阅读说明：本技术 一种基于蒸发诱导纳米颗粒液相自组装的方法 (Method for inducing liquid-phase self-assembly of nano particles based on evaporation ) 是由 陈云飞 王永康 张艳 魏志勇 于 2020-04-29 设计创作，主要内容包括：本发明公开了一种基于蒸发诱导纳米颗粒液相自组装的方法,该方法包括如下步骤：(1)制备银纳米颗粒胶体；(2)向步骤(1)中制备的银纳米颗粒胶体中加入0.5％体积比的丙三醇,混合均匀形成纳米颗粒悬浊液；(3)将步骤(2)中得到的纳米颗粒悬浊液液滴滴到疏水玻璃基底上,室温干燥蒸发溶剂水实现纳米颗粒自组装形成丙三醇稳定的纳米颗粒团簇。本发明采用蒸发诱导自组装技术,无需对纳米颗粒表面进行官能团修饰,无需使用DNA、表面修饰剂等共轭连接分子,可直接在任意基底上进行纳米颗粒自组装,组装后的纳米颗粒间隙均匀,速度快,效率高,成本低。(The invention discloses a method for inducing liquid-phase self-assembly of nanoparticles based on evaporation, which comprises the following steps: (1) preparing silver nanoparticle colloid; (2) adding 0.5% of glycerol by volume into the silver nanoparticle colloid prepared in the step (1), and uniformly mixing to form a nanoparticle suspension; (3) dripping the nano-particle suspension liquid obtained in the step (2) on a hydrophobic glass substrate, drying at room temperature and evaporating solvent water to realize self-assembly of nano-particles to form a nano-particle cluster with stable glycerol. The invention adopts the evaporation-induced self-assembly technology, does not need to modify the surface of the nano-particles by functional groups, does not need to use conjugate connecting molecules such as DNA, surface modifier and the like, can directly carry out self-assembly of the nano-particles on any substrate, and has the advantages of uniform gaps of the assembled nano-particles, high speed, high efficiency and low cost.)

1. A method for inducing liquid-phase self-assembly of nanoparticles based on evaporation is characterized in that: the method comprises the following steps:

(1) preparing silver nanoparticle colloid;

(2) adding 0.5% of glycerol by volume into the silver nanoparticle colloid prepared in the step (1), and uniformly mixing to form a nanoparticle suspension;

(3) dripping the nano-particle suspension liquid obtained in the step (2) on a hydrophobic glass substrate, drying at room temperature and evaporating solvent water to realize self-assembly of nano-particles to form a nano-particle cluster with stable glycerol.

2. The method for inducing nanoparticle liquid phase self-assembly based on evaporation in accordance with claim 1, wherein the silver nanoparticle colloid in step (1) comprises 30 nm silver nanoparticles and solvent water, and the concentration of the silver nanoparticles is 8 × 10¹⁰Each per milliliter.

3. The evaporation-based method for inducing liquid-phase self-assembly of nanoparticles according to claim 2, wherein: the 30 nano silver nanoparticles are synthesized by a chemical method, and specifically comprise the following steps: firstly, mixing and stirring solvent water and glycerol uniformly according to the mass ratio of 6:5, adding silver nitrate with the mass of 0.003% of the mass of the solvent water when heating to 95 ℃, preserving heat for one minute, then adding sodium citrate with the mass of 0.33% of the mass of the silver nitrate, preventing the solvent water from evaporating through a condensation reflux device, preserving heat for 95 ℃ continuously, stirring for one hour, and cooling to room temperature to obtain a silver nanoparticle suspension with the diameter of 30 nanometers.

4. The evaporation-based method for inducing liquid-phase self-assembly of nanoparticles according to claim 3, wherein: the 30 nanometer silver nanometer particles synthesized by adopting a chemical method are reduced by adopting sodium citrate, and the specific method comprises the following steps: and (3) centrifugally washing the prepared 30 nano silver nanoparticle suspension at 12000 r/s at a high speed, and then dispersing the suspension in solvent water, wherein the citrate is adsorbed on the silver nanoparticles and cannot be removed by centrifugal washing, and the surface functional groups of the dispersed 30 nano silver nanoparticles are negatively charged citrate.

