An organic gel with multi-stimulus responsiveness and a preparation method and application thereof

Abstract

The present application relates to a kind of organic gel with multi-stimulus response and its preparation method, application;Belong to stimulus-responsive material field.The organic gel of the present application is polymerized by monomer, two different organic solvents.The organic gel responds to temperature stimulus, has UCST characteristics: become transparent with the increase of temperature, become opaque with the decrease of temperature.The organic gel responds to solvent stimulus: show that bad solvent reduces transmittance, good solvent increases transmittance.The transition temperature of the organic gel prepared in the present application can be adjusted, can respond in the wide temperature range of 16 ℃-70 ℃.The organic gel of the present application can be applied to in the field of intelligent window, information display and encryption, temperature indication, solvent indication due to its multi-stimulus response.

Description

Technical Field

[0001] This invention relates to the field of stimulus-responsive materials, and more specifically, to an organic gel with multi-stimulus responsiveness, its preparation method, and its applications. Background Technology

[0002] Hydrogels are polymer materials with a three-dimensional hydrophilic network structure, using water as the dispersion medium. They are water-soluble polymers with a network cross-linked structure, incorporating both hydrophobic and hydrophilic groups. The hydrophilic residues bind to water molecules, connecting them within the network, while the hydrophobic residues swell upon contact with water, resulting in a cross-linked polymer. Hydrogels are polymeric network systems that are flexible, maintain a certain shape, and can absorb large amounts of water. Their raw materials are inexpensive and readily available, and their synthesis process is simple, leading to extensive research in recent years.

[0003] Based on their response to external stimuli, hydrogels can be broadly classified into two categories: traditional hydrogels and environmentally sensitive hydrogels. Traditional hydrogels are insensitive to changes in the environment, such as temperature or pH. Environmentally sensitive hydrogels, on the other hand, are polymeric gels that can sense minute changes or stimuli in the external environment (such as temperature, pH, light, electricity, and pressure) and produce corresponding changes or even abrupt changes in their physical structure and chemical properties. A prominent characteristic of this type of gel is the significant change in its swelling behavior during the response to the environment. In the field of polymers, researchers are particularly interested in stimulus-responsive hydrogels, also known as smart hydrogels, which consist of a cross-linked polymer network and a high water content. When stimulated by external stimuli, they can automatically change their physical and / or chemical properties. For example, Ahmet... Polyvinyl alcohol (PVA) modified chitosan-grafted poly(NIPAM-co-AAc) hydrogels were synthesized via free radical copolymerization. This novel combination of three-component hydrogels can be effectively used as an alternative material for developing stimulus-triggered drug delivery systems. Sijia Ge et al. developed a novel PNIPAm / PNAGA dual-network hydrogel using a self-assembly crosslinking strategy, creating a smart temperature-sensitive hydrogel with a wide response range, high stretchability, and healing properties to mimic the temperature-sensing function of human skin. However, hydrogel failure due to poor mechanical properties, dehydration, and freezing is an inherent drawback of hydrogel-rich sensors. For hydrogel-based sensors, the undesirable mechanical properties of the hydrogel are a common problem limiting their practical use, resulting in a narrow operating range. Furthermore, hydrogels are often unstable in external environments, especially in low-temperature and drought conditions, where freezing and dehydration lead to sensitivity loss or even failure. Therefore, various attempts have been made to overcome the inherent shortcomings of traditional hydrogels.

[0004] Organic hydrogels are typically obtained by partially replacing the water in a hydrogel with an organic solvent. For example, Chengcheng Cai et al. developed a dual-network organic hydrogel based on hyaluronic acid (HA), poly(PAA-co-PAM, PC), glycerol, and LiCl3. They obtained a dual-network 3D hydrogel by physically crosslinking PC and HA in a one-step process, and then introduced glycerol through a solvent replacement strategy to fabricate the organic hydrogel, creating a wearable sensor that exhibits stable and sensitive multi-stimulus responses to changes in strain, temperature, and humidity. However, weight loss data showed that even after immersion in glycerol for 60 minutes, the organic hydrogel still lost 20% of its weight after being left indoors for 24 hours. In summary, the most common solvent replacement method involving the introduction of organic solvents is complex to operate, has limited performance optimization potential, cannot determine the specific content of the replacement solvent, and may cause the original system to lose its temperature responsiveness. Therefore, developing functional stimulus-responsive organic gels for practical applications remains a promising research area. Summary of the Invention

[0005] To address the problems in existing technologies, this invention provides an organogel with multi-stimulus responsiveness, its preparation method, and its applications. This invention uses hydroxyl-containing acrylates and two different organic solvents as raw materials, and directly prepares the organogel via photopolymerization under the action of an initiator.

