APDMS / PAAc supramolecular gel, hydrogel and xerogel as well as preparation method and application thereof as water-shrinkable sleeve

Abstract

The invention belongs to the field of hydrogel, and particularly relates to APDMS / PAAc supramolecular gel, hydrogel and xerogel, a preparation method of the supramolecular gel, the hydrogel and the xerogel and application of the supramolecular gel, the hydrogel and the xerogel as a water-shrinkable sleeve. The preparation method comprises the following steps: mixing amino silane or a mixture of amino silane and silane with water and a catalyst, heating and refluxing, and removing by-products, the catalyst and impurities to obtain APDMS; the preparation method comprises the following steps: dissolving APDMS in an acrylic acid aqueous solution, adding an initiator to form a mixed solution, removing dissolved oxygen from the mixed solution, and initiating polymerization under an anaerobic condition to obtain the APDMS / PAAc supramolecular gel. And drying the APDMS / PAAc supramolecular gel to obtain dry gel, and incubating with water to obtain the hydrogel. The hydrogel has excellent mechanical property, expansion resistance, shape memory ability, fatigue resistance, self-repairing property, recoverability and physiological inertia. The APDMS / PAAc supramolecular gel / xerogel / hydrogel can be applied to a plurality of fields, and especially can be used as a water-shrinkable sleeve in a living body or in a water environment.

Description

Technical Field

[0001] The present invention belongs to the field of hydrogels, and particularly relates to an APDMS / PAAc supramolecular gel, a hydrogel, a dry gel, a preparation method thereof, and an application as a water shrinkable sleeve. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Polymer hydrogels, composed of a three-dimensional cross-linked network formed by physical, ionic or covalent interactions cross-linking polymer chains and a large amount of water, are a typical soft and wet material. Their soft and wet properties endow them with broad application prospects. In practical applications, hydrogel materials require more properties, including strength, stiffness, toughness, fatigue resistance, recyclability, self-healing property, anti-swelling property, shape memory and biocompatibility. For example, materials simulating tendons or ligaments require high strength and high toughness, wearable electronic skin materials require good fatigue resistance, cartilage replacement materials require better stiffness and anti-swelling property, and intelligent structural materials in surgical operations require shape memory characteristics. In addition, self-healing and recyclable properties can significantly extend the service life of polymer materials, reduce raw material consumption and environmental pollution, thus contributing to the realization of a sustainable development society. Biocompatibility enables the material to be used safely and reassuringly. Traditional hydrogels are difficult to simultaneously possess the above characteristics, which limits their actual application scenarios.

[0004] Organic silicon polymers are polysiloxanes with a silicon-oxygen bond (-Si-O-) as the backbone and organic groups (methyl, phenyl, vinyl, etc.) attached to silicon atoms. Because of the unique organic-inorganic structure, they have the properties of both inorganic and organic materials, including resistance to high and low temperatures, air permeability, flame retardancy, water repellency, chemical stability, biocompatibility and physiological inertness, and also have characteristics such as processability and controllable structure. Introducing organic silicon into the hydrogel matrix can play some unique functions. For example, it can be used as a tissue matrix material to promote cell adhesion and proliferation, as a scaffold material for supporting and repairing human organs and tissues, and as a reinforcing polymer to improve strength, durability and reliability. However, due to its extremely hydrophobic property, its solid content ratio in medical hydrogel materials is very low, resulting in limited functions. Summary of the Invention

[0005] To solve the deficiencies of the prior art, the object of the present invention is to provide an APDMS / PAAc supramolecular hydrogel, its preparation method, and its application as a water shrinkable sleeve. The basic structure is composed of hydrophobic aminopolysiloxane (APDMS) and polyacrylic acid (PAAc) to obtain an APDMS / PAAc supramolecular gel / hydrogel / xerogel, in which the hydrophobic skeleton aggregates to form nano-hydrophobic domains, inducing in-situ microphase separation, and through multiple ionic interactions, it has excellent mechanical properties, anti-swelling properties, shape memory ability, anti-fatigue properties, self-healing properties, recyclability, and physiological inertness. The APDMS / PAAc supramolecular gel / xerogel / hydrogel can be applied in multiple fields, especially as a water shrinkable sleeve for use in vivo or in an aqueous environment.

