressure-resistance relative change rate of the samples 5, 6 and 7 prepared in this example, respectively, and it can be seen from the graphs that the sensor sensitivity becomes higher as the number of the composite layers increases.
Example 3
The embodiment provides a high sensitivity and wide range's compound electrically conductive nanofiber aerogel sensor, the sensor includes the two-layer compound electrically conductive nanofiber aerogel of establishing of stacking gradually from bottom to top, just nanofiber's content is the gradient from bottom to top in the two-layer compound electrically conductive nanofiber aerogel and decreases progressively.
The preparation method of the composite conductive nanofiber aerogel sensor with high sensitivity and wide range comprises the following steps:
s1, dissolving polyvinyl alcohol-ethylene copolymer nanofibers (PVA-CO-PE) in an alcohol-water mixed solution to form thermoplastic polymer nanofiber suspensions with the mass percentage concentrations of 2% and 5%, and then sequentially adding PEDOT, a PSS conductive material and glutaraldehyde crosslinking agent to ensure that the mass percentage concentrations of the PEDOT and the PSS conductive material are respectively 6% and 1% to obtain an aerogel glue solution through uniform mixing; the mass ratio of the alcohol to the water is 5: 5;
s2, carrying out freeze drying treatment on the aerogel glue solution with the mass percentage concentration of 5% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 by adopting a freeze drying treatment process to prepare the composite conductive nanofiber aerogel, and marking the composite conductive nanofiber aerogel as a sample 8;
s3, coating the aerogel glue solution with the mass percentage concentration of 2% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 on the composite conductive nanofiber aerogel prepared in the step S2;
and S4, performing freeze drying treatment on the composite conductive nanofiber aerogel processed in the step S3 to obtain a two-layer composite conductive nanofiber aerogel sensor, and marking as a sample 9.
The graphs of the pressure-resistance relative change rate of samples 8 and 9 obtained in this example are shown in fig. 12 and 13, respectively, and it can be seen that the sensor sensitivity becomes higher as the number of composite layers increases.
Examples 4 to 7
Examples 4-7 provide a high sensitivity and wide range composite conductive nanofiber aerogel sensor, which differs from example 1 in that: the mass percentage concentration of the PEDOT and PSS conductive materials is changed, other operations are the same, and are not repeated, and specific experimental condition parameters and performance test results are shown in the following table.
From the above table results, it can be seen that: the dosage ratio of the thermoplastic polymer nanofiber to the conductive material is changed, the nanofiber aerogel material with a three-dimensional structure is prepared by a freeze-drying method, different composite conductive nanofiber aerogels with high sensitivity in different pressure ranges are combined, high-sensitivity detection of the composite conductive nanofiber aerogels at all levels on the pressure in different force value ranges is realized, and therefore the high sensitivity in the whole range from small pressure to large pressure is obtained, and a wide pressure range is still maintained. Comparing the results of examples 1 and 5 to 6 with the results of examples 4 and 7, it can be seen that changing the amount of the conductive material significantly affects the sensitivity of the prepared multilayer composite conductive nanofiber aerogel sensor, and when the amount of the conductive material is within the range of 1 to 10% defined in the present invention, the prepared multilayer composite conductive nanofiber aerogel sensor has higher sensitivity and pressure range.
Comparative example 1
The present comparative example provides a high sensitivity and wide range composite conductive nanofiber aerogel sensor comprised of a single layer of composite conductive nanofiber aerogel.
The preparation method of the composite conductive nanofiber aerogel sensor with high sensitivity and wide range comprises the following steps:
s1, dissolving polyvinyl alcohol-ethylene copolymer nanofibers (PVA-CO-PE) in an alcohol-water mixed solution to form thermoplastic polymer nanofiber suspensions with the mass percentage concentrations of 2%, and then sequentially adding PEDOT, PSS conductive materials and glutaraldehyde crosslinking agents to enable the mass percentage concentrations of the PEDOT and the PSS conductive materials and the glutaraldehyde crosslinking agents to be 6% and HCl with the mass percentage concentration of 1% respectively, and uniformly mixing to obtain an aerogel glue solution; the mass ratio of the alcohol to the water is 5: 5;
and S2, carrying out freeze drying treatment on the aerogel glue solution with the mass percentage concentration of 2% of the polyvinyl alcohol-ethylene copolymer nanofiber (PVA-CO-PE) prepared in the step S1 by adopting a freeze drying treatment process to prepare the composite conductive nanofiber aerogel sensor, and marking as a sample 10.
Fig. 14 is a graph of the pressure-resistance relative rate of change of the sample 10 prepared in the present comparative example, from which it can be seen that the single-layer sample with the lowest concentration has higher sensitivity than the other single-layer samples (sample 1, sample 5, sample 8), but lower sensitivity than the four-layer composite aerogel (sample 4) and the two-layer composite aerogel (sample 9).
While the invention has been described with respect to specific embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes, omissions and deviations in the form and detail thereof may be made without departing from the scope of this invention; those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the spirit and scope of the invention; meanwhile, any equivalent changes, modifications and alterations of the above embodiments according to the spirit and techniques of the present invention are also within the scope of the present invention.
