A method for preparing a hydrophobic molecular aqueous dispersion

Abstract

This invention relates to a method for preparing an aqueous dispersion of hydrophobic molecules. First, hydrophobic molecules are dissolved in an organic solvent to form a hydrophobic molecule / organic solvent solution. Then, ultrapure water is rapidly added to the hydrophobic molecule / organic solvent solution, and the mixture is mixed to obtain a colloidal dispersion A. Finally, the organic solvent is removed from colloidal dispersion A to obtain colloidal dispersion B, which is the aforementioned aqueous dispersion of hydrophobic molecules. The rapid addition of ultrapure water to the hydrophobic molecule / organic solvent solution refers to injecting or pouring ultrapure water into the hydrophobic molecule / organic solvent solution within 3 seconds. The hydrophobic molecules are soluble in the organic solvent. The hydrophobic molecules are hydrophobic molecules containing π-conjugated groups, and these hydrophobic molecules are capable of encapsulating water within the formed assembly during the assembly process. The organic solvent is a water-miscible organic solvent. This method enables the preparation of stable aqueous colloids in various water-miscible organic solvents.

Description

Technical Field

[0001] This invention belongs to the technical field of preparing stable aqueous dispersions through hydrophobic molecules, and relates to a method for preparing hydrophobic molecular aqueous dispersions. Background Technology

[0002] Nanospheres are small particles with a diameter ranging from 5 nanometers to 1000 micrometers, and they have a wide range of applications as liquid crystal spacers, drug carriers, and enzyme carriers. Various methods exist for preparing nanospheres, among which using water as a dispersion medium is an important one. Water is inexpensive, environmentally friendly, and pollution-free. However, existing methods for preparing nanospheres all require the addition of an auxiliary agent (surfactant) to stabilize the molecules in the aqueous phase. Surfactants often have amphiphilic structures; or the molecules constituting the nanospheres themselves have amphiphilic structures (CN201710023290.5 A polypyridine naphthylimide fluorescent dendritic molecule and its preparation method and application; CN201710158228.7 A size-tunable perylene imide multifunctional nanoparticle and its preparation and application). Especially in the preparation of hydrophobic nanospheres, amphiphilic dispersants are key to their stable dispersion in the aqueous phase (CN201810689542.2 A nanosphere based on aggregation-induced emission material and its preparation method and application; CN201110387145.8 A class of polymerizable fluorescent dyes, their preparation method and application; CN201810742582.9 A method for preparing fluorescent magnetic microspheres; CN201310048740.8 Quantum dot nanoparticles containing hydrophobic interlayers and their preparation method; CN201210436603.7 A method for enabling hydrophobic nanoparticles to simultaneously achieve aqueous phase transfer and cell nucleus targeting). On the other hand, achieving aqueous dispersion of nanoparticles is also a crucial step in their application. Amphiphilic nanoparticles are relatively easy to disperse in aqueous phase (CN201310553560.5 A single-molecule fluorescent polymer micelle and its application as a pH probe; CN201910467076.8 A method for preparing and applying light-controlled fluorescent polymer nanoparticles). However, uniform dispersion of hydrophobic nanoparticles in aqueous phase is more difficult and requires the assistance of additives. Existing dispersion methods mainly involve adding surfactants to disperse hydrophobic nanoparticles (CN201110342740.X A method for aqueous dispersion of hydrophobic organic dye nanoparticles; CN201110353986.7 A method for preparing dye nanoparticles with tunable wavelength in aqueous phase dispersion); or modifying the surface of hydrophobic nanoparticles (CN201710961337.2 A method for preparing hydrophobic magnetic nanoparticles that are easily dispersed in aqueous phase).

[0003] The large-scale discharge of wastewater containing surfactants not only directly harms the aquatic environment, killing microorganisms and inhibiting the degradation of other toxic substances, but also leads to a reduction in dissolved oxygen in the water. In particular, surfactants containing nitrogen and phosphorus can cause eutrophication. When the surfactant concentration in wastewater entering a sewage treatment plant reaches a certain level, it affects many processes such as aeration, sedimentation, and sludge nitrification. Residual surfactants in the soil have a certain impact on the growth of soil microorganisms. Generally speaking, when the surfactant concentration is less than 100.0 mg / L, the microbial population begins to decline when the concentration is greater than 500.0 mg / L. Furthermore, some surfactants have very weak adsorption capacity in soil, and their potential for downward migration and groundwater pollution cannot be ignored. While using chemical surfactants for environmental remediation, surfactants inevitably remain in the environment. Therefore, for environmental and soil protection, it is necessary to achieve surfactant-free aqueous dispersion of hydrophobic particles. The above illustrates that hydrophobic molecules require the introduction of surfactants to achieve stability.

