阅读说明：本技术 基于聚丙烯酰胺-丝素蛋白导电水凝胶传感器的制备方法 (Preparation method of conductive hydrogel sensor based on polyacrylamide-silk fibroin ) 是由 叶美丹 何发亮 游兴艳 陈星� 白天 王伟国 于 2019-11-27 设计创作，主要内容包括：基于聚丙烯酰胺-丝素蛋白导电水凝胶传感器的制备方法,涉及柔性可穿戴电子器件。将桑蚕茧去蛹后的茧层剪成小片放入煮沸的碳酸氢钠溶液中煮,烘干后的干丝素纤维,放入溴化锂溶液中溶解,透析,得丝素蛋白溶液；将丙烯酰胺溶于去离子水中,然后加入过硫酸铵、N,N’-亚甲基双丙烯酰胺搅拌均匀得到聚丙烯酰胺溶液,在聚丙烯酰胺溶液中依次加入丝素蛋白溶液、氧化石墨烯溶液和聚3,4-乙烯二氧噻吩/聚苯乙烯磺酸盐溶液,混匀后注入模具中,加热后得到导电水凝胶,两端接上导线,即得导电水凝胶传感器。方法简单、弹性高、宽响应范围、可大规模生产、反应灵敏,能同时测试拉伸和压缩信号。(A preparation method of a sensor based on polyacrylamide-silk fibroin conductive hydrogel relates to a flexible wearable electronic device. Cutting the cocoon layer of silkworm cocoon after pupation removal into small pieces, boiling in a boiling sodium bicarbonate solution, putting dried dry silk cellulose fiber into a lithium bromide solution for dissolving, and dialyzing to obtain a silk fibroin solution; dissolving acrylamide in deionized water, adding ammonium persulfate and N, N' -methylene-bisacrylamide, uniformly stirring to obtain a polyacrylamide solution, sequentially adding a silk fibroin solution, a graphene oxide solution and a poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate solution into the polyacrylamide solution, uniformly mixing, injecting into a mold, heating to obtain conductive hydrogel, and connecting leads at two ends to obtain the conductive hydrogel sensor. The method is simple, high in elasticity, wide in response range, capable of realizing large-scale production, sensitive in response and capable of simultaneously testing tensile and compressive signals.)

1. The preparation method of the conductive hydrogel sensor based on the polyacrylamide-silk fibroin is characterized by comprising the following steps:

1) cutting the cocoon layer of silkworm cocoon after pupation removal into small pieces, boiling in boiling sodium bicarbonate solution, repeatedly boiling for 3 times, dissolving dried silk fibroin fiber in lithium bromide solution, and dialyzing to obtain silk fibroin solution;

2) dissolving acrylamide in deionized water, adding ammonium persulfate and N, N' -methylene bisacrylamide, uniformly stirring to obtain a polyacrylamide solution, sequentially adding a silk fibroin solution, a graphene oxide solution and a poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate solution into the polyacrylamide solution, uniformly mixing, injecting into a mold, heating to obtain PAM/SF/GO/PEDOT (Polyacrylamide/silicon dioxide/polyethylene glycol sulfonate) PSS (Polyacrylamide/SF/GO/PEDOT) conductive hydrogel, and connecting leads at two ends of the conductive hydrogel to obtain the polyacrylamide-silk fibroin-based conductive hydrogel sensor.

2. The method for preparing the polyacrylamide-silk fibroin-based conductive hydrogel sensor as claimed in claim 1, wherein in step 1), the patch is a 1cm x 1cm patch.

3. The method for preparing the polyacrylamide-silk fibroin-based conductive hydrogel sensor as claimed in claim 1, wherein in step 1), the concentration of the sodium bicarbonate solution is 7.5 g/L; the above boiling for 3 times can be carried out by adding into boiling sodium bicarbonate, boiling for 30min, taking out, adding into new sodium bicarbonate solution, boiling for 30min, and boiling for 3 times.

4. The preparation method of the sensor based on the polyacrylamide-silk fibroin conductive hydrogel of claim 1, wherein in the step 1), the drying is performed in an oven at 55-65 ℃.

5. The preparation method of the polyacrylamide-silk fibroin-based conductive hydrogel sensor as claimed in claim 1, wherein in step 1), a 9.3M lithium bromide solution is adopted as the lithium bromide solution; 7mL of lithium bromide solution per 1g of dry silk cellulose fiber was required.