Claims (10)
1. The high-sensitivity wide-range composite conductive nanofiber aerogel sensor is characterized by comprising a plurality of layers of composite conductive nanofiber aerogels which are sequentially stacked from bottom to top, wherein the content of nanofibers in the multilayer composite conductive nanofiber aerogel is gradually reduced from bottom to top;
the preparation method of the composite conductive nanofiber aerogel sensor comprises the following steps:
s1, dissolving the thermoplastic polymer nanofiber in an alcohol-water mixed solution to form a suspension with the mass percentage concentration of 0.1-10%, and then sequentially adding a conductive material with the mass percentage concentration of 1-10% and a cross-linking agent with the mass percentage concentration of 1-10% to uniformly mix to obtain an aerogel glue solution;
s2, carrying out freeze drying treatment on the aerogel glue solution prepared in the step S1 by adopting a freeze drying treatment process to prepare the composite conductive nanofiber aerogel;
s3, coating the aerogel glue solution prepared in the step S1 on the composite conductive nanofiber aerogel prepared in the step S2;
s4, performing freeze drying treatment on the composite conductive nanofiber aerogel processed in the step S3 to obtain a multilayer composite conductive nanofiber aerogel;
s5, successively coating the aerogel glue solution prepared in the step S1 on the prepared multilayer composite conductive nanofiber aerogel, and performing freeze drying treatment to obtain the high-sensitivity and wide-range composite conductive nanofiber aerogel sensor;
in the process that the external pressure on the multilayer composite conductive nanofiber aerogel is gradually increased, the multilayer composite conductive nanofiber aerogel is sequentially pressed from top to bottom;
the Young modulus of the composite conductive nanofiber aerogel which is firstly pressed is smaller than that of the composite conductive nanofiber aerogel which is secondly pressed; and the small pressure sensitivity of the composite conductive nanofiber aerogel which is firstly pressed is higher than that of the composite conductive nanofiber aerogel which is secondly pressed.
2. The highly sensitive and wide-ranging composite conductive nanofiber aerogel sensor according to claim 1, wherein the filling concentration of the conductive material in the composite conductive nanofiber aerogel under pressure first is higher than the filling concentration of the conductive material in the composite conductive nanofiber aerogel under pressure later.
3. The high-sensitivity and wide-range composite conductive nanofiber aerogel sensor according to claim 2, wherein the high-sensitivity pressure range of the composite conductive nanofiber aerogel under pressure first is smaller than the high-sensitivity pressure range of the composite conductive nanofiber aerogel under pressure later; and when the sensor is pressed, the pressure borne by at least one layer of the composite conductive nanofiber aerogel is within a high-sensitivity pressure range.
4. The composite conductive nanofiber aerogel sensor with high sensitivity and wide range according to claim 1, wherein the thermoplastic polymer nanofiber is a polyvinyl alcohol-ethylene copolymer nanofiber, a polyamide nanofiber, a polyethylene terephthalate nanofiber or a polyurethane nanofiber; the mass ratio of alcohol to water in the alcohol-water mixed solution is 7: 3-3: 7, the alcohol is one of n-propanol, isopropanol, n-butanol or tert-butanol.
5. The composite conductive nanofiber aerogel sensor with high sensitivity and wide range according to claim 1, wherein the conductive material is selected from one of single-walled/multi-walled carbon nanotubes, graphene oxide, carbon black, graphite micro-sheets, metal nanoparticles, metal nanowires/sheets, liquid metal, metal oxide powder, conductive titanium dioxide, ionic liquid, or conductive polymer; the conductive polymer is selected from one or more of polyaniline, polythiophene, polypyrrole, polyacetylene, polyphenylene sulfide, polyparaphenylene, polyaniline derivatives, polythiophene derivatives and polypyrrole derivatives.
6. The composite conductive nanofiber aerogel sensor with high sensitivity and wide range according to claim 1, wherein the cross-linking agent is one or more of glutaraldehyde, formaldehyde or acetaldehyde.
7. The high-sensitivity and wide-range composite conductive nanofiber aerogel sensor according to claim 1, wherein the composite conductive nanofiber aerogel further comprises an acid added with a mass percentage concentration of 0.1-2% as a catalyst.
8. The high-sensitivity wide-range composite conductive nanofiber aerogel sensor according to claim 1, wherein the freezing temperature in the freeze drying process is-55 ℃ to-30 ℃, and the drying time is 12-48 h.
9. The highly sensitive and wide-ranging composite conductive nanofiber aerogel sensor according to claim 1, wherein in step S3, the composite conductive nanofiber aerogel is coated by dip coating, drop coating, pulling or spin coating.
10. The composite conductive nanofiber aerogel sensor with high sensitivity and wide range according to claim 1, wherein the density of the composite conductive nanofiber aerogel material is 5-10 mg/cm, the specific surface area is 300-800 m/g, and the average pore diameter is 1-3 μm.
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| CN104446304B (en) * | 2014-11-13 | 2016-05-04 | 向军辉 | Aerogel composite of multiple dimensioned multimeshed network composite construction and preparation method thereof |
| CN105675182A (en) * | 2015-11-30 | 2016-06-15 | 重庆大学 | Preparation method of cellulose-based flexible stress-strain sensitive material |
| CN105921083B (en) * | 2016-06-07 | 2019-06-11 | 东华大学 | The preparation method and its product of graded composite aeroge based on three-dimensional network shape |
| CN106187269B (en) * | 2016-07-19 | 2018-11-23 | 青岛科技大学 | A kind of amphiphilic graphene aerogel of intensity controlled and preparation method thereof |
| US10919262B2 (en) * | 2017-01-12 | 2021-02-16 | Northeastern University | Fire-retardant nanocellulose aerogels, and methods of preparation and uses thereof |
| CN109331751B (en) * | 2018-11-14 | 2021-11-30 | 武汉纺织大学 | Graphene-based aerogel material with tough structure and preparation method thereof |
| CN110057474B (en) * | 2019-03-01 | 2021-04-13 | 杭州电子科技大学 | Copper-based aerogel-PDMS composite piezoresistive pressure sensing material and application thereof |
| CN109813470B (en) * | 2019-03-25 | 2021-09-21 | 重庆大学 | High-sensitivity and wide-range pressure sensor |
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