CN113546043A

CN113546043A - Method for preparing super-amphiphilic host-guest alginic acid base anisotropic structure soft substance

Info

Publication number: CN113546043A
Application number: CN202110849850.9A
Authority: CN
Inventors: 李嘉诚; 冯玉红; 杨淑娟; 余高波
Original assignee: Hainan University
Current assignee: Hainan University
Priority date: 2021-07-27
Filing date: 2021-07-27
Publication date: 2021-10-26

Abstract

The invention provides a Pickering emulsion which comprises an oil phase and an oil phase, wherein the volume ratio of the oil phase is 4.2-90%, Alg-beta-CD is dispersed in the water phase, and AzoC12 is dispersed in the oil phase. The invention also provides a super-amphiphilic host-guest alginic acid base anisotropic structure soft substance prepared by adopting the Pickering emulsion. The invention designs and prepares a novel amphiphilic Alg-beta-CD/AzoC 12 self-assembly with adjustable and controllable amphipathy, has better interface adsorption performance, and can prepare W/O/W emulsion with good stability by a phase inversion method. The amphipathy of the super-amphipathy aggregate can be properly regulated based on the host-guest action, an ideal and convenient strategy can be provided for carrying out phase separation behavior regulation and control on the host-guest multiphase emulsion so as to realize the structural diversity of soft materials, and the super-amphipathy aggregate has potential application value in colloid materials.

Description

Method for preparing super-amphiphilic host-guest alginic acid base anisotropic structure soft substance

Technical Field

The invention relates to a method for preparing a soft substance with a super-amphiphilic host-guest alginic acid base anisotropic structure.

Background

The multiphase Pickering emulsion has great application potential in the aspects of medicine encapsulation, industrial production, material science and the like. In recent years, multiphase Pickering emulsions have been explored as ideal interfacial self-assembly templates to achieve diverse morphologies of anisotropic structures. Due to the irreversible adsorption of the interfacial stabilizer, the colloidal nanoparticle stabilized multiphase Pickering emulsions exhibit better stability, in sharp contrast to traditional surfactant stabilized multiphase emulsions with different hydrophobic and hydrophilic balance values (HLB). Furthermore, conventional multiphase emulsions not only require two emulsification steps, but also require a large energy input to reduce the interfacial potential. In the forming mechanism of the multiphase Pickering emulsion, the amphipathy of the colloidal emulsifier is a key factor which obviously influences the formation and the stability of the multiphase Pickering emulsion. A great deal of research reports that the rigid nanoparticles can be subjected to amphiphilic modification by adsorbing different numbers of polymers or amphiphilic molecules with proper charges, and further endow the rigid nanoparticles with proper wettability so as to stabilize the curvature of an oil-water interface. Meanwhile, the solvent induces the polymer chain to recombine on the surface of the nano particle to change the interface conformation of the nano particle, so that the multiphase Pickering emulsion is stabilized, the change of the surface wettability finally causes the change of amphipathy, and different types of phase behaviors can be caused by regulating and controlling the amphipathy of the interface stabilizer. In addition, diblock copolymers with proper symmetry are rendered suitably amphiphilic, giving complementary interfacial curvatures with very high interfacial coverage density, thus stabilizing the internal and external O/W and W/O interfaces. Therefore, the control of the amphipathy has important significance for the formation of the multiphase Pickering emulsion stabilized by the polymer colloid nano particles.

The self-assembly behavior of the polymer can be regulated and controlled by a supermolecule non-covalent interaction method, wherein the super-amphiphilic host-guest polymer is widely applied to complex polymer self-assembly due to relatively good hydrophilic-hydrophobic controllability. The self-assembly of the host-guest interface can realize the reversible conversion from the 'ramming' structure to the 'solid-like' ramming state with relatively enhanced interface mechanical property. In addition, the self-assembly behavior of a host-guest dynamic interface can be adjusted through external stimulation (light, magnetism and the like), so that the reversible emulsification and emulsion breaking of the Pickering emulsion can be controlled. However, the controllable interfacial behavior of the super amphiphilic host-guest polymers has not been further studied. Therefore, it is expected that the supramolecular host-guest interaction induced interfacial self-assembly method can provide a conceptually and technically innovative emulsification strategy for the multiphase Pickering emulsion, and further generate a soft substance with a controllable structure through phase separation action.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provides a novel amphiphilic Alg-beta-CD/AzoC 12 self-assembly with adjustable and controllable amphipathy, and can be used as a high-efficiency soft colloid emulsifier to prepare W/O/W emulsion with good stability by a phase inversion method.