5. The evaporation-induced nanoparticle liquid phase self-assembly-based method according to claim 1 or 2 or 3 or 4, characterized in that: the hydrophobic glass substrate in the step (3) is obtained by chemically modifying a glass substrate, and comprises the following steps: firstly, sequentially and respectively ultrasonically cleaning a glass sheet by acetone, ethanol and deionized water in turn, and carrying out ultrasonic cleaning in nitrogenAfter drying under flowing down, the cleaned glass sheet was immersed in H having a mass fraction of 30%₂O₂Mixing the glass sheet with 98% concentrated sulfuric acid in a mixed solution of 3:7 volume, heating to 80 ℃, preserving heat for 30 minutes, cooling, and repeatedly washing the glass sheet with deionized water; then, immersing the glass sheet into a 1% triethoxy 1H, 2H-trifluoro-n-octylsilane solution for one hour, rinsing the glass sheet by using ethanol, and drying the glass sheet under a nitrogen flow; finally, the glass sheet was dried in a drying cabinet at 80 ℃ for three hours and cooled to room temperature to obtain a hydrophobic glass substrate.

Technical Field

The invention belongs to the technical field of nano material self-assembly, and particularly relates to a method for inducing nano particle liquid phase self-assembly based on evaporation.

Background

Due to the continuous development of research on the preparation of nanoparticles with different shapes, sizes and materials in recent years, the rapid, efficient and large-area assembly of nanoparticles has huge application prospects in the aspects of biosensing, drug delivery, disease diagnosis, new material preparation and the like. However, unlike interatomic interactions, nanoparticle interactions are very complex involving van der waals, static electricity, solvation/depletion, friction/lubrication, capillary forces, and the like. Furthermore, most nanoparticles do not self-assemble into the thermodynamically lowest energy state, but form kinetically trapped non-equilibrium structures, and thus, experimental techniques for assembling nanoparticles into controllable nanostructures remain limited. Modifying the surface of nanoparticles with surfactants to control nanoparticle assembly is an effective approach. The surfactant can form a self-assembled bilayer film on the nano-structure, and generate net positive charges on the surfaces of the nano-particles, so that net repulsive interaction is provided between the nano-particles, random disordered aggregation in the solvent evaporation process is prevented, and ordered assembly of the nano-particles is realized. The method is a simple, convenient and economic self-assembly method for realizing nanoparticle assembly by utilizing the positive charges on the surface of the indium-doped tin oxide glass and adsorbing the gold nanoparticles with the negative charges. Another important method of assembling highly ordered nanoparticles is to utilize a conjugated structure between DNA and the nanoparticles. Due to base complementary pairing, nanoparticles bound to complementary ssDNA can be linked and assembled to each other after mixing and incubation. In addition, the DNA origami strategy is a relatively new technique that can be used to design combinations of almost any pattern. However, these methods are too complicated or expensive, and a fast, efficient, and low-cost method for self-assembling liquid-phase large-area nanoparticles is still lacking.

Disclosure of Invention

In order to solve the problems, the invention discloses a method for inducing nanoparticle liquid phase self-assembly based on evaporation, which comprises the steps of adding glycerol into a nanoparticle aqueous solution in a proper proportion, evaporating water by utilizing the characteristic that the glycerol is not easy to volatilize at room temperature, separating nanoparticles in nanoparticle colloid and depositing the nanoparticles on a hydrophobic glass substrate, and forming a layer of protective film on the surface of the deposited nanoparticles by using the glycerol as a stabilizer and a protective agent to realize rapid and stable self-assembly of the nanoparticles.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a method based on evaporation-induced liquid-phase self-assembly of nanoparticles, comprising the steps of:

(1) preparing silver nanoparticle colloid;

(2) adding 0.5% of glycerol by volume into the silver nanoparticle colloid prepared in the step (1), and uniformly mixing to form a nanoparticle suspension;

(3) dripping the nano-particle suspension liquid obtained in the step (2) on a hydrophobic glass substrate, drying at room temperature and evaporating solvent water to realize self-assembly of nano-particles to form a nano-particle cluster with stable glycerol.

In the method based on evaporation-induced nanoparticle liquid-phase self-assembly, the silver nanoparticle colloid in the step (1) comprises 30 nanometer silver nanoparticles and solvent water, and the concentration of the silver nanoparticles is 8 × 10¹⁰Each per milliliter.

The method for inducing nanoparticle liquid phase self-assembly based on evaporation is characterized in that the 30-nanometer silver nanoparticles are synthesized by a chemical method, and the method specifically comprises the following steps: firstly, mixing and stirring solvent water and glycerol uniformly according to the mass ratio of 6:5, adding silver nitrate with the mass of 0.003% of the mass of the solvent water when heating to 95 ℃, preserving heat for one minute, then adding sodium citrate with the mass of 0.33% of the mass of the silver nitrate, preventing the solvent water from evaporating through a condensation reflux device, preserving heat for 95 ℃ continuously, stirring for one hour, and cooling to room temperature to obtain a silver nanoparticle suspension with the diameter of 30 nanometers.

