PVDF (Polyvinylidene Fluoride) fiber membrane doped with surface modified boron nitride nano material and preparation method of PVDF fiber membrane

Abstract

The invention belongs to the technical field of flexible electronic materials and sensing, and particularly relates to a PVDF (polyvinylidene fluoride) fiber membrane doped with a surface modified boron nitride nano material and a preparation method of the PVDF fiber membrane. The PVDF fiber membrane is prepared by adopting an electrostatic spinning method, and a surface-modified boron nitride (BN) nano material is doped during spinning, so that the electrospun PVDF / BN composite fiber membrane is prepared. The piezoelectric property of the electrospun PVDF fiber membrane can be effectively improved by adding the boron nitride, the dispersity of the boron nitride nano material in PVDF can be improved after the boron nitride nano material is subjected to surface modification, and the piezoelectric property of the composite fiber membrane is further enhanced. The electrospinning PVDF / BN flexible piezoelectric fiber membrane provided by the invention can be widely applied to the fields of human health monitoring, intelligent wearable equipment, biomedical treatment and the like.

Description

Technical Field

[0001] The invention relates to the technical field of flexible sensing material preparation, and in particular to a PVDF fiber membrane doped with surface-modified boron nitride nanomaterial and a preparation method thereof. Background Art

[0002] Flexible piezoelectric pressure sensors use the physical properties of piezoelectric materials, namely the piezoelectric effect, to convert mechanical pressure signals into electrical signals in real time and accurately, thereby performing precise pressure monitoring. This type of sensor has a series of advantages such as high sensitivity, fast response speed, high output signal-to-noise ratio, and flexibility, and has significant advantages in dynamic pressure measurement. In addition, piezoelectric pressure sensors rely on the natural charge generated when pressure or strain is applied, so it does not require an external power supply and is a self-powered pressure sensor. This feature is very advantageous in applications that require low power consumption or long-term independent operation. Based on the above excellent sensing performance, flexible piezoelectric pressure sensors have been widely used in human health monitoring, smart wearable devices, biomedicine and other fields.

[0003] Piezoelectric material is one of the important factors that determine the performance of flexible piezoelectric pressure sensors. Among many flexible piezoelectric materials, PVDF has become a research hotspot due to its high piezoelectric coefficient, high flexibility, easy processing and high stability. However, compared with inorganic piezoelectric materials, PVDF has poor piezoelectric properties. Summary of the invention

[0004] The main purpose of the present invention is to provide a PVDF fiber membrane doped with surface-modified boron nitride nanomaterials and a preparation method thereof, in order to improve the piezoelectric properties of the PVDF fiber membrane.

[0005] To achieve the above objectives, the present invention provides a PVDF fiber membrane doped with surface-modified boron nitride nanomaterials, comprising a PVDF fiber membrane and a surface-modified boron nitride nanomaterial doped in the PVDF fiber membrane, wherein the surface modification of the boron nitride nanomaterial refers to modifying amino groups on the surface of the boron nitride nanomaterial.

[0006] Furthermore, boron nitride nanomaterials include hexagonal boron nitride nanospheres, nanotubes, nanorods, nanosheets, and the like.

[0007] The present invention also provides a method for preparing the PVDF fiber membrane doped with the surface-modified boron nitride nanomaterial, which specifically comprises the following steps:

[0008] S1, adding a certain amount of PVDF powder to a mixed solution of acetone and DMF (dimethylformamide), then adding a small amount of NaCl solid powder thereto, stirring the mixture evenly with a magnetic force in a constant temperature water bath, and preparing a PVDF electrospinning precursor solution with a certain mass fraction;

[0009] S2, performing surface modification treatment on the boron nitride nanomaterial to modify amino groups on its surface;

[0010] S3, taking a certain amount of surface-modified boron nitride nanomaterial, adding it to the PVDF electrospinning precursor solution, dispersing the powder into the solution by ultrasonic treatment, and then magnetically stirring it in a constant temperature water bath to obtain a PVDF / BN electrospinning precursor solution;

[0011] S4, loading the spinning precursor solution into the syringe, setting the electrospinning parameters and then spinning, and obtaining a PVDF-based flexible piezoelectric fiber membrane composed of PVDF fibers and surface-modified boron nitride nanomaterials after the electrospinning is completed.

