A method for regulating a self-assembled structure by dual-energy irradiation of light / heat and its preparation

Abstract

The present invention discloses a photo / thermal dual-energy irradiation-regulated self-assembled structure and a preparation method thereof, relating to the technical field of self-assembly of metal nanoparticles. This structure is obtained by regulating the self-assembly of AgNO3 / PVP composite nanofibers through photo / thermal dual-energy irradiation to form an AgNLs "bundle" structure or an AgNLs "spike" structure. The photo / thermal dual-energy irradiation-regulated self-assembled "bundle" and "spike" structures provided by the present invention are prepared by electrospinning AgNO3 / polymer composite nanofibers and precisely assembling them into AgNLs "bundle" and "spike" structures through a method combining thermal irradiation and ultraviolet irradiation. The present invention solves the problem that in the prior art, the shape control growth and distribution of Ag nanocrystals on nanofibers are mostly regulated through physical templates.

Description

Technical Field

[0001] The present invention relates to the technical field of self-assembly of metal nanoparticles, and particularly to a photo / thermal dual-energy irradiation-regulated self-assembly structure and a preparation method thereof. Background Art

[0002] Due to their special physical and chemical properties, AgNPs (silver nanoparticles) play an important role in fields such as medicine, electronics, and catalysis. With the development of electrospinning technology, introducing AgNPs into nanofibers can effectively improve their performance. Currently, there are mainly two methods for preparing AgNPs / polymer nanofibers. One is surface post-treatment: compounding AgNPs micelles on the surface of electrospun nanofibers to obtain nanofibers compounded with AgNPs through physical adsorption and mechanical anchoring. The other is in-situ electrospinning using a mixed solution of a polymer and a metal salt precursor, and the nanoparticles are uniformly distributed inside or on the surface of the nanofibers through complexation with the polymer.

[0003] The self-assembly of metal nanoparticles generally includes self-assembly on the substrate surface, at the interface, or in solution. Among them, self-assembly on the substrate surface includes solvent evaporation self-assembly, template-assisted self-assembly, and external field-assisted self-assembly; interface self-assembly includes gas-liquid interface self-assembly and liquid-liquid interface self-assembly; self-assembly in solution includes self-assembly through chemical bonding between particles and self-assembly through molecular connectors between particles. In the self-assembly of metal nanoparticles on the substrate surface under the action of an external field, the external field includes the action of light, electric field, and magnetic field. However, for the shape-controlled growth and distribution of Ag nanocrystals on nanofibers, most are achieved by physically regulating the growth space and position of nanoparticles through a template. Summary of the Invention

[0004] In order to solve the above technical problems, the object of the present invention is to provide a photo / thermal dual-energy irradiation-regulated self-assembly structure and a preparation method thereof to solve the problem in the prior art that the shape-controlled growth and distribution of Ag nanocrystals on nanofibers are regulated through a physical template.

[0005] The technical solution for the present invention to solve the above technical problems is as follows: Provide a photo / thermal dual-energy irradiation-regulated self-assembly structure, which is a structure obtained by self-assembling AgNO3 / PVP composite nanofibers through photo / thermal dual-energy irradiation to form an AgNLs "bundle" structure or an AgNLs "spike" structure.

[0006] Based on the above technical solution, the present invention can be further improved as follows:

[0007] Further, the diameter of the AgNLs "bundle" structure is 200 - 300 nm; the diameter of the AgNLs "spike" structure is 400 - 500 nm.

[0008] Furthermore, the AgNO3 / PVP composite nanofibers are prepared by the following method:

[0009] (1) Dissolve PVP in a solvent, stir, add AgNO3, and stir again to obtain an electrospinning precursor solution;

[0010] (2) Perform electrospinning on the electrospinning precursor solution prepared in step (1) to obtain AgNO3 / PVP composite nanofibers.

[0011] Furthermore, in step (1), PVP is dissolved in a volatile solvent.

[0012] Furthermore, in step (1), the solvent is a mixture of deionized water and ethanol with a volume ratio of 3:1.5 - 2.5.

[0013] Furthermore, in step (1), the solvent is a mixture of deionized water and ethanol with a volume ratio of 3:2.

[0014] Furthermore, in step (1), the solvent is ethanol.