[0006] The organic gel prepared by this invention exhibits responsiveness to multiple stimuli: First, it responds to temperature stimuli, displaying UCST characteristics: it becomes more transparent as temperature increases and less transparent as temperature decreases; second, it responds to solvent stimuli: poor solvents reduce transmittance, while good solvents increase transmittance. The temperature at which the visible light transmittance of the organic gel reaches 50% is its transition temperature. The transition temperature of the organic gel prepared by this invention is adjustable and can respond within a wide temperature range of 16℃ to 70℃.

[0007] One of the objectives of this invention is to provide an organic gel with multi-stimuli responsiveness.

[0008] The multi-stimuli responsive organic gel is photopolymerized from raw materials comprising the following components:

[0009] The components are measured in the following parts by weight:

[0010]

[0011]

[0012] The monomer is at least one of hydroxyl-containing acrylates, preferably at least one of hydroxypropyl acrylate and hydroxyl-containing acrylates having 5 to 7 carbon atoms.

[0013] The organic solvent A is different from the organic solvent B.

[0014] The organic gel prepared by this invention does not contain water and will not freeze or lose water in low temperature and dry environments, thus avoiding loss of sensitivity or even failure of stimulus responsiveness.

[0015] The organic gel prepared in this invention is a physical organic gel, whose internal cross-linking is achieved solely through hydrogen bonding. Analysis suggests that the hydrogen bonding in the system includes the following types: 1) interactions between polymer molecular chains; 2) interactions between polymer molecular chains and the solvent; and 3) interactions between solvents. At lower temperatures, the interactions between polymer molecular chains are stronger, causing the chains to curl up and the particle diameter to increase. Light scattering occurs when light strikes the particles, resulting in lower transmittance. As the temperature increases, the interactions between molecular chains are disrupted, allowing the polymer molecular chains to move and expand within the solvent, resulting in higher transmittance. This manifests as: phase separation at low temperatures and homogeneity at high temperatures; or, opaque at low temperatures and transparent at high temperatures.

[0016] The organic gel prepared in this invention exhibits different responses to solvent stimulation when immersed in different types of solvents. These responses are as follows: 1) When immersed in a poor solvent, the poor solvent accelerates phase separation of the organic gel, resulting in a decrease in gel permeability; 2) When immersed in a good solvent, the good solvent accelerates the homogenization of the organic gel, resulting in an increase in gel permeability. Good and poor solvents are distinguished based on whether the monomer can polymerize with a single organic solvent; organic solvents that can polymerize with monomers to form a gel are defined as poor solvents, while organic solvents that cannot polymerize with monomers to form a gel are defined as good solvents.

[0017] Theoretically, any monomer with a similar structure and carbon number to hydroxypropyl acrylate (HPA) can be used to prepare an organogel with multi-stimulus responsiveness using this system. In some embodiments of the present invention, the monomer is hydroxypropyl acrylate. First, HPA has double bonds, which facilitates photopolymerization to obtain hydrogel materials; second, due to its hydroxyl groups, it can not only participate in the formation of intrachain hydrogen bonds but also form hydrogen bonds with the hydroxyl groups of the solvent in the system, forming a polymer network through physical crosslinking to form a gel.

[0018] In this reaction system, organic solvent A and organic solvent B form a binary solvent; organic solvent A acts as a poor solvent, while organic solvent B acts as a good solvent. The two organic solvents play different roles in the preparation of multi-stimulus responsive organic gels; using only one organic solvent may not be sufficient to prepare organic gels with UCST properties and solvent responsiveness.

[0019] In this reaction system, organic solvent A acts as a poor solvent, promoting gelation. The selection of organic solvent A depends on its polarity, fluidity, and the presence of hydroxyl groups, and is independent of the number of carbon atoms. Experiments have shown that alcohols can be chosen as organic solvents; for example, at least one of ethylene glycol, propylene glycol, glycerol, diethylene glycol, and n-decanol can be selected as organic solvent A. In some embodiments of this invention, glycerol was selected as organic solvent A.