The method for inducing the liquid-phase self-assembly of the nano-particles based on evaporation adopts a chemical method to synthesize the 30 nano-silver nano-particles, and adopts sodium citrate for reduction, and the specific method is as follows: and (3) centrifugally washing the prepared 30 nano silver nanoparticle suspension at 12000 r/s at a high speed, and then dispersing the suspension in solvent water, wherein the citrate is adsorbed on the silver nanoparticles and cannot be removed by centrifugal washing, and the surface functional groups of the dispersed 30 nano silver nanoparticles are negatively charged citrate.

The method for inducing nanoparticle liquid phase self-assembly based on evaporation is characterized in that in the step (3), the hydrophobic glass substrate is obtained by chemically modifying a glass substrate, and the method comprises the following steps: firstly, respectively ultrasonically cleaning a glass sheet by acetone, ethanol and deionized water in sequence, drying the glass sheet under nitrogen flow, and immersing the cleaned glass sheet into H with the mass fraction of 30%₂O₂Mixing the glass sheet with 98% concentrated sulfuric acid in a mixed solution of 3:7 volume, heating to 80 ℃, preserving heat for 30 minutes, cooling, and repeatedly washing the glass sheet with deionized water; then, immersing the glass sheet into a 1% triethoxy 1H, 2H-trifluoro-n-octylsilane solution for one hour, rinsing the glass sheet by using ethanol, and drying the glass sheet under a nitrogen flow; finally, the glass sheet was dried in a drying cabinet at 80 ℃ for three hours and cooled to room temperature to obtain a hydrophobic glass substrate.

Has the advantages that:

1. the invention adopts the evaporation-induced self-assembly technology, does not need to modify the surface of the nano-particles by functional groups, does not need to use conjugate connecting molecules such as DNA, surface modifier and the like, can directly carry out self-assembly of the nano-particles on any substrate, and has the advantages of uniform gaps of the assembled nano-particles, high speed, high efficiency and low cost.

2. The volume of glycerol is one of the key technologies for realizing the high-efficiency self-assembly of the nanoparticle liquid phase. Firstly, preparing silver nanoparticle colloid with the diameter of 30 nanometers by adopting a chemical synthesis method, wherein a reducing reagent adopts sodium citrate, so that citrate is modified on the surface of the synthesized silver nanoparticles, and the silver nanoparticles with negative electricity are obtained. The synthesized silver nanoparticles were dispersed in water after three centrifugal washes to remove excess residual chemical agent. The negatively charged nanoparticles have electrostatic repulsion interaction and can be stably dispersed in water. After glycerol with a proper volume ratio is added, the suspension of the nanoparticles is dried on a hydrophobic glass substrate, water is volatilized, glycerol remains, the nanoparticles are dispersed in the glycerol again due to the fact that the glycerol volume ratio is too large, self-assembly is not uniform, a complete protective film is difficult to form due to the fact that the glycerol volume ratio is too small, self-assembly of the nanoparticles is not uniform, and the area is small. The volume ratio of the added glycerol is adjusted to realize the rapid and efficient self-assembly of the nano particles.

3. Hydrophobic glass substrates are another key technology. The evaporation separation process is carried out on a hydrophobic glass substrate, when liquid drops are dried on the hydrophobic glass substrate, liquid in the liquid drops generates Marangoni flow due to surface tension gradient, nano particles are conveyed to the glass substrate, the nano particles on the hydrophilic glass substrate tend to be conveyed to a three-phase contact line position, the clustered nano particles form a coffee ring, and the uniform self-assembly of the nano particles is damaged. The transport direction of the nano particles on the hydrophobic glass substrate is radial, the nano particles are transported more uniformly, and self-assembled nano particle clusters which are distributed uniformly are formed. Meanwhile, the area of the liquid drops exposed in the air is large on the hydrophobic substrate, the evaporation speed of water is high, and the self-assembly of the liquid phase of the nano particles is high.

Drawings

FIG. 1 is a schematic diagram of the evaporation-induced nanoparticle liquid phase self-assembly process of the present invention.

Fig. 2 is a schematic diagram of the movement of the marangoni flow driven nanoparticles formed by water evaporation according to the present invention, (a) the marangoni flow on a hydrophilic glass substrate, (b) the marangoni flow on a hydrophobic glass substrate, (c) the clustered nanoparticles after drying of the nanoparticle suspension on the hydrophilic substrate, and (d) the clustered nanoparticles after drying of the nanoparticle suspension on the hydrophobic substrate.