[0015] Furthermore, in step (1), the mass - volume ratio of PVP, AgNO3, and the solvent is 1 - 1.5 g: 0.039 - 0.07 g: 8 - 12 mL.

[0016] Furthermore, in step (2), the electrospinning precursor solution is drawn with a syringe, the air bubbles are removed, and it is connected to a stainless - steel spinning nozzle. The syringe is horizontally fixed on a microfluidic injection pump for electrospinning.

[0017] Furthermore, in step (2), the prepared AgNO3 / PVP composite nanofibers are connected to a clean aluminum foil. The aluminum foil is 10 cm away from the nozzle, the voltage is 15 - 20 kV, and the rotation speed of the microfluidic pump is 0.2 - 0.5 mL / h.

[0018] The present invention also provides a preparation method for the above - mentioned light / heat dual - energy irradiation - regulated self - assembly structure, including the following steps:

[0019] S1: Pretreat the AgNO3 / PVP composite nanofibers to obtain composite nanofibers loaded with AgNPs;

[0020] S2: Irradiate the composite nanofibers loaded with AgNPs obtained in step S1 with ultraviolet light for 2 - 3 h, and then irradiate with thermal energy for 5 - 6 h to obtain an AgNLs "chain" - shaped structure;

[0021] S3: Irradiate the AgNLs "chain" - shaped structure obtained in step S2 with ultraviolet light for 5 - 6 h to obtain an AgNLs "bundle" - shaped structure, that is, the light / heat dual - energy irradiation - regulated self - assembly structure.

[0022] S4: Irradiate the "bundle" structure of AgNLs prepared in step S3 with ultraviolet light for 2 - 3 h, and then irradiate it with thermal radiation for 5 - 6 h to obtain the "spike" structure of AgNLs, that is, the self-assembled structure regulated by dual-energy irradiation of light / heat.

[0023] Further, in step S1, the AgNO3 / PVP composite nanofibers are placed perpendicular to the ultraviolet lamp at a distance of 8 - 10 cm and irradiated for 0.8 - 1.2 h to complete the pretreatment process.

[0024] Further, irradiate for 0.8 - 1.2 h under the conditions of 180 - 220 W and 350 - 380 nm.

[0025] Further, in steps S2 and S4, thermal irradiation is carried out at 50 - 60 °C.

[0026] Further, in steps S2 - S4, ultraviolet light irradiation is carried out under the conditions of 180 - 220 W and 350 - 380 nm.

[0027] Further, in steps S2 - S4, ultraviolet light irradiation is carried out under the conditions of 200 W and 365 nm.

[0028] Further, in steps S2 - S4, perpendicular to the ultraviolet light at 8 - 10 cm, ultraviolet light irradiation is carried out.

[0029] Further, in step S2, the assembly rate of the "chain" structure of AgNLs is 80 - 90%.

[0030] Further, in step S3, the assembly rate of the "bundle" structure of AgNLs is 70 - 80%.

[0031] Further, in step S3, the "bundle" structure of AgNLs is composed of 10 - 15 "chain" structures of AgNLs.

[0032] Further, in step S4, the assembly rate of the "spike" structure of AgNLs is 70 - 80%.

[0033] Further, in step S4, the "spike" structure of AgNLs is composed of 20 - 30 "chain" structures of AgNLs.

[0034] The present invention has the following beneficial effects:

[0035] The self-assembled "bundle" and "spike" structures regulated by photo / thermal dual-energy irradiation provided by the present invention are prepared by electrospinning AgNO3 / polymer composite nanofibers, and the AgNLs "bundle" and "spike" structures are precisely assembled through a method combining thermal irradiation and ultraviolet irradiation. The polymer nanofibers are PVP nanofibers, which provide attachment sites and carriers for AgNPs. Thermal irradiation can promote the uniform distribution and growth of AgNPs in the nanofibers, and ultraviolet irradiation can in-situ reduce AgNO3 to obtain AgNLs arranged in an oriented manner. The method of the present invention can regulate the growth and arrangement of silver nanoparticles (AgNPs) in nanofibers to achieve their functionalization, and is expected to be applied in the directions of electronics and sensing, etc. Description of the Drawings

[0036] Figure 1 SEM image of the AgNLs "bundle" structure prepared in Example 1;

[0037] Figure 2 SEM image of the AgNLs "spike" structure prepared in Example 1. Detailed Embodiments