[0006] To achieve the above object, the present invention is realized through the following technical solutions:

[0007] In the first aspect, the present invention provides a preparation method of an APDMS / PAAc supramolecular hydrogel, comprising the following steps:

[0008] S1. Mix an amino silane or a mixture of an amino silane and a silane with water and a catalyst, heat under reflux, and then remove by-products, the catalyst, and impurities to obtain APDMS;

[0009] S2. Dissolve APDMS in an aqueous acrylic acid solution, add an initiator to form a mixed solution, and after removing dissolved oxygen from the mixed solution, initiate polymerization under anaerobic conditions to obtain an APDMS / PAAc supramolecular gel.

[0010] Preferably, in step S1, the amino silane includes at least one of 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldiethoxysilane, and trimethoxy[3-(methylamino)propyl]silane, the silane includes at least one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane, the catalyst includes tetramethylammonium hydroxide, and the molar ratio of amino groups to silicon atoms in the mixture of the amino silane and the silane is (0.1 - 1):1 and does not include 1:1.

[0011] Preferably, in step S1, before heating under reflux, replace with an inert gas 2 - 4 times and carry out the reaction under an inert atmosphere. The temperature of heating under reflux is 80°C - 120°C, and the time of heating under reflux is 5 - 100 h.

[0012] Preferably, in step S2, the mass ratio of APDMS to acrylic acid is (0.5 - 1.5):1, and the mass concentration of acrylic acid in the aqueous acrylic acid solution is 10 - 30 wt.%.

[0013] Preferably, in step S2, the initiation includes photoinitiation or thermal initiation. For photoinitiation, the wavelength of the light source is 360 - 370 nm, the power of the light source is 90 - 110 W, and the time is 30 - 120 min. When photoinitiating, the initiator includes α-ketoglutaric acid. For thermal initiation, the temperature is 0°C - 80°C, and the initiation time is 1 - 60 min. When thermally initiating, the initiator includes at least one of ammonium persulfate, hydrogen peroxide, sodium persulfate, azobisisobutyronitrile, azobisisoheptonitrile, and benzoyl peroxide.

[0014] In a second aspect, the present invention provides an APDMS / PAAc supramolecular gel obtained by the preparation method as described in the first aspect.

[0015] In a third aspect, the present invention provides an APDMS / PAAc supramolecular hydrogel, which is obtained by dehydrating and drying the APDMS / PAAc supramolecular gel as described in the second aspect and then incubating it in water.

[0016] In a fourth aspect, the present invention provides an APDMS / PAAc supramolecular xerogel, which is obtained by dehydrating and drying the APDMS / PAAc supramolecular gel as described in the second aspect or the APDMS / PAAc supramolecular hydrogel as described in the third aspect.

[0017] In a fifth aspect, the present invention provides the application of the APDMS / PAAc supramolecular gel as described in the second aspect, the APDMS / PAAc supramolecular hydrogel as described in the third aspect, or the APDMS / PAAc supramolecular xerogel as described in the fourth aspect in the fields of structural materials, photoluminescent devices, intelligent switches, actuators, or biomedical materials.

[0018] In a sixth aspect, the present invention provides the application of the APDMS / PAAc supramolecular gel as described in the second aspect, the APDMS / PAAc supramolecular hydrogel as described in the third aspect, or the APDMS / PAAc supramolecular xerogel as described in the fourth aspect as a water shrinkable sleeve. The water shrinkable sleeve is specifically a polymer material protection sleeve that shrinks when encountering water.

[0019] The beneficial effects obtained by one or more of the above technical solutions of the present invention are as follows:

[0020] The basic structure is composed of hydrophobic amino polysiloxane and polyacrylic acid to obtain the APDMS / PAAc supramolecular gel / hydrogel / xerogel. Among them, the hydrophobic skeleton aggregates to form a nano-hydrophobic domain, inducing in-situ microphase separation, and through multiple ionic interactions, the hydrogel has excellent mechanical properties, anti-swelling properties, shape memory ability, anti-fatigue properties, self-healing properties, recyclability, and physiological inertness.

[0021] By regulating the feeding concentration of APDMS, the tensile strength of the hydrogel can reach up to 16.2 MPa, which is about two orders of magnitude higher than that of traditional hydrogels. The high strength of the hydrogel mainly stems from the ionic interactions between supramolecules and the microphase separation structure caused by hydrophobic interactions.

[0022] By regulating the proportion of amino linkages in APDMS molecules, the strength of ionic interactions and hydrophobic interactions in the hydrogel can be controlled, and the mechanical properties of the hydrogel can be precisely regulated within a large range.

