KR102042856B1 - Nanofiber web piezocapacitive sensor and fabricating method of the same - Google Patents

Abstract

The present invention discloses a nanofiber web tack capacitive sensor and a manufacturing method thereof. A nanofiber web tack capacitive sensor according to an embodiment of the present invention is formed on a nanofiber web including a lower electrode, a void formed on the lower electrode, and the nano-fiber web. A sandwich structure including an upper electrode; And an insulating layer formed outside the sandwich structure to encapsulate the sandwich structure, wherein the nanofiber web contains an ionic liquid.

Description

Nanofiber web tack capacitive sensor and its manufacturing method {NANOFIBER WEB PIEZOCAPACITIVE SENSOR AND FABRICATING METHOD OF THE SAME}

The present invention relates to a nanofiber web tack capacitive sensor (piezocapacitive) sensor and a manufacturing method thereof, and more particularly, nanofiber web tack capacitive sensor and an ionic liquid contained in the nanofiber web It relates to a manufacturing method.

Pressure sensors in the form of films or fibers are areas of increasing need with the development and development of wearable devices. Polymer-based pressure sensors can be categorized as piezocapacitive sensors and piezoresistive sensors.Tack-capacitive sensors using dual polymer elastomers have superior characteristics compared to piezoresistive sensors in terms of power consumption and long-term durability. Shows.

Nevertheless, a general polymer elastomer has a low dielectric constant and has a disadvantage in that a change in capacitance value with respect to pressure is small. The thermoplastic polyurethane-based material in the polymer elastomer has a relatively large capacitance compared to other polymer elastomers because of its polarity, but the change in capacitance value is only a few to several tens of pF.

Polymer-based nanofiber webs formed through electrospinning processes have attracted attention in various fields due to their high surface area-to-volume ratio and inherent advantages resulting from nanostructures.

In view of the advantages of such nanofiber webs, there have been attempts to form organic polymers into nanofiber webs and use them as tack capacitive sensors, but they have insufficient elastic restoring force and relative capacitance to small pressures caused by many voids. It has the disadvantage of having large hysteresis due to change.

Korean Patent No. 10-1502762, "Hybrid Pressure Sensor Using Nano Fiber Web" Korean Registered Patent No. 10-1730396, "Pressure Sensor Using PLA Piezoelectric Materials in the Form of Nanofiber Web Obtained by Electrospinning" Korean Patent No. 10-1708113, "High Sensitivity Pressure Sensor"

The present invention provides a nanofiber web tack capacitive sensor having excellent elastic restoring force and low hysteresis and a method of manufacturing the same.

The nanofiber web tack capacitive sensor according to an embodiment of the present invention includes a lower electrode, a nanofiber web including a void formed on the lower electrode, and a nano-fiber web. A sandwich structure including an upper electrode formed; And an insulating layer formed outside the sandwich structure to encapsulate the sandwich structure, wherein the nanofiber web contains an ionic liquid.

In the nanofiber web tack capacitive sensor according to an embodiment of the present invention, the electrode is formed of at least one of a metal foil paper, a conductive fiber fabric, and an elastic conductor.

In the nanofiber web tack capacitive sensor according to an embodiment of the present invention, the insulating layer is formed of at least one of an insulating paper, an insulating film, and an insulating fiber.

In the nanofiber web tack capacitive sensor according to an embodiment of the present invention, the nanofiber web tack capacitive sensor includes an electrode connection portion of the structure electrically connected to the electrode, the electrode connection portion is external to the insulating layer It is characterized by extending to.

In the nanofiber web tack capacitive sensor according to an embodiment of the present invention, the polymer is a polymer, polyurethane, polyester-polyurethane copolymer (polyester-polyurethane) and polyether-polyurethane copolymer (polyether) -polyurethane) characterized in that it comprises at least one.

In the nanofiber web tack capacitive sensor according to an embodiment of the present invention, the ionic liquid is 1-methyl-3-methylimidazolium (1-Methyl-3-methylimidazolium), 1-ethyl-3-methyl Midazolium (1-Ethyl-3-methylimidazolium), 1-propyl-3-methylimidazolium (1-Propyl-3-methylimidazolium), 1-butyl-3-methylimidazolium (1-Butyl-3-methylimidazolium) ), 1-hexyl-3-methylimidazolium (1-Hexyl-3-methylimidazolium), 1-methyl-2,3-dimethylimidazolium (1-Methyl-2,3-dimethylimidazolium), 1-ethyl- 2,3-dimethylimidazolium (1-Ethyl-2,3-dimethylimidazolium), 1-propyl-2,3-methylimidazolium (1-Propyl-2,3-dimethylimidazolium), 1-butyl-2, Cation of one of 3-dimethylimidazolium (1-Butyl-2,3-dimethylimidazolium), 1-hexyl-2,3-dimethylimidazolium (1-Hexyl-2,3-dimethylimidazolium) and bis (tri Trifluoromethylsulfonyl) imide, Hexafluorophospate, meso In Methyl Sulfate, Ethyl Sulfate, Tetrafluoroborate, Trifluoromethanesulfonate, Iodide, Bromide, Chloride It characterized in that it comprises at least one of the ionic liquid made of a combination of one anion.