[0038] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention. For those not specified in the examples, they are carried out under conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified for the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0039] Example 1:

[0040] A self-assembled structure regulated by photo / thermal dual-energy irradiation, comprising the following steps:

[0041] (1) Dissolve 1.32 g of PVP in 10 mL of a volatile solvent (a mixture of deionized water and ethanol with a volume ratio of 3:2), magnetically stir for 4 h until completely dissolved at room temperature, add 0.066 g of AgNO3, and stir for 24 h for complete dissolution to obtain an electrospinning precursor solution;

[0042] (2) Draw the electrospinning precursor solution prepared in step (1) with a 5 mL syringe, remove the bubbles, connect it to a stainless-steel spinning nozzle (inner diameter 0.7 mm), horizontally fix the syringe on a microfluidic injection pump, perform electrospinning, and connect the obtained AgNO3 / PVP composite nanofibers to a clean aluminum foil. The aluminum foil is 10 cm away from the nozzle, the voltage is 18 kV, and the rotation speed of the microfluidic pump is 0.3 mL / h;

[0043] (3) Place the AgNO3 / PVP composite nanofibers prepared in step (2) perpendicular to the ultraviolet lamp at a distance of 10 cm, and irradiate them for 1 h under the conditions of 200 W and 365 nm to complete the pretreatment process and obtain the composite nanofibers loaded with AgNPs;

[0044] (4) Place the composite nanofibers loaded with AgNPs prepared in step (3) perpendicular to the ultraviolet light at 10 cm, irradiate them with ultraviolet light for 3 h under the conditions of 200 W and 365 nm, and then irradiate them thermally for 6 h in an incubator at 60 °C to obtain the "chain" - shaped structure of AgNLs (assembly rate: 90%);

[0045] (5) Place the "chain" - shaped structure of AgNLs prepared in step (4) perpendicular to the ultraviolet light at 10 cm, irradiate them with ultraviolet light for 6 h under the conditions of 200 W and 365 nm to obtain the "bundle" - shaped structure of AgNLs (assembly rate: 80%), that is, the self - assembled structure regulated by photo / thermal dual - energy irradiation;

[0046] (6) Place the "bundle" - shaped structure of AgNLs prepared in step (5) perpendicular to the ultraviolet light at 10 cm, irradiate them with ultraviolet light for 3 h under the conditions of 200 W and 365 nm, and then irradiate them thermally for 6 h in an incubator at 60 °C to obtain the "ear" - shaped structure of AgNLs (80%), that is, the self - assembled structure regulated by photo / thermal dual - energy irradiation.

[0047] Example 2:

[0048] A self - assembled structure regulated by photo / thermal dual - energy irradiation, comprising the following steps:

[0049] (1) Dissolve 1 g of PVP in 8 mL of a volatile solvent (a mixture of deionized water and ethanol with a volume ratio of 3:1.5), magnetically stir for 4 h until completely dissolved at room temperature, add 0.039 g of AgNO3, and stir for 24 h for complete dissolution to obtain an electrospinning precursor solution;

[0050] (2) Draw the electrospinning precursor solution prepared in step (1) with a 5 - mL syringe, remove the air bubbles, connect it to a stainless - steel spinning nozzle (inner diameter 0.7 mm), horizontally fix the syringe on a microfluidic injection pump, perform electrospinning, and connect the obtained AgNO3 / PVP composite nanofibers to a clean aluminum foil. The aluminum foil is 10 cm away from the nozzle, the voltage is 15 kV, and the rotation speed of the microfluidic pump is 0.2 mL / h;

[0051] (3) Place the AgNO3 / PVP composite nanofibers prepared in step (2) perpendicular to the ultraviolet lamp at a distance of 8 cm, and irradiate them for 0.8 h under the conditions of 180 W and 350 nm to complete the pretreatment process and obtain the composite nanofibers loaded with AgNPs;

[0052] (4) Vertically place the composite nanofibers loaded with AgNPs prepared in step (3) 8 cm under ultraviolet light, and irradiate with ultraviolet light for 2 h at 180 W and 350 nm. Then, place it in an incubator at 50 °C and irradiate with heat for 5 h to obtain the "chain" - shaped structure of AgNLs;

