Search

CN-121992466-A - Electric field controllable preparation and strain sensing application of multi-stage structure polypyrrole modified graphene lamellar composite conductive film

CN121992466ACN 121992466 ACN121992466 ACN 121992466ACN-121992466-A

Abstract

The invention relates to an electric field controllable preparation and strain sensing application of a multi-level structure polypyrrole modified graphene lamellar composite conductive film. Firstly, a GO film is obtained through a vacuum filtration technology, a rGO film is prepared through chemical reduction, and then a polypyrrole (PPy) nano structure with adjustable morphology is grown and constructed on the rGO film by adopting a three-electrode constant potential deposition strategy. And constructing an NS-PPy@rGO composite film with an interconnection network structure by taking the rGO film as a working electrode through a one-step deposition method, and performing second-step deposition on the basis to design a multi-level structure MLS-PPy@rGO composite film. According to the one-step deposition process disclosed by the invention, the chemical action between the PPy layer and the rGO layer is constructed to slow down the slip and fracture of the rGO layer, the two-step deposition multi-stage structure PPy provides more electric contact sites under large strain, and the chemical-physical double synergistic effect ensures the high sensitivity of the sensor and simultaneously effectively widens the strain range of the sensor. The preparation process of the whole composite film is simple, convenient, controllable, green and efficient, and is easy for industrial mass production.

Inventors

  • LIN HUIJUAN
  • WANG HUINAN
  • HE JIAQI

Assignees

  • 南京工业大学

Dates

Publication Date
20260508
Application Date
20241101

Claims (8)