In the nanofiber web tack capacitive sensor according to an embodiment of the present invention, the nanofiber web tack capacitive sensor is characterized in that it has a capacitance-pressure hysteresis in the range of 0.1% to 5%.

Method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention, preparing a nanofiber web; Attaching an upper electrode and a lower electrode to upper and lower portions of the nanofiber web, respectively, to form a sandwich structure; Encapsulating by attaching an insulating layer to the outside of the sandwich structure; It includes.

In the method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention, the first polymer solution manufacturing step of dissolving a polymer in a first solvent; A second polymer solution preparing step of adding a second solvent to the first polymer solution; A third polymer solution preparing step of adding an ionic liquid to the second polymer solution; And electrospinning the third polymer solution to form a nanofiber web.

In the method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention, the first solvent is N, N-dimethylacetamide (N, N-dimethylacetamide, DMAc), N, N-dimethylformamide ( N, N-dimethylformamide, DMF), N-methylpyrrolidinone (N-methylpyrrolidinone, NMP) and dimethyl sulfoxide (dimethyl sulfoxide, DMSO) is characterized in that at least one.

In the method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention, the second solvent is acetone, methyl ethyl ketone, methanol, ethanol, propanol, butanol, t-butyl T-butyl alcohol, isopropylalcohol (iPA, 2-propanol), benzyl alcohol, tetrahydrofuran (THF), ethyl acetate, butyl acetate , Propylene glycol diacetate, propylene glycol methyl ether acetate (PGMEA), acetonitrile, chloroform, chloroform, dichloromethane, trifluoroacetonitrile ( trifluoroacetonitrile), ethylene glycol (ethylene glycol), pyridine (pyridine) and pyrrolidine (pyrrolidine) is characterized in that at least one or more.

In the method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention, the second solvent is characterized by increasing the volatility of the solvent during electrospinning and electrospinning stability.

In the method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention, the polymer is a polymer, polyurethane (polyurethane), polyester-polyurethane copolymer (polyester-polyurethane) and polyether-polyurethane aerial It characterized in that it comprises at least one of (polyether-polyurethane).

In the nanofiber web tack capacitive sensor according to an embodiment of the present invention, the ionic liquid is 1-methyl-3-methylimidazolium (1-Methyl-3-methylimidazolium), 1-ethyl-3-methyl Midazolium (1-Ethyl-3-methylimidazolium), 1-propyl-3-methylimidazolium (1-Propyl-3-methylimidazolium), 1-butyl-3-methylimidazolium (1-Butyl-3-methylimidazolium) ), 1-hexyl-3-methylimidazolium (1-Hexyl-3-methylimidazolium), 1-methyl-2,3-dimethylimidazolium (1-Methyl-2,3-dimethylimidazolium), 1-ethyl- 2,3-dimethylimidazolium (1-Ethyl-2,3-dimethylimidazolium), 1-propyl-2,3-methylimidazolium (1-Propyl-2,3-dimethylimidazolium), 1-butyl-2, Cation of one of 3-dimethylimidazolium (1-Butyl-2,3-dimethylimidazolium), 1-hexyl-2,3-dimethylimidazolium (1-Hexyl-2,3-dimethylimidazolium) and bis (tri Trifluoromethylsulfonyl) imide, Hexafluorophospate, meso In Methyl Sulfate, Ethyl Sulfate, Tetrafluoroborate, Trifluoromethanesulfonate, Iodide, Bromide, Chloride It characterized in that it comprises at least one of the ionic liquid made of a combination of one anion.

In the method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention, the ionic liquid is characterized in that less than 0.1% by weight to 5.0% by weight phr to the weight of the polymer.

According to an embodiment of the present invention, an ionic liquid is included in the nanofiber web, thereby providing a nanofiber web tack capacitive sensor having a high dielectric constant and capable of sensitively detecting a small pressure.

According to an embodiment of the present invention can form a nanofiber web close to the full elastic body can provide a nanofiber web tack capacitive sensor having a high durability even under repeated application of pressure.

According to one embodiment of the present invention, it is possible to provide a nanofiber web tack capacitive sensor having excellent capacitance-pressure hysteresis in the range of 0.1% to 5%.