6. The preparation method of the sensor based on the polyacrylamide-silk fibroin conductive hydrogel of claim 1, wherein in the step 1), deionized water is used as dialysate for dialysis continuously for 3 days, and water is replaced every 4h to remove lithium bromide in the solution.

7. The preparation method of the polyacrylamide-silk fibroin-based conductive hydrogel sensor as claimed in claim 1, wherein in step 2), the ratio of acrylamide, deionized water, ammonium persulfate, N '-methylenebisacrylamide, silk fibroin solution, graphene oxide solution, and poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate solution is 30 g: 70 mL: 0.1 g: 0.05 g: 10-50 mL: 10 mL-50 mL: 3-5 mL, wherein acrylamide, ammonium persulfate, and N, N' -methylenebisacrylamide are calculated by mass, and the ratio of deionized water, silk fibroin solution, graphene oxide solution, and poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate solution is calculated by volume.

8. The preparation method of the polyacrylamide-silk fibroin-based conductive hydrogel sensor as claimed in claim 1, wherein in step 2), the concentration of the graphene oxide solution is 3 mg/mL; the concentration of the poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate solution is 10 mg/mL.

9. The method for preparing the polyacrylamide-silk fibroin-based conductive hydrogel sensor as claimed in claim 1, wherein in step 2), the volume of the mold is 5 mL.

10. The method for preparing the polyacrylamide-silk fibroin-based conductive hydrogel sensor as claimed in claim 1, wherein in step 2), the heating temperature is 80 ℃ and the heating time is 15 min.

Technical Field

The invention relates to a flexible wearable electronic device, in particular to a preparation method of a sensor based on polyacrylamide-silk fibroin conductive hydrogel.

Background

Flexible wearable electronics have gained widespread attention in recent years due to their particular capabilities, and have found widespread use particularly in the field of flexible sensors. The materials used for preparing the flexible wearable sensor must have the characteristics of good flexibility, good conductivity and the like.

Current flexible sensors are typically made by dispersing conductive components (e.g., carbon nano-particles, graphene oxide, and metal nanowires) in a substrate with good elasticity (e.g., hydrogel and silicone rubber) (y.cai, j.shen, z.dai, x.zang, q.dong, g.guan, l.j.li, w.huang and x.dong, Advanced materials,2017,29), which generally have a wide sensing range, high sensitivity, and mechanical stability. However, their function is often relatively singular and as sensors they cannot test signals generated by both tension and compression. Therefore, they cannot be used to simultaneously discriminate many human signals (such as joint flexion and facial expression changes), greatly limiting their range of applications (m.xu, j.qi, f.land y.zhang, Nanoscale,2018,10, 5264-.

Polyacrylamide has been widely used in the medical field due to its good biocompatibility and adjustable elasticity, but pure acrylamide still has poor mechanical properties and needs to be crosslinked with other materials to obtain a good elastomer.

Chinese patent application CN110105590A discloses a method for preparing a flexible strain sensor based on carboxymethyl cellulose/lithium chloride-polyacrylamide hydrogel, comprising the following steps: a. preparing a carboxymethyl cellulose/lithium chloride-polyacrylamide mixed solution; b. preparing carboxymethyl cellulose/lithium chloride-polyacrylamide hydrogel; c. preparing a polydimethylsiloxane elastomer; d. flexible strain sensors based on carboxymethyl cellulose/lithium chloride-polyacrylamide hydrogels were prepared. Also disclosed is the use of a flexible strain sensor based on a carboxymethylcellulose/lithium chloride-polyacrylamide hydrogel for flexible and wearable electronics.

Disclosure of Invention

The invention aims to provide a preparation method of a polyacrylamide-silk fibroin-based conductive hydrogel sensor, which is simple in method, high in elasticity, wide in response range, capable of realizing large-scale production, sensitive in reaction and capable of simultaneously testing tensile and compressive signals.