The invention provides a Pickering emulsion, which comprises an oil phase and an oil phase, wherein the volume ratio of the oil phase is 4.2-90%, Alg-beta-CD is dispersed in the water phase, AzoC12 is dispersed in the oil phase, and the structural formula of the AzoC12 is as follows:

preferably, the volume fraction of the oil phase is 42% to 70%, or the volume fraction of the oil phase is < 42%, or the volume fraction of the oil phase is > 70%.

When the volume ratio of the oil phase is 42-70%, stable W/O/W type Pickering emulsion can be formed in the range; when the oil phase volume ratio is less than this range, an O/W type Pickering emulsion is formed, and when it is more than this range, a W/O type Pickering emulsion is formed.

Wherein the concentration of Alg- β -CD dispersed in the aqueous phase is 0.01-2mg/mL, such as 0.01mg/mL, 0.03mg/mL, 0.05mg/mL, 0.06mg/mL, 0.08mg/mL, 0.09mg/mL, 0.1mg/mL, 0.2mg/mL, 0.3mg/mL, 0.4 mg/mL, 0.5mg/mL, 0.6mg/mL, 0.7mg/mL, 0.8mg/mL, 0.9mg/mL, 1mg/mL, 1.2mg/mL, 1.4mg/mL, 1.5mg/mL, 1.7mg/mL, 1.8mg/mL, 2mg/mL, and the like. Preferably, the concentration of Alg- β -CD dispersed in the aqueous phase is 0.05-1mg/mL, more preferably ≧ 0.1 mg/mL.

Wherein, the content of the AzoC12 in the Pickering emulsion is 1-3mg/mL, such as 1mg/mL, 1.1mg/mL, 1.2mg/mL, 1.3mg/mL, 1.4mg/mL, 1.5mg/mL, 1.6mg/mL, 1.67mg/mL, 1.7mg/mL, 1.8mg/mL, 1.9mg/mL, 2mg/mL, 2.2mg/mL, 2.4mg/mL, 2.5mg/mL, 2.7mg/mL, 2.9mg/mL, 3mg/mL, etc. Preferably, the content of AzoC12 in the Pickering emulsion is 1.5-2.5mg/mL, preferably 1.67-2.5 mg/mL.

Wherein the oil phase comprises a solvent which is immiscible with water or slightly soluble in water, and the solvent is preferably any one or a mixture of at least two of silicone oil, fatty esters, aromatic hydrocarbon, alkane and alcohol with the chain length of 6-16 and petroleum hydrocarbon with the chain length of 22-50, and is further preferably any one or a mixture of at least two of fatty esters, alkane with the chain length of 6-16 and alcohol.

The oil phase can be a common oil phase used for Pickering emulsion, the invention is not particularly limited, and the oil phase can be reasonably selected by a person skilled in the art according to the needs of practical application. Preferably, the oil phase may consist of only water-immiscible or sparingly water-soluble solvents, and preferably, the oil phase may contain other soluble substances selected from any one or a mixture of at least two of fat-soluble drugs, fat-soluble markers, fat-soluble enzymes, or fat-soluble proteins.

The aqueous phase may be a common aqueous phase used in Pickering emulsions, and the present invention is not particularly limited thereto, and may be appropriately selected by those skilled in the art according to the needs of practical applications. Preferably, the aqueous phase comprises any one of water, phosphate buffer, acetate buffer, citrate buffer or Tris buffer, or a mixture of at least two thereof.

Preferably, the water phase also comprises other water-soluble substances, and the water-soluble substances are any one or a mixture of at least two of salts, antibodies, protein polypeptide drugs and enzymes, cytokines or saccharides. The salt substances are sodium chloride, sodium acetate, potassium chloride, calcium chloride and the like.

In a second aspect of the present invention, a preparation method of the Pickering emulsion according to the first aspect of the present invention is provided, wherein the Pickering emulsion stabilized by the super-amphiphilic polymer of Alg-beta-CD/AzoC 12 can be formed by mixing the water phase containing Alg-beta-CD and the oil phase containing AzoC12, shaking and self-assembling based on the beta-CD/AzoC host-guest interface.

The third aspect of the invention provides a super-amphiphilic host-guest alginic acid base anisotropic structure soft substance, which is prepared by adopting the Pickering emulsion of the first aspect of the invention.