1 illustrates a nanofiber web tack capacitive sensor according to an embodiment of the present invention.
Figure 2 shows a three-dimensional view of the nanofiber web tack capacitive sensor according to an embodiment of the present invention.
3 is a flowchart illustrating a method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention.
Figure 4 is a flow chart of the nanofiber web preparation step of the nanofiber web tack capacitive sensor manufacturing method according to another embodiment of the present invention.
5 illustrates an electrospinning process apparatus of a method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention.
Figure 6a shows a field emission scanning electron microscopy (FE-SEM) image of the surface of the nanofiber web according to Comparative Example 5 of the present invention.
FIG. 6B shows a field emission scanning electron microscope image of the surface of a nanofiber web according to Example 1 of the present invention.
7A to 7D are graphs showing a time versus capacitance curve according to periodic force application for 20 cycles of the nanofiber web tack capacitive sensor according to Example 1 and Comparative Examples 1 to 3 of the present invention.
8A to 8D are graphs showing capacitance-pressure hysteresis curves of nanofiber web tack capacitive sensors according to Example 1 and Comparative Examples 1 to 3 of the present invention.
9A to 9D are graphs showing capacitance-pressure hysteresis curves according to the change amount of the ionic liquid in the nanofiber web tack capacitance sensors according to Examples 1 to 3 and Comparative Example 1 of the present invention.
10A is a graph showing hysteresis (%) and capacitance change (ΔC) for Example 1 and Comparative Examples 1 to 3 of the present invention.
10B is a graph showing hysteresis (%) and capacitance change (ΔC) according to changes in the amount of ionic liquid added in Examples 1 to 3 and Comparative Example 1 of the present invention.
11A to 11D are graphs illustrating creep characteristics of nanofiber web tack capacitive sensors according to Example 1 and Comparative Examples 1 to 3. FIG.
12A to 12D show stress relaxation at constant capacitance according to Example 1 and Comparative Examples 1 to 3 as time versus pressure curves.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited to the embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprises” and / or “comprising” refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions.

As used herein, “an embodiment”, “an example”, “side”, “an example”, etc., should be construed that any aspect or design described is better or advantageous than other aspects or designs. It is not.

In addition, the term 'or' refers to an inclusive or 'inclusive or' rather than an exclusive or 'exclusive or'. In other words, unless stated otherwise or unclear from the context, the expression 'x uses a or b' means any one of natural inclusive permutations.

Also, the singular forms “a” or “an”, as used in this specification and in the claims, generally refer to “one or more” unless the context clearly dictates otherwise or in reference to a singular form. Should be interpreted as

The terminology used in the description below has been selected to be general and universal in the art to which it relates, although other terms may vary depending on the development and / or change in technology, conventions, and preferences of those skilled in the art. Therefore, the terms used in the following description should not be understood as limiting the technical spirit, and should be understood as exemplary terms for describing the embodiments.

In addition, in certain cases, there is a term arbitrarily selected by the applicant, and in this case, the meaning thereof will be described in detail in the corresponding description. Therefore, the terms used in the following description should be understood based on the meanings of the terms and the contents throughout the specification, rather than simply the names of the terms.

Meanwhile, terms such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

In addition, when a part such as a film, layer, area, configuration request, etc. is said to be "on" or "on" another part, the other film, layer, area, component in the middle, as well as when it is directly above another part It also includes the case where it is interposed.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. In addition, the terms defined in the commonly used dictionaries are not ideally or excessively interpreted unless they are specifically defined clearly.

On the other hand, in describing the present invention, when it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terminology used herein is a term used to properly express an embodiment of the present invention, which may vary according to a user, an operator's intention, or a custom in the field to which the present invention belongs. Therefore, the definitions of the terms should be made based on the contents throughout the specification.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 illustrates a nanofiber web tack capacitive sensor according to an embodiment of the present invention.

Referring to FIG. 1, the nanofiber web tack capacitive sensor 100 according to an exemplary embodiment of the present invention includes a nanofiber web 110 and a nanofiber web formed on the lower electrode 120 and the lower electrode 120. The sandwich structure 140 includes an upper electrode 130 formed on the 110 and an insulating layer 150 encapsulating the sandwich structure 140.

The nanofiber web 110 includes a plurality of pores, and includes an ionic liquid in the nanofiber web 110.

When the nanofiber web 110 is formed to include the ionic liquid therein, the fundamental dielectric constant value of the material is increased, thereby increasing the sensitivity to the pressure of the nanofiber web tack capacitive sensor 100.

In addition, the nanofiber web 110 containing the ionic liquid has a high elastic restoring force is mainly entered into the softening region compared with the conventional nanofiber web, and when added more than necessary, the elastic restoring force is reduced. Therefore, using the nanofiber web 110 containing an ionic liquid at an appropriate level, it is possible to manufacture a nanofiber web tack capacitive sensor 100 having high durability even under repeated application of pressure.

In addition, since the ionic liquid is contained in the nanofiber web 110, it may serve to reduce the number of voids, thereby achieving very low hysteresis of 0.1% to 5%.

The polymer forming the nanofiber web 110 may include any one of a polyurethane, a polyester-polyurethane copolymer, and a polyether-polyurethane copolymer. Can be.

In addition, the polyether-polyurethane may be a material capable of making elastic fibers collectively referred to as spandex.

Preferably, the ionic liquid may be a polyurethane series in which the ionic liquid enters the softening region well and the hysteresis of the elastic force is reduced.