[0004] In existing reports, stable aqueous dispersions are obtained by rapidly adding water to a THF or DMSO solution of the molecules. The molecules are linear polymers with multiple polar groups—carbonyl groups—as binding sites for water molecules. For example, different masses of PFpP (CpFe(CO)2(CH2)3PPh2) were dissolved in 1.00 mL of tetrahydrofuran, and 10.00 mL of deionized water was rapidly injected into the tetrahydrofuran solution. The tetrahydrofuran was then removed by bubbling with nitrogen for 1 hour to obtain PFpP aqueous colloids of different concentrations, with Zeta potentials of -37 to -47 mV and polydispersity indices of 0.004 to 0.214 (Macromolecules 2015, 48(21), 7968-7977.DOI:10.1021 / acs.macromol.5b01531). 1 mg of FpC6 (CpFe(PPh3)(CO)CO(CH2)5CH3) was dissolved in 1.00 mL of tetrahydrofuran. 10.00 mL of distilled deionized water was added to the THF solution with stirring. The tetrahydrofuran was then removed by bubbling under nitrogen for 1.5 hours to obtain a 0.1 mg / mL FpC6 aqueous colloid with a Zeta potential of -65 mV and a polydispersity index of 0.018 (Chemistry-A European Journal 2015, 21(52), 19223-19230.DOI:10.1002 / chem.201502121). 1 mg of FpC3Bithiophene (CpFe(PPh3)(CO)CO(CH2)2CH3Bithiophene) was dissolved in 1.00 mL of tetrahydrofuran. 10 mL of distilled water was rapidly injected into 1 mL of 1 mg / mL tetrahydrofuran solution, and then the tetrahydrofuran was removed by bubbling with nitrogen for 1.5 hours. The Zeta potential was approximately -48 to -55.5 mV, and the polydispersity index was 0.05 (Journal of Materials Chemistry C 2016,4(23),5231-5240.DOI:10.1039 / c6tc01222a.Journal of Physical Chemistry B 2020,124(41),9239-9245.DOI:10.1021 / acs.jpcb.0c06678).1 mg of P(FpC3P)7 was dissolved in 1.00 mL of DMSO. Distilled water was then rapidly added to the 1 mg / mL P(FpC3P)7DMSO solution to obtain a 0.1 mg / mL colloid, i.e., a water to DMSO volume ratio of 9:1 (Note: the distilled water and P(FpC3P)7DMSO solution were heated at 25 °C, 40 °C, and 60 °C for 24 h respectively before colloid preparation). At 25 °C, the polydispersity index was 0.21; at 40 °C, the polydispersity index was 0.361; and at 60 °C, the polydispersity index was 0.236 (Soft Matter 2017, 13(30), 5130-5136.DOI:10.1039 / c7sm01101f). 1 mg of FpC. n (n=1,6,8,10,14,18) were dissolved in 1.00 mL of tetrahydrofuran. 10.0 mL of distilled deionized water was rapidly added to 1.0 mL of the above six tetrahydrofuran solutions (1.0 mg / mL). The tetrahydrofuran was then removed by bubbling under nitrogen for 90 min, yielding a 0.1 mg / mL solution. The polydispersity index (PDI) of FpC1 was 0.75, that of FpC6 was 0.03, that of FpC8 was 0.06, and that of FpC... 10 The polydispersity index is 0.05, and the FpC is... 14 The polydispersity index is 0.05, and the FpC is... 18The polydispersity index was 0.04 (Journal of Physical Chemistry B 2017, 121(25), 6280-6285.DOI:10.1021 / acs.jpcb.7b04353). Fp-pyrene(Fe(CO){CO(CH2)5CH2-pyrene}(Cp)(PPh3) was dissolved in X mL of DMSO or THF, and then 10-X mL of water was added to prepare a solution. The polydispersity index was approximately 0.162 (Chemistry-A European Journal). 2017, 23(41), 9736-9740.DOI:10.1002 / chem.201702281). The above are all preparations of colloids by polymer chains in THF or DMSO, and the hydrogen bonding sites are polar carbonyl groups and water. However, the molecules are all linear polymers and have more carbonyl groups as binding sites, which increases the interaction between water molecules and molecules. However, such reports do not involve the assembly of more hydrophobic molecules of more shapes to form a stable aqueous dispersion system. Most molecules of organic solvents that are miscible with water have strong interactions with water molecules. Organic solvents interact with solute molecules on the one hand and with water molecules on the other hand, which is conducive to connecting solute molecules and water molecules, enhancing the connection between solute molecules and water molecules, and is conducive to the dispersion of solute molecules in the aqueous phase. However, the existing technology involves fewer organic solvent systems. Due to the differences in molecular shape and polarity, the solubility in different organic solvents is different, which is conducive to constructing hydrophobic stable aqueous dispersions in more water-miscible organic solvent systems. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide a method for preparing a hydrophobic molecular aqueous dispersion.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a hydrophobic molecular aqueous dispersion involves first dissolving hydrophobic molecules (M) in an organic solvent (S) to form a hydrophobic molecule / organic solvent (M / S) solution, then rapidly adding ultrapure water to the hydrophobic molecule / organic solvent solution and mixing to obtain a colloidal dispersion A, and finally removing the organic solvent from the colloidal dispersion A to obtain a colloidal dispersion B, which is the hydrophobic molecular aqueous dispersion.

