3-(diethylamino)-1, 2-propylene glycol derived polyurethane fluorescent film as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of polymer synthesis, and provides a polyurethane fluorescent film derived from 3-(diethylamino)-1, 2-propylene glycol, and the molecular structure of the polyurethane fluorescent film is shown in the specification. The fluorescent film has the light-emitting property and the tensile property, in addition, a complex conjugated structure does not need to be constructed in the synthesis process, the preparation route is simple, and feasibility is provided for large-scale production.

Description

Technical Field

[0001] This invention belongs to the technical field of polymer synthesis, specifically relating to a 3-(diethylamino)-1,2-propanediol-derived polyurethane (PUE) prepared by a one-pot reaction, and the fabrication of a stretchable flexible fluorescent film using the synthesized polyurethane derivative. Background Technology

[0002] With the rapid development of flexible electronics technology, the demand for materials that combine high mechanical flexibility and functionality is becoming increasingly urgent in fields such as wearable devices, implantable medical devices, and biomimetic sensors. While traditional organic light-emitting materials possess advantages such as high brightness and low power consumption, their inherent rigidity limits the optimization of their mechanical properties. In contrast, non-conjugated polymers offer unique advantages in mechanical-optical synergistic optimization of their structure. Compared to traditional conjugated systems, the non-conjugated backbone can effectively disperse tensile stress and achieve high ductility by introducing flexible spacer groups such as polyethylene glycol segments or non-covalent interactions such as hydrogen bonds and ionic bonds to prepare a dynamic cross-linked network. Simultaneously, the rigid planar arrangement of isolated aromatic rings or heteroatom clusters of non-conjugated light-emitting units facilitates the maintenance of high fluorescence quantum yield, avoiding the limitations imposed by conjugated polymers. π-π Aggregation-induced fluorescence quenching exhibits significant comprehensive performance advantages in fields such as flexible electronics and intelligent sensing.

[0003] Polyurethane derivatives have attracted widespread attention in recent years due to their unique molecular designability and multi-level structural control capabilities. The microphase separation design of non-conjugated polyurethane flexible frameworks and rigid luminescent domains holds promise for overcoming the inherent contradictions in the mechano-optical synergistic optimization of conjugated systems. The luminescence mechanism of non-conjugated systems differs from that of traditional conjugated materials; their fluorescence performance largely depends on non-covalent intermolecular forces. This interaction allows materials to retain excellent luminescence properties while achieving good stretchable mechanical properties. However, the design is more challenging, and the preparation routes are generally complex, making large-scale production difficult. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film. The synthesis of this polyurethane fluorescent film does not require the construction of complex conjugated structures, and the preparation route is simple, providing feasibility for large-scale production. The technical solution adopted in this invention is as follows: A 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film has the following molecular structure: .

[0005] Preferably, its number-average molecular weight M n = 2000~2200 g mol -1 .

[0006] The preparation method of the 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film comprises the following steps: (1) L -Lysine diisocyanate and 3-(diethylamino)-1,2-propanediol were mixed in a molar ratio of 1:(1.2~1.6) and added to a 25 mL round-bottom flask, along with the catalyst triethylenediamine and an organic solvent. (2) Under a protective atmosphere, under anhydrous and oxygen-free conditions, heat to 70~90℃ and stir under reflux for 8~12 h. After the reaction is completed, cool to room temperature and precipitate from excess diethyl ether to obtain a white viscous product, which is the 3-(diethylamino)-1,2-propanediol-derived polyurethane. (3) Transfer the obtained white viscous product to a clean petri dish. By adjusting the tilt angle of the petri dish, the product is allowed to spread evenly in the petri dish under gravity. Then place it in a vacuum drying oven to dry, and obtain a flexible polyurethane fluorescent film with stretchability.

[0007] Preferably, the organic solvent in step (1) is tetrahydrofuran.

