Flexible touch sensor based on adhesive bandage and preparation method and application thereof

Abstract

The invention discloses a flexible touch sensor based on a multi-scale structure of an adhesive bandage and a preparation method and application of the flexible touch sensor. According to the sensor, a commercial adhesive bandage serves as a base material, cellulose nanofibers are used for assisting in dispersing multi-walled carbon nanotubes to form stable conductive suspension liquid, the surface of the adhesive bandage is coated with the conductive suspension liquid in a dipping mode to form a conductive layer, and then the flexible tactile sensor of a layered multi-scale structure is constructed through assembling. The sensor integrates the synergistic effect of a nano-scale conductive network, a micron-scale surface microstructure and a millimeter-scale arched structure, and realizes high sensitivity (66.8 kPa <-1 >), a wide detection range (0-219.2 kPa) and quick response (lt; 1ms) and ultra-low detection limit (7Pa). The method is simple in preparation process, low in cost and environment-friendly, and has important application value in the fields of flexible electronics, wearable equipment, human-computer interaction and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a flexible tactile sensor using a multi-walled carbon nanotube and cellulose nanofiber composite conductive material, and a band-aid sponge as a conductive substrate, and a preparation method and application thereof. BACKGROUND

[0002] Flexible pressure sensors, as emerging electronic devices, play an important role in wearable sensing, human-computer interaction, health monitoring and electronic skin, etc. According to the working principle, pressure sensors are mainly divided into four types: capacitive, piezoelectric, triboelectric and piezoresistive. Among them, piezoresistive pressure sensors are of great concern due to their simple structure, low cost, relatively low power consumption, wide measurement range, high sensitivity, fast response time and good temperature stability.

[0003] In the prior art, in order to improve the sensitivity of the sensor, a microstructure design strategy is generally adopted, such as using sandpaper texture, rose petals, lotus leaves and other natural templates to prepare sensors. However, the microstructure produced by these template-based methods has randomness and unpredictable geometry, affecting the reproducibility and linear response range. While precise engineering microstructures such as micro-pyramids and micro-hemispheres can improve device performance, they require complex manufacturing techniques, are costly and have limited accessibility.

[0004] Band-aid, as a daily medical supply, has a unique surface microstructure and a continuous deformable fiber framework, providing an excellent substrate for sensor design. Commercial band-aid contains three different levels: an absorbent pad, an adhesive backing and a non-toxic protective film. However, the band-aid itself is insulating and needs to be combined with a conductive material to achieve sensing function.

[0005] As a multifunctional conductive material, carbon nanotubes have been widely used to develop high-performance conductive composites, and the excellent dispersion performance of cellulose nanofiber makes it an ideal nanocarrier for dispersing carbon nanotubes in aqueous media. By integrating multi-walled carbon nanotubes with cellulose nanofiber, we obtained an aqueous multi-walled carbon nanotube / cellulose nanofiber suspension with excellent flowability, remarkable stability and good interfacial adhesion to the band-aid substrate. Subsequently, the band-aid was immersed in the suspension to obtain a conductive composite coating that retains the natural microstructure, thereby enabling the manufacture of conductive band-aid.

[0006] The present application proposes an innovative design method of flexible tactile sensor based on multi-scale structure strategy. This method involves hierarchical optimization at nanoscale, microscale and millimeter scale. Specifically, it integrates the synergistic effect of nanoscale conductive film composed of multi-walled carbon nanotubes, microscale regular network microstructure and millimeter scale arch layer structure, thereby realizing enhanced mechanical strength and optimized compression performance. This multi-scale design significantly improves sensitivity and detection range, solving the classic sensitivity range trade-off problem. Most importantly, the commercial pedigree of the band-aid ensures biocompatibility and scalable manufacturing. By transforming commercial band-aids into high-performance sensing platforms without the need for expensive nanofabrication, this work bridges the gap between academic innovation and industrial scalability, providing a universal framework for epidermal adaptive electronics in telemedicine, soft robotics and AR / VR haptics. SUMMARY

[0007] One of the purposes of the present application is to provide a multi-walled carbon nanotube / cellulose nanofiber suspension with uniform dispersion and a preparation method thereof.

[0008] The second purpose of the present application is to provide an innovative design method of flexible sensor with multi-scale structure.

[0009] The third purpose of the present application is to provide a flexible tactile sensor with excellent electrical conductivity, strain sensitivity, simple preparation, low cost and green environmental protection.

