Biodegradable polypeptide-based circularly-polarized room-temperature phosphorescent material and preparation method thereof

Abstract

The invention discloses a biodegradable polypeptide-based circularly-polarized room-temperature phosphorescent material and a preparation method thereof, and relates to the technical field of photo-electromagnetic functional polymer materials. According to the invention, L-type or D-type glutamic acid-N-carboxyl anhydride is used as a monomer, and a small molecule initiator containing a phosphorescent element is adopted to initiate ring-opening polymerization to form chiral polypeptide; based on the chiral polypeptide, the biodegradable polypeptide-based circularly polarized room-temperature phosphorescent material is prepared through high-temperature drop casting and annealing treatment. The material prepared by the invention has excellent circular polarization room temperature phosphorescence performance and complete biodegradability, has wide application prospects in the fields of information encryption, biological probes, environment-friendly optical devices and the like, and realizes cooperation and unification of a high-performance photoelectric function and green sustainable development.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic functional polymer materials technology, and in particular to a biodegradable polypeptide-based circularly polarized room-temperature phosphorescent material and its preparation method. Background Technology

[0002] Driven by the rapid advancements in materials science, multifunctional optical materials have become a core area of ​​interdisciplinary research due to their ability to meet diverse needs such as high sensitivity in optoelectronic devices, precise imaging in biomedicine, and high security in information encryption. Among them, pure organic circularly polarized room-temperature phosphorescent materials, with their synergistic advantages of long excited-state lifetimes, large Stokes shifts, and chiral light absorption / emission characteristics of circularly polarized luminescence, have shown irreplaceable application potential