[0008] Preferably, in step (1) L -Lysine diisocyanate and 3-(diethylamino)-1,2-propanediol in a molar ratio of 1:1.4.

[0009] Preferably, nitrogen is used as the protective atmosphere in step (2).

[0010] Preferably, in step (2), the temperature is heated to 80°C and stirred and refluxed for 8 hours.

[0011] Preferably, the drying temperature in step (3) is 65°C and the drying time is 12 h.

[0012] The positive effects of this invention are as follows: This invention proposes a novel functional polymeric luminescent material and fabricates a fluorescent thin film with stretchable properties, which has excellent development prospects in the field of flexible soft materials.

[0013] This invention eliminates the need for complex conjugated structure construction during the synthesis process, resulting in a simple preparation route and providing feasibility for large-scale production. Attached Figure Description

[0014] Figure 1 For the PUE of this invention 1 H-NMR spectrum; Figure 2 This is the infrared absorption spectrum of the PUE of the present invention; Figure 3The illustration shows the ultraviolet absorption spectrum of the PUE of the present invention and the fluorescence emission of the PUE under 365 nm excitation. The inset is a photograph of the PUE under 365 nm ultraviolet light illumination. Figure 4 The fluorescence emission spectrum and UV-Vis spectrum of PUE in DMSO solvent are shown in this invention. Figure 5 The PUE of this invention is 0.1 mg / mL -1 DMSO solution in different λ ex The fluorescence emission spectrum below; Figure 6 The PUE and 3-(diethylamino)-1,2-propanediol monomers of this invention are dispersed in ethanol (20 mg / mL). −1 SEM images in ) Figure 7 This image shows the effect of the PUE stretchable fluorescent film of the present invention under ultraviolet light irradiation.

[0015] Figure 8 This is the stress-strain curve of the PUE film of the present invention under uniaxial tension measured at 25°C. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1 Will L Lysine diisocyanate (3.14 mmol) and 3-(diethylamino)-1,2-propanediol (2.62 mmol) were added to a 25 mL round-bottom flask. Then, catalyst DABCO (12 mg) and tetrahydrofuran (10 mL) were added to the flask. Under nitrogen protection and anhydrous and oxygen-free conditions, the mixture was slowly heated to 80 °C and stirred under reflux for 8 h. After the reaction was completed, the mixture was cooled to room temperature, and a white viscous product was precipitated from excess diethyl ether, which is 3-(diethylamino)-1,2-propanediol polyurethane.

[0018] Example 2 Will LLysine diisocyanate (1.44 mmol) and 3-(diethylamino)-1,2-propanediol (1.11 mmol) were added to a 25 mL round-bottom flask. Then, catalyst DABCO (12 mg) and tetrahydrofuran (10 mL) were added to the flask. Under nitrogen protection and anhydrous and oxygen-free conditions, the mixture was slowly heated to 80 °C and stirred under reflux for 8 h. After the reaction was completed, the mixture was cooled to room temperature, and a white viscous product was precipitated from excess diethyl ether, which is 3-(diethylamino)-1,2-propanediol polyurethane.

[0019] Example 3 Will L Lysine diisocyanate (3.93 mmol) and 3-(diethylamino)-1,2-propanediol (2.62 mmol) were added to a 25 mL round-bottom flask. Then, catalyst DABCO (12 mg) and tetrahydrofuran (10 mL) were added to the flask. Under nitrogen protection and anhydrous and oxygen-free conditions, the mixture was slowly heated to 80 °C and stirred under reflux for 8 h. After the reaction was completed, the mixture was cooled to room temperature, and a white viscous product was precipitated from excess diethyl ether, which is 3-(diethylamino)-1,2-propanediol polyurethane.