[0008] Rapidly adding ultrapure water to a hydrophobic molecule / organic solvent solution refers to injecting or pouring ultrapure water into the hydrophobic molecule / organic solvent solution within 3 seconds.

[0009] The hydrophobic molecule dissolves in the organic solvent;

[0010] The hydrophobic molecule is a hydrophobic molecule containing a π-conjugated group, and the hydrophobic molecule is capable of encapsulating water in the assembled structure during the assembly process; the hydrophobic molecule needs to possess the following properties: it needs to be soluble in the aforementioned organic solvents. The hydrophobic molecule needs to have an interaction site with water, which is a π-conjugated group. The π-conjugated group is a conventionally accepted group with large π-conjugation characteristics, capable of forming π-OH bonds or π-H2O interactions with water; and the hydrophobic molecule is capable of encapsulating water in the assembled structure during the assembly process;

[0011] The organic solvent is a water-miscible organic solvent.

[0012] As a preferred technical solution:

[0013] The method for preparing a hydrophobic molecular aqueous dispersion as described above, wherein the organic solvent is tetrahydrofuran, acetic acid, methanol, dioxane, dimethylformamide, acetone, acetonitrile, dimethyl sulfoxide, ethanol, or n-propanol.

[0014] In the method for preparing a hydrophobic molecular aqueous dispersion as described above, the mass-volume ratio of hydrophobic molecules to organic solvent is 1-30 mg: 1-10 mL.

[0015] In the method for preparing a hydrophobic molecular aqueous dispersion as described above, the volume ratio of hydrophobic molecule / organic solvent solution to ultrapure water is 1:10-20.

[0016] The method for preparing a hydrophobic molecular aqueous dispersion as described above, wherein the concentration of the hydrophobic molecular aqueous dispersion is 0.005–3 mg / mL.

[0017] The method for preparing a hydrophobic molecular aqueous dispersion as described above involves removing the organic solvent from the colloidal dispersion A by dialysis, bubbling, or vacuum evaporation (where organic solvents with a boiling point higher than 75°C cannot be removed by bubbling or vacuum evaporation).

[0018] The organic solvent in colloidal dispersion A was removed by dialysis as follows: Colloidal dispersion A was transferred to a dialysis bag with a molecular weight cutoff >500, and the colloid was dialyzed with pure water. The pure water was replaced at 1.5h, 4h and 8h after the start of dialysis. The volume ratio of pure water to colloidal dispersion A was 2000-6000:11 each time. Dialysis was completed after 24h.