[0012] Furthermore, in step S2, the specific steps of surface modification are: adding urea and boron nitride nanomaterials with a mass ratio of 60:1 to a certain amount of deionized water to make a paste, and then ball-milling them in a planetary ball mill at a speed of 400-700 rpm for 15-20 hours, collecting the boron nitride powder after ball milling, and placing the cleaned boron nitride powder in a vacuum drying oven, and drying it at 40-50° C. for 0.5-1 hour to obtain a surface amino-modified boron nitride nanomaterial.

[0013] Furthermore, in the PVDF / BN electrospinning precursor solution described in step S3, the mass fraction of PVDF is between 10 and 12 wt%, the mass fraction of NaCl is between 0.01 and 0.5 wt%, and the mass fraction of BN is between 0.1 wt% and 1 wt%.

[0014] Furthermore, in step S4, the specific parameters of the electrospinning are: spinning voltage 10-15 kV, solution flow rate 0.1-1 ml / h, collection distance 15-20 cm, collection drum rotation speed 500-1000 rpm.

[0015] Beneficial effects of the present invention:

[0016] 1. The technical solution provided by the present invention is that the PVDF flexible piezoelectric fiber film is composited by PVDF fiber and surface-modified boron nitride nanomaterial. The surface-modified boron nitride nanomaterial is added during PVDF electrospinning, which effectively enhances the piezoelectric properties of PVDF and greatly improves its piezoelectric signal output. In addition, the addition of boron nitride significantly improves the thermal conductivity and stretchability of the composite film, provides better heat dissipation capacity for the piezoelectric sensor, and improves its wearing comfort in human biological signal detection.

[0017] 2. The PVDF piezoelectric fiber membrane produced according to the technical solution provided by the present invention has high flexibility, good stability, good thermal conductivity, excellent sensing performance, simple preparation steps, low preparation cost, and good biocompatibility, and can be widely used in medical health monitoring and wearable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the specific implementation or the prior art description. Obviously, the drawings described below are some implementations of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0019] Figure 1 is a SEM (scanning electron microscope) image of the boron nitride nanosheets (BNNS) used in the examples;

[0020] Figure 2 FTIR (Fourier transform infrared spectrum) diagram of the boron nitride nanosheets prepared in the example before and after surface modification with amino groups;

[0021] Figure 3 This is a SEM image of the electrospun PVDF / NH2-BNNS composite piezoelectric fiber membrane prepared in the example;

[0022] Figure 4 This is a voltage output comparison test chart of the PVDF flexible piezoelectric film prepared in the example. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] A PVDF fiber membrane doped with surface-modified boron nitride nanomaterials comprises a PVDF fiber membrane and a surface-modified boron nitride nanomaterial doped in the PVDF fiber membrane, wherein the surface modification of the boron nitride nanomaterial refers to modifying amino groups on the surface of the boron nitride nanomaterial, and the purpose of the surface modification is to improve the dispersibility of the boron nitride nanomaterial in PVDF and enhance the interaction between the two.

[0025] Specifically, the boron nitride nanomaterial used is a boron nitride nanosheet with a size of about 300 nm. The nanosheet has a high specific surface area and provides a high contact area for the interaction between interface molecules in the nanocomposite matrix.

[0026] A method for preparing a PVDF fiber membrane doped with surface-modified boron nitride nanomaterials comprises the following steps:

[0027] S1, 1.4 g PVDF powder was added to 12 ml of a mixed solution of acetone and DMF in a volume ratio of 3:2, and then 0.012 g of NaCl solid powder was added thereto, and magnetic stirring was performed in a constant temperature water bath at 60 °C for 4 h to prepare a PVDF electrospinning precursor solution with a certain mass fraction;

[0028] S2, surface modification of boron nitride nanomaterials: 30 g urea and 0.5 g boron nitride nanosheets were added to 12 ml deionized water to make a paste, and then ball-milled in a planetary ball mill at 500 rpm for 20 h. The boron nitride powder after ball milling was collected, and the cleaned boron nitride powder was placed in a vacuum drying oven and dried at 40° C. for 1 h to obtain surface amino-modified boron nitride nanomaterials.