The process of including the ionic liquid in the nanofiber web 100 will be described in detail in the manufacturing method to be described later.

The lower electrode 120 and the upper electrode 130 of the nanofiber web tack capacitive sensor 100 according to an embodiment of the present invention may be formed of metal foil paper, conductive fabric, and conductive material. At least one of a polymer film and a conductive nanoweb may be formed, and the electrodes 120 and 130 may be elastic electrodes that can be compressed and stretched.

In addition, the insulating layer of the nanofiber web tack capacitive sensor 100 according to an embodiment of the present invention (150) may be formed of at least one of insulating paper, insulating film and insulating fiber, the insulating layer 150 is elastic It can be formed or adhesively formed.

As such, the nanofiber web tack capacitive sensor 100 according to the embodiment of the present invention formed of an electrically conductive electrode portion and an insulating film and an insulating layer in the form of insulating fibers has a light weight, flexibility, compression, and expansion. It can have as much elasticity as possible and can be manufactured at low cost.

Figure 2 shows a three-dimensional view of the nanofiber web tack capacitive sensor according to an embodiment of the present invention.

Referring to FIG. 2, a lower electrode electrode connector 121 electrically connected to a lower electrode (not shown) formed under the nanofiber web 110 and an upper electrode formed on the nanofiber web 110. An upper electrode electrode connector 131 may be further formed to be electrically connected to and extend from the 130.

The electrode connectors 121 and 131 extend outward of the insulating layer 150 to electrically connect the sandwich structure encapsulated by the insulating layer 150 and external measuring equipment.

3 is a flowchart illustrating a method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention.

Method of manufacturing a nanofiber web tack capacitive sensor 100 according to another embodiment of the present invention 3 comprises a nanofiber web preparation step (S110), sandwich structure forming step (S120), sandwich structure encapsulation step (S130) The nanofiber web tack capacitive sensor 100 may be formed in a step process.

Nanofiber web preparation step (S110), the step of forming a nanofiber web by electrospinning the polymer solution, it will be described in detail in FIG.

Sandwich structure forming step (S120) is a step of forming the lower electrode 120 and the upper electrode 130 on the lower and upper nanofiber web 110 formed in the nanofiber web preparation step (S110), respectively.

The lower electrode 120 and the upper electrode 130 may be formed of at least one of a metal foil paper, a conductive fiber woven fabric, a conductive polymer film, and a conductive nanoweb, and the electrodes 120 and 130 may be compressed and stretched. Electrodes are also available, allowing for light weight, flexibility, compression and stretching elasticity, and low cost and easy processing.

The sandwich structure encapsulation step S130 is a step of encapsulating the sandwich structure 140 formed in the sandwich structure forming step S120 using the insulating layer 150.

The insulating layer 150 may use an adhesive insulating paper or an insulating film, and in the case of an elastic sensor, at least one of an elastic insulating film (eg, a silicon film), an elastic fiber, and an elastic nanoweb may be used. As with the advantages of the electrode material, it can have light weight and flexibility, elasticity that can be compressed and stretched, and can be formed at low cost and easy process.

Figure 4 is a flow chart of the nanofiber web preparation step of the nanofiber web tack capacitive sensor manufacturing method according to another embodiment of the present invention.

4 is a nanofiber web preparation step (S110) of the manufacturing method of the nanofiber web tack capacitive sensor according to another embodiment of the present invention, the first polymer solution manufacturing step (S111), the second polymer solution manufacturing step (S112) ), The nanofiber web 110 may be formed in a four-step process including a third polymer solution preparing step (S113) and a nanofiber web forming step (S114).

The first polymer solution preparing step (S111) is a step of dissolving a polymer in a first solvent.

The first solvent is N, N-dimethylacetamide (DMAc), N, N-dimethylformamide (DMF), N-methylpyrrolidinone (NMP ) And dimethyl sulfoxide (DMSO).

The polymer may be at least one of polyurethane, polyester-polyurethane, and polyether-polyurethane.

In addition, the polyether-polyurethane may be a material capable of making elastic fibers collectively referred to as spandex.

Preferably, the ionic liquid may be a polyurethane series in which the ionic liquid enters the softening region well and the hysteresis of the elastic force is reduced.

In the preparing of the first polymer solution (S111), 10 g of the polymer is added to 60 ml of the first solvent and stirred for 12 hours at a temperature of 25 ° C. to 100 ° C. until it is completely dissolved.

The second polymer solution preparing step (S112) is a step of adding a second solvent to the first polymer solution prepared in the first polymer solution preparing step (S111).

The second solvent is acetone, methyl ethyl ketone, methanol, ethanol, propanol, butanol, t-butyl alcohol, isopropyl alcohol (isoPA, 2-propanol), Benzyl alcohol, tetrahydrofuran (THF), ethyl acetate, ethyl acetate, butyl acetate, propylene glycol diacetate, propylene glycol methyl ether acetate, PGMEA), acetonitrile, chloroform, dichloromethane, trifluoroacetonitrile, ethylene glycol, pyridine and pyrrolidine It may include at least one of.