[0019] The method of removing organic solvents from colloidal dispersion A by bubbling is as follows: Colloidal dispersion A is placed in a closed sample bottle with two needles of different lengths inserted. Nitrogen gas is introduced into and out of the two needles. The longer needle is placed below the liquid surface to introduce gas, and the shorter needle is placed on the surface to expel gas. Nitrogen gas is blown into colloidal dispersion A at a rate of 2 to 3 bubbles per second for 90 to 120 minutes.

[0020] The method of removing organic solvents from colloidal dispersion A by vacuum evaporation is as follows: Colloidal dispersion A is placed in a vacuum evaporation device with a vacuum degree of -0.093 to -0.1 MPa and a temperature of 70 to 80°C, and evaporation is completed in 30 to 60 minutes.

[0021] The method for preparing a hydrophobic molecular aqueous dispersion as described above involves particles with a diameter of 40–500 nm and a polydispersity index of 0.1–0.7 (a smaller polydispersity index indicates a more uniform size distribution). The particle size and polydispersity index are measured using dynamic laser light scattering (DLS) at a temperature of 25–30 °C for 3–5 min. The zeta potential is -20–-60 mV, and the zeta potential is measured at a temperature of 25–30 °C.

[0022] The mechanism of this invention is as follows:

[0023] The π-conjugated groups on the hydrophobic molecule (M) serve as interaction sites with water. When water is poured into a hydrophobic molecule / organic solvent (M / S) solution (dispersion A) using a rapid mixing method, the organic solvent partially diffuses into the aqueous phase over this timescale due to the fast mixing speed. Simultaneously, under hydrophobic interaction, M assembles, and the assembled particles still contain organic solvent, forming independent small colloidal particles. During this process, M encapsulates water molecules within the colloidal particles, forming internal water. The stabilization mechanism is as follows: Because the M molecule is hydrophobic, it cannot move freely in the aqueous phase. Dynamic hydrogen bonds exist between the internal water and the colloidal dispersion (bulk water). Furthermore, since M has polar groups that act as hydrogen bonding sites, there is also interaction between the internal water and M. Before dialysis, the organic solvent interacts with the M molecule and is present in greater quantities within the colloidal particles. Moreover, the organic solvent and water are miscible; therefore, the organic solvent acts as a link between the colloidal particles and water. Under these multiple interactions, the hydrophobic molecule establishes hydrogen bonds with the bulk water, stabilizing within the hydrogen bond network of the aqueous phase. After removing the organic solvent from dispersion A, dispersion B is obtained. The system contains only water molecules and hydrophobic molecules. The mobility of molecule M is further restricted in an aqueous environment. Since the π-conjugated group of molecule M is a hydrogen bond interaction site, the internal water interacts with the interaction site, and the bulk water interacts with the internal water, so that the colloidal particles are stably assembled in the aqueous phase.

[0024] Beneficial effects:

[0025] (1) A method for preparing a hydrophobic molecular aqueous dispersion of the present invention realizes the water molecules participating in the aqueous assembly of hydrophobic molecules through assembly under restricted molecular motion;

[0026] (2) A method for preparing a hydrophobic molecular aqueous dispersion according to the present invention achieves stable aqueous phase assembly of hydrophobic molecules under the action of weak hydrogen bonds and internal water.

[0027] (3) The present invention provides a method for preparing a hydrophobic molecular aqueous dispersion, which enables the preparation of a stable aqueous colloid in a variety of water-miscible organic solvents. Attached Figure Description

[0028] Figure 1 A schematic diagram of the dispersion (colloidal dispersion A) before dialysis after rapid addition of water;

[0029] Figure 2 for Figure 1 A schematic diagram of the dispersion (colloidal dispersion B) obtained after colloid dialysis. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0031] The substances used in this invention are as follows:

[0032] (1) Polystyrene: weight average molecular weight is 35,000, sourced from ALDRICH, brand name is 331651-500G;

[0033] (2) Pyrene: It comes from TCI Company, and its brand name is P1104;

[0034] (3) Naphthalene: sourced from Sinopharm Reagent Company, brand number 80087117;

[0035] (4) Styrene-butadiene-styrene block copolymer: sourced from Kraton, brand name D1102K(SBS) linear, with a Brookfield viscosity of 1100 cps and a styrene / rubber ratio of 28 / 72.

