Preparation and application of rosin-based self-powered sensing gel

Abstract

The invention discloses preparation and application of rosin-based self-powered sensing gel, epoxidized soybean oil is induced to be subjected to ring-opening reaction on the basis of synergistic catalysis of rosin and itaconic acid, and a three-dimensional cross-linked network structure is formed through free radical polymerization under a high-temperature condition. Wherein a carboxyl functional group of itaconic acid participates in a cross-linking reaction to construct a gel skeleton with a high cross-linking degree, and rosin inhibits excessive cross-linking through competitiveness, so that the flexibility and stretchability of the gel are remarkably improved. In the contact-separation process, interface charges between the gel and the friction layer are transferred to form a potential difference, electrons in the rosin gel conducting layer are driven to flow, and therefore a stable voltage signal is output. A self-powered sensor assembled by the rosin-based self-powered sensing gel prepared by the invention is strong in voltage signal and good in stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of natural polymer materials, and particularly relates to preparation and application of a rosin-based self-powered sensing gel. BACKGROUND

[0002] With the rapid development of Internet of Things (IoT), smart wearable devices and health monitoring technology, there is a sharp increase in the demand for flexible, sustainable and low-power sensors. Traditional sensors rely on external power supply, and have problems such as limited service life, large size and environmental pollution. Based on the principle of energy conversion, self-powered sensing technology can directly capture environmental mechanical energy and convert it into a usable electrical signal, so that the sensing system is free from dependence on external power supply. At present, self-powered sensing is mainly based on piezoelectric, triboelectric, thermoelectric and photovoltaic energy conversion mechanisms. Among them, triboelectric nanogenerators (TENG) and piezoelectric materials have great potential in the fields of wearable electronics, electronic skin and human-computer interaction due to their high sensitivity, simple structure and low manufacturing cost. However, traditional self-powered materials (such as inorganic piezoelectric ceramics and synthetic polymer polymers) often have poor flexibility, low biocompatibility and non-degradability, which limits their application in biological medicine and environmental protection fields. In response to the demand for environmental sustainability, bio-based materials (such as natural polymers and plant oil derivatives) have become an ideal choice to replace petroleum-based materials due to their renewable, degradable and low toxicity properties. However, pure bio-based materials usually have poor electrical conductivity, insufficient mechanical strength and low environmental stability, which makes it difficult to meet the high performance requirements of self-powered sensing. Therefore, how to improve the electrical properties and sensing sensitivity of bio-based materials while maintaining their environmental protection properties through molecular design, composite modification and structure optimization is a core challenge in current research.

[0003] Itaconic acid, as a bio-based unsaturated dicarboxylic acid compound prepared by microbial fermentation of glucose, not only has environmental friendliness and good biocompatibility, but also has two carboxyl functional groups in its molecular structure, which endows it with chemical reactivity. In the present application, through molecular design, the synergistic effect of itaconic acid, epoxy soybean oil and rosin is used to construct a dynamic crosslinking network system. In this system, epoxy soybean oil provides flexible segments through ring-opening reaction to enhance the tensile properties of the material, and the rigid phenyl ring structure in rosin effectively regulates the mechanical properties of the material. Itaconic acid not only acts as an inducer for ring-opening reaction, but also participates in the final crosslinking polymerization reaction. The rosin gel formed by the synergistic effect of multiple components provides an environmentally friendly material solution for the fields of flexible electronics and intelligent medical treatment. SUMMARY

[0004] The purpose of the present application is to provide a preparation and application of a rosin-based self-powered sensing gel, aiming at the current self-powered sensor assembly complexity, and the self-powered material relies on petroleum-based polymers, leading to degradation and recycling difficulties of self-powered sensors, which is not conducive to sustainable application. The synergistic catalysis of rosin and itaconic acid induces ring-opening reaction of epoxy soybean oil, and forms a three-dimensional cross-linked network structure through free radical polymerization under high temperature conditions. Among them, the carboxyl functional group of itaconic acid participates in the cross-linking reaction to build a high cross-linking degree gel skeleton, while rosin competes to inhibit excessive cross-linking, significantly improving the flexibility and stretchability of the gel. In the contact-separation process, the interfacial charge transfer between the gel and the friction layer forms a potential difference, driving the electron flow in the rosin gel conductive layer, thereby outputting a stable voltage signal. The self-powered sensor assembled by the rosin-based self-powered sensing gel prepared by the present application has strong voltage signal and good stability.

[0005] To achieve the above purpose, the present application adopts the following technical solutions: A preparation and application of a rosin-based self-powered sensing gel, comprising the following steps: (1) A certain amount of rosin, itaconic acid and octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate are added to epoxy soybean oil to form a rosin-based gel through oil bath reaction.

[0006] (2) The conductive tape is connected between the rosin-based gel and the glove to assemble a self-powered sensor.

[0007] In step (1), the mass ratio of epoxy soybean oil to rosin is (5:1)-(1:1), and the mass ratio of itaconic acid to rosin is (1:4)-(1:30).

[0008] In step (1), the amount of octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate is 0.1-5ml.

[0009] In step (1), the oil bath reaction temperature is 120-190℃, and the reaction time is 0.5-4h.

[0010] In step (2), the glove is any one of nitrile glove, polyethylene glove and polyvinyl chloride glove.

[0011] The present application has the following advantages: (1) The present application uses biomass as raw material, which is environmentally friendly. The rosin-based gel prepared has strong electron transport ability, which improves the output signal strength of the sensor.