[0023] The APDMS / PAAc supramolecular hydrogel has certain application potential in the fields of structural materials, photoluminescent devices, intelligent switches, actuators, and biomedical materials. In particular, it can be used as a water shrinkable sleeve in vivo or in a water environment. Description of the Drawings

[0024] The specification drawings that form part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0025] Figure 1 For APDMS 20 -AAc 20 gel, APDMS 20 -AAc 20 xerogel, APDMS 20 -AAc 20 SEM images of the hydrogel;

[0026] Figure 2 For (a) APDMS 20 -AAc 20 gel and APDMS 20 -AAc 20 stress-strain curves of the hydrogel, and APDMS 20 -AAc 20 hydrogel (b) loading-unloading cycle curves at different strains, (c) continuous 8 loading-unloading cycle curves at 500% strain, and (d) self-recovery of the loading-unloading curve;

[0027] Figure 3 For APDMS 20 -AAc 20 energy spectrum of the hydrogel;

[0028] Figure 4 For (a) stress-strain curves and (b) Young's modulus and toughness of the hydrogels in Examples 1-4;

[0029] Figure 5(a) Stress-strain curves and (b) Young's modulus and toughness of the hydrogels in Examples 1 and 5-7;

[0030] Figure 6 For APDMS in Example 8 20 -AAc 20 Shape memory behavior of the hydrogel;

[0031] Figure 7 For APDMS 20 -AAc 20 (a) Stress-strain curves of the APDMS 20 -AAc 20 hydrogel at different healing times, (b) G′ and G″ values of the APDMS 20 -AAc 20 hydrogel under strain amplitude sweep tests at a strain range of 0.1% - 100% at 1 Hz frequency, (c) G′ and G″ values of the APDMS

[0032] Figure 8 For APDMS 20 -AAc 20 Grinding and recycling process of the APDMS

[0033] Figure 9 (a) Stress-strain curve of the pre-stretched APDMS 20 -AAc 20 xerogel, (b) Stress relaxation curve of the APDMS 20 -AAc 20 xerogel, (c) Load-bearing test of the APDMS 20 -AAc 20 xerogel after healing;

[0034] Figure 10 For APDMS 20 -AAc 20 Dissociation behavior of the APDMS

[0035] Figure 11 -AAc hydrogel in 0.1 M NaOH (a) and 0.1 M HCl (b) aqueous solutions; 20 -AAc 20 Process diagrams of the APDMS

[0036] Figure 12 For APDMS 20 -AAc 20Shape memory behaviors of the hydrogel bent into σ-shaped (a), helical-shaped (b), coiled-shaped (c), and long straight bar-shaped (d);

[0037] Figure 13 The deformation process of the pre-stretched dry gel in the shape of a circle sleeved on the weight;

[0038] Figure 14 For APDMS 20 -AAc 20 Shape memory behaviors of the hydrogel at different temperatures and shapes;

[0039] Figure 15 For APDMS where the left half is not pre-stretched and the right half is pre-stretched 20 -AAc 20 The deformation processes of the hydrogel after (a) drying for 24 h, (b) drying for 1 h, and (c) soaking in 100% EtOH and then placing in water;

[0040] Figure 16 For in the medium containing APDMS 20 -AAc 20 (a) Viability and proliferation and (b) live / dead experimental results of rat nucleus pulposus cells in the culture medium containing the hydrogel;

[0041] Figure 17 For APDMS 20 -AAc 20 (a) Absorption, excitation, and emission spectra, and (b) emission spectra at different excitation wavelengths of the hydrogel;

[0042] Figure 18 For thermally initiated APDMS 20 -AAc 20 The stress-strain curve of the hydrogel. Detailed implementation manners

[0043] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in combination with specific examples and comparative examples.

[0044] Example 1

[0045] Octamethylcyclotetrasiloxane (D4, 74.0 g, 0.25 mol), N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane (AEAPMDS, 88.7 g, 0.43 mol), deionized water (15.5 g, 0.86 mol) and tetramethylammonium hydroxide (0.05 g, Me4OH) were successively added to a 500 ml three-necked flask and mixed. After three replacements with N2, the hydrolysis, ring-opening and polymerization processes were carried out by refluxing at 100 °C for 8 h under a N2 atmosphere. Next, the temperature was lowered to 50 °C and the mixture was evacuated to remove the by-products methanol and water, which helped to further promote the condensation of siloxane molecules. After the by-products were completely removed, the temperature was raised to 150 °C again and maintained for 30 min to remove Me4OH, and then vacuum-treated at 170 °C for 2 h to remove small molecule low-boiling substances. Finally, the product was cooled to 25 °C under reduced pressure to obtain a colorless viscous liquid APDMS, denoted as APDMS-30% according to the designed proportion of amino linkages.