[0020] In this reaction system, organic solvent B acts as a good solvent, promoting the UCST behavior. Experiments showed that UCST behavior began to appear with the addition of a good solvent, and the higher the amount added, the lower the transition temperature. The organic solvent B can be at least one of ethanol, ethylene glycol, propylene glycol, n-propanol, isopropanol, n-butanol, isobutanol, triethanolamine, dimethyl sulfoxide, N,N-dimethylformamide, acetone, and butanone; preferably at least one of ethylene glycol, N,N-dimethylformamide, dimethyl sulfoxide, propylene glycol, and isopropanol. In some embodiments of the present invention, ethylene glycol, N,N-dimethylformamide, and dimethyl sulfoxide were selected as organic solvent B.

[0021] In this reaction system, with the amount of the binary solvent consisting of organic solvent A and organic solvent B remaining constant, changing the mass ratio of the good solvent organic solvent B to the binary solvent changes the transition temperature of the prepared organic gel accordingly. In some embodiments of the present invention, the mass ratio of the good solvent organic solvent B to the total mass of organic solvent A and organic solvent B is 0.1 to 0.6:1, preferably 0.2 to 0.5:1. Experimental data from the embodiments show that as the relative amount of organic solvent B increases, the transition temperature of the prepared organic gel decreases.

[0022] The role of the photoinitiator in this invention is to generate free radicals under ultraviolet light irradiation, thereby initiating the polymerization reaction. Most photoinitiators are soluble in organic solvents; therefore, theoretically, any photoinitiator can be used to achieve this invention. Specifically, the photoinitiator can be a free radical photoinitiator; for example, at least one of photoinitiators BP, TPO, 2959, 1173, and 184. In some embodiments of this invention, photoinitiator 1173 is used.

[0023] Among them, photoinitiator BP has the chemical name benzophenone. Photoinitiator TPO has the chemical name diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide. Photoinitiator 2959 has the chemical name 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone. Photoinitiator 1173 has the chemical name 2-hydroxy-2-phenyl-1-phenyl-1-propanone. Photoinitiator 184 has the chemical name 1-hydroxycyclohexylphenyl ketone.

[0024] This invention, through experimental research, has discovered that the transition temperature of the prepared organic gel can also be adjusted by adding additives to the reaction system. That is, the role of additives in this invention is to adjust the transition temperature of the prepared organic gel. Different additives have different effects on the transition temperature: those with a molecular chain length shorter than that of hydroxypropyl acrylate can lower the transition temperature, while those with a molecular chain length longer than that of hydroxypropyl acrylate can raise the transition temperature. The additive can be at least one of acrylic acid and acrylate; based on 100 parts by weight of monomer, the additive is 0.01 to 2 parts by weight; preferably 0.02 to 1.5 parts by weight. In some embodiments of this invention, the amount of additive relative to the monomer is 0.01-0.5 wt%.

[0025] The acrylate may be at least one selected from methyl acrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, isobutyl acrylate, n-hexyl acrylate, and octadecyl acrylate, preferably at least one selected from methyl acrylate, ethyl acrylate, butyl acrylate, n-hexyl acrylate, and isooctyl acrylate. In some embodiments of the present invention, methyl acrylate, ethyl acrylate, butyl acrylate, n-hexyl acrylate, or n-hexyl acrylate are selected as additives.

[0026] The second objective of this invention is to provide a method for preparing the above-mentioned organogel with multi-stimulus responsiveness.

[0027] The method for preparing the multi-stimuli responsive organic gel includes: mixing the raw materials evenly according to the specified weight proportions and then irradiating them under ultraviolet light to obtain the multi-stimuli responsive organic gel.

[0028] The ultraviolet light wavelength is determined by the type of photoinitiator used; different photoinitiators absorb different wavelengths of ultraviolet light to generate free radicals. When at least one of the photoinitiators BP, TPO, 2959, 1173, and 184 is used as the photoinitiator, the ultraviolet light wavelength is 365–405 nm. The ultraviolet light source can be a UV LED lamp.