The fourth aspect of the present invention provides a method for preparing a super amphiphilic host-guest alginic acid base anisotropic structure soft material according to the third aspect of the present invention, comprising the following steps:

(1) pouring the Pickering emulsion of any of claims 1-4 into a spinning solution containing polyvinyl alcohol, stirring to evaporate the solvent and solidify the interfacial super-amphiphilic Alg- β -CD/AzoC12 self-assembly;

(2) centrifuging to remove supernatant, washing precipitate with alkaline water (pH of 10-12), and centrifuging to remove excessive polyvinyl alcohol;

(3) suspending the particles in alkaline water and freeze-drying to obtain the soft material with the super-amphiphilic host-guest alginic acid base anisotropic structure.

Preferably, the concentration of polyvinyl alcohol is 1-5 wt%, such as 1 wt%, 1.4 wt%, 1.7 wt%, 2 wt%, 2.3 wt%, 2.8 wt%, 3 wt%, 3.5 wt%, 3.7 wt%, 4 wt%, 4.2 wt%, or a combination thereof. 4.6 wt% and (b). 4.8 wt%, 5 wt%, etc., preferably 3 wt%.

The proportion of the Pickering emulsion to the spinning solution is not particularly limited in the present invention, and may be added by those skilled in the art as appropriate according to experience. Preferably, the volume ratio of Pickering emulsion to spinning solution is 1:0.5-2, more preferably 1: 1.

In a fifth aspect of the present invention, there is provided a Pickering emulsion according to the first aspect of the present invention, or a super amphiphilic host-guest alginic acid based anisotropic structure soft material according to the third aspect of the present invention, for use in preparing soft materials.

The invention designs and prepares a novel amphiphilic Alg-beta-CD/AzoC 12 self-assembly with adjustable and controllable amphipathy, and the novel amphiphilic Alg-beta-CD/AzoC 12 self-assembly is used as a high-efficiency soft colloid emulsifier to prepare W/O/W emulsion with good stability by a phase inversion method. Compared with an amphiphilic copolymer (Alg-beta-CD), the Alg-beta-CD/AzoC 12 super-amphiphilic polymer has better interface adsorption performance, forms a viscoelastic adsorption layer with higher interface coverage, and realizes efficient interface stabilization through a steric hindrance mechanism. The novel soft colloid particle not only expands the range of the traditional soft colloid stabilizer, but also is expected to establish close relation between colloid interface science and host-guest chemistry of a supramolecular polymer interface. In addition, the amphipathy of the super-amphipathy aggregate can be properly regulated and controlled based on the host-guest action, an ideal and convenient strategy can be provided for regulating and controlling the phase separation behavior of the host-guest multiphase emulsion so as to realize the structural diversity of soft materials, the colloidal material has potential application value, an innovative strategy is provided for the preparation of multifunctional soft materials, and a potential application prospect is opened up for drug encapsulation.

Drawings

FIG. 1 is a diagram showing the synthetic pathway of Alg-. beta. -CD.

Fig. 2 is a synthetic route diagram of AzoC 12.

Fig. 3 is a graph showing the phase inversion behavior of the emulsion as the volume ratio of the oil phase increases, wherein a: beta-CD/AzoC 12; b: Alg-beta-CD; c: alg-. beta. -CD/AzoC 12; d: the fluorescent image of the emulsion was stabilized by Alg-beta-CD/AzoC 12; (e) and (f): two-dimensional phase diagram of Alg-. beta. -CD/AzoC 12.

FIG. 4 is a diagram showing self-assembly behavior of host-guest interface of Alg-. beta. -CD/AzoC12 (a) and ITC curve (left) and thermodynamic parameters (right) (b).

Fig. 5 is a graph for visualizing the morphology of a styrene-water interface self-assembly by an oil phase solidification method, wherein a1-a 3: beta-CD/AzoC 12; b1-b 3: Alg-beta-CD; c1-c 3: alg-. beta. -CD/AzoC 12; d1-d3 are confocal fluorescence microscope two-dimensional images of beta-CD/AzoC 12, Alg-beta-CD and Alg-beta-CD/AzoC 12 respectively; e1-e3 are corresponding 3D rendered images D1-D3, respectively.

FIG. 6 shows graphs Δ D, Δ f (a) and Δ D/Δ f (b) of Alg-. beta. -CD/AzoC12 with Alg-. beta. -CD, and also shows interfacial quality (c), interfacial thickness (D), interfacial viscosity (e) and interfacial elastic modulus (f) of Alg-. beta. -CD.