[0010] The fourth purpose of the present application is to provide the application of the above-mentioned flexible tactile sensor based on band-aid in human activity monitoring, and the monitoring of human activity signals includes movements such as clenched fist, finger bending and arm bending, but is not limited to the above monitoring features.

[0011] The technical scheme is as follows:

[0012] Step 1: Add multi-walled carbon nanotubes to deionized water and perform intermittent ultrasonic treatment under ice bath conditions to obtain a multi-walled carbon nanotube suspension;

[0013] Step 2: Mix the multi-walled carbon nanotube suspension obtained in step 1 with a cellulose nanofiber solution and perform ultrasonic treatment to form a uniform multi-walled carbon nanotube / cellulose nanofiber suspension;

[0014] Step 3: Dip and dry the conductive suspension obtained in step 2 in the band-aid multiple times to prepare a conductive band-aid;

[0015] Step 4: Assemble the flexible tactile sensor by circuit connection by using the upper and lower layers of the conductive band-aid obtained in step 3 in a face-to-face manner, wherein the upper conductive band-aid adopts an arch structure and the lower conductive band-aid is a flat structure.

[0016] As preferred, the mass concentration of the multi-walled carbon nanotube suspension is 1%.

[0017] As preferred, the mass ratio of the multi-walled carbon nanotube suspension and the cellulose nanofiber solution is 20:1, and the stirring and ultrasonic time is 3 hours.

[0018] As preferred, the wound plaster sponge is a rectangular model with a size of 3cm*1cm.

[0019] As preferred, the soaking time is 10 minutes, the drying time is 2 hours, the drying temperature is room temperature, and the cycle number is 6 times.

[0020] As preferred, the sensor structure is an arch structure, and the ratio of the arch height of the upper layer of conductive wound plaster to the length of the lower layer of conductive wound plaster is 1:5.

[0021] The flexible tactile sensor has excellent conductivity, strain sensitivity, simple preparation, low cost, and is green and environmentally friendly.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] 1. The multi-walled carbon nanotube / cellulose nanofiber suspension prepared by the present application has good flowability, good stability, high conductivity, and strong adhesion to the surface of the material due to its good properties.

[0024] 2. The flexible tactile sensor prepared by the present application has excellent response rate.

[0025] 3. The flexible tactile sensor prepared by the present application has zero standby power consumption.

[0026] 4. The flexible tactile sensor prepared by the present application has high sensitivity.

[0027] 5. The flexible tactile sensor prepared by the present application has a wide detection range. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a picture of the flexible tactile sensor based on wound plaster.

[0029] Figure 2 It is a Fourier transform infrared spectrum (FT-IR) graph of multi-walled carbon nanotubes, cellulose nanofibers, and multi-walled carbon nanotube / cellulose nanofiber suspension.

[0030] Figure 3 It is a Fourier transform infrared spectrum (FT-IR) graph of multi-walled carbon nanotube / cellulose nanofiber suspension, wound plaster, and conductive wound plaster.

[0031] Figure 4Raman spectrum of multi-walled carbon nanotube / cellulose nanofiber suspension.

[0032] Figure 5 TEM image of multi-walled carbon nanotube / cellulose nanofiber suspension.

[0033] Figure 6 SEM image of multi-walled carbon nanotube / cellulose nanofiber suspension after impregnation and drying on the adhesive plaster.

[0034] Figure 7 Surface structure diagram of the conductive adhesive plaster.

[0035] Figure 8 Side structure diagram of the conductive adhesive plaster.

[0036] Figure 9 Data diagram of response time and recovery time of the flexible tactile sensor.

[0037] Figure 10 Strain sensing curve diagram of the flexible tactile sensor attached to the outside of the human finger. DETAILED DESCRIPTION

[0038] The application will be further described below in conjunction with specific examples.

[0039] Example 1

[0040] The embodiment provides a flexible tactile sensor preparation method, which is prepared according to the following steps:

[0041] Step 1: multi-walled carbon nanotubes are added to deionized water, and intermittent ultrasonic treatment is performed under ice bath conditions to obtain a multi-walled carbon nanotube suspension with a mass concentration of 1%;

[0042] Step 2: the multi-walled carbon nanotube suspension obtained in step 1 is mixed with a cellulose nanofiber solution according to a mass ratio of 20:1 and ultrasonic treatment is performed to form a uniform multi-walled carbon nanotube / cellulose nanofiber suspension;

[0043] Step 3: the adhesive plaster is immersed in the suspension obtained in step 2 for 10 minutes for multiple times, and dried for 2 hours, and the cycle is repeated for 6 times to prepare a conductive adhesive plaster;

[0044] Step 4: two pieces of the conductive adhesive plaster obtained in step 3 are attached to each other in a face-to-face manner to assemble a flexible tactile sensor through circuit connection, wherein the upper conductive adhesive plaster adopts an arch structure, and the lower conductive adhesive plaster adopts a planar structure.