[0046] 20 g of AAc and 60 g of anaerobic distilled water were added to a 150 ml single-necked flask and kept at 5 °C for 10 min. Then, 20 g of APDMS-30% was slowly added dropwise to the AAc aqueous solution under stirring. After APDMS-30% was completely dissolved, 0.02 g of α-ketoglutaric acid was added. After all the raw materials were completely dissolved, N2 was bubbled under the liquid surface for 20 minutes to remove the dissolved oxygen in the mixed solution. Then, the mixed solution was poured into a glass mold and covered with a layer of transparent PET film to isolate oxygen. Finally, it was irradiated under a 365 nm (100 W) ultraviolet lamp for 60 minutes to form a white APDMS / PAAc supramolecular gel.

[0047] The APDMS / PAAc supramolecular gel was clamped with two transparent glass slides under a pressure of 10 kPa to dehydrate, and then dried at room temperature for 3 days to obtain the APDMS / PAAc supramolecular xerogel. The APDMS / PAAc supramolecular xerogel was incubated in distilled water at 37 °C for 24 hours to achieve the equilibrium adsorption of water, and the APDMS / PAAc supramolecular hydrogel was obtained. The APDMS / PAAc supramolecular hydrogel can be converted into the APDMS / PAAc supramolecular xerogel after complete drying.

[0048] For convenience of description, the APDMS / PAAc supramolecular gel obtained in this example is denoted as APDMS 20 -AAc 20 gel or APDMS30 20 -AAc 20 gel, and the APDMS / PAAc supramolecular xerogel is denoted as APDMS 20 -AAc 20 xerogel or APDMS30 20 -AAc20 The xerogel, the APDMS / PAAc supramolecular hydrogel is denoted as APDMS 20 -AAc 20 hydrogel or APDMS30 20 -AAc 20 hydrogel.

[0049] APDMS 20 -AAc 20 The water content of the APDMS-AAc hydrogel is 28.24%, much lower than that of the APDMS 20 -AAc 20 gel (determined to be 60% by the feed concentration). High solid content usually has higher mechanical properties. As Figure 1 shown, APDMS 20 -AAc 20 gel is an aggregate-connected penetrative colloidal network with continuous micron-scale channels filled with water among its gaps, which means it has large defects. While the APDMS 20 -AAc 20 hydrogel has a rather uniform and dense structure with almost no voids.

[0050] During the drying process of the APDMS-AAc gel, the aggregates in the colloidal network structure approach each other and are tightly connected through intermolecular interactions (such as hydrogen bond interaction and ionic interaction), thus reducing the void defects and enhancing the mechanical properties. As Figure 2 shown in a of , the tensile strength and elongation at break of the APDMS 20 -AAc 20 gel are 521.40% and 0.53 MPa respectively, while those of the APDMS 20 -AAc 20 hydrogel are as high as 728.41% and 11.51 MPa respectively, and it can even lift a weight more than 12,800 times its own weight, two orders of magnitude higher than ordinary hydrogels. The APDMS 20 -AAc 20 hydrogel shows a gradually increasing hysteresis loop in the continuous loading-unloading cycle test under different strains (50% - 600%) ( Figure 2 shown in b of ). This is a significant energy dissipation caused by ionic interaction as sacrificial bonds. This strong ionic interaction leads to high energy dissipation of the polymer during stretching to ensure high strength, high elongation and low stiffness. Figure 2 c in shows the APDMS 20 -AAc 20The continuous 8 - cycle loading - unloading test of the hydrogel under 500% strain shows that there is an obvious hysteresis loop in the first cycle, indicating significant energy dissipation. However, since the sacrificial bonds broken in the first cycle do not have enough time to reconstruct to their original state, the area of the hysteresis loop decreases significantly from the second cycle. After the samples subjected to the loading - unloading test are placed in water at room temperature for 10 min, their tensile strength and the area of the hysteresis loop can recover to the initial level ( Figure 2 d) in

[0051] As Figure 3 shown, the EDS spectrum of the APDMS 20 -AAc 20 hydrogel shows that the distributions of Si, O, and C elements are very uniform, while the N element, although having a low content, is very unevenly distributed. The N element is mainly distributed at the cross - link points of the polymer, and the uneven distribution of cross - link points means the existence of a microphase - separated structure.