FIG. 7 shows the interfacial tension of Alg-. beta. -CD/AzoC12 super-amphiphillic polymers at different oil-water ratios.

FIG. 8 is a graph showing the effect of oil-to-water ratio and light on the phase separation of host-guest assembled W/O/W Pickering emulsion, wherein the oil-to-oil phase volume ratio in a is 50%; b, the volume ratio of the oil phase is 60 percent; c, the volume proportion of the oil phase is 70 percent; d is Pickering emulsion prepared by the oil phase with the volume proportion of 60 percent after being irradiated by ultraviolet light.

Detailed Description

The invention will be better understood from the following description of specific embodiments with reference to the accompanying drawings. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

1. Synthesis of amphiphilic host molecule Alg-beta-CD

An amphiphilic polymer molecule Alg-beta-CD is synthesized by utilizing a mild Ugi reaction, and the method comprises the following steps:

sodium alginate with the mass fraction of 2.5 wt% is mechanically stirred at room temperature for 6h, diluted with water to the mass fraction of 2.0 wt%, the pH of the solution is adjusted to 3.6 by using 0.5mol/L HCl solution, and formaldehyde (0.542mL), cyclohexyl isonitrile (0.653 mL) and mono-6-amino-cyclodextrin (2.0g) are added in one portion. After mechanical stirring for 24h, the reaction was diluted to 0.7 wt% with water, dialyzed for 3 days using a dialysis bag with a molecular weight cut-off of 3500, and freeze-dried for 3 days to give the pure final product (Alg-. beta. -CD). The reaction scheme is shown in figure 1.

2. Synthesis of hydrophobic guest molecule AzoC12

The guest molecule, AzoC12, was synthesized using a one-pot method, and the reaction scheme is shown in fig. 2.

Bromododecane (15mL), anhydrous K₂CO₃(5.2g), Potassium iodide (1.8g) was added to Dimethylformamide (DMF) (45mL) solvent, mechanically stirred for 1h, followed by 4-benzil hydroxyphenol DMF solution (0.34g/mL,15mL) and heated to 80 ℃ under N₂Heating and refluxing for 12h under protection. The reaction was then filtered off the inorganic salts in vacuo, and the filtrate was concentrated in vacuo, and the concentrate was washed with a large amount of petroleum ether, pure water, and dried in vacuo to give a golden yellow solid (AzoC12) (reaction yield: 84.32%). The reaction scheme is shown in figure 2.

3. Preparation of Alg-beta-CD/AzoC 12 super amphiphilic Polymer stabilized W/O/W emulsion

6ml of Pickering emulsion stabilized by Alg-beta-CD/AzoC 12 super amphiphilic polymer is prepared: mixing an aqueous solution (with the concentration of 0.1mg/mL) of an amphiphilic polymer (Alg-beta-CD) and a toluene oil phase containing AzoC12 (with the amount of 10mg), wherein the volume ratio of the toluene oil phase is 4.2%, 8.4%, 12.5%, 17.2%, 22%, 28%, 33.3%, 38%, 42%, 50%, 54%, 60%, 70%, 80%, 85%, 90%, and 30s by hand shaking, and the Pickering emulsion (represented by 'Alg-beta-CD/AzoC 12') stabilized by the Alg-beta-CD/AzoC 12 super-amphiphilic polymer can be formed based on self-assembly of a beta-CD/AzoC host-guest interface.

Preparing 6ml of Pickering emulsion stabilized by Alg-beta-CD amphiphilic polymer: the amphiphilic polymer Alg-beta-CD stable Pickering emulsion (expressed by 'Alg-beta-CD') can be formed by mixing an aqueous solution (with the concentration of 0.1mg/mL) of the amphiphilic polymer Alg-beta-CD with a toluene oil phase, wherein the volume ratio of the toluene oil phase is 4.2%, 8.4%, 12.5%, 17.2%, 22%, 28%, 33.3%, 38%, 42%, 50%, 54%, 60%, 70%, 80%, 85%, 90% and shaking by hand for 30s based on the self-assembly of a beta-CD/Azo host-guest interface.