[0029] Photopolymerization generally has a short preparation time. The irradiation time depends on the light intensity used; higher light intensity results in a faster rate of free radical generation, thus requiring only a short irradiation time to complete polymerization. Therefore, the irradiation time is 30 s to 20 min, more preferably 1 to 5 min. In some embodiments of the present invention, the light intensity is 80 mW / cm². 2 Under these conditions, the illumination time is 3 minutes.

[0030] Compared to solvent displacement methods that introduce organic solvents, the photopolymerization method of this invention produces anhydrous organic gels, and the content of organic solvents in the organic gels is fixed. Furthermore, the raw materials used in the photopolymerization method of this invention are widely available, economical, and environmentally friendly; the preparation method is rapid, efficient, and simple to operate.

[0031] A third objective of this invention is to provide an application of the aforementioned multi-stimulus responsive organic gel. Specifically, it is the application of the aforementioned multi-stimulus responsive organic gel in the fields of smart windows, temperature indicators, solvent indicators, and information encryption.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] The organic gel provided by this invention possesses environmental stability such as drought and frost resistance, as well as excellent fundamental properties such as mechanical properties. Specifically, for example... Figure 5 As shown, the organic gel prepared by this invention still exhibits a low weight loss rate at high temperatures, indicating that the resulting organic gel possesses excellent drought resistance properties. Figure 4 As shown, the organic gel prepared by this invention has not yet reached a freezing point at at least -70°C, meaning the resulting organic gel has good freeze resistance. Figure 6 As shown, the obtained organic gel has good mechanical properties, and the mechanical properties become better and better with the increase of monomer content.

[0034] The organic gel provided by this invention also exhibits multi-stimulus responsiveness to temperature and solvent, and this responsiveness also demonstrates good cyclic repeatability, meaning that the resulting organic gel's response to temperature and solvent can be repeatedly reproduced. These significant advantages greatly broaden the potential applications of temperature-sensitive organic gels in fields such as smart windows, temperature indicators, solvent indicators, and information encryption.

[0035] The organic gel provided by this invention has an adjustable transition temperature, which can be achieved by changing the monomer content, solvent composition and adding additives in the system.

[0036] Compared with existing preparation methods, the preparation method of the present invention uses widely available raw materials, is economical and environmentally friendly; the preparation method is fast and efficient, and the preparation process is simple to operate. Attached Figure Description

[0037] Figure 1 The temperature responsiveness of the organic gels with multi-stimulus responsiveness obtained in Examples 13-16 of the present invention is shown.

[0038] Figure 2 The temperature-transmittance curves of the multi-stimuli responsive organogels prepared in Examples 13-16 of this invention are shown. In the figures, the horizontal axis represents temperature and the vertical axis represents visible light transmittance. The curves are fitting curves corresponding to different visible light transmittances at different temperatures, indicating the trend of visible light transmittance changes of the organogel with temperature.

[0039] Figure 3 The solvent responsiveness of the multi-stimuli responsive organic gel obtained in Example 15 of the present invention is shown. The dimensions and visible light transmittance of the organic gel at the different solvents indicated on the left side of the figure, and the immersion times indicated on the upper side of the figure, are also shown.

[0040] Figure 4 The DSC curve of the multi-stimuli responsive organic gel obtained in Example 15 of the present invention is shown. In the figure, the horizontal axis represents temperature, and the vertical axis represents heat flow rate.

[0041] Figure 5 The TGA curve of the multi-stimuli responsive organic gel obtained in Example 15 of the present invention is shown. In the figure, the horizontal axis represents temperature, and the vertical axis represents weight loss rate.

[0042] Figure 6 The mechanical properties of the multi-stimulus responsive organogels obtained in Examples 1-4 of the present invention are shown. In the figures, the horizontal axis represents strain, and the vertical axis represents stress. Detailed Implementation

[0043] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0044] The raw material procurement information used in the specific embodiments of this invention is as follows:

[0045] All acrylate raw materials were purchased from Beijing Solarbio Science & Technology Co., Ltd., and were of analytical grade.

[0046] Photoinitiator 1173 was purchased from Tianjin Jiurixin Co., Ltd.

[0047] All solvents were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., and were of analytical grade.

[0048] This invention uses a solar film tester to test the visible light transmittance of organic gels at different temperatures.

