KR20200017958A - High sensitive microporous pressure sensor with low hysteresis fabricated by microfluidic systems - Google Patents

Abstract

The present invention relates to a method for manufacturing a pressure sensor which adjusts a size of micelle structures by using a microfluid system, enables a pore size adjustment of a porous pressure sensor, synthesizes conductive polymers on a surface and has high durability and high sensitivity. The present invention provides a method for manufacturing a high sensitive pressure sensor having a low hysteresis, which comprises: a step (a) of mixing a non-polar solvent and linear polymers; a step (b) of supplying a mixing solution in the step (a) and a polar solvent to one channel to form a micelle structure; a step (c) of heating the micelle structure leaked from the channel to polymerize the linear polymers, and evaporating a solvent to obtain a porous structure; and a step (d) of deposing conductive polymers on a surface of the porous structure manufactured in the step (c).

Description

High sensitive microporous pressure sensor with low hysteresis fabricated by microfluidic systems

The present invention relates to a method for manufacturing a high sensitivity sensitivity pressure sensor having a low hysteresis using a microfluidic system. Not only possible, but also to a method of manufacturing a pressure sensor that can have a high durability and high sensitivity by synthesizing a conductive polymer on the surface.

Interest in robots is increasing along with the 4th Industrial Revolution, and research on tactile sensors to give robots a human-like sense is also actively conducted. Since pressure is at the heart of human touch, research on pressure sensors among tactile sensors is focused. Many pressure sensors have been developed and studied so far, but there are many problems to be solved for commercialization.

One of the problems is uniformity. Uniformity refers to the same performance when a plurality of sensors are manufactured. Sensors reported in the existing literature are outstanding in performance, but are less reproducible and less uniform due to structural constraints.

Another problem with currently reported pressure sensors is hysteresis. Hysteresis means that the sensor is stimulated and does not return to the same signal point before and after the structure changes. When this occurs, the initial resistance of the sensor continuously fluctuates, making accurate signal measurement impossible and reducing the reliability of the sensor's data.

Therefore, when solving the problems of the uniformity, hysteresis, and sensitivity of the sensors currently preventing the commercialization of the pressure sensor, it will be possible to manufacture a pressure sensor that can be used in various ways such as artificial skin, touch screen, and wearable material.

(0001) Republic of Korea Patent Publication No. 10-2018-0072521 (0002) Republic of Korea Patent Publication No. 10-0605028

The present invention is to control the size of the micelle structure using a microfluidic system, not only to control the pore size of the porous pressure sensor, but also to manufacture a pressure sensor having high durability and high sensitivity by synthesizing a conductive polymer on the surface. To provide a method.

In order to solve the above problems, the present invention comprises the steps of (a) mixing a non-polar solvent and a linear polymer; (b) supplying the mixed solution and the polar solvent of step (a) to one channel to form a micelle structure; (c) heating the micelle structure flowing out of the channel to polymerize the linear polymer and evaporating the solvent to obtain a porous structure; And (d) provides a high pressure sensitive sensor manufacturing method having a low hysteresis comprising the step of depositing a conductive polymer on the surface of the porous structure prepared in step (c).

The nonpolar solvent may be benzene, hexane, toluene, xylene, hexadecane, octadecane or nonadecane.

The linear polymer may be polydimethylsiloxane (PDMS) or allyhydrocarboxsliane.

The polar solvent may be water or chloroform.

Step (b) may be performed using a microfluidic system.

The step (c) is carried out at 50 ~ 100 ℃, polymerization of the linear polymer may be performed first, and then evaporation of the solvent may be performed.

Prior to depositing the conductive polymer of step (d), the method may further include attaching a functional group through a plasma treatment and then attaching a polymer polymerization aid.

The plasma treatment may be performed using O 2 plasma.

The polymer synthesis preparation may be pyrrolesilane.

The conductive polymer of step (d) may be pyrrole or poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT; PSS).

Step (d) may be performed in the presence of a Fe 3+ catalyst.

The present invention also provides a pressure sensor manufactured by the above production method.

The method of manufacturing a highly sensitive pressure sensor having a low hysteresis using a microfluidic system according to the present invention overcomes the low sensitivity and non-uniformity of sensor characteristics by manufacturing a porous structure through a micelle structure using a microfluidic system. In addition to having a strong chemical bond with the conductive polymer synthesized on the surface through surface activation, the occurrence of hysteresis can be minimized, and a pressure sensor having high sensitivity and accuracy can be provided. It can be usefully used for medical surgical instruments, flexible touch screens, wearable electronic materials, and the like.

