Preparation and application of a starch-based self-powered flexible sensor

Abstract

The invention relates to the technical field of sensor manufacturing, and discloses a method for preparing a starch-based self-powered flexible sensor, comprising the following steps: S1: preparing a calcium chloride solution of a certain concentration as solution 1; S2: adding a metal salt to solution 1 as solution 2; S3: mixing a certain amount of high-amylose starch with solution 1 and solution 2 respectively and stirring evenly to obtain starch emulsion 1 and starch emulsion 2; S4: heating the starch emulsions in S1 for gelatinization to obtain gelatinized liquid 1 and gelatinized liquid 2; S5: adding glycerol and metal powder to gelatinized liquid 1 and gelatinized liquid 2 respectively, and pouring them into a film mold for cooling after mixing evenly; S6: taking out the materials in S5 respectively, restoring them to room temperature and bonding them to each other. The production process of the product is green and environmentally friendly, does not generate three wastes, and does not pollute the environment; and the process flow is simple, can be applied to industrial production, does not require additional new equipment, has a rapid process, and has a fast production speed.

Description

Technical Field

[0001] The present invention relates to the technical field of sensor manufacturing, and in particular to the preparation and application of a starch-based self-powered flexible sensor. Background Art

[0002] As a detection device, flexible sensors are widely used in wearable devices. They are generally composed of multiple parts such as sensing materials and power sources. According to statistics, the market demand has exceeded 300 million pieces, and the demand is still increasing year by year. Further simplifying the components of sensors can not only reduce the difficulty of processing, but also save resources and reduce costs, which will help further popularize wearable devices.

[0003] The sensing material is the core part of the sensor, and its function is to sense external signals and record them. The main types of sensing materials on the market are: photosensitive sensing materials, deformation sensing materials, thermal sensing materials, etc. However, most of the sensing materials on the market usually cannot be used independently, but need to be combined with a power source to form a sensor, which greatly limits the portability and usage scenarios of the material. Therefore, the market potential of creating a self-powered sensing material will be huge.

[0004] Starch material is a polymer material made from natural products. It is processed from starch particles and has the characteristics of low price, renewable, degradable, and good biocompatibility. Using it as a sensing material can not only solve the problems of high processing costs and recycling difficulties, but also solve the pollution problem of electronic waste. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation and application of a starch-based self-powered flexible sensor, so that the sensor can detect human body movement and be self-powered at the same time, thereby realizing the functional integration of sensing materials and external power supplies.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing a starch-based self-powered flexible sensor, comprising the following steps:

[0007] S1: Prepare a calcium chloride solution of a certain concentration as solution 1;

[0008] S2: adding metal salt to solution 1 to obtain solution 2;

[0009] S3: mixing a certain amount of high-amylose starch with solution 1 and solution 2 respectively and stirring evenly to obtain starch emulsion 1 and starch emulsion 2;

[0010] S4: The starch emulsions in S1 are heated and gelatinized to obtain gelatinized liquid 1 and gelatinized liquid 2;

[0011] S5: adding glycerin and metal powder to gelatinized liquid 1 and gelatinized liquid 2 respectively, and pouring into a film mold to cool after mixing evenly;

[0012] S6: Take out the materials in S5 separately, restore them to room temperature and bond them together, then bond the non-bonded surface of the materials to the conductive cloth to obtain a flexible self-powered sensor.

[0013] Preferably, the mass ratio of the calcium chloride solid to water in S1 is 1 to 1:5, preferably 1:2.

[0014] Preferably, the metal salt described in S2 is a copper ion salt, a silver ion salt, a zinc ion salt, a ferrous ion salt, preferably cupric chloride dihydrate.

[0015] Preferably, the mass ratio of the metal salt in S2 to the calcium chloride in (1) is 1 to 1:5, preferably 1:2.5.

[0016] Preferably, the high amylose starch described in S3 refers to starch having a starch content of more than 50% in starch granules.

[0017] Preferably, the mass ratio of the high-amylose starch to calcium chloride in S3 is 1 to 1:6, preferably 1:2.