[0020] Example 4 Will L Lysine diisocyanate (2.82 mmol) and 3-(diethylamino)-1,2-propanediol (2.02 mmol) were added to a 25 mL round-bottom flask. Then, catalyst DABCO (12 mg) and tetrahydrofuran (10 mL) were added to the flask. Under nitrogen protection and anhydrous and oxygen-free conditions, the mixture was slowly heated to 80 °C and stirred under reflux for 8 h. After the reaction was completed, the mixture was cooled to room temperature, and a white viscous product was precipitated from excess diethyl ether, which was the purified 3-(diethylamino)-1,2-propanediol polyurethane.

[0021] Example 5 Will L Lysine diisocyanate (4.06 mmol) and 3-(diethylamino)-1,2-propanediol (2.62 mmol) were added to a 25 mL round-bottom flask. Then, catalyst DABCO (12 mg) and tetrahydrofuran (10 mL) were added to the flask. Under nitrogen protection and anhydrous and oxygen-free conditions, the mixture was slowly heated to 80 °C and stirred under reflux for 8 h. After the reaction was completed, the mixture was cooled to room temperature, and a white viscous product was precipitated from excess diethyl ether, which is 3-(diethylamino)-1,2-propanediol polyurethane.

[0022] Example 6 Will LLysine diisocyanate (4.19 mmol) and 3-(diethylamino)-1,2-propanediol (2.62 mmol) were added to a 25 mL round-bottom flask. Then, catalyst DABCO (12 mg) and tetrahydrofuran (10 mL) were added to the flask. Under nitrogen protection and anhydrous and oxygen-free conditions, the mixture was slowly heated to 80 °C and stirred under reflux for 8 h. After the reaction was completed, the mixture was cooled to room temperature, and a white viscous product was precipitated from excess diethyl ether, which is 3-(diethylamino)-1,2-propanediol polyurethane.

[0023] The structure and properties of 3-(diethylamino)-1,2-propanediol polyurethane (PUE) are characterized as follows: 1. Hydrogen nuclear magnetic resonance spectroscopy analysis (¹H-NMR): Figure 1 The 1H-NMR (300 MHz, DMSO-d6) spectrum of PUE clearly shows its fine structure, such as the presence of hydrogen nuclei on the methylene group of L-lysine diisocyanate at 0.7 ~ 1.6 ppm and 2.8 ~ 3.2 ppm, and the presence of amino groups on the polyurethane backbone at 5.7 / 7.1 / 7.6 ppm.

[0024] 2. Infrared absorption spectroscopy analysis: Figure 2 This is the infrared absorption spectrum of PUE. The peak at 3324 cm⁻¹ is the stretching vibration peak of N-H in the carbamate; the peaks at 2975 and 2928 cm⁻¹ are the stretching vibration peaks of methyl and methylene groups; the peak at 1635 cm⁻¹ is the stretching vibration peak of C=O; and the peak at 1048 cm⁻¹ is the stretching vibration peak of COC in the urethane group.

[0025] 3. Emission and absorption properties: Figure 3 This invention presents the ultraviolet absorption spectrum and fluorescence emission spectrum of the PUE solid powder under 365 nm excitation. The absorption peak of the PUE solid powder in the ultraviolet absorption spectrum is at 304 nm, which originates from the n-π* transition in the R band, indicating spatial conjugation between the O or N atoms and the aromatic rings in the system. Under 365 nm ultraviolet light excitation, PUE exhibits blue emission with an emission peak at 444 nm and a large Stokes shift. Figure 4The absorption and emission behavior of different concentrations of the PUE of this invention in DMSO solvent were studied to evaluate their aggregate luminescence behavior. As the concentration gradually increased from 0.1 mg mL−1 to 20 mg mL−1, the emission peak intensity of PUE near 423 nm continuously increased, but the emission peak position remained almost unchanged, exhibiting a clear concentration-enhanced emission characteristic. Simultaneously, its absorption also gradually increased with increasing solution concentration, exhibiting a concentration-dependent absorption characteristic.