6ml of beta-CD/AzoC 12 super-amphiphilic polymer stabilized Pickering emulsion is prepared: the aqueous solution of the polymer beta-CD (with the concentration of 0.1mg/mL) and the toluene oil phase containing the AzoC12 (with the dosage of 10mg) are mixed, the volume ratio of the toluene oil phase is 4.2%, 8.4%, 12.5%, 17.2%, 22%, 28%, 33.3%, 38%, 42%, 50%, 54%, 60%, 70%, 80%, 85%, 90%, and 30s by hand shaking, and the beta-CD/AzoC 12 super-amphiphilic polymer stable Pickering emulsion (expressed by 'beta-CD/AzoC 12') can be formed based on the self-assembly of the beta-CD/AzoC host-guest interface.

As shown in FIG. 3, the phase inversion behavior of Alg-beta-CD/AzoC 12 self-assembled emulsion occurred with the increase of oil phase ratio, and stable O/W Pickering emulsion, W/O/W Pickering emulsion and W/O Pickering emulsion were obtained when the volume fraction of oil phase was gradually increased from 4.2% to 90% (FIG. 3c, d). However, when Alg- β -CD or β -CD/AzoC12 was used alone to stabilize the emulsion from the assembly, no phase inversion occurred (FIGS. 3a, b). More importantly, through macroscopic observations of the phase inversion process at different concentrations of Alg- β -CD and AzoC12, two binary phase diagrams were established (fig. 3e, f), indicating that low Alg- β -CD and AzoC12 concentrations also enable formation of a large number of multiphase Pickering emulsions, and that Alg- β -CD/AzoC12 self-assembled emulsions exhibit better physical stability than Pickering emulsions stabilized with amphiphilic polymers alone (Alg- β -CD) when the polymer host molecule Alg- β -CD concentration is as low as 0.1mg/mL, which is much lower than the amount required for surfactants or amphiphilic copolymers traditionally used to prepare Pickering emulsions. The present invention requires only low energy emulsification with very low polymer concentrations, in contrast to conventional phase inversion methods which typically utilize high concentrations of surfactants and co-surfactants.

4. Characterization of host-guest interface self-assembly behavior of Alg-beta-CD/AzoC 12

(1) Analysis of interfacial association force of host-guest molecule of Alg-beta-CD/AzoC 12

Host-guest interfacial self-assembly behavior of Alg- β -CD/AzoC12 superamphiphilic polymers was measured using an isothermal titration calorimeter (TA instrument, USA) at 25 ℃,50 μ L of a styrene oil phase containing AzoC12 (AzoC12 concentration 4.39mg/mL in styrene oil phase) (25 needles, 2 μ L/needle) was injected into a reactor containing 200 μ L of an aqueous solution of Alg- β -CD (0.1mg/mL) to induce host-guest oil-water interfacial self-assembly, and titration curves were analyzed using Launch NanoAnalyze software to obtain host-guest interfacial self-assembly parameters.

The results are shown in FIG. 4, which is an Isothermal Titration Calorimeter (ITC) measuring the host-guest interface association constant between Alg-beta-CD/AzoC 12 of 5.12X 10^-4M^-1(FIG. 4b), it is demonstrated that Alg-beta-CD/AzoC 12 super amphiphile polymers can be formed based on the beta-CD/Azo host-guest interface effect.

(2) Interface morphology analysis of Alg-beta-CD/AzoC 12 super-amphiphilic self-assembly

6ml of stable Pickering emulsion of Alg-beta-CD/AzoC 12 was prepared: an aqueous solution (concentration of 0.1mg/mL) of an amphiphilic polymer (Alg-beta-CD) and a styrene oil phase (containing 2.0 mol% of AIBN initiator) containing AzoC12 (dosage of 10mg) (concentration of 4.39mg/mL in the styrene oil phase) were mixed, and the volume ratio of the styrene oil phase was 38%, so as to obtain a Pickering emulsion stabilized by Alg-beta-CD/AzoC 12.

Preparing 6ml of stable Pickering emulsion of Alg-beta-CD: mixing an aqueous solution (with the concentration of 0.1mg/mL) of an amphiphilic polymer (Alg-beta-CD) and a styrene oil phase (containing 2.0 mol% of AIBN initiator), wherein the volume ratio of the styrene oil phase is 38%, and obtaining the Pickering emulsion with stable Alg-beta-CD.