In the preparing of the second polymer solution (S112), a second solvent is added to the first polymer solution and stirred for 1 hour to 12 hours at a temperature condition of 25 ° C. to 50 ° C. until it is completely dissolved.

The first solvent and the second solvent may be mixed in a ratio of 5: 1 to 5: 5 by weight.

The reason for adding the second solvent in the second polymer solution preparing step (S112) has the purpose of increasing the volatility of the solvent during the electrospinning process, which will be described later, and helping to electrospin.

The third polymer solution preparing step (S113) is a step of adding an ionic liquid to the second polymer solution prepared through the second polymer solution preparing step (S112).

Ionic liquids include 1-methyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium, and 1-propyl-3- Methylimidazolium (1-Propyl-3-methylimidazolium), 1-Butyl-3-methylimidazolium (1-Butyl-3-methylimidazolium), 1-hexyl-3-methylimidazolium (1-Hexyl-3 -methylimidazolium), 1-methyl-2,3-dimethylimidazolium (1-Methyl-2,3-dimethylimidazolium), 1-ethyl-2,3-dimethylimidazolium (1-Ethyl-2,3-dimethylimidazolium ), 1-propyl-2,3-methylimidazolium (1-Propyl-2,3-dimethylimidazolium), 1-butyl-2,3-dimethylimidazolium (1-Butyl-2,3-dimethylimidazolium), A cation of one of 1-hexyl-2,3-dimethylimidazolium (1-Hexyl-2,3-dimethylimidazolium), bis (trifluoromethylsulfonyl) imide (Bis), hexaflo Hexafluorophospate, Methyl Sulfate, Ethyl Sulfate, Tetrafluoroborbo Containing at least one of an ionic liquid made of a combination of anions of tetrafluoroborate, trifluoromethanesulfonate, iodide, bromide, and chloride It features.

The amount of the ionic liquid added to the second polymer solution may be 0.1 wt% phr to 5.0 wt% phr.

The time point at which the ionic liquid is added to the second polymer solution is added before the electrospinning process, which will be described later, and may be preferably 1 hour to 2 hours before. This is because the phase separation may proceed gradually when the compatibility of the ionic liquid is low, and varies depending on the type of the polymer and the ionic liquid used, and the type of the solvent used.

Nanofiber web forming step (S114) is a step of forming a nanofiber web 110 through the electrospinning process of the third polymer solution prepared in the third polymer solution manufacturing step (S113).

Detailed conditions and steps of the electrospinning process will be described in detail later with reference to FIG. 5.

5 illustrates an electrospinning process apparatus of a method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention.

Referring to FIG. 5, the electrospinning process apparatus 200 includes a syringe pump 210, a needle 220, a rotatable cylinder collector and ground 230, and a power source 240.

Electrospinning process of the method of manufacturing a nanofiber web tack capacitive sensor according to another embodiment of the present invention to prepare a third polymer solution in the syringe pump 210, 0.1 ml / h while the power supply 240 is applied The third polymer solution is ejected through the needle 220 at a rate of from 10 ml / h. The needle 220 for ejecting the third polymer solution has a size of 10 G to 30 G, and several needles 220 may be used. The ejected third polymer solution may be in the form of nanofibers in the rotary cylinder collector and the ground 230 to form the nanofiber webs 110. At this time, the cylinder rotates at 60 rpm and the rotary cylinder collector and ground 230 may reciprocate in the direction of the axis of rotation of the cylinder.

The content described in this embodiment shows only one example of a method for manufacturing a nanofiber web tack capacitive sensor, which can be manufactured by various methods, and the scope of the present invention is not limited by these examples.

Nanofiber web tack capacitive sensor 100 according to an embodiment of the present invention formed through the above-described process forms a nanofiber web 110 including an ionic liquid inside the nanofiber web, so Sensitivity to pressure of the capacitive sensor 100 is increased, has the physical properties of a fully elastomer, and has a low hysteresis of 0.1% to 5% due to entering the polyurethane softening region of the ionic liquid.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by these examples.

Reagents and Substances

Polyether-polyurethane copolymer (spantex) was purchased from Hyosung Co. Ltd. Korea.The thermoplastic polyurethane (Estane® R190A) was made from Lubrizol, USA, and poly (styrene-b-butadiene). -b-Styrene) copolymer (SBS) is available from LG Chem. Ltd, Korea, 1-ethyl-3-methylimidazolium bis (trifluluormethylsulfonyl) imide (1-Ethyl-3- methylimidazolium bis (trifluoromethylsulfonyl) imide) was purchased from Tokyo Chemical Industry Co. Ltd. Japan (TCI), while N, N-dimethylformamide (NMF) and tetrahydrofuran (THF) It was purchased from Samchun Inc., Korea, and the purchased reagent was used as it was without purification.

In addition, commercially available aluminum foil was used for the electrodes 120 and 130.