[0052] Example 2

[0053] Different from Example 1, 10 g of APDMS - 30% was slowly dropped into the aqueous AAc solution. The obtained APDMS / PAAc supramolecular gel is denoted as APDMS 10 -AAc 20 gel, the APDMS / PAAc supramolecular xerogel is denoted as APDMS 10 -AAc 20 xerogel, and the APDMS / PAAc supramolecular hydrogel is denoted as APDMS 10 -AAc 20 hydrogel.

[0054] Example 3

[0055] Different from Example 1, 15 g of APDMS - 30% was slowly dropped into the aqueous AAc solution. The obtained APDMS / PAAc supramolecular gel is denoted as APDMS 15 -AAc 20 gel, the APDMS / PAAc supramolecular xerogel is denoted as APDMS 15 -AAc 20 xerogel, and the APDMS / PAAc supramolecular hydrogel is denoted as APDMS 15 -AAc 20 hydrogel.

[0056] Example 4

[0057] Different from Example 1, 30 g of APDMS - 30% was slowly dropped into the aqueous AAc solution. The obtained APDMS / PAAc supramolecular gel is denoted as APDMS30 -AAc 20 Gel. The APDMS / PAAc supramolecular xerogel is denoted as APDMS 30 -AAc 20 Xerogel. The APDMS / PAAc supramolecular hydrogel is denoted as APDMS 30 -AAc 20 Hydrogel.

[0058] Figure 4 It shows that the mechanical properties of the hydrogel first increase and then decrease with the increase of the APMDS content. The APDMS 20 -AAc 20 hydrogel has the best mechanical properties, with a tensile strength and toughness of up to 16.20 MPa and 48.37 MJ / m 3 .

[0059] Example 5

[0060] Different from Example 1, the molar amount of AEAPMDS is 0.25 mol. The obtained colorless viscous liquid APDMS is denoted as APDMS-20% according to the designed proportion of amino linkages. 20 g of APDMS-20% is used to synthesize the APDMS / PAAc supramolecular gel. The obtained APDMS / PAAc supramolecular gel is denoted as APDMS20 20 -AAc 20 Gel. The APDMS / PAAc supramolecular xerogel is denoted as APDMS20 20 -AAc 20 Xerogel. The APDMS / PAAc supramolecular hydrogel is denoted as APDMS20 20 -AAc 20 Hydrogel.

[0061] Example 6

[0062] Different from Example 1, the molar amount of AEAPMDS is 0.67 mol. The obtained colorless viscous liquid APDMS is denoted as APDMS-40% according to the designed proportion of amino linkages. 20 g of APDMS-40% is used to synthesize the APDMS / PAAc supramolecular gel. The obtained APDMS / PAAc supramolecular gel is denoted as APDMS40 20 -AAc 20 Gel. The APDMS / PAAc supramolecular xerogel is denoted as APDMS40 20 -AAc 20 Xerogel. The APDMS / PAAc supramolecular hydrogel is denoted as APDMS40 20 -AAc 20 Hydrogel.

[0063] Example 7

[0064] Different from Example 1, the molar amount of AEAPMDS was 1 mol, and the obtained colorless viscous liquid APDMS was denoted as APDMS-50% according to the designed proportion of amino linkages. 20 g of APDMS-50% was used to synthesize the APDMS / PAAc supramolecular gel. The obtained APDMS / PAAc supramolecular gel was denoted as APDMS50 20 -AAc 20 gel, and the APDMS / PAAc supramolecular xerogel was denoted as APDMS50 20 -AAc 20 xerogel, and the APDMS / PAAc supramolecular hydrogel was denoted as APDMS50 20 -AAc 20 hydrogel.

[0065] As Figure 5 shown, with the increase in the content of amino linkages, the tensile strength, Young's modulus, and toughness of the hydrogel all gradually decreased, while the elongation at break gradually increased. This law conforms to the characteristic of a decrease in crosslinking points. It can be inferred that while the proportion of amino linkages increases, the proportion of dimethyl linkages decreases, resulting in a weakened degree of microphase separation caused by hydrophobic interactions in the hydrogel. The microphase separation structure can play a role in physical crosslinking and strengthening in the polymer. The weakened degree of microphase separation leads to a decrease in mechanical properties. At the same time, this also shows that the influence of ionic interactions on mechanical properties is lower than that of hydrophobic interactions.