[0029] S3, taking 0.038 amino-modified boron nitride nanosheets, adding them to 12wt% PVDF electrospinning precursor solution, ultrasonically treating for 1h, and then magnetically stirring for 4h in a 60℃ constant temperature water bath to obtain 12wt% PVDF / 0.5wt% NH2-BNNS electrospinning precursor solution;

[0030] S4, the spinning precursor solution is loaded into the syringe, and the electrospinning parameters are set: spinning voltage 12kV, solution flow rate 0.5ml / h, collection distance 20cm, collection drum speed 1000rpm, and spinning is started. After the electrospinning is completed, a PVDF-based flexible piezoelectric fiber membrane composed of PVDF fibers and surface-modified amino-group boron nitride nanosheets is obtained;

[0031] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A PVDF fiber membrane doped with surface-modified boron nitride nanomaterials, characterized in that: The invention comprises a PVDF fiber membrane and a surface-modified boron nitride nano material doped in the PVDF fiber membrane. The surface modification of the boron nitride nano material refers to modifying amino groups on the surface of the boron nitride nano material.

2. The PVDF fiber membrane doped with surface-modified boron nitride nanomaterial according to claim 1, characterized in that: The boron nitride nanomaterials include hexagonal boron nitride nanospheres, nanotubes, nanorods, nanosheets and the like.

3. A method for preparing a PVDF fiber membrane doped with a surface-modified boron nitride nanomaterial as claimed in any one of claims 1 to 2, comprising the following steps: S1, adding a certain amount of PVDF powder to a mixed solution of acetone and DMF (dimethylformamide), then adding a small amount of NaCl solid powder thereto, stirring evenly with a magnetic force in a constant temperature water bath, and preparing a PVDF electrospinning precursor solution with a certain mass fraction; S2, performing surface modification treatment on the boron nitride nanomaterial to modify amino groups on its surface; S3, taking a certain amount of surface-modified boron nitride nanomaterial, adding it to the PVDF electrospinning precursor solution, dispersing the powder into the solution by ultrasonic treatment, and then magnetically stirring it in a constant temperature water bath to obtain a PVDF / BN electrospinning precursor solution; S4, loading the spinning precursor solution into the syringe, setting the electrospinning parameters and then spinning, and obtaining a PVDF-based flexible piezoelectric fiber membrane composed of PVDF fibers and surface-modified boron nitride nanomaterials after the electrospinning is completed.

4. The method for preparing a PVDF fiber membrane doped with surface-modified boron nitride nanomaterial according to claim 3, characterized in that: The specific steps of the surface modification in step S2 are: adding urea and boron nitride nanomaterials in a mass ratio of 60:1 into a certain amount of deionized water to make a paste, and then ball-milling them in a planetary ball mill at a speed of 400-700 rpm for 15-20 hours, collecting the boron nitride powder after ball milling, and placing the cleaned boron nitride powder in a vacuum drying oven, and drying it at 40-50° C. for 0.5-1 hour to obtain a surface-amino-treated boron nitride nanomaterial.

5. The method for preparing a PVDF fiber membrane doped with surface-modified boron nitride nanomaterial according to claim 3, characterized in that: In the PVDF / BN electrospinning precursor solution in step S3, the mass fraction of PVDF is between 10 and 12 wt%, the mass fraction of NaCl is between 0.01 and 0.5 wt%, and the mass fraction of BN is between 0.1 wt% and 1 wt%.

6. The method for preparing a PVDF fiber membrane doped with surface-modified boron nitride nanomaterial according to claim 3, characterized in that: The specific parameters of the electrospinning in step S4 are: spinning voltage 10-15 kV, solution flow rate 0.1-1 ml / h, collection distance 15-20 cm, collection drum rotation speed 500-1000 rpm.

Images