Example 1

10 g of polyether-polyurethane copolymer (spantex) is mixed with 60 ml of N, N-dimethylformamide and stirred at a temperature of 100 ° C. for 12 hours until complete dissolution. 40 ml of tetrahydrofuran is then added and further stirred at a temperature of 35 ° C. for 8 hours. Thereafter, 0.1 g of 1-ethyl-3-methylimidazolium bis (tripulluormethylsulfonyl) imide is added 1 hour before electrospinning. The formed solution is electrospun through an electrospinning process to prepare a nanofiber web.

Subsequently, an aluminum foil electrode was attached to the prepared lower and upper nanofiber webs to form a sandwich structure, and the sandwich structure was encapsulated with an adhesive insulating paper to prepare a nanofiber web tack capacitive sensor.

Example 2

[Example 2] was prepared in the same manner as in [Example 1], except that 0.01 g of 1-ethyl-3-methylimidazolium bis (trifulluormethylsulfonyl) imide was added.

Example 3

[Example 3] was prepared in the same manner as in [Example 1], except that 0.3 g of 1-ethyl-3-methylimidazolium bis (tripuloormethylsulfonyl) imide was added.

Comparative Example 1

[Comparative Example 1] was prepared in the same manner as in [Example 1], except that 1-ethyl-3-methylimidazolium bis (tripulluormethylsulfonyl) imide was not added.

Comparative Example 2

[Comparative Example 2] is a tack capacitive sensor using a nanofiber web formed by electrospinning a conventional thermoplastic polyurethane (Estane® R190A).

Comparative Example 3

[Comparative Example 3] is a tack capacitive sensor using a nanofiber web formed by electrospinning conventional poly (styrene-b-butadiene-b-styrene) (Poly (styrene-b-butadiene-b-styrene), SBS) to be.

Hereinafter, the characteristics of the nanofiber web tack capacitive sensor according to the embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 6a shows a field emission scanning electron microscopy (FE-SEM) image of the surface of the nanofiber web according to Comparative Example 5 of the present invention.

Referring to Figure 6a, it can be seen that nanofibers having a diameter of 600 nm to 800 nm was formed through an electrospinning process.

FIG. 6B shows a field emission scanning electron microscope image of the surface of a nanofiber web according to Example 1 of the present invention.

Referring to FIG. 6B, as in FIG. 6A, nanofibers having a diameter of 600 nm to 800 nm may be formed through an electrospinning process.

From the field emission scanning electron microscope images of FIGS. 6A and 6B, it can be seen that even when an ionic liquid is added in the nanofiber web 110 forming process, no beads or fibers are aggregated on the microstructure.

7A to 7D are graphs showing a time versus capacitance curve according to periodic force application for 20 cycles of the nanofiber web tack capacitive sensor according to Example 1 and Comparative Examples 1 to 3 of the present invention.

In the graphs of FIGS. 7A-7D, the periodic application of force is 2 N and 100 N, T represents the thickness of the nanofiber web, and the dashed lines at the bottom and top represent the capacitance values upon application of the force of 2 N and 100 N. Indicates interval

Figure 7a is a graph according to the experimental results of the nanofiber web tack capacitive sensor of Example 1 of the present invention.

Referring to FIG. 7A, the nanofiber web tack capacitance sensor according to Example 1 of the present invention shows a constant tack capacitance upon application of force in the first to twentieth cycles, and thus shows excellent repeatability. Even when the removal is showing a fairly fast recovery. Appearing in the form of a slight creep is judged to be due to the effect of the protective film on the outside, it can be seen that the capacitance is stabilized after several cycles.

Referring to FIG. 7B, the nanofiber web tack capacitive sensor according to Comparative Example 1 of the present invention has a smaller variation in tack capacitance than the nanofiber web tack capacitive sensor according to Example 1, and has a longer stabilization time. It can be seen that, in particular with reference to Figure 8b to be described later, the hysteresis appears significantly larger than 7.5 in Example 1.

Referring to the graphs of Comparative Examples 2 to 3 of the present invention of FIGS. 7C to 7D, the conventional nanofiber web tack capacitive sensor has a relatively small capacitance width and does not recover after the first cycle. Gradually increasing, it can be seen that the thickness of the tack capacitive sensor does not recover and gradually decreases (FIG. 7c) or the capacitance width decreases (FIG. 7d).

8A to 8D are graphs showing capacitance-pressure hysteresis curves of nanofiber web tack capacitive sensors according to Example 1 and Comparative Examples 1 to 3 of the present invention.

Figure 8a is a graph according to the experimental results of the nanofiber web tack capacitive sensor of Example 1 of the present invention.

Referring to FIG. 8A, it can be seen that the nanofiber web tack capacitive sensor according to Example 1 of the present invention has a capacitance-pressure hysteresis curve of 1% to 2%.

On the other hand, referring to the graphs of Comparative Examples 1 to 3 of the present invention of FIGS. 8B to 8D, it is confirmed that the conventional nanofiber web tack capacitive sensor has a large capacitance-pressure hysteresis curve exceeding 7%. Can be.