Fig. 3 is an optical photograph of glycerol-stabilized nanoparticle clusters according to the present invention, with 0.5 mm scale bars.

Fig. 4 shows the cluster condition of nanoparticles according to the invention as a function of the concentration of glycerol added. Nanoparticle cluster uniformity can be expressed in terms of the signal intensity of surface enhanced raman scattering spectroscopy after clustering. The more uniform the nanoparticle cluster is, the more remarkable the local surface plasmon resonance effect generated after laser incidence is, and the stronger the generated surface enhanced raman scattering spectrum signal is.

List of reference numerals:

1. a centrifugal tube, 2, nanoparticle colloid, 3, glycerol, 4, nanoparticle suspension, 5, a hydrophobic glass substrate, 6, solvent water, 7, a nanoparticle cluster stabilized by glycerol, and 8.30 nano silver nanoparticles.

Detailed Description

For the purpose of enhancing an understanding of the present invention, the present embodiment will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the method for inducing liquid-phase self-assembly of nanoparticles based on evaporation according to the present invention comprises the following steps:

a method based on evaporation-induced liquid-phase self-assembly of nanoparticles, comprising the steps of:

(1) preparing silver nano-particle colloid, 30 nano-silver nano-particles and solvent water, wherein the concentration of the silver nano-particles is 8 × 10¹⁰Each per milliliter. The 30 nano silver nanoparticles are synthesized by a chemical method, and specifically comprise the following steps: firstly, mixing 30 g of solvent water and 25 g of glycerol, uniformly stirring, adding 9 mg of silver nitrate when heating to 95 ℃ in a flask, preserving heat for one minute, then adding 0.03 mg of sodium citrate, installing a condensation reflux device on the flask, preventing the solvent water from evaporating, continuously preserving heat at 95 ℃, stirring for one hour, and cooling to room temperature to obtain a 30-nanometer-diameter silver nanoparticle suspension. And (3) centrifuging and washing the prepared 30 nano silver nanoparticles at 12000 r/s at a high speed, and then re-dispersing the 30 nano silver nanoparticles in solvent water, wherein the citrate is adsorbed on the silver nanoparticles and cannot be removed by the centrifugal washing, so that the surface functional groups of the re-dispersed 30 nano silver nanoparticles are negatively charged citrate.

(2) Adding 0.5% of glycerol by volume into the silver nanoparticle colloid prepared in the step (1), and uniformly mixing to form a nanoparticle suspension;

(3) dripping the nano-particle suspension liquid obtained in the step (2) on a hydrophobic glass substrate, drying at room temperature and evaporating solvent water to realize self-assembly of nano-particles to form a nano-particle cluster with stable glycerol. The nano-particle suspension liquid drops are dried on a hydrophobic glass substrate, the evaporation condition is a room temperature environment, the solvent is volatile at room temperature, the Marangoni flow formed by the surface tension gradient drives the nano-particles to move towards the hydrophobic glass substrate and deposit on the hydrophobic glass substrate, the glycerol is very slow in volatilization at room temperature and also deposits on the hydrophobic glass substrate, and a layer of protective film is formed on the nano-particles of the cluster to form the nano-particle cluster with stable glycerol.

The hydrophobic glass substrate is obtained by chemically modifying a glass substrate and comprises the following steps: firstly, respectively ultrasonically cleaning a glass sheet by acetone, ethanol and deionized water in sequence, drying the glass sheet under nitrogen flow, immersing the glass sheet into a mixed solution of 30 ml of H2O2 with the mass fraction of 30% and 70 ml of concentrated sulfuric acid with the mass fraction of 98%, heating to 80 ℃, preserving heat for 30 minutes, cooling, and repeatedly washing the glass sheet by the deionized water; then, immersing the cleaned glass sheet in a 1% (mass ratio) solution of triethoxy 1H, 2H-trifluoro-n-octylsilane for one hour, then rinsing the glass sheet with ethanol, and drying under a nitrogen stream; finally, the glass sheet was dried in a drying cabinet at 80 ℃ for three hours and cooled to room temperature to obtain a hydrophobic glass substrate.

The nano particles assembled by the method have uniform gaps, high speed and high efficiency, and can be prepared in ten minutes generally.

The present invention may have other embodiments, and any minor modifications, equivalent changes, and substitutions adopted according to the technical spirit of the present invention fall within the scope of the claims of the present invention.