6ml of beta-CD/AzoC 12-stabilized Pickering emulsion were prepared: an aqueous solution (concentration: 0.1mg/mL) of the polymer (. beta. -CD) and a styrene oil phase (containing 2.0 mol% of AIBN initiator) containing AzoC12 (in an amount of 10mg) (concentration: 4.39mg/mL in the styrene oil phase) were mixed at a volume ratio of the styrene oil phase of 38%, to obtain a stabilized Pickering emulsion of. beta. -CD/AzoC 12.

Polymerizing the obtained stable Pickering emulsion of Alg-beta-CD/AzoC 12, Alg-beta-CD, beta-CD/AzoC 12 at 65 ℃ for 24h, carrying out vacuum filtration and centrifugal washing on the collected products, carrying out vacuum drying on the final products at 35 ℃ for 48h, placing the solidified emulsion on a copper disc, carrying out sputtering and plating on the emulsion with thin gold, and observing the emulsion by using a scanning electron microscope (S-3000N, Hitachi, Japan) at 20kv accelerating voltage to visualize the microstructure of the host-object interface self-assembly of Alg-beta-CD/AzoC 12.

As a result, as shown in FIG. 5, the Alg-beta-CD/AzoC 12 supramolecular polymer forms a spherical microstructure (FIG. 5c1-c3) on the oil-water interface, and forms a dense protective adsorption layer to prevent collision and coalescence between droplets, thereby further improving the physical stability of the Pickering emulsion. However, a large number of vacancies exist on the surface of the solidified oil drops stabilized by using Alg-beta-CD alone (FIG. 5b1-b3), in addition, the self-assembly of the beta-CD/AzoC 12 interface also appears obvious phase separation, and the solidified oil drops are very smooth (FIG. 5a1-a3), which shows that the alginic acid polymer chain is not only beneficial to the super-amphiphilic interface adsorption of the host-guest but also beneficial to the interface structure stability of the supramolecular polymer, therefore, the supramolecular host-guest polymer provided by the invention is expected to establish a new bridge between the colloid interface science and the supramolecular host-guest interface chemistry.

(3) Interfacial film visualization analysis of Alg-beta-CD/AzoC 12 super-amphiphilic self-assembly

6ml of stable Pickering emulsion of Alg-beta-CD/AzoC 12 was prepared: an aqueous solution (containing 10. mu.L of 1X 10 concentration) of amphiphilic polymer (Alg-. beta. -CD) at a concentration of 0.1mg/mL^-3A rhodamine solution in mol/L) and a styrene oil phase (containing 2.0 mol% of AIBN initiator and 10. mu.L of 1X 10 in concentration) containing AzoC12 (in an amount of 10mg) (concentration of 4.39mg/mL in the styrene oil phase)^-3A nile red solution of mol/L) is mixed, the volume ratio of the styrene oil phase is 38 percent, and the Pickering emulsion with stable Alg-beta-CD/AzoC 12 is obtained.

The thickness of the interfacial adsorption layer was visualized with a confocal laser scanning microscope (Leica TCC-SP8, Leica Microsystems Inc.). And analyzed by ImageJ software (Scion Corp, USA) to obtain rhodamine B (1X 10)^-3mol/L) is added into the water phase of the Alg-beta-CD polymer main molecule, the oil phase containing the AzoC12 is marked with nile red (1X 10)^-3mol/L)。

At present, there are a lot of reports that the confocal laser scanning microscope can perform visual research on the interface self-assembly process, and in order to quantitatively evaluate the positioning degree of the supramolecular polymer on the oil-water interface, the fluorescence intensity distribution of the cross section is quantified, and the result shows that the supramolecular aggregate has an interface thickness (fig. 6d) of 10.12% ± 0.14% (mean ± standard deviation) relative to the droplet radius, which further proves that the interface film plays a steric hindrance role in the aggregation behavior among droplets to efficiently stabilize the emulsion.

(4) Analysis of rheological properties of interfacial film of Alg-beta-CD/AzoC 12 super-amphiphilic self-assembly

Water phase: 0.1mg/mL Alg-beta-CD aqueous solution, oil phase: 4.39mg/mL AzoC12 toluene solution, the volume ratio of the oil phase was 38%.

QCM-D model of Q-Sense E4 was used to study the host and guest adsorption kinetics and interfacial rheology for coconut oil/water interfaces (Biolin Scientific AB, Sweden). QCM-D detection temperature was 25 deg.C, flow rate was 50 μ L/min. After stable frequency delta f and dissipation delta D baselines are established, the interfacial adsorption kinetics and the interfacial viscoelasticity of the supermolecular host-guest polymer are determined by using a Voigt model.