[0018] Preferably, the heating gelatinization in S4 refers to heating to 30-100° C. for gelatinization for 10-100 min under stirring conditions, preferably heating to 70° C. for gelatinization for 60 min.

[0019] Preferably, the amount of glycerol used in S5 satisfies a volume ratio of water to glycerol of 1:0 to 1:1, preferably 1:0.2.

[0020] Preferably, the metal powder added to the gelatinized liquid 1 in S5 includes at least one of magnesium powder, aluminum powder, zinc powder, iron powder, tin powder and lead powder, and the metal reducing order is greater than the metal element added in S2; preferably zinc powder.

[0021] Preferably, the metal powder added to the gelatinized liquid 2 in S5 includes at least one of magnesium powder, aluminum powder, zinc powder, iron powder, tin powder, lead powder, copper powder, silver powder, platinum powder and gold powder; preferably copper powder.

[0022] Preferably, the cooling in S6 refers to cooling at a temperature of 0-20°C for 12-60h, the cooling time is preferably 4°C, and the cooling time is preferably 24h.

[0023] Preferably, the conductive cloth described in S6 includes nickel-plated conductive cloth, gold-plated conductive cloth, carbon-plated conductive cloth, and aluminum foil fiber composite cloth; preferably, it is carbon-plated conductive cloth.

[0024] A starch-based self-powered flexible sensor can be prepared by the above method.

[0025] The starch-based self-powered flexible sensor can be applied to fields such as wearable devices and portable batteries.

[0026] The mechanism of the present invention is:

[0027] A certain concentration of calcium chloride solution can deconstruct high-amylose starch particles, making the amylose therein free in the solution, thereby entangled with each other to form a gel electrolyte network. Adding glycerol to this gel electrolyte can promote the mutual movement between starch molecular chains, thereby improving the flexibility of the gel system and enabling it to withstand greater deformation. After adding metal powder to this gel electrolyte, the powder will be dispersed in the gel network. The entire system relies on the replacement reaction of metal powder and metal ions to form a primary battery, that is, the metal powder with stronger reducing properties serves as the negative electrode of the battery, loses electrons to form metal ions, and the electrons react with the ions dissolved in the gel through an external circuit to gain electrons. The reaction formula is as follows:

[0028] Negative electrode: M-2e-=M 2+

[0029] Positive electrode: Q 2+ +2e-=Q

[0030] Note: The metal reduction order is M>Q.

[0031] Because the gel system is flexible and compressible, the resistance inside the gel decreases after compression and the density of the electrolyte increases. Therefore, although the voltage of the chemical reaction remains unchanged, the output current can change with the gel deformation caused by pressure, thus showing the stimulation response of the current to external pressure.

[0032] The present invention provides a preparation and application of a starch-based self-powered flexible sensor, which has the following beneficial effects:

[0033] (1) The production process of this product is green and environmentally friendly, without generating any three wastes and causing no pollution to the environment; the process is simple and can be applied to industrial production without requiring any additional new equipment, and the process is rapid and the production speed is fast.

[0034] (2) This product is self-powered and can respond to external stimuli without the need for an external power source. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a graph showing the measurement of pulse beats by the self-powered flexible sensor. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0037] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0038] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] Unless otherwise specified, the reagents used in the examples can be purchased from the market.

[0041] Embodiment 1

[0042] (1) Weigh 50 g of solid calcium chloride and add it to 100 ml of water. Stir and dissolve until a clear solution is obtained. Cool to room temperature.

[0043] (2) Weigh 50 g of solid calcium chloride and 20 g of solid copper chloride dihydrate and add them to 100 ml of water, stir and dissolve until a clear solution is obtained, and cool to room temperature.