The invention comprises the following steps:

1) cutting the cocoon layer of silkworm cocoon after pupation removal into small pieces, boiling in boiling sodium bicarbonate solution, repeatedly boiling for 3 times, dissolving dried silk fibroin fiber in lithium bromide solution, and dialyzing to obtain silk fibroin solution;

2) dissolving acrylamide in deionized water, adding ammonium persulfate and N, N' -methylene bisacrylamide, uniformly stirring to obtain a polyacrylamide solution, sequentially adding a silk fibroin solution, a graphene oxide solution and a poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate solution into the polyacrylamide solution, uniformly mixing, injecting into a mold, heating to obtain PAM/SF/GO/PEDOT (Polyacrylamide/silicon dioxide/polyethylene glycol sulfonate) PSS (Polyacrylamide/SF/GO/PEDOT) conductive hydrogel, and connecting leads at two ends of the conductive hydrogel to obtain the polyacrylamide-silk fibroin-based conductive hydrogel sensor.

In step 1), the tablet may be about 1cm × 1 cm; the sodium bicarbonate (NaHCO)₃) The concentration of the sodium bicarbonate solution of the solution is 7.5 g/L; the above boiling for 3 times can be carried out by adding into boiling sodium bicarbonate, boiling for 30min, taking out, and boiling againAdding into new sodium bicarbonate solution, and decocting for 30min for 3 times; the drying can be carried out in an oven at 55-65 ℃; the lithium bromide solution can adopt a 9.3M lithium bromide solution; every 1g of dry silk cellulose needs 7mL of lithium bromide solution; the dialysis adopts deionized water as dialysate, and the dialysis is continued for 3 days, and the water is changed every 4h to remove the lithium bromide component in the solution.

In the step 2), the ratio of the acrylamide, deionized water, ammonium persulfate, N '-methylenebisacrylamide, silk fibroin solution, graphene oxide solution and poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate solution can be 30 g: 70 mL: 0.1 g: 0.05 g: 10-50 mL: 3-5 mL, wherein the mass of the acrylamide, the mass of the ammonium persulfate and the mass of the N, N' -methylenebisacrylamide are calculated, and the volume of the deionized water, the silk fibroin solution, the graphene oxide solution and the poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate solution is calculated; the concentration of the graphene oxide solution may be 3 mg/mL; the concentration of the poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate solution can be 10 mg/mL; the volume of the mold can be 5 mL; the heating temperature can be 80 ℃, and the heating time can be 15 min.

The prepared flexible hydrogel sensor can adopt a micro-tensiometer for testing and a bridge instrument for acquiring real-time resistance.

The flexible sensor is prepared by mixing Polyacrylamide (PAM), Silk Fibroin (SF), Graphene Oxide (GO), poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate (PEDOT: PSS) according to a certain proportion to obtain conductive hydrogel (PAM/SF/GO/PEDOT: PSS), and the sensor is prepared by utilizing the conductive hydrogel, so that the flexible sensor has the advantages of high elasticity, wide response range (capable of monitoring 2-600% of tensile deformation and 15.9-119.4 kPa pressure range), high sensitivity and excellent resistance response performance, and can distinguish a plurality of human body signals (such as joint bending and facial expression change). The preparation method is simple, can be used for large-scale production, is sensitive in reaction, can be used for simultaneously testing tensile and compressive signals, and provides a new idea for the preparation of the flexible wearable sensor.

Drawings

FIG. 1 is a SEM (scanning electron microscope) front view of a conductive hydrogel prepared according to an embodiment of the invention. In the figure, the scale is 50 μm.

FIG. 2 shows stress-strain curves of four kinds of hydrogels, i.e., PAM/SF/GO/PEDOT, under tension.

FIG. 3 is a Raman spectrum of PAM hydrogel and PAM/SF/GO/PEDOT/PSS conductive hydrogel.

FIG. 4 shows the real-time resistance change rate of the PAM/SF/GO/PEDOT/PSS hydrogel sensor when the tensile strain is 2% -50%.

FIG. 5 shows the real-time resistance change rate of the PAM/SF/GO/PEDOT/PSS hydrogel sensor when the tensile strain is 100% -600%.

FIG. 6 shows real-time resistance change rates of PAM/SF/GO/PEDOT/PSS hydrogel sensors under different pressures (0.5-119.4 kPa).

FIG. 7 is a graph of the change in resistance produced by the wrist movement when the sensor is attached to the wrist.

Fig. 8 is a diagram showing a change in resistance generated when the sensor blinks near the temple.

FIG. 9 is a reference view of a hydrogel sensor according to an embodiment of the invention.

Detailed Description

The following examples will further illustrate the present invention with reference to the accompanying drawings.