QCM-D was used to further explore the adsorption kinetics of the host-guest interface self-assembly and the interfacial rheological properties, and the results are shown in FIG. 6. The Alg-beta-CD/AzoC 12 supramolecular polymers show the lowest negative frequency (Δ f) and the highest dissipation (Δ D) (FIG. 6a), the large deposition of Alg-beta-CD on the surface of the AzoC12 oil layer, which can be measured by approaching 600ng/cm^-2The interfacial adsorption coverage of (A) was confirmed (FIG. 6c), in contrast to a conventional amphiphilic polymer (Alg-. beta. -CD) corresponding to an adsorption layer density of 0ng/cm^-2. The results show that the super-amphiphilic self-assembly of Alg-beta-CD/AzoC 12 can form a denser protective barrier and a more viscoelastic interfacial adsorption film (fig. 6d, e and f), and provides steric hindrance for coalescence among droplets, thereby enhancing the physical stability of the Pickering emulsion. Therefore, the Alg-beta-CD/AzoC 12 super-amphiphilic self-assembly can be used as an efficient and innovative soft emulsifier, not only can expand the variety of the traditional polymer soft stabilizer in Pickering emulsion, but also is expected to develop multifunctional supermolecule soft materials.

Δ D/Δ f further revealed host-guest interfacial adsorption kinetics and interfacial viscoelasticity of Alg- β -CD/AzoC12 super amphiphilic self-assemblies. The Δ D/Δ f curves both exhibit an initial relatively fast adsorption followed by slower adsorption kinetics. The Alg-beta-CD/AzoC 12 host-guest interface self-assembly body shows a two-phase adsorption stage, a relatively viscoelastic adsorption layer is generated in the initial stage until-40 Hz, and then the slope of delta D/delta f is reduced, which means that the Alg-beta-CD/AzoC 12 super-amphiphilic polymer forms a harder interface adsorption layer.

(5) Interfacial amphipathy analysis of Alg-beta-CD/AzoC 12 super-amphiphatic self-assemblies

Water phase: 0.1mg/mL Alg-beta-CD aqueous solution, oil phase: 4.39mg/mL of AzoC12 toluene solution, and the volume ratio of the oil phase is 4.2%, 17.2%, 33.3%, 50%, 70%, 85%.

The interfacial tension was measured according to the Wilhelmy plate method using a Kruss K100 tensiometer (Hamburg, Germany). Before each measurement, the platinum plate was burned and rinsed with distilled water.

The result is shown in fig. 7, as the volume ratio of the oil phase increases, the interfacial tension shows a tendency of first decreasing and then increasing, and at the oil-water ratio of 42-70%, the interfacial tension is lowest, which indicates that the formed Alg-beta-CD/AzoC 12 super-amphiphilic polymer has the highest adsorption capacity on the oil-water interface, and provides a layer of protective barrier for collision and aggregation between oil droplets, so as to form a stable multiphase emulsion.

5. Preparation of soft material by Alg-beta-CD/AzoC 12 host-guest interface self-assembly template method

6ml of Pickering emulsion stabilized by Alg-beta-CD/AzoC 12 super amphiphilic polymer is prepared: mixing an aqueous solution (with the concentration of 1mg/mL) of an amphiphilic polymer (Alg-beta-CD) with a toluene oil phase containing AzoC12 (the dosage of 15mg), wherein the volume ratio of the toluene oil phase is 50% (the concentration of AzoC12 in the toluene oil phase is 5mg/mL), 60% (the concentration of AzoC12 in the toluene oil phase is 4.16mg/mL), 70% (the concentration of AzoC12 in the toluene oil phase is 3.57mg/mL), correspondingly changing the concentration of AzoC12 by hand shaking for 30s, and forming a Pickering emulsion stabilized by the super-amphiphilic polymer of Alg-beta-CD/AzoC 12 based on the self-assembly of a main-object interface of beta-CD/AzoC.

6ml of UV-light-treated Alg-. beta. -CD/AzoC12 superamphiphilic polymer-stabilized Pickering emulsion were prepared: mixing an aqueous solution (with the concentration of 1mg/mL) of an amphiphilic polymer (Alg-beta-CD) with a toluene oil phase containing AzoC12 (with the dosage of 15mg) and irradiated by UV light for 10min, wherein the volume ratio of the toluene oil phase is 60% (the concentration of AzoC12 in the toluene oil phase is 4.16mg/mL), shaking by hand for 30s, and self-assembling based on a beta-CD/AzoC host-guest interface to form a Pickering emulsion with the stability of the Alg-beta-CD/AzoC 12 super-amphiphilic polymer.