  1. 1. The electric field controllable preparation method of the polypyrrole modified graphene lamellar composite conductive film with the multilevel structure is characterized by comprising the following steps of: a. vacuum filtering a certain amount of Graphene Oxide (GO) nanosheet dispersion liquid on a microporous filter membrane to form a membrane, and air-drying at room temperature, wherein the GO membrane can be completely peeled off from the filter membrane; b. Respectively dissolving disodium hydrogen phosphate dodecahydrate (Na 2 HPO 4 ·12H 2 O), sodium dihydrogen phosphate dihydrate (NaH 2 PO 4 ·2H 2 O) and p-toluenesulfonic acid (TsOH) in deionized water, and then adding a certain amount of pyrrole monomer (Py) for ultrasonic dissolution to obtain colorless transparent solution; c. C, growing and constructing polypyrrole (PPy) nanowires on the rGO film by a three-electrode constant potential deposition strategy, taking the rGO film obtained in the step a as a working electrode for one-step electrochemical deposition, taking the colorless transparent solution prepared in the step b as electrolyte in the electrodeposition process, setting the deposition voltage to be 1.0V, depositing 200-800 s to obtain an NS-PPy@rGO composite film with an interconnection network structure, flushing the film with deionized water and ethanol for multiple times, and then drying in a vacuum drying oven for standby; d. In the two-step electrodeposition, the NS-PPy@rGO composite film obtained in the step c is used as a working electrode, the deposition voltage is set to be 0.8V, and the MLS-PPy@rGO composite film with a multi-stage structure is obtained by depositing 200-800 s, and is respectively washed by deionized water and ethanol for multiple times, and then is placed in a vacuum drying oven for drying for standby.
  2. 2. The method for preparing the multi-stage polypyrrole-modified graphene sheet composite conductive film according to claim 1, wherein the concentration ratio of Na 2 HPO 4 ·12H 2 O∶NaH 2 PO 4 ·2H 2 O to TsOH in the step b is 2:2:1, the deposition time in the step c is 600 s, and the deposition time in the step d is 600 s.
  3. 3. The method for preparing the multi-stage structure polypyrrole modified graphene sheet composite conductive film by controllable electric field is characterized in that the concentration of GO dispersion liquid in the step a is 1 mg mL -1 , the suction filtration time is more than or equal to 6 h, the chemical reducing agent in the step a is hydrazine hydrate, the reduction time is 6 h (90 ℃) and the chemical reduction method is used for restoring the conjugated structure of the rGO film by eliminating oxygen-containing groups of the GO film to enhance the conductivity of the rGO film, and the size of the rGO film after cutting in the step a is 10 mm multiplied by 15 mm.
  4. 4. The method for preparing the electric field controllable multi-stage polypyrrole modified graphene sheet composite conductive film according to claim 1, wherein the ultrasonic parameters in the step b are set to 10min (300W), and the deposition processes in the steps c and d are completed in an electrochemical workstation (CHI 660E), wherein the reference electrode and the counter electrode in the three-electrode system are a silver/silver chloride (Ag/AgCl) electrode and a platinum sheet (Pt) electrode respectively.
  5. 5. The method for preparing the electric field controllable multi-stage polypyrrole modified graphene sheet composite conductive film according to claim 1, which is characterized by comprising the following steps: Performing film forming treatment on a 10 mL Graphene Oxide (GO) nanosheet dispersion liquid (1 mg mL -1 ) on a microporous filter film with the thickness of 0.1 mu m through a vacuum filtration process, completely stripping the GO film from the filter film after the filter film is air-dried at room temperature after the suction filtration is finished, and then chemically reducing the GO film placed in a sealed reaction bottle by using a reducing agent hydrazine hydrate at 90 ℃ for 6h to obtain a reduced graphene oxide (rGO) film; The preparation method comprises the steps of growing and constructing a polypyrrole (PPy) nano structure on an rGO film through a three-electrode constant potential deposition strategy, completing a deposition process in an electrochemical workstation (CHI 660E), wherein a reference electrode and a counter electrode in a three-electrode system are respectively a silver/silver chloride (Ag/AgCl) electrode and a platinum sheet (Pt) electrode, sequentially dissolving 0.2 moL L -1 disodium hydrogen phosphate (Na 2 HPO 4 ·12H 2 O)、0.2 moL L -1 sodium dihydrogen phosphate (NaH 2 PO 4 ·2H 2 O) and 0.2 moL L -1 p-toluenesulfonic acid (TsOH) in 50 mL deionized water respectively, adding 0.35 mL pyrrole monomer (Py) to carry out 10 min ultrasonic dissolution (300W), preparing a colorless transparent solution as electrolyte in the electrodeposition process, setting the working electrode as the rGO film in a one-step deposition method, setting the deposition voltage as 1.0V, depositing an NS-PPy@rGO (600 s) composite film with an interconnection network structure after 600 s, respectively washing the film with deionized water and ethanol for multiple times, and placing the film in a vacuum drying box for standby; In the two-step electrodeposition, the obtained NS-PPy@rGO composite film is used as a working electrode, the deposition voltage is set to be 0.8V, the MLS-PPy@rGO 3 composite film with a multi-stage structure is obtained by depositing 600 s, and the film is respectively washed by deionized water and ethanol for multiple times and then is placed in a vacuum drying oven for drying for standby.
  6. 6. The strain sensing application of the multi-stage structure polypyrrole modified graphene sheet composite conductive film prepared by the method of claim 1 is characterized in that the MLS-PPy@rGO film can be used as a film strain sensor material.
  7. 7. The strain sensing application of the multi-level structure polypyrrole modified graphene sheet composite conductive film of claim 6, wherein the method for packaging the MLS-PPy@rGO film into the strain sensor comprises the following steps: a. Uniformly mixing a certain amount of Polydimethylsiloxane (PDMS) prepolymer and a curing agent in the same surface dish in a stirring manner, then pouring the mixed prepolymer solution into a Polytetrafluoroethylene (PTFE) mold completely, and placing the Polytetrafluoroethylene (PTFE) mold in a 60 ℃ oven for pre-curing; b. Cutting an MLS-PPy@rGO film into the same size, attaching the film on a pre-cured PDMS substrate, leading out copper wires at two ends of the film, fixing the film by using conductive silver paste, pouring an equal amount of prepolymer solution into a mold for upper packaging, and placing the mold in a 60 ℃ oven for complete curing to obtain the MLS-PPy@rGO film strain sensor.
  8. 8. The strain sensing application of the multi-stage structure polypyrrole modified graphene sheet composite conductive film according to claim 7, wherein the mass ratio of PDMS prepolymer to curing agent in the step a is 10:1, the pre-curing time is 1 h, the size of the MLS-PPy@rGO film in the step b is 10 mm ×10 mm, and the complete curing time is 4 h.