[0049] Example 1

[0050] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 65 parts by weight of the hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0051] Example 2

[0052] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 100 parts by weight of hydroxypropyl acrylate are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0053] Example 3

[0054] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 150 parts by weight of hydroxypropyl acrylate are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0055] Example 4

[0056] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0057] Example 5

[0058] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and N,N-dimethylformamide, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 65 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of N,N-dimethylformamide as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0059] Example 6

[0060] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and N,N-dimethylformamide, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 100 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of N,N-dimethylformamide as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0061] Example 7

[0062] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and N,N-dimethylformamide, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 150 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of N,N-dimethylformamide as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0063] Example 8

[0064] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and N,N-dimethylformamide, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of N,N-dimethylformamide as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0065] Example 9

[0066] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and dimethyl sulfoxide, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 65 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of dimethyl sulfoxide as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0067] Example 10

[0068] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and dimethyl sulfoxide, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 100 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of dimethyl sulfoxide as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0069] Example 11

[0070] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and dimethyl sulfoxide, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 150 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of dimethyl sulfoxide as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0071] Example 12

[0072] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and dimethyl sulfoxide, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of dimethyl sulfoxide as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0073] Example 13

[0074] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 120 parts by weight of glycerol as organic solvent A and 30 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0075] Example 14

[0076] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 105 parts by weight of glycerol as organic solvent A and 45 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at an amount equal to 1 wt% of the hydroxypropyl acrylate content, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0077] Example 15

[0078] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0079] Example 16

[0080] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 75 parts by weight of glycerol as organic solvent A and 75 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, photoinitiator 1173 is added at 1 wt% of the amount of hydroxypropyl acrylate, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0081] Example 17

[0082] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, the additive is methyl acrylate, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, methyl acrylate and photoinitiator 1173 are added, at amounts of 0.01 wt%–0.5 wt% and 1 wt% of the hydroxypropyl acrylate amount, respectively, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0083] Example 18

[0084] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, the additive is ethyl acrylate, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, ethyl acrylate and photoinitiator 1173 are added at amounts of 0.01 wt%–0.5 wt% and 1 wt% of the amount of hydroxypropyl acrylate, respectively, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0085] Example 19

[0086] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, the additive is butyl acrylate, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, butyl acrylate and photoinitiator 1173 are added, at amounts of 0.01 wt%–0.5 wt% and 1 wt% of the hydroxypropyl acrylate amount, respectively, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0087] Example 20

[0088] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, the additive is n-hexyl acrylate, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, n-hexyl acrylate and photoinitiator 1173 are added, at amounts of 0.01 wt%–0.5 wt% and 1 wt% of the amount of hydroxypropyl acrylate, respectively, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0089] Example 21

[0090] In this embodiment, the monomer is hydroxypropyl acrylate, the solvent is glycerol and ethylene glycol, the additive is isooctyl acrylate, and the initiator is photoinitiator 1173 (2-hydroxy-2-phenyl-1-phenyl-1-propanone). The specific process is as follows: 225 parts by weight of hydroxypropyl acrylate monomer are mixed with 150 parts by weight of a mixed organic solvent (wherein, the 150 parts by weight of the mixed organic solvent consists of 90 parts by weight of glycerol as organic solvent A and 60 parts by weight of ethylene glycol as organic solvent B) until homogeneous. Then, isooctyl acrylate and photoinitiator 1173 are added at amounts of 0.01wt%–0.5wt% and 1wt% of the hydroxypropyl acrylate content, respectively, and the mixture is ultrasonically mixed for 10 minutes. The resulting solution is transferred to a mold and subjected to light at an intensity of 80 mW / cm². 2 An organogel with multi-stimulus responsiveness was obtained by irradiating the product under a 365nm ultraviolet LED lamp for 3 minutes.

[0091] Related performance tests

[0092] Test 1

[0093] Photographs were taken of the organic gels prepared in Examples 13-16 under high and low temperature environments, respectively. Additionally, the organic gels prepared in Examples 13-16 were placed above the graphic; since temperature affects their transmittance, they would have different occlusion effects on the graphic, for ease of comparison. The photographs are as follows: Figure 1 As shown.