[0036] (5) Anthracene: sourced from Wokai Company, brand number XW01201272;

[0037] (6) C8-NDI-C8: Prepared in-house. 0.5 g of 1.87 mmol of 1,4,5,8-naphthyltetracarboxylic anhydride was placed in a three-necked flask, and 20 mL of N,N-dimethylformamide was added. The mixture was heated to 80 °C in an oil bath. After the 1,4,5,8-naphthyltetracarboxylic anhydride was completely dissolved, 540 μL of n-octylamine (4.1 mmol) was added. The reaction was carried out at 110 °C for 24 hours under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, and needle-like solids appeared. The crude product was obtained by filtration. The crude product was dissolved in dichloromethane and extracted with water to remove N,N-dimethylformamide. The product was purified by column chromatography (using dichloromethane as the eluent) to obtain transparent needle-like crystals, which were identified as C8-NDI-C8.

[0038] In the embodiments of the present invention, the particle size and polydispersity index were measured by dynamic laser light scattering (DLS) at a temperature of 25°C for a duration of 4 min; the zeta potential was measured at a temperature of 25°C.

[0039] Example 1

[0040] A method for preparing a polystyrene aqueous dispersion, comprising the following specific steps:

[0041] (1) First, dissolve polystyrene in tetrahydrofuran at a mass-to-volume ratio of 8 mg: 2 mL to form a polystyrene / tetrahydrofuran solution;

[0042] (2) Then, ultrapure water is injected into the polystyrene / tetrahydrofuran solution within 3 seconds. The volume ratio of polystyrene / tetrahydrofuran solution to ultrapure water is 1:10. The mixture is then mixed to obtain colloidal dispersion A.

[0043] (3) Finally, place colloidal dispersion A into a closed sample bottle with two needles of different lengths inserted. Nitrogen gas enters and exits through the two needles. The longer needle is placed below the liquid surface to enter the gas, and the shorter needle is placed on the surface to exit the gas. Nitrogen gas is blown into colloidal dispersion A at a rate of 2 bubbles per second for 95 minutes to remove tetrahydrofuran from colloidal dispersion A and obtain colloidal dispersion B with a concentration of 0.8 mg / mL, which is polystyrene aqueous dispersion.

[0044] The obtained polystyrene aqueous dispersion has a particle size of 200 nm, a polydispersity index of 0.15, and a zeta potential of -25 mV.

[0045] Example 2

[0046] A method for preparing a pyrene aqueous dispersion, the specific steps of which are as follows:

[0047] (1) First, dissolve pyrene in acetic acid at a mass-to-volume ratio of 5 mg: 5 mL to form a pyrene / acetic acid solution;

[0048] (2) Then, ultrapure water is injected into the pyrene / acetic acid solution within 3 seconds. The volume ratio of the pyrene / acetic acid solution to the ultrapure water is 1:20. The mixture is then mixed to obtain colloidal dispersion A, as shown below. Figure 1 As shown;

[0049] (3) Finally, the colloidal dispersion A was transferred to a dialysis bag with a molecular weight cutoff >500, and the colloid was dialyzed with pure water. The pure water was replaced at 1.5h, 4h, and 8h after the start of dialysis, with the volume ratio of pure water to colloidal dispersion A being 5800:11 each time. Dialysis was completed after 24h to remove acetic acid from colloidal dispersion A, yielding colloidal dispersion B with a concentration of 0.25mg / mL, i.e., the pyrene aqueous phase dispersion. Figure 2 As shown;

[0050] The obtained pyrene aqueous dispersion has a particle size of 150 nm, a polydispersity index of 0.2, and a zeta potential of -35 mV.

[0051] Figure 1 The ellipsoid is an assembly of hydrophobic molecules formed in the colloidal particles. The solid dots are the sites where hydrophobic molecules interact with water molecules, the black thin lines are the hydrogen bond network, the cube is the internal water in the colloidal particles, and the dashed lines are the dynamic hydrogen bonds between the internal water and the bulk water. The gray solid particles are organic solvent molecules. Organic solvents are more abundant in the colloidal particles and also serve as the connection points for the interaction between the colloidal particles and water molecules.