9A to 9D are graphs showing capacitance-pressure hysteresis curves according to the change amount of the ionic liquid in the nanofiber web tack capacitance sensors according to Examples 1 to 3 and Comparative Example 1 of the present invention.

FIG. 9A shows the capacitance-pressure hysteresis curve of a nanofiber web tack capacitive sensor to which 1 phr of ionic liquid is added according to Example 1 of the present invention.

9A, it can be seen that the nanofiber web tack capacitive sensor according to Example 1 of the present invention has a capacitance-pressure hysteresis curve of 1% to 2%.

FIG. 9B shows a capacitance-pressure hysteresis curve of a nanofiber web tack capacitive sensor to which 0.1 phr of ionic liquid is added according to Example 2 of the present invention.

9C shows the capacitance-pressure hysteresis curve of the nanofiber web tack capacitive sensor with 3 phr of ionic liquid according to Example c of the present invention.

Based on the results of FIGS. 9A to 9C, in order to become an ideal tack capacitive sensor, it is best to enter an appropriate amount of ionic liquid, and when the excess is added, the sensitivity is excellent as shown in FIG. 9C, but the hysteresis increases greatly. . This is because some of the ionic liquid comes out of the nanofibers.

10A is a graph showing hysteresis (%) and capacitance change (ΔC) for Example 1 and Comparative Examples 1 to 3 of the present invention.

According to FIG. 10A, when the ionic liquid is added, the hysteresis is the smallest in the case of Example 1, while the capacitance change is relatively higher than that of the other comparative examples, indicating that it is an excellent capacitance sensor.

10B is a graph showing hysteresis (%) and capacitance change (ΔC) according to changes in the amount of ionic liquid added, in Examples 1 to 3 and Comparative Example 1 of the present invention.

According to Figure 10b, it can be seen that Example 1 of the present invention shows better performance than Example 2, Example 3 and Comparative Example 1, it can be seen that the appropriate level of ionic liquid should be added.

11A to 11D are graphs illustrating creep characteristics of nanofiber web tack capacitive sensors according to Example 1 and Comparative Examples 1 to 3. FIG.

According to FIG. 11a, when a constant load of 200 N is applied, the result shows that the change in capacitance per hour shows little result, which shows that it is a good elastic body.

11B to 11D, unlike FIG. 11A, the capacitance is gradually increased with time, and thus the thickness of the sensor film is gradually decreased, indicating that it is not suitable as a tack capacitive sensor.

12A to 12D show stress relaxation at constant capacitance according to Example 1 and Comparative Examples 1 to 3 as time versus pressure curves.

This is a diagram of the force required to achieve a constant capacitance. Inversely of FIGS. 11A-11D, the results of Example 1 show that the degree of change is the smallest and shows excellent characteristics.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely presented specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

100: nanofiber web tack capacitive sensor 110: nanofiber web
120: lower electrode 121: lower electrode electrode connection portion
130: upper electrode 131: upper electrode electrode connection portion
140: sandwich structure 150: insulating layer
200: electrospinning process apparatus 210: syringe pump
220: needle 230: rotary cylinder collector and ground
240: power

Claims (15)