[0066] Example 8

[0067] Use a blade to cut the APDMS 20 -AAc 20 hydrogel into two completely independent parts. To make the self-healing effect more obvious, one of the samples was colored red and the other remained unchanged. As Figure 6 shown, the two samples healed and were able to be stretched after being re-contacted in warm water and maintained for a period of time. As Figure 7 shown in a of Figure 7 , extending the healing time can improve the healing efficiency. The healing efficiency exceeds 40% after 1 h and reaches 70% after 12 h. As Figure 7As shown in c of [reference], when the hydrogel is subjected to small - amplitude oscillatory shear (strain = 0.1%), G′ is greater than G″, and the moduli of both do not change with time, indicating that a self - supporting gel with a complete network is formed under small strain. Subsequently, when the hydrogel is subjected to large - amplitude shear (strain = 50%), the values of G′ and G″ immediately reverse and are accompanied by a sharp drop, indicating that the gel network is destroyed and the gel transforms into a sol state. At a fixed frequency (1.0 Hz), when the strain is switched from a large strain of 50% to a small strain of 0.1%, the gel - like characteristics (G'>G″) can be immediately restored, and there is no obvious decrease in each repeatable recovery cycle.

[0068] As Figure 8 shown, the polymer was ground into powder and then transferred to a circular polytetrafluoroethylene mold, and a large amount of water was added. After the compression molding process at about 3 kPa pressure, the polymer hydrogel was re - obtained and was able to lift a weight of 500 g without damage. This process can be repeated multiple times.

[0069] Example 9

[0070] The APDMS 20 - AAc 20 hydrogel was dried while maintaining different tensile strains to obtain a pre - stretched dry gel. As Figure 9 shown in a of [reference], the pre - stretching process can significantly enhance the mechanical properties of the dry gel. The tensile strength of the dry gel obtained at 100% strain is even as high as 91.64 MPa, and the modulus is also increased to 2.15 GPa. The tensile strength of the dry gel obtained at 300% strain drops to 86.58 MPa, but the modulus continues to increase to 3.09 GPa. It was also found that there is a yield point in the pre - stretched dry gel, which leads to a significant increase in the toughness of the pre - stretched dry gel, an increase of 6.6 times. As Figure 9 shown in b of [reference], stress relaxation occurred in the dry gel over time, however, the residual stress was still as high as more than 12 MPa after 40 min. In addition, as Figure 9 shown in c of [reference], the dry gel after cross - section repair and drying can still bear a weight 1000 times its own weight without cracking.

[0071] Example 10

[0072] The APDMS 20 - AAc 20 hydrogels were placed in 0.1 M NaOH and 0.1 M HCl respectively, and the network was dissociated into isolated molecules by disrupting the intermolecular ionic interactions and then recovered. As Figure 10 shown in a of [reference], two circular pieces of APDMS 20 - AAc 20The hydrogel was immersed in 0.1M NaOH solution, and the edges began to dissociate after 5 minutes. Disk 1, which was blown with a pipette, dissociated into small pieces of gel after 0.5 hours. Disk 2, which was kept still, had no obvious dissociation effect after 0.5 hours. Finally, disk 1 and disk 2 were completely dissociated after 2 hours and 8 hours, respectively. Figure 10 As shown in Figure b, the hydrogel also degraded in 0.1 M HCl solution with the aid of pipette blowing. Figure 11 As shown, the recovery of the hydrogel can be achieved by adding HCl to the NaOH dissociation solution.