[0052] Figure 2 It appeared Figure 1 The ellipsoid in the middle, but it did not appear. Figure 1 The gray solid particles are due to the fact that after the organic solvent is removed, the hydrophobic molecules cannot move freely, and the macroscopic morphology of the colloidal particles remains unchanged. However, since there are still hydrogen bonding sites in the molecules, they can interact with water molecules through hydrogen bonds. In addition, hydrogen bonds exist between the internal water and the bulk water, which work together to achieve stable aqueous phase assembly of hydrophobic molecules.

[0053] Example 3

[0054] A method for preparing an aqueous naphthalene dispersion, comprising the following specific steps:

[0055] (1) First, dissolve naphthalene in methanol at a mass-to-volume ratio of 2 mg: 8 mL to form a naphthalene / methanol solution;

[0056] (2) Then, ultrapure water is injected into the naphthalene / methanol solution within 3 seconds. The volume ratio of naphthalene / methanol solution to ultrapure water is 1:15. The mixture is then mixed to obtain colloidal dispersion A.

[0057] (3) Finally, the colloidal dispersion A was placed in a closed sample bottle with two needles of different lengths inserted. Nitrogen gas was introduced into the colloidal dispersion A. The longer needle was placed below the liquid surface to introduce gas, and the shorter needle was placed on the surface to expel gas. Nitrogen gas was blown into the colloidal dispersion A at a rate of 3 bubbles per second for 100 minutes to remove methanol from the colloidal dispersion A and obtain a colloidal dispersion B with a concentration of 0.13 mg / mL, which is the naphthalene aqueous phase dispersion.

[0058] The obtained naphthalene aqueous dispersion has a particle size of 75 nm, a polydispersity index of 0.12, and a zeta potential of -55 mV.

[0059] Example 4

[0060] A method for preparing a POSS-NH2 aqueous dispersion, the specific steps of which are as follows:

[0061] (1) First, dissolve SBS in tetrahydrofuran at a mass-to-volume ratio of 6mg:4mL to form an SBS / tetrahydrofuran solution.

[0062] (2) Then, the ultrapure water is poured into the SBS / tetrahydrofuran solution within 3 seconds. The volume ratio of SBS / tetrahydrofuran solution to ultrapure water is 1:12. The mixture is then mixed to obtain colloidal dispersion A.

[0063] (3) Finally, the colloidal dispersion A was transferred to a dialysis bag with a molecular weight cutoff of >500 and dialyzed with pure water. The pure water was replaced at 1.5h, 4h and 8h after the start of dialysis. The volume ratio of pure water to colloidal dispersion A was 5800:11 each time. Dialysis was completed after 24h to remove tetrahydrofuran from colloidal dispersion A and obtain colloidal dispersion B with a concentration of 0.5mg / mL, i.e. SBS aqueous dispersion.

[0064] The POSS-NH2 aqueous dispersion had a particle size of 320 nm, a polydispersity index of 0.13, and a zeta potential of -30 mV.

[0065] Example 5

[0066] A method for preparing an anthracene aqueous dispersion, comprising the following specific steps:

[0067] (1) First, anthracene was dissolved in dimethylformamide at a mass-to-volume ratio of 4 mg: 6 mL to form an anthracene / dimethylformamide solution;

[0068] (2) Then, the ultrapure water is poured into the anthracene / dimethylformamide solution within 3 seconds. The volume ratio of the anthracene / dimethylformamide solution to the ultrapure water is 1:18. The mixture is then mixed to obtain colloidal dispersion A.

[0069] (3) Finally, the colloidal dispersion A was transferred to a dialysis bag with a molecular weight cutoff of >500 and dialyzed with pure water. The pure water was replaced at 1.5h, 4h and 8h after the start of dialysis. The volume ratio of pure water to colloidal dispersion A was 4500:11 each time. Dialysis was completed after 24h to remove dimethylformamide from colloidal dispersion A and obtain colloidal dispersion B with a concentration of 0.22mg / mL, i.e. anthracene aqueous phase dispersion.

[0070] The particle size of the anthracene aqueous dispersion was 120 nm, the polydispersity index was 0.3, and the zeta potential was -32 mV.