A sandwich structure including a lower electrode, a nanofiber web including a void formed on the lower electrode, and an upper electrode formed on the nano-fiber web; And
An insulating layer formed outside the sandwich structure to encapsulate the sandwich structure
Including,
An ionic liquid is contained in the nanofiber web,
The polymer forming the nanofiber web is a piezocapacitive sensor, characterized in that the ionic liquid is polyurethane-based to enter the softening region.
The method of claim 1,
And the lower electrode and the upper electrode are formed of at least one of a metal foil paper, a conductive fiber fabric, and an elastic conductor.
The method of claim 1,
The insulating layer is formed of at least one of an elastic insulating layer and an adhesive insulating layer,
And the elastic insulating layer and the adhesive insulating layer are formed of at least one of an insulating paper, an insulating film, and an insulating fiber.
The method of claim 1,
The nanofiber web tack capacitive sensor includes an electrode connection part having a structure electrically connected to the lower electrode and the upper electrode,
And the electrode connection part extends to the outside of the insulating layer.
The method of claim 1,
The polymer forming the nanofiber web includes at least one of polyurethane, polyester-polyurethane copolymer, and polyether-polyurethane. Nanofiber web tack capacitive sensor.
The method of claim 1,
The ionic liquid is 1-methyl-3-methylimidazolium (1-Methyl-3-methylimidazolium), 1-ethyl-3-methylimidazolium (1-Ethyl-3-methylimidazolium), 1-propyl-3 -Methylimidazolium (1-Propyl-3-methylimidazolium), 1-Butyl-3-methylimidazolium (1-Butyl-3-methylimidazolium), 1-hexyl-3-methylimidazolium (1-Hexyl- 3-methylimidazolium), 1-methyl-2,3-dimethylimidazolium (1-Methyl-2,3-dimethylimidazolium), 1-ethyl-2,3-dimethylimidazolium (1-Ethyl-2,3- dimethylimidazolium), 1-propyl-2,3-methylimidazolium (1-Propyl-2,3-dimethylimidazolium), 1-butyl-2,3-dimethylimidazolium (1-Butyl-2,3-dimethylimidazolium) , Cation of one of 1-hexyl-2,3-dimethylimidazolium (1-Hexyl-2,3-dimethylimidazolium), bis (trifluoromethylsulfonyl) imide (Bis), hexa Hexafluorophospate, Methyl Sulfate, Ethyl Sulfate, Tetrafluoro At least one of an ionic liquid made of a combination of anions of one of the following: tetrafluoroborate, trifluoromethanesulfonate, iodide, bromide, chloride Nanofiber web tack capacitive sensor, characterized in that.
The method of claim 1,
The nanofiber web tack capacitive sensor has a capacitance-pressure hysteresis in the range of 0.1% to 5%.
Preparing a nanofiber web;
Attaching an upper electrode and a lower electrode to upper and lower portions of the nanofiber web, respectively, to form a sandwich structure;
Encapsulating by attaching an insulating layer to the outside of the sandwich structure;
Including,
An ionic liquid is contained in the nanofiber web,
The polymer forming the nanofiber web is a nanofiber web tack capacitive sensor manufacturing method characterized in that the ionic liquid is a polyurethane-based to enter the softening region.
The method of claim 8,
Preparing the nanofiber web,
Preparing a first polymer solution to dissolve the polymer in a first solvent;
A second polymer solution preparing step of adding a second solvent to the first polymer solution;
A third polymer solution preparing step of adding an ionic liquid to the second polymer solution; And
Nanofiber web tack capacitive sensor manufacturing method comprising the step of electrospinning the third polymer solution to form a nanofiber web.
The method of claim 9,
The first solvent is N, N-dimethylacetamide (N, N-dimethylacetamide, DMAc), N, N-dimethylformamide (N, N-dimethylformamide, DMF), N-methylpyrrolidinone (N-methylpyrrolidinone, NMP) and dimethyl sulfoxide (DMSO) at least one of the nanofiber web tack capacitive sensor manufacturing method.
The method of claim 9,
The second solvent is acetone, methyl ethyl ketone, methanol, ethanol, propanol, butanol, t-butyl alcohol, isopropyl alcohol (isoPA, 2-propanol) , Benzyl alcohol, tetrahydrofuran (THF), ethyl acetate, ethyl acetate, butyl acetate, propylene glycol diacetate, propylene glycol methyl ether acetate ether acetate (PGMEA), acetonitrile, chloroform, dichloromethane, trifluoroacetonitrile, ethylene glycol, pyridine and pyrrolidine ) At least one or more nanofiber web tack capacitive sensor manufacturing method.
The method of claim 9,
The second solvent is nanofiber web tack capacitive sensor manufacturing method characterized in that to increase the volatility and electrospinning stability of the solvent during the electrospinning.
The method of claim 9,
The polymer is a nanofiber web tack capacity, characterized in that it comprises at least one of polyurethane (polyurethane), polyester-polyurethane copolymer (polyester-polyurethane) and polyether-polyurethane copolymer (polyether-polyurethane) Sensor manufacturing method.
The method of claim 9,
The ionic liquid is 1-methyl-3-methylimidazolium (1-Methyl-3-methylimidazolium), 1-ethyl-3-methylimidazolium (1-Ethyl-3-methylimidazolium), 1-propyl-3 -Methylimidazolium (1-Propyl-3-methylimidazolium), 1-Butyl-3-methylimidazolium (1-Butyl-3-methylimidazolium), 1-hexyl-3-methylimidazolium (1-Hexyl- 3-methylimidazolium), 1-methyl-2,3-dimethylimidazolium (1-Methyl-2,3-dimethylimidazolium), 1-ethyl-2,3-dimethylimidazolium (1-Ethyl-2,3- dimethylimidazolium), 1-propyl-2,3-methylimidazolium (1-Propyl-2,3-dimethylimidazolium), 1-butyl-2,3-dimethylimidazolium (1-Butyl-2,3-dimethylimidazolium) , Cation of one of 1-hexyl-2,3-dimethylimidazolium (1-Hexyl-2,3-dimethylimidazolium), bis (trifluoromethylsulfonyl) imide (Bis), hexa Hexafluorophospate, Methyl Sulfate, Ethyl Sulfate, Tetrafluoro At least one of an ionic liquid made of a combination of anions of one of the following: tetrafluoroborate, trifluoromethanesulfonate, iodide, bromide, chloride Nanofiber web tack capacitive sensor manufacturing method characterized in that.
The method of claim 9,
The ionic liquid is a nanofiber web tack capacitive sensor manufacturing method, characterized in that less than 0.1% by weight to 5.0% by weight phr to the weight of the second polymer solution.

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