[0044] (3) Weigh 25 g of high-amylose starch, add it to the solution in (1), and stir to form a starch emulsion;

[0045] (4) Weigh 25 g of high-amylose starch, add it to the solution in (2), and stir to form a starch emulsion;

[0046] (5) Add 20 mL of glycerol and 25 g of zinc powder to the mixture in (3);

[0047] (6) Add 20 mL of glycerol and 25 g of copper powder to the mixture in (4);

[0048] (7) The mixture in (5) was heated and stirred at 70°C for 1 h;

[0049] (8) The mixture in (6) was heated and stirred at 70°C for 1 h;

[0050] (9) pouring the mixtures obtained in (7) and (8) into rectangular molds respectively;

[0051] (10) The mold in (9) was placed at 4° C. for 24 h, then taken out and placed at room temperature for 2 h before use;

[0052] (11) bonding the two materials obtained in (10) to each other;

[0053] (12) The non-bonded surface of the material obtained in (11) is bonded to the carbon-coated cloth to obtain a sensor;

[0054] The starch-based self-powered flexible sensor obtained in the above steps is used as a sensing signal of a finger motion sensor.

[0055] The sensor obtained by the above steps can generate a current signal change when the finger moves.

[0056] Embodiment 2

[0057] (1) Weigh 50 g of solid calcium chloride and add it to 100 ml of water. Stir and dissolve until a clear solution is obtained. Cool to room temperature.

[0058] (2) Weigh 50 g of solid calcium chloride and 20 g of solid copper chloride dihydrate and add them to 100 ml of water, stir and dissolve until a clear solution is obtained, and cool to room temperature.

[0059] (3) Weigh 25 g of high-amylose starch, add it to the solution in (1), and stir to form a starch emulsion;

[0060] (4) Weigh 25 g of high-amylose starch, add it to the solution in (2), and stir to form a starch emulsion;

[0061] (5) Add 20 mL of glycerol and 25 g of iron powder to the mixture in (3);

[0062] (6) Add 20 mL of glycerol and 25 g of copper powder to the mixture in (4);

[0063] (7) The mixture in (5) was heated and stirred at 70°C for 1 h;

[0064] (8) The mixture in (6) was heated and stirred at 70°C for 1 h;

[0065] (9) pouring the mixtures obtained in (7) and (8) into rectangular molds respectively;

[0066] (10) The mold in (9) was placed at 4° C. for 24 h, then taken out and placed at room temperature for 2 h before use;

[0067] (11) bonding the two materials obtained in (10) to each other;

[0068] (12) The non-bonding surface of the material obtained in (11) is bonded to a carbon-coated cloth to obtain a sensor.

[0069] The sensor obtained by the above steps can monitor the changes in the current signal generated by the pulse beating. Figure 1 shown.

[0070] Embodiment 3

[0071] (1) Weigh 50 g of solid calcium chloride and add it to 100 ml of water. Stir and dissolve until a clear solution is obtained. Cool to room temperature.

[0072] (2) Weigh 50 g of solid calcium chloride and 20 g of solid copper chloride dihydrate and add them to 100 ml of water, stir and dissolve until a clear solution is obtained, and cool to room temperature.

[0073] (3) Weigh 25 g of high-amylose starch, add it to the solution in (1), and stir to form a starch emulsion;

[0074] (4) Weigh 25 g of high-amylose starch, add it to the solution in (2), and stir to form a starch emulsion;

[0075] (5) Add 20 mL of glycerol and 25 g of magnesium powder to the mixture in (3);

[0076] (6) Add 20 mL of glycerol and 25 g of silver powder to the mixture in (4);

[0077] (7) The mixture in (5) was heated and stirred at 70°C for 1 h;

[0078] (8) The mixture in (6) was heated and stirred at 70°C for 1 h;

[0079] (9) pouring the mixtures obtained in (7) and (8) into rectangular molds respectively;

[0080] (10) The mold in (9) was placed at 4° C. for 24 h, then taken out and placed at room temperature for 2 h before use;

[0081] (11) bonding the two materials obtained in (10) to each other;

[0082] (12) The non-bonded surface of the material obtained in (11) is bonded to a gold-plated conductive cloth to obtain a sensor.

[0083] The sensor obtained by the above steps can monitor the changes in the current signal generated by the pulse beating. Figure 1 shown.