[0012] (2) The self-powered sensor of the present application is easy to assemble. It does not need to be packaged in the friction layer by a complex packaging method. It only needs to adhere the rosin-based gel to the glove, and the output voltage change in the contact-separation process generates a sensing signal. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 Formation mechanism of rosin-based gel.

[0014] Figure 2 Self-powered sensing working mechanism diagram of rosin-based gel.

[0015] Figure 3 Rosin-based gel sample diagram.

[0016] Figure 4 Different angle self-powered sensing picture.

[0017] Figure 5 Stress-strain curve of rosin-based gel of Example 1-4.

[0018] Figure 6 Sensing signal of self-powered sensor assembled by rosin-based gel of Example 1 to different bending angles of index finger.

[0019] Figure 7 Sensing signal of self-powered sensor assembled by rosin-based gel of Example 2 to different bending angles of index finger.

[0020] Figure 8 Sensing signal of self-powered sensor assembled by rosin-based gel of Example 3 to different bending angles of index finger.

[0021] Figure 9 Sensing signal of self-powered sensor assembled by rosin-based gel of Example 4 to different bending angles of index finger. DETAILED DESCRIPTION

[0022] In order to make the content described in the present application more convenient to understand, the technical solutions described in the present application will be further described below in combination with specific embodiments, but the present application is not limited thereto.

[0023] Example 1 (1) Take 10 g of rosin, 2 g of itaconic acid and 3 ml of octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate into 15 g of epoxy soybean oil, and react in an oil bath at 160°C for 1 h to form a rosin-based gel.

[0024] (2) Connect the conductive tape between the rosin-based gel and the polyethylene glove, and connect the conductive tape to the electrometer (KEITHLEY 6514) to test the sensing performance of different bending angles of the index finger.

[0025] Example 2 (1) Take 8 g of rosin, 2 g of itaconic acid and 2 ml of octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate into 15 g of epoxy soybean oil, and react in an oil bath at 120°C for 4 h to form a rosin-based gel.

[0026] (2) The conductive tape was connected between the rosin-based gel and the nitrile glove, and the conductive tape was connected to the electrometer (KEITHLEY 6514) to test the sensing performance of the different bending angles of the index finger.

[0027] Example 3 (1) 5 g of rosin, 1 g of itaconic acid, and 1 ml of octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate were weighed and added to 7.5 g of epoxy soybean oil in an oil bath at 160°C for 1 h to form a rosin-based gel.

[0028] (2) The conductive tape was connected between the rosin-based gel and the polyvinyl chloride glove, and the conductive tape was connected to the electrometer (KEITHLEY 6514) to test the sensing performance of the different bending angles of the index finger.

[0029] Example 4 (1) 11 g of rosin, 0.5 g of itaconic acid, and 0.5 ml of octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate were weighed and added to 15 g of epoxy soybean oil in an oil bath at 190°C for 0.5 h to form a rosin-based gel.

[0030] (2) The conductive tape was connected between the rosin-based gel and the polyvinyl chloride glove, and the conductive tape was connected to the electrometer (KEITHLEY 6514) to test the sensing performance of the different bending angles of the index finger.

[0031] Figure 1 It is shown that itaconic acid and rosin synergistically induce the ring-opening of epoxy soybean oil, and rosin is inserted into the network as a branched chain regulating unit to build a "rigid-flexible" network structure through controllable crosslinking, avoiding excessive crosslinking of itaconic acid and epoxy soybean oil. Figure 2 The mechanism diagram of the self-powered sensing process is shown, based on the triboelectric effect. This change causes charge transfer between the glove and the skin during the contact-separation process, resulting in corresponding fluctuations in the output voltage. The gel adheres to the glove to form a gel self-powered sensor, and the sample picture after gel preparation is shown in Figure 3 . Figure 4 Pictures of the gel sensor under different bending angles are shown. As the wearer's fingers bend, the contact area between the gel electrode and the glove and the skin changes dynamically, causing a change in voltage. Figure 5 The stress-strain curve of the rosin-based gel in the middle shows that the gel can achieve an elongation at break of more than 2000%, indicating that the gel has excellent flexibility and stretchability. Figures 6-9 The sensing signals of the self-powered sensor assembled by the rosin-based gel under different examples to the different bending angles of the index finger are shown. The peak intensity of the signal peaks produced by different bending angles shows a clear gradient change, indicating that the gel is sensitive to strain and can be used for human motion monitoring.

[0032] The above merely describes preferred embodiments of the present application, and any equivalent changes and modifications made within the scope of the present application should be included in the scope of the present application.

Claims

1. Use of a rosin-based self-powered sensing gel in a self-powered sensor, characterized in that, It comprises the following steps: (1) adding a certain amount of rosin, itaconic acid and octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate into epoxy soybean oil to form rosin-based gel through oil bath reaction; (2) connecting the conductive adhesive tape between the rosin-based gel and the glove to assemble into a self-powered sensor.

2. Use according to claim 1, characterized in that: The mass ratio of epoxy soybean oil to rosin in step (1) is (5:1)-(1:1), and the mass ratio of itaconic acid to rosin is (1:4)-(1:30).

3. Use according to claim 1, characterized in that: The dosage of octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate in step (1) is 0.1-5ml.

4. Use according to claim 1, characterized in that: The temperature of oil bath reaction in step (1) is 120-190℃, and the time is 0.5-4h.

5. Use according to claim 1, characterized in that: The glove in step (2) is any one of butyronitrile glove, polyethylene glove and polyvinyl chloride glove.

6. The rosin-based gel for use according to any one of claims 1-5.

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