[0045] Example 2

[0046] The embodiment provides a flexible tactile sensor preparation method, which is prepared according to the following steps:

[0047] Step 1: adding carbon black into deionized water and carrying out intermittent ultrasonic treatment under ice bath conditions to obtain a carbon black suspension with a mass concentration of 1%;

[0048] Step 2: mixing the carbon black suspension obtained in step 1 with a cellulose nanofiber solution according to a mass ratio of 20:1 and carrying out ultrasonic treatment to form a uniform carbon black / cellulose nanofiber suspension;

[0049] Step 3: immersing a band-aid into the suspension obtained in step 2 for 10 minutes for 6 cycles of drying for 2 hours, to prepare a conductive band-aid;

[0050] Step 4: using the upper and lower conductive band-aids obtained in step 3 to form a flexible tactile sensor through circuit connection and assembly, wherein the upper conductive band-aid adopts an arch-shaped structure, and the lower conductive band-aid adopts a planar structure.

[0051] Embodiment 3

[0052] The embodiment provides a flexible tactile sensor preparation method, which is different from the preparation method of embodiment 1 in that the mass ratio of the multi-walled carbon nanotube suspension and the cellulose nanofiber solution in step 2 is 15:1.

[0053] Embodiment 4

[0054] The embodiment provides a flexible tactile sensor preparation method, which is different from the preparation method of embodiment 1 in that the mass ratio of the multi-walled carbon nanotube suspension and the cellulose nanofiber solution in step 2 is 10:1.

[0055] Embodiment 5

[0056] The embodiment provides a flexible tactile sensor preparation method, which is different from the preparation method of embodiment 1 in that the mass ratio of the multi-walled carbon nanotube suspension and the cellulose nanofiber solution in step 2 is 5:1.

[0057] Embodiment 6

[0058] The embodiment provides a flexible tactile sensor preparation method, which is different from the preparation method of embodiment 1 in that the structure in step 4 is a parallel structure.

Claims

1. A flexible tactile sensor based on a bandage and a preparation method thereof, characterized in that: The specific steps are as follows: Step 1: adding multi-walled carbon nanotubes to deionized water and performing intermittent ultrasonic treatment in an ice bath to obtain a multi-walled carbon nanotube suspension; Step 2: mixing the multi-walled carbon nanotube suspension obtained in step 1 with the cellulose nanofiber solution and ultrasonically treating the mixture to form a uniform multi-walled carbon nanotube / cellulose nanofiber suspension; Step 3: dipping the wound dressing in the conductive suspension obtained in step 2 for multiple times and drying the mixture to prepare a conductive wound dressing; Step 4: The two conductive bandages obtained in step 3 are assembled into a flexible tactile sensor by bonding the upper and lower layers face to face through circuit connection, wherein the upper conductive bandage adopts an arched structure and the lower conductive bandage has a flat structure.

2. The preparation method according to claim 1, characterized in that The multi-walled carbon nanotubes in step 1 have a diameter of 8 to 15 nm, a length of 10 to 50 μm, and a solid content greater than 99%.

3. The preparation method according to claim 1, characterized in that The concentration of the multi-walled carbon nanotube suspension in step 1 is 0.8% to 1.2%.

4. The preparation method according to claim 1, characterized in that In step 2, the diameter of the cellulose nanofibers is 5 to 10 nm, the length is 1 to 3 μm, and the solid content of the solution is greater than 1%.

5. The preparation method according to claim 1, characterized in that The ultrasonic time in step 2 is 2 to 4 hours.

6. The preparation method according to claim 1, characterized in that The mass ratio of the multi-walled carbon nanotube suspension to the cellulose nanofiber solution in step 2 is 5:1 to 25:

1.

7. The preparation method according to claim 1, characterized in that The number of times the wound dressing is soaked and dried in step 3 is 4 to 8 times.

8. The preparation method according to claim 1, characterized in that In step 4, the ratio of the arch height of the upper conductive wound patch to the length of the lower conductive wound patch of the arch structure is 1:6 to 1:

4.

9. A flexible tactile sensor based on a bandage, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the flexible tactile sensor based on a wound dressing as claimed in claim 9 in human motion monitoring and pressure monitoring for purposes other than disease diagnosis and treatment.

Images