1 is an optical micrograph after the micelle structure, porous structure and conductive polymer polymerization according to an embodiment of the present invention.
Figure 2 is a graph of the result of FT-IR analysis after depositing a conductive polymer (pyrrole) according to an embodiment of the present invention.
Figure 3 is a graph showing the sensitivity according to the size of the micelle structure of the pressure sensor according to an embodiment of the present invention.
Figure 4 is a graph measuring the reaction rate of the pressure sensor according to an embodiment of the present invention.
Figure 5 is a graph measuring the hysteresis of the pressure sensor according to an embodiment of the present invention.
6 is a graph showing the durability test results of the pressure sensor according to an embodiment of the present invention.
Figure 7 is a graph of the durability test results of the conventional CNT-based sensor.

Hereinafter, a preferred embodiment of the present invention will be described in detail. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. Throughout the specification, when a part is said to "include" a certain component, it means that it may further include other components, not to exclude other components, unless specifically stated otherwise.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present invention, the terms including or having are intended to indicate that there is a feature, number, step, operation, component, part, or a combination thereof described in the specification, but one or more other features, numbers, steps It is to be understood that the present disclosure does not exclude the possibility of the presence or the addition of any operation, a component, a part, or a combination thereof.

The present invention comprises the steps of (a) mixing a non-polar solvent and a linear polymer; (b) supplying the mixed solution and the polar solvent of step (a) to one channel to form a micelle structure; (c) heating the micelle structure flowing out of the channel to polymerize the linear polymer and evaporating the solvent to obtain a porous structure; And (d) relates to a high-sensitivity pressure sensor manufacturing method having a low hysteresis phenomenon comprising the step of depositing a conductive polymer on the surface of the porous structure prepared in step (c).

Step (a) is a step of mixing linear polymers with a nonpolar solvent to form a micelle structure. When the linear polymers mixed with the nonpolar solvent are mixed with a polar solvent, the micelles are arranged in a spherical shape while containing a nonpolar solvent therein. To form a structure. In this case, the nonpolar solvent used may be benzene, hexane, toluene, xylene, hexadecane, octadecane or nonadecan, preferably hexadecane. In addition, the linear polymer is preferably polydimethylsiloxane (PDMS) or allyhydrocarboxsilane (allyhydrocarboxsliane). In addition, the linear polymer and the non-polar solvent is preferably mixed to have a ratio of 1:10 to 3: 1 by weight. When mixed to have a ratio of less than 1:10, the proportion of linear polymers may be lowered to prevent the formation of a micelle structure, and when mixed to have a ratio of less than 1: 3, the proportion of linear polymers may be increased to cause agglomeration. This, in turn, can result in nonuniformity of porous diatoms and reduction of voids.

Step (b) is a step of supplying the mixed solution and the polar solvent of the step (a) to one channel to form a micelle structure, it is preferably carried out using a microfluidic system. In this case, the solution and the polar solution of step (a) are supplied through different supply passages, and are mixed in a channel in the microfluidic system to form a micelle. In addition, when the microfluidic system is used, since micelles having the same diameter as the diameter of the channel are formed, the size of the pore in the porous structure can be adjusted by adjusting the diameter of the channel. At this time, the polar solvent used is preferably water or chloroform, it is possible to control the amount of the micelle structure outflow by adjusting the amount of water supplied.

The step (c) is a step of heating the micelle structure flowing out of the channel to polymerize the linear polymer, and evaporating the solvent to obtain a porous structure, which is carried out at 50 to 100 ° C., followed by polymerization of the linear polymer first. , May be a step of evaporating the solvent. As shown in the first figure of FIG. 1, when the micelle structure is uniformly arranged and the polymer forming the micelle structure is polymerized, a porous structure having the same structure as that of the micelle structure may be manufactured. However, if the non-polar solvent or the external polar solvent constituting the core portion of the micelle structure evaporates before the polymerization of the polymer, such a porous structure may not be manufactured. Therefore, the linear polymer is preferably polymerized at a lower temperature than the evaporation of the solvent, and it is preferable that the polymerization of the linear polymer is performed first and then the solvent is evaporated and removed as the temperature is increased. Therefore, when the step (c) is performed at less than 50 ° C., the solvent may be evaporated in a state in which the polymerization of the polymer is not performed. Since evaporation of is performed, it is difficult to obtain a uniform porous structure. The step (c) is more preferably carried out at 80 ℃.

Step (d) is a step of polymerizing the conductive polymer on the surface of the porous structure prepared in step (c), before the polymerization of the conductive polymer to increase the bonding strength of the porous structure and the conductive polymer, through a plasma treatment After attaching the functional group, it is preferable to attach the polymer synthesis aid. At this time, the plasma treatment is carried out using O 2 plasma, it is more preferable to use pyrrole silane as a polymer synthesis aid. In the case of the conductive polymer, it is preferable to use pyrrole or poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT; PSS), and more preferably, in the presence of a Fe 3+ catalyst to smoothly perform the polymerization.