[0094] Test 2

[0095] The visible light transmittance of the multi-stimulus responsive organogels prepared in Examples 13-16 was tested at different temperatures, and temperature-transmittance curves were plotted; the temperature-transmittance curves of the organogels are shown below. Figure 2 As shown. According to Figure 2 The curve can be used to derive:

[0096] The organic gel prepared in Example 13 has a visible light transmittance of 23.4 at 20°C and a visible light transmittance of 94.2 at 60°C, with a transition temperature of 39.4°C.

[0097] The organic gel prepared in Example 14 has a visible light transmittance of 24.2 at 20°C and a visible light transmittance of 94.3 at 60°C, with a transition temperature of 37.8°C.

[0098] The organic gel prepared in Example 15 has a visible light transmittance of 31.0 at 20°C and a visible light transmittance of 94.3 at 60°C, with a transition temperature of 31.9.

[0099] The organic gel prepared in Example 16 has a visible light transmittance of 37.6 at 20°C and a visible light transmittance of 94.3 at 60°C, with a transition temperature of 25.7°C.

[0100] Test 3

[0101] The organic gel obtained in Example 15 was immersed in different solvents, and its solvent response behavior was observed. The effect of immersion time on permeability was also recorded. The results are as follows: Figure 3 As shown in Table 1.

[0102] When the obtained organic gel is immersed in glycerol, the visible light transmittance gradually decreases with increasing immersion time, and no significant swelling occurs, indicating that the organic gel has poor compatibility with the solvent. This characteristic, namely the change in swelling rate and visible light transmittance, can be used to indicate different solvents.

[0103] The obtained organic gel was immersed in DMF, DMSO, ethanol, and ethylene glycol. With increasing immersion time, the visible light transmittance gradually increased, and significant swelling occurred, indicating good compatibility between the organic gel and the solvent. This characteristic, namely the changes in swelling rate and visible light transmittance, can be used to indicate the compatibility with different solvents.

[0104] When the obtained organic gel is immersed in water, the visible light transmittance decreases with increasing immersion time, and no swelling occurs, indicating that the organic gel has poor compatibility with the solvent. This characteristic, namely the change in swelling rate and visible light transmittance, can be used to indicate different solvents.

[0105] Table 1

[0106]

[0107] Test 4

[0108] The heat flow rate of the multi-stimulus responsive organic gel prepared in Example 15 of this invention was tested as a function of temperature, and the DSC curve of the multi-stimulus responsive organic gel of this invention was plotted. The plotted DSC curve is shown in the figure below. Figure 4 As shown.

[0109] The freezing point of the organogel samples was determined using differential scanning calorimetry (DSC) at a rate of 10 °C / min from 0 °C to -70 °C.

[0110] The DSC curve shows that the organic gel of the present invention has not yet reached a freezing point at least at -70°C, that is, the obtained organic gel has good antifreeze properties.

[0111] Test 5

[0112] The weight loss of the multi-stimuli-responsive organic gel prepared in Example 15 of this invention was tested as a function of temperature, and the TGA curve of the multi-stimuli-responsive organic gel of this invention was plotted. The plotted TGA curve is shown in Figure 15. Figure 5 As shown.

[0113] The weight loss of organogel samples at high temperatures was measured using a thermogravimetric analyzer (TGA), with a heating range of 0-200℃ and a heating rate of 10℃ / min.

[0114] The TGA curves show that the organic gel prepared in this invention has a weight loss rate of less than 4% at 100°C; the weight loss rate is controlled to be less than 8% at 150°C; and the weight loss rate is less than 20% at 200°C. That is, the weight loss rate remains low even at high temperatures, and the resulting organic gel has good drought resistance properties.

[0115] Test 6

[0116] The strain-stress tunneling of the multi-stimulus responsive organogels prepared in Examples 1-4 of this invention was tested to observe the changes in monomer content, and curves were plotted. The plotted curves are shown in the figure below. Figure 6 As shown.

[0117] The tensile properties of the organic gel samples were tested using a universal testing machine. The organic gel was cut into dumbbell shapes and stretched at a rate of 50 mm / min.

[0118] The curve in the figure shows that the maximum stress is 0.55 MPa.

[0119] Test 7

[0120] The visible light transmittance of the multi-stimulus responsive organogels prepared in Examples 1-21 was tested at different temperatures to obtain their transition temperatures. The transition temperatures of the multi-stimulus responsive organogels prepared in each example are shown in Table 2.