[0053] (5) Vertically place the "chain" - shaped structure of AgNLs prepared in step (4) 8 cm under ultraviolet light, and irradiate with ultraviolet light for 5 h at 180 W and 350 nm to obtain the "bundle" - shaped structure of AgNLs, that is, the photo - thermal dual - energy irradiation - regulated self - assembled structure;

[0054] (6) Vertically place the "bundle" - shaped structure of AgNLs prepared in step (5) 8 cm under ultraviolet light, and irradiate with ultraviolet light for 2 h at 180 W and 350 nm. Then, place it in an incubator at 50 °C and irradiate with heat for 5 h to obtain the "spike" - shaped structure of AgNLs, that is, the photo - thermal dual - energy irradiation - regulated self - assembled structure.

[0055] Example 3:

[0056] A photo - thermal dual - energy irradiation - regulated self - assembled structure, comprising the following steps:

[0057] (1) Dissolve 1.5 g of PVP in 12 mL of a volatile solvent (a mixture of deionized water and ethanol with a volume ratio of 3:2.5), magnetically stir for 4 h until completely dissolved at room temperature, add 0.07 g of AgNO3, and stir for another 24 h until completely dissolved to obtain an electrospinning precursor solution;

[0058] (2) Draw the electrospinning precursor solution prepared in step (1) with a 5 - mL syringe, remove the air bubbles, connect it to a stainless - steel spinning nozzle (inner diameter 0.7 mm), horizontally fix the syringe on a microfluidic injection pump, perform electrospinning, and connect the prepared AgNO3 / PVP composite nanofibers to a clean aluminum foil. The aluminum foil is 10 cm away from the nozzle, the voltage is 20 kV, and the rotation speed of the micro - pump is 0.5 mL / h;

[0059] (3) Vertically place the AgNO3 / PVP composite nanofibers prepared in step (2) under ultraviolet light, at a distance of 9 cm, and irradiate for 1.2 h at 220 W and 380 nm to complete the pretreatment process and obtain the composite nanofibers loaded with AgNPs;

[0060] (4) Vertically place the composite nanofibers loaded with AgNPs prepared in step (3) 9 cm under ultraviolet light, and irradiate with ultraviolet light for 2.5 h at 220 W and 380 nm. Then, place it in an incubator at 55 °C and irradiate with heat for 5.5 h to obtain the "chain" - shaped structure of AgNLs;

[0061] (5) Vertically place the AgNLs "chain" structure obtained in step (4) 9 cm under ultraviolet light, and irradiate it with ultraviolet light for 5.5 h under the conditions of 220 W and 380 nm to obtain the AgNLs "bundle" structure, that is, the photo / thermal dual-energy irradiation-regulated self-assembled structure;

[0062] (6) Vertically place the AgNLs "bundle" structure obtained in step (5) 9 cm under ultraviolet light, irradiate it with ultraviolet light for 2.5 h under the conditions of 220 W and 380 nm, and then thermally irradiate it for 5.5 h in an incubator at 55 °C to obtain the AgNLs "ear" structure, that is, the photo / thermal dual-energy irradiation-regulated self-assembled structure.

[0063] Example 4:

[0064] A photo / thermal dual-energy irradiation-regulated self-assembled structure, comprising the following steps:

[0065] In step (1), the volatile solvent is ethanol, and the rest is the same as in Example 1.

[0066] Example 5:

[0067] A photo / thermal dual-energy irradiation-regulated self-assembled structure, comprising the following steps:

[0068] In step (1), 0.039 g of AgNO3 is added, and the rest is the same as in Example 1.

[0069] Example 6:

[0070] A photo / thermal dual-energy irradiation-regulated self-assembled structure, comprising the following steps:

[0071] In steps (5) and (6), it is vertically placed 8 cm under ultraviolet light, and the rest is the same as in Example 1.

[0072] Example 7:

[0073] A photo / thermal dual-energy irradiation-regulated self-assembled structure, comprising the following steps:

[0074] In steps (5) and (6), it is vertically placed 8 cm under ultraviolet light, and the rest is the same as in Example 1.

[0075] Example 8:

[0076] A photo / thermal dual-energy irradiation-regulated self-assembled structure, comprising the following steps:

[0077] In steps (4) and (6), the ultraviolet light irradiation is 2 h and the thermal irradiation is 5 h, and the rest is the same as in Example 1.