[0026] 4. Solution-induced dependence like Figure 5 As shown, to gain a more detailed understanding of the excitation-dependent emission behavior of the PUE in this invention, excitation light in the ultraviolet and visible light regions was used, and the emission spectrum of PUE was measured every 20 nm. With the continuous increase of the excitation light wavelength, the emission of PUE also redshifted. Due to the good flexibility of the PUE molecular chain and the high degree of freedom of random movement of its groups, the interactions between them are dynamic, forming luminescent clusters with different degrees of conjugation. Under excitation light of different wavelengths, different types of luminescent clusters exhibit different emission colors.

[0027] 5. Microscopic morphology like Figure 6 As shown, to better understand the influence of different polymerization conditions on the luminescence properties of the PUE in this invention, we used scanning electron microscopy (SEM) to study the microstructure of the 3-(diethylamino)-1,2-propanediol monomer and solid PUE. Under the same sample amount, the 3-(diethylamino)-1,2-propanediol monomer exhibited a very dispersed volume and random free state, while the PUE exhibited a plate-like aggregate structure.

[0028] 6. Optical-mechanical properties like Figure 7 As shown, the PUE stretchable polyurethane fluorescent film exhibits excellent blue luminescence under 365 nm UV irradiation.

[0029] The white, viscous PUE product was transferred to a clean petri dish. By adjusting the tilt angle of the petri dish (15-30°), the product was allowed to spread evenly and naturally under gravity. It was then placed in a vacuum drying oven at 65°C for 12 hours to obtain a stretchable, flexible polyurethane fluorescent film. The film was carefully peeled off using precision tweezers and precisely cut using a rectangular mold to obtain rectangular sample films.

[0030] This flexible film can achieve... Figure 7 b. Bending deformation Figure 7 c Torsional deformation and Figure 7 Three mechanical responses to tensile deformation. For example... Figure 8As shown, the stress-strain curve of the PUE film under uniaxial tension measured at 25°C shows that it can generate a large strain (630%) under a low tensile stress (0.05MPa), which indicates that the material has excellent flexibility and high ductility.

Claims

1. A 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film, characterized in that, Its molecular structure is as follows: 。 2. The 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film according to claim 1, characterized in that, Its number-average molecular weight M n = 2000~2200 g mol -1 .

3. A method for preparing a 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film as described in claim 1, characterized in that, The steps of this method are as follows: (1) L -Lysine diisocyanate and 3-(diethylamino)-1,2-propanediol were mixed in a molar ratio of 1:(1.2~1.6) and added to a 25 mL round-bottom flask, along with the catalyst triethylenediamine and an organic solvent. (2) Under a protective atmosphere, under anhydrous and oxygen-free conditions, heat to 70~90℃ and stir under reflux for 8~12 h. After the reaction is completed, cool to room temperature and precipitate from excess diethyl ether to obtain a white viscous product, which is the 3-(diethylamino)-1,2-propanediol-derived polyurethane. (3) Transfer the obtained white viscous product to a clean petri dish. By adjusting the tilt angle of the petri dish, the product is allowed to spread evenly in the petri dish under gravity. Then place it in a vacuum drying oven to dry, and obtain a flexible polyurethane fluorescent film with stretchability.

4. The method for preparing the 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film according to claim 3, characterized in that, The organic solvent in step (1) is tetrahydrofuran.

5. The method for preparing the 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film according to claim 3, characterized in that, In step (1) L -Lysine diisocyanate and 3-(diethylamino)-1,2-propanediol in a molar ratio of 1:1.

4.

6. The method for preparing the 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film according to claim 3, characterized in that, Nitrogen is used as the protective atmosphere in step (2).

7. The method for preparing the 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film according to claim 3, characterized in that, In step (2), heat to 80°C and stir and reflux for 8 hours.

8. The method for preparing the 3-(diethylamino)-1,2-propanediol-derived polyurethane fluorescent film according to claim 3, characterized in that, In step (3), the drying temperature is 65℃ and the drying time is 12 h.

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