The present invention also provides a pressure sensor manufactured by the above method.

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present disclosure. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention.

Example

While supplying a solution of 1: 1 mixture of polydimethylsiloxane and hexadecane in a weight ratio to the microfluidic system, water was injected into the other inlet of the channel to form a micelle structure. At this time, the inner diameter of the channel and the transfer pipe was 300㎛, and thus could form a micelle structure having a size of about 300㎛ (the first picture of Figure 1).

The micelle structure was arranged in a constant shape and then heated to 80 ° C. for 1 hour. At this time, the polydimethylsilonic acid was polymerized, and the hexadecane and water were evaporated to form a porous structure (FIG. 1). Second picture).

A functional group was attached to the prepared porous structure by O 2 plasma treatment, and then pyrrole silane was bonded to the functional group through chemical vapor deposition. Finally, the polymerization was carried out on the surface of the structure using a mixture of pyrrole and Fe + catalyst (third figure in FIG. 1).

Experimental Example

Figure 1 shows a picture of the micelle structure formed by the microfluidic system in a predetermined shape, a picture of the porous structure after curing, and a picture after the polymerization of the pyrrole conductive polymer. As shown in the first figure of FIG. 1, as the micelle structure was uniformly repeated, a porous structure in which a uniform shape was repeated was obtained, and accordingly, it was confirmed that a uniform shape was maintained even after the conductive polymer was polymerized. .

2 is a graph of FT-IR analysis after depositing a conductive polymer (pyrrole). As shown in FIG. 2, it was confirmed that pyrrole was normally deposited.

Figure 3 is a graph measuring the sensitivity of the sensor according to the size of the pore, that is, the size of the micelle structure. As shown in FIG. 3, the sensitivity of the sensor can be changed by adjusting the size of the micelle, which can be confirmed by adjusting the size of the delivery tube of the microfluidic system.

4 is a result of measuring the reaction rate of the pressure sensor produced by the present invention was confirmed that the change in resistance is carried out immediately according to the change in pressure.

Figure 5 is a graph measuring the hysteresis of the pressure sensor according to the present invention, it can be seen that the hysteresis limit appears to be small enough to be ignored when three different pressures are applied.

6 is a graph of the durability test results, it can be seen that the magnitude of the signal does not change even after 1000 repeated pressure experiments. In contrast, in the case of the conventional CNT-based pressure sensor, the magnitude of the signal was confirmed to change (FIG. 7).

As described above in detail specific parts of the present invention, it will be apparent to those skilled in the art that these specific descriptions are merely preferred embodiments, and thus the scope of the present invention is not limited thereto. will be. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (12)

(a) mixing a nonpolar solvent and a linear polymer;
(b) supplying the mixed solution and the polar solvent of step (a) to one channel to form a micelle structure;
(c) heating the micelle structure flowing out of the channel to polymerize the linear polymer and evaporating the solvent to obtain a porous structure; And
(d) polymerizing a conductive polymer on the surface of the porous structure prepared in step (c);
High sensitivity sensitivity pressure sensor manufacturing method having a low hysteresis, including.
The method of claim 1,
The non-polar solvent is a benzene, hexane, toluene, xylene, hexadecane, octadecane or nonadecan, the method of manufacturing a pressure sensor.
The method of claim 1,
The linear polymer is a polydimethylsiloxane (PDMS), allyn hydrocarboxysilane (allyhydrocarboxsliane) method for producing a pressure sensor, characterized in that.
The method of claim 1,
The polar solvent is water, chloroform manufacturing method of the pressure sensor, characterized in that.
The method of claim 4, wherein
The step (b) is a manufacturing method of the pressure sensor, characterized in that performed using a microfluidic system.
The method of claim 1,
The step (c) is carried out at 50 ~ 100 ℃, the polymerization of the linear polymer is first carried out, then the method of producing a pressure sensor, characterized in that the evaporation of the solvent is carried out.
The method of claim 1,
Prior to depositing the conductive polymer of step (d), after attaching the functional group through a plasma treatment, and further comprising the step of attaching a polymer polymerization aid.
The method of claim 7, wherein
The plasma treatment is a method of manufacturing a pressure sensor, characterized in that carried out using O 2 plasma.
The method of claim 7, wherein
The polymer synthesis preparation is a method for producing a pressure sensor, characterized in that the pyrrole silane.
The method of claim 1,
The conductive polymer of step (d) is pyrrole or poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT; PSS) characterized in that the manufacturing method of the pressure sensor.
The method of claim 1,
The step (d) is a manufacturing method of the pressure sensor, characterized in that carried out in the presence of the Fe 3 + catalyst.
Pressure sensor manufactured by the method of any one of claims 1 to 11.

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