[0078] Test Example

[0079] 1. SEM detection was carried out on the "chain" - shaped structure and "spike" - shaped structure of AgNLs prepared in Example 1, and the results are shown in Figure 1-2 .

[0080] It can be seen from Figure 1-2 that the "chain" - shaped structure and "spike" - shaped structure of AgNLs can be prepared by the method of the present invention.

[0081] The above - mentioned are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A photo / thermal dual-energy irradiation-regulated self-assembled structure, characterized in that, This structure is obtained by self-assembly of AgNO3 / PVP composite nanofibers through photo / thermal dual-energy irradiation to form an AgNLs "bundle" structure or an AgNLs "spike" structure; The light is ultraviolet light; The AgNLs "bundle" structure is composed of 10 - 15 AgNLs "chain" structures; The AgNLs "spike" structure is composed of 20 - 30 AgNLs "chain" structures; Among them, the AgNLs "chain" structure is prepared by the following method: S1: Pretreat the AgNO3 / PVP composite nanofibers to obtain composite nanofibers loaded with AgNPs; S2: Irradiate the composite nanofibers loaded with AgNPs obtained in step S1 with ultraviolet light for 2 - 3 h, and then irradiate with thermal energy for 5 - 6 h to obtain the AgNLs "chain" structure; In step S1, the AgNO3 / PVP composite nanofibers are placed perpendicular to the ultraviolet lamp at a distance of 8 - 10 cm and irradiated for 0.8 - 1.2 h to complete the pretreatment process.

2. The photo / thermal dual-energy irradiation-regulated self-assembled structure according to claim 1, wherein The diameter of the AgNLs "bundle" structure is 200 - 300 nm; the diameter of the AgNLs "spike" structure is 400 - 500 nm.

3. The photo / thermal dual-energy irradiation-regulated self-assembled structure according to claim 1, wherein The AgNO3 / PVP composite nanofibers are prepared by the following method: (1) Dissolve PVP in a solvent, stir, add AgNO3, and stir again to obtain an electrospinning precursor solution; (2) Electrospin the electrospinning precursor solution obtained in step (1) to obtain AgNO3 / PVP composite nanofibers.

4. The photo / thermal dual-energy irradiation-regulated self-assembled structure according to claim 3, wherein In step (1), the mass-volume ratio of PVP, AgNO3, and the solvent is 1 - 1.5 g: 0.039 - 0.07 g: 8 - 12 mL.

5. The preparation method of the photo / thermal dual-energy irradiation-regulated self-assembled structure according to any one of claims 1-4, characterized in that, It includes the following steps: S1: Pretreat the AgNO3 / PVP composite nanofibers to obtain composite nanofibers loaded with AgNPs; S2: Irradiate the composite nanofibers loaded with AgNPs obtained in step S1 with ultraviolet light for 2 - 3 h, and then irradiate with thermal energy for 5 - 6 h to obtain the AgNLs "chain" structure; S3: Irradiate the AgNLs "chain" structure obtained in step S2 with ultraviolet light for 5 - 6 h to obtain the AgNLs "bundle" structure, that is, the photo / thermal dual-energy irradiation-regulated self-assembly structure; S4: Irradiate the AgNLs "bundle" structure obtained in step S3 with ultraviolet light for 2 - 3 h, and then irradiate with thermal energy for 5 - 6 h to obtain the AgNLs "spike" structure, that is, the photo / thermal dual-energy irradiation-regulated self-assembly structure.

6. The preparation method of the opto- / thermo-dual-energy irradiation-regulated self-assembled structure according to claim 5, wherein In steps S2 and S4, thermal irradiation is carried out at 50 - 60 °C.

7. The preparation method of the photo / thermal dual-energy irradiation-regulated self-assembled structure according to claim 5, wherein In steps S2 - S4, ultraviolet light irradiation is carried out at 180 - 220 W and 350 - 380 nm.

8. The preparation method of the photo / thermal dual-energy irradiation-regulated self-assembled structure according to claim 5, wherein, In steps S2 - S4, ultraviolet light irradiation is carried out at 200 W and 365 nm.

9. The preparation method of the photo / thermal dual-energy irradiation-regulated self-assembled structure according to claim 5, characterized in that, In step S2, the assembly rate of the AgNLs "chain" structure is 80 - 90%.

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