[0084] Embodiment 4

[0085] (1) Weigh 50 g of solid calcium chloride and add it to 100 ml of water. Stir and dissolve until a clear solution is obtained. Cool to room temperature.

[0086] (2) Weigh 50 g of solid calcium chloride and 20 g of solid copper chloride dihydrate and add them to 100 ml of water, stir and dissolve until a clear solution is obtained, and cool to room temperature.

[0087] (3) Weigh 25 g of high-amylose starch, add it to the solution in (1), and stir to form a starch emulsion;

[0088] (4) Weigh 25 g of high-amylose starch, add it to the solution in (2), and stir to form a starch emulsion;

[0089] (5) Add 20 mL of glycerol and 25 g of magnesium powder to the mixture in (3);

[0090] (6) Add 20 mL of glycerol and 25 g of silver powder to the mixture in (4);

[0091] (7) The mixture in (5) was heated and stirred at 100°C for 1 h 30 min;

[0092] (8) The mixture in (6) was further heated and stirred at 100° C. for 1 h 30 min;

[0093] (9) pouring the mixtures obtained in (7) and (8) into rectangular molds respectively;

[0094] (10) The mold in (9) was placed at 8° C. for 18 h, then taken out and placed at room temperature for 2 h before use;

[0095] (11) bonding the two materials obtained in (10) to each other;

[0096] (12) The non-bonded surface of the material obtained in (11) is bonded to an aluminum foil fiber composite cloth to obtain a sensor.

[0097] The sensor obtained by the above steps can monitor the changes in the current signal generated by the pulse beating. Figure 1 shown.

[0098] In summary, although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a starch-based self-powered flexible sensor, characterized in that: The following steps are involved: S1: preparing a calcium chloride solution as solution 1, wherein the mass ratio of calcium chloride solid to water is 1 to 1:5; S2: adding a metal salt to solution 1 as solution 2, wherein the metal salt is a copper ion salt, a silver ion salt, a zinc ion salt or a ferrous ion salt, and the mass ratio of the metal salt to the calcium chloride in S1 is 1 to 1:5; S3: mixing high-amylose starch with solution 1 and solution 2 respectively and stirring evenly to obtain starch emulsion 1 and starch emulsion 2, wherein the high-amylose starch refers to starch with a starch content of more than 50% in starch granules, and the mass ratio of the high-amylose starch to calcium chloride is 1 to 1:6; S4: The starch emulsions in S1 are heated and gelatinized to obtain gelatinized liquid 1 and gelatinized liquid 2; S5: adding glycerol and metal powder to gelatinized liquid 1 and gelatinized liquid 2 respectively, wherein the metal powder added to gelatinized liquid 1 includes at least one of magnesium powder, aluminum powder, zinc powder, iron powder, tin powder and lead powder and has a greater reducing order than the metal element added in S2, and the metal powder added to gelatinized liquid 2 includes at least one of magnesium powder, aluminum powder, zinc powder, iron powder, tin powder, lead powder, copper powder, silver powder, platinum powder and gold powder, and after mixing evenly, pouring into a mold to cool; S6: Take out the materials in S5 separately, restore them to room temperature and bond them together, then bond the non-bonded surface of the materials to the conductive cloth to obtain a flexible self-powered sensor.

2. The method for preparing a starch-based self-powered flexible sensor according to claim 1, characterized in that: The heating gelatinization described in S4 refers to heating to 30-100° C. for gelatinization for 10-100 minutes under stirring conditions, and the amount of glycerol used in S5 satisfies the volume ratio of water to glycerol of 1:0 to 1:

1.

3. The method for preparing a starch-based self-powered flexible sensor according to claim 1, characterized in that: The cooling described in S6 refers to cooling at a temperature of 0-20° C. for 12-60 hours.

4. A flexible self-powered sensor prepared according to the method according to any one of claims 1-3.

5. Application of the flexible self-powered sensor according to claim 4 in the fields of wearable devices and portable battery devices.

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