Poured into an equal volume of spinning solution containing 3 wt% polyvinyl alcohol, respectively, and stirred for 8 hours to evaporate the solvent and solidify the interfacial super amphiphilic Alg-beta-CD/AzoC 12 self-assembly. Followed by centrifugation (15min, 8500rap/min), removal of the supernatant, washing with alkaline water (ph11.2), centrifugation three times to remove excess PVA (15min, 8500rap/min), then suspension of the microparticles in alkaline water and freeze-drying for two days to obtain supramolecular polymer soft materials.

The scanning result of the electron microscope is shown in fig. 8, and when the oil-water ratio is 50%, the internal liquid drops are completely encapsulated in the host-guest self-assembly polymer to form a hemispherical structure. When the oil-water ratio is increased to 60%, more internal water droplets gradually go beyond and adhere to the matrix assembled by the solidified polymer host-guest. Under ultraviolet illumination, due to the accelerated agglomeration process of the inner droplets, the inner droplets fully protrude from the outer O/W interface thereof, and excessive phase separation occurs. At an oil-to-water ratio of 70%, the Alg- β -CD/AzoC12 multiphase emulsion formed a soft dumbbell-like material during phase separation. Therefore, different oil-water ratios finally cause the interface self-assembly behavior of the host-guest super-amphiphilic polymer to change, a specific amphiphilic range is further endowed, and a soft material with various structures is further formed, and meanwhile, the multiphase Pickering emulsion with stable super-amphiphilic polymer can effectively avoid a fussy polymerization process and the use of a large amount of specific surfactants.

The embodiments of the present invention have been described in detail, but the embodiments are merely examples, and the present invention is not limited to the embodiments described above. Any equivalent modifications and substitutions to those skilled in the art are also within the scope of the present invention. Accordingly, equivalent changes and modifications made without departing from the spirit and scope of the present invention should be covered by the present invention.

Claims

1. The Pickering emulsion is characterized by comprising an oil phase and an oil phase, wherein the volume ratio of the oil phase is 4.2-90%, Alg-beta-CD is dispersed in the water phase, AzoC12 is dispersed in the oil phase, the concentration of the Alg-beta-CD dispersed in the water phase is 0.01-2mg/mL, the content of AzoC12 in the Pickering emulsion is 1-3mg/mL, and the structural formula of AzoC12 is shown as follows:

2. pickering emulsion according to claim 1, characterized in that the proportion by volume of the oil phase is 42% to 70%, or the proportion by volume of the oil phase is < 42%, or the proportion by volume of the oil phase is > 70%.

3. Pickering emulsion according to claim 1, characterized in that the concentration of Alg- β -CD dispersed in the aqueous phase is 0.05-1mg/mL, preferably ≥ 0.1 mg/mL.

4. Pickering emulsion according to claim 1, characterized in that the content of AzoC12 in the Pickering emulsion is 1.5-2.5mg/mL, preferably 1.67-2.5 mg/mL.

5. A method for preparing a Pickering emulsion as claimed in claim 1, wherein the aqueous phase containing Alg- β -CD and the oil phase containing AzoC12 are mixed, shaken and self-assembled based on β -CD/AzoC host-guest interface to form a Pickering emulsion stabilized by Alg- β -CD/AzoC12 super amphiphilic polymer.

6. A super-amphiphilic host-guest alginic acid base anisotropic structure soft substance, which is characterized by being prepared from the Pickering emulsion as claimed in any one of claims 1-4.

7. A method for preparing the super amphiphilic host-guest alginic acid based soft material with anisotropic structure as claimed in claim 6, comprising the following steps:

(2) centrifuging, removing supernatant, washing precipitate with alkaline water, and centrifuging to remove excessive polyvinyl alcohol;

8. The method according to claim 7, wherein the concentration of the polyvinyl alcohol is 1 to 5 wt%, preferably 3 wt%.

9. The method according to claim 7, wherein the volume ratio of the Pickering emulsion to the spinning solution is 1:0.5 to 2, preferably 1: 1.

10. Use of a Pickering emulsion according to any one of claims 1-4, or a super amphiphilic host-guest alginic acid based anisotropic structure soft material according to claim 6 for the preparation of soft materials.