Description

Electric field controllable preparation and strain sensing application of multi-stage structure polypyrrole modified graphene lamellar composite conductive film Technical Field The invention relates to an electric field controllable preparation and strain sensing application of a multi-level structure polypyrrole modified graphene lamellar composite conductive film, and belongs to the technical field of functional nano materials. Background Along with development of technological innovation and requirements of application scenes, ideal wearable sensors are expected to have the characteristics of good flexibility, high sensitivity, long durability and the like, and the traditional sensors with easy rigidity and brittleness cannot completely meet market requirements. Under the background, the flexible strain sensor is developed, and researchers are continuously innovating active materials, conductive structures and device designs, so that the flexible strain sensor has wide application prospects in the fields of electronic skin, medical care, wearable equipment and the like. In order to meet the application requirements of the current flexible electronic strain sensor, high requirements are put forward on two key performance indexes of response sensitivity and strain range of the sensor. As such, the choice of active material system and the design of specific conductive structures are hot spots for the study of flexible strain sensors in order to optimize the balance of these two properties. Common active materials include carbon-based materials, metal-based materials, conductive polymers, and the like. The carbon-based nano material has great potential in the field of strain sensor materials due to the advantages of high conductivity, good stability, low cost and the like. The typical two-dimensional nanomaterial graphene has the advantages of high strength, light weight, good flexibility, stable layered structure and the like, and plays an important role as a most representative active material in the sensor manufacturing process. The reduced graphene oxide (rGO) is used as one of the derivatives of graphene, and the conjugated structure in the lamellar layer is recovered through reduction treatment, so that the conductivity of the film is enhanced, and meanwhile, the graphene oxide/graphene oxide composite film has the characteristics of easiness in functional modification, good chemical and mechanical stability and the like. The conductive polymer has the advantages of adjustable mechanical property, excellent electrochemical property and the like besides the excellent conductivity of the carbon material and the metal material. Among them, the environmental adaptability and synthesis strategies of polypyrrole (PPy) make it a high-performance conductive polymer widely used at present. In addition to relying on the inherent advantages of active nanomaterials, the design strategy of conductive structures is a potential study to increase the sensitivity and strain range of the sensor. For example, some conductive structures inspired by biological organs (such as microcrack structures, skin-like fold structures, serpentine structures, spider web structures, etc.) can delay the breakage of the conductive path of the active layer during the strain process, and conductive path connection points are added, thereby greatly improving the stretchability of the device. Based on the carefully designed active layer of the conductive structure, the microscopic morphology of the active layer is no longer in a random state, so that the inherent characteristics of the active material can be maintained, the active layer can obtain unexpected mechanical and electrical properties, and the overall performance of the sensor is further improved. At present, a plurality of reports are provided for the design and research of an active layer of a graphene-based thin film sensor. Literature (Zhang, R.; Qi, L.; Chao, X.; Lian, H.; Luo, J.; Chen, S.; A highly stable and sensitive sensor with linear response enabled by embedded droplet printing and bio-inspired design, Chemical Engineering Journal 2024, 485, 149729.) uses embedded drop printing techniques to design a microcrack structure to deposit patterned rGO layers with tunable shapes on PDMS substrates. The sensor has a very limited sensing range (only 3%) although it has a high sensitivity up to 2200 due to its surface embedded structure and micro-crack propagation mechanism. Literature (Cheng, X.; Cai, J.; Xu, J.; Gong, D.; High-performance strain sensors based on Au/graphene composite films with hierarchical cracks for wide linear-range motion monitoring, ACS Applied Materials Interfaces 2022, 14, 39230-39239.) introduces a hierarchical crack strategy, wherein a self-assembled graphene film is covered on a PDMS substrate, then an Au film is sputtered, and the generation of a hierarchical crack structure is promoted by pre-stretching the substrate. The crack structure and fur