[0073] Embodiment 11

[0074] APDMS 20 -AAc 20 The hydrogels are bent into σ shapes ( Figure 12 a), spiral ( Figure 12 b), winding shape ( Figure 12 c) and the long straight bar ( Figure 12 d) and fixed by slow spontaneous dehydration at room temperature for 24 h. When immersed in deionized water at 25 °C, the σ-shaped dry gel absorbed water and gradually unfolded over time, recovering its original shape after about 24 h. After 36 h, the spiral and winding hydrogels did not completely recover their original shapes due to their complex structures. The shape of the long strip hydrogel was basically completely restored after 30 h. Figure 13 As shown, the long strip of APDMS 20 -AAc 20 The dry gel is dried at room temperature to form a round pre-stretched dry gel, whose diameter is larger than the diameter of the weight. The weight is placed in a beaker filled with water, and the round dry gel is placed on the weight. At this time, the weight cannot be lifted by pulling the dry gel. After 5 hours, the pre-stretched dry gel shrinks and fits tightly on the weight, and the weight can be easily lifted when the gel is pulled. Figure 14 As shown in the figure, the shape memory process of water diffusion has a significant temperature dependence, and at the same shape and water temperature, the 0.6 mm xerogel recovers faster than the 1.2 mm xerogel. Figure 15 As shown in a, the thickness of the left half of the hydrogel before pre-stretching is set to 1.2mm, and the thickness of the right half after pre-stretching is set to 0.6mm, and both are curled into a σ shape, and then dried at room temperature for 24h (completely dried). It was soaked in deionized water at 25°C, and the 0.6mm part began to gradually recover its shape after 1h, and basically recovered to its original shape after 15h. The 1.2mm part began to gradually recover after 5h, and was basically fully recovered after 24h. This is because the dry gel is thinner after pre-stretching, and water is easier to diffuse completely. In addition, the drying time of the hydrogel at room temperature also has a great influence on the shape memory recovery time. As Figure 15As shown in b in [reference], the drying time of the hydrogel at room temperature was shortened to 1 h, and at this time the hydrogel was not completely dry. Compared with Figure 15 a in [reference], the recovery time of the 1.2 mm non-pre-stretched part was faster, and it was completely recovered in only 2 min, while the 0.6 mm pre-stretched part required 10 min. This is because the pre-stretched part is thinner and has a higher degree of dryness. The higher the degree of dryness, the slower the water diffusion, which is also one of the basic characteristics of shape memory hydrogels based on the water diffusion mechanism. The hydrogel can also temporarily fix the shape of the hydrogel in solvents such as EtOH, DMSO, DMF, and THF, and then recover in an aqueous solution. As shown in Figure 15 c in [reference], the longer the immersion time in 100% EtOH, the longer the deformation recovery time.

[0075] In summary, APDMS 20 -AAc 20 The APDMS / PAAc supramolecular hydrogel / xerogel represented by the xerogel can be used as a water shrinkable sleeve, that is, a polymer material protection sleeve that shrinks when encountering water. By changing the thickness of the gel and controlling the pre-stretching length and direction, the speed and degree of water shrinkage can be controlled, and the lengths of the "dormant period" and "deformation period" can be artificially regulated, so that the deformation can be started after reaching the target position, so as to be applicable to the protection of nerves, bones, and ligaments after fracture repair in vivo in different environments and the sealing protection of underwater electronic devices and other fields.

[0076] Example 12

[0077] Rat nucleus pulposus cells were seeded on the surface of APDMS 20 -AAc 20 hydrogel and cultured for 1 d, 2 d, and 3 d respectively. As shown in Figure 16 a in [reference], after 3 days of culture, the cell viability of rat nucleus pulposus cells was greater than 100%, and the cell growth and proliferation trends were obvious. This may be because some substances that can promote cell proliferation and differentiation were separated from the gel. In addition, in the culture medium containing APDMS 20 -AAc 20 hydrogel, the cells were in a healthy growth state ( Figure 16 b in [reference]). Based on this, the supramolecular xerogel has advanced applications in the field of biomedicine. For example, a circular pre-stretched xerogel is sleeved on a broken bone, ligament, or even nerve. The xerogel softens and shrinks by absorbing tissue fluid, achieving the purpose of fixation and repair; the pre-stretched xerogel is attached to the surface of a human torn wound. The xerogel absorbs tissue fluid and shrinks to close the wound, avoiding the suture process. The reduced contractility of diabetic wounds is one of the roots of the slow healing of diabetic wounds. This potential treatment strategy may play a miraculous effect in the healing of diabetic wounds.

[0078] Example 13

[0079] As shown Figure 17 below, the APDMS 20 -AAc 20 hydrogel has a broad absorption peak between 300 nm and 400 nm, with the best excitation and the best emission being 430 nm and 505 nm respectively. Moreover, the fluorescence emission has excitation wavelength dependence, indicating that it can emit bright blue fluorescence without conjugated structures such as benzene rings and has advanced applications in optoelectronic devices, fluorescence probes, sensors, etc.