[0121] Table 2

[0122]

[0123]

[0124] The data in Examples 1-12 of Table 2 show that the organic gel transition temperature decreases with increasing monomer content; and that different organic solvents B result in variations in the organic gel transition temperature. The data in Examples 13-16 of Table 1 show that the organic gel transition temperature decreases with decreasing mass ratio of organic solvent A to organic solvent B (relatively increasing the amount of organic solvent B). The data in Examples 17-21 of Table 2 show that adding different additives can adjust the organic gel transition temperature; specifically, adding methyl acrylate or ethyl acrylate lowers the organic gel transition temperature; adding butyl acrylate, n-hexyl acrylate, or isooctyl acrylate raises the organic gel transition temperature.

Claims

1. An organic gel with multi-stimulus responsiveness, characterized in that, It is formed by photopolymerization of raw materials including the following components: The components are measured in the following parts by weight: 50-250 parts by weight of monomer; Organic solvent A: 60-120 parts by weight; Organic solvent B20~90 parts by weight; Photoinitiator 0.5~5 parts by weight; The monomer is at least one of acrylates containing hydroxyl groups; The organic solvent A is glycerol; The organic solvent B is at least one selected from ethanol, ethylene glycol, propylene glycol, n-propanol, isopropanol, n-butanol, isobutanol, triethanolamine, dimethyl sulfoxide, N,N-dimethylformamide, acetone, and butanone. The organic solvent A is different from the organic solvent B.

2. The multi-stimuli responsive organic gel as described in claim 1, characterized in that, The components are measured in the following parts by weight: 200-240 parts by weight of monomer; Organic solvent A: 80-100 parts by weight; Organic solvent B: 40-60 parts by weight; 1-3 parts by weight of photoinitiator.

3. The multi-stimuli responsive organic gel as described in claim 1, characterized in that, The monomer is at least one of acrylates containing hydroxyl groups and having 5 to 7 carbon atoms.

4. The multi-stimuli responsive organic gel as described in claim 1, characterized in that, The organic solvent B is at least one of ethylene glycol, N,N-dimethylformamide, dimethyl sulfoxide, propylene glycol, and isopropanol.

5. The multi-stimuli responsive organic gel as described in claim 1, characterized in that, The ratio of the mass of organic solvent B to the total mass of organic solvent A and organic solvent B is 0.1~0.6:

1.

6. The multi-stimuli responsive organic gel as described in claim 1, characterized in that, The ratio of the mass of organic solvent B to the total mass of organic solvent A and organic solvent B is 0.2~0.5:

1.

7. The multi-stimuli responsive organic gel as described in claim 1, characterized in that, The photoinitiator is a free radical photoinitiator.

8. The multi-stimuli responsive organic gel as described in claim 1, characterized in that, The photoinitiator is at least one of the photoinitiators BP, TPO, 2959, 1173 and 184.

9. The multi-stimuli responsive organic gel as described in claim 1, characterized in that, Its raw materials also include additives; The additive is at least one selected from acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, isobutyl acrylate, n-hexyl acrylate, and octadecyl acrylate; The additive is 0.01 to 2 parts by weight per 100 parts by weight of monomer.

10. The multi-stimuli responsive organic gel as described in claim 9, characterized in that, The additive is 0.02 to 1.5 parts by weight.

11. The multi-stimuli responsive organic gel as described in claim 9, characterized in that, The additive is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, n-hexyl acrylate, and isooctyl acrylate.

12. The method for preparing an organogel with multi-stimulus responsiveness as described in any one of claims 1 to 11, characterized in that, include: After the raw materials are mixed evenly according to the specified weight proportions, an organic gel with multi-stimuli responsiveness is obtained under ultraviolet light irradiation.

13. The preparation method according to claim 12, characterized in that, The ultraviolet light wavelength is 365~405nm. The illumination time is 30 seconds to 20 minutes; The source of the ultraviolet light is a UV LED lamp.

14. The preparation method according to claim 12, characterized in that, The illumination time is 1-5 minutes.

15. The application of the multi-stimuli responsive organic gel as described in any one of claims 1 to 11 in the fields of smart windows, temperature indicators, solvent indicators, and information encryption.

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