[0071] Example 6

[0072] A method for preparing a C8-NDI-C8 aqueous dispersion, the specific steps of which are as follows:

[0073] (1) First, C8-NDI-C8 is dissolved in acetone at a mass-to-volume ratio of 1 mg: 10 mL to form a C8-NDI-C8 / acetone solution;

[0074] (2) Then, the ultrapure water is poured into the C8-NDI-C8 / acetone solution within 3 seconds. The volume ratio of the C8-NDI-C8 / acetone solution to the ultrapure water is 1:16. The colloidal dispersion A is obtained by mixing.

[0075] (3) Finally, the colloidal dispersion A was placed in a vacuum evaporation device with a vacuum degree of -0.1MPa and a temperature of 70℃. The evaporation was completed in 45 minutes to remove acetone from the colloidal dispersion A and obtain colloidal dispersion B with a concentration of 0.0625mg / mL, namely C8-NDI-C8 aqueous dispersion.

[0076] The particle size of the prepared C8-NDI-C8 aqueous dispersion was 80 nm, the polydispersity index was 0.35, and the zeta potential was -55 mV.

Claims

1. A method for preparing a hydrophobic molecular aqueous dispersion, characterized in that: First, hydrophobic molecules are dissolved in an organic solvent to form a hydrophobic molecule / organic solvent solution. Then, ultrapure water is quickly added to the hydrophobic molecule / organic solvent solution and mixed to obtain colloidal dispersion A. Finally, the organic solvent in colloidal dispersion A is removed to obtain colloidal dispersion B, which is the aqueous phase dispersion of the hydrophobic molecules. Rapidly adding ultrapure water to a hydrophobic molecule / organic solvent solution refers to injecting or pouring ultrapure water into the hydrophobic molecule / organic solvent solution within 3 seconds. The hydrophobic molecule dissolves in the organic solvent; The hydrophobic molecule is a hydrophobic molecule containing π-conjugated groups, and the hydrophobic molecule is able to encapsulate water in the formed assembly during the assembly process; The organic solvent is a water-miscible organic solvent; The mass-to-volume ratio of hydrophobic molecules to organic solvents is 1–30 mg: 1–10 mL; The volume ratio of hydrophobic molecules / organic solvent solution to ultrapure water is 1:10 to 20.

2. The method for preparing a hydrophobic molecular aqueous dispersion according to claim 1, characterized in that, The organic solvent is tetrahydrofuran, acetic acid, methanol, dioxane, dimethylformamide, acetone, acetonitrile, dimethyl sulfoxide, ethanol, or n-propanol.

3. The method for preparing a hydrophobic molecular aqueous dispersion according to claim 1, characterized in that, The concentration of the hydrophobic molecular aqueous dispersion is 0.005–3 mg / mL.

4. The method for preparing a hydrophobic molecular aqueous dispersion according to claim 1, characterized in that, The organic solvent in colloidal dispersion A is removed by dialysis, bubbling, or vacuum evaporation. The organic solvent in colloidal dispersion A was removed by dialysis as follows: Colloidal dispersion A was transferred to a dialysis bag with a molecular weight cutoff >500, and the colloid was dialyzed with pure water. The pure water was replaced at 1.5h, 4h and 8h after the start of dialysis. The volume ratio of pure water to colloidal dispersion A was 2000-6000:11 each time. Dialysis was completed after 24h. The method of removing organic solvents from colloidal dispersion A by bubbling is as follows: Colloidal dispersion A is placed in a closed sample bottle with two needles of different lengths inserted. Nitrogen gas is introduced into and out of the two needles. The longer needle is placed below the liquid surface to introduce gas, and the shorter needle is placed on the surface to expel gas. Nitrogen gas is blown into colloidal dispersion A at a rate of 2 to 3 bubbles per second for 90 to 120 minutes. The method of removing organic solvents from colloidal dispersion A by vacuum evaporation is as follows: Colloidal dispersion A is placed in a vacuum evaporation device with a vacuum degree of -0.093 to -0.1 MPa and a temperature of 70 to 80°C, and evaporation is completed in 30 to 60 minutes.

5. The method for preparing a hydrophobic molecular aqueous dispersion according to claim 1, characterized in that, The particle size in the hydrophobic molecular aqueous dispersion is 40–500 nm, the polydispersity index is 0.1–0.7, and the zeta potential is -20–-60 mV.

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