[0080] Example 14

[0081] Different from Example 1, 0.02 g of α-ketoglutaric acid was replaced with 0.02 g of ammonium persulfate, and after pouring the mixed solution into a glass mold and covering it with a layer of transparent PET film to isolate oxygen, it was placed at room temperature for thermal initiation for 5 min to obtain APDMS 20 -AAc 20 gel, and further obtained APDMS 20 -AAc 20 xerogel and APDMS 20 -AAc 20 hydrogel.

[0082] Since APDMS is a strongly basic polyamine organosilicon polymer, it can also be used as an accelerator, enabling the polymerization reaction to be simply completed at room temperature. As Figure 18 shown, the tensile strength of the APDMS 20 -AAc 20 hydrogel obtained by thermal initiation is 7.95 MPa, only half of that of photoinitiation. This may be because the difference in the initiation system leads to the production of PAAc with different molecular weights or different configurations, thereby resulting in different hydrogel structures. However, large, thick, and complex-structured components can be synthesized by thermal initiation and colored functional fillers such as carbon black, carbon nanotubes, and graphene can be introduced.

[0083] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, 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 preparation method of an APDMS / PAAc supramolecular gel, characterized in that, It includes the following steps: S1. Mix an aminosilane or a mixture of an aminosilane and a silane with water and a catalyst, heat under reflux, and then remove by-products, the catalyst and impurities to obtain APDMS; S2. Dissolve APDMS in an aqueous acrylic acid solution, add an initiator to form a mixed solution, remove dissolved oxygen from the mixed solution, and initiate polymerization under anaerobic conditions to obtain an APDMS / PAAc supramolecular gel.

2. The preparation method according to claim 1, wherein In step S1, the aminosilane includes at least one of 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldiethoxysilane, and trimethoxy[3-(methylamino)propyl]silane; the silane includes at least one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane; the catalyst includes tetramethylammonium hydroxide; the molar ratio of amino groups to silicon atoms in the mixture of the aminosilane and the silane is (0.1 - 1):1 and does not include 1:

1.

3. The preparation method according to claim 1, characterized in that, In step S1, before heating under reflux, replace with an inert gas 2 - 4 times and carry out under an inert atmosphere. The temperature for heating under reflux is 80°C - 120°C, and the time for heating under reflux is 5 - 100 h.

4. The preparation method according to claim 1, characterized in that, In step S2, the mass ratio of APDMS to acrylic acid is (0.5 - 1.5):1, and the mass concentration of acrylic acid in the aqueous acrylic acid solution is 10 - 30 wt.%.

5. The preparation method according to claim 1, characterized in that, In step S2, the initiation includes photoinitiation or thermal initiation. For photoinitiation, the wavelength of the light source is 360 - 370 nm, the power of the light source is 90 - 110 W, the time is 30 - 120 min, and the initiator for photoinitiation includes α-ketoglutaric acid. For thermal initiation, the temperature is 0°C - 80°C, the time is 1 - 60 min, and the initiator for thermal initiation includes at least one of ammonium persulfate, hydrogen peroxide, sodium persulfate, azobisisobutyronitrile, azobisisoheptonitrile, and benzoyl peroxide.

6. An APDMS / PAAc supramolecular gel, characterized in that, Obtained by the preparation method according to any one of claims 1 - 5.

7. An APDMS / PAAc supramolecular hydrogel, characterized in that, The APDMS / PAAc supramolecular gel as claimed in claim 6 is subjected to pressure dehydration, drying, and incubation in water to obtain it.

8. An APDMS / PAAc supramolecular xerogel, characterized in that, The APDMS / PAAc supramolecular gel as claimed in claim 6 or the APDMS / PAAc supramolecular hydrogel as claimed in claim 7 is subjected to pressure dehydration and drying to obtain it.

9. The application of the APDMS / PAAc supramolecular hydrogel as claimed in claim 6, the APDMS / PAAc supramolecular hydrogel as claimed in claim 7, or the APDMS / PAAc supramolecular dry gel as claimed in claim 8 in the fields of structural materials, photoluminescent devices, intelligent switches, actuators, or biomedical materials.

10. The application of the APDMS / PAAc supramolecular gel as claimed in claim 6, the APDMS / PAAc supramolecular hydrogel as claimed in claim 7, or the APDMS / PAAc supramolecular dry gel as claimed in claim 8 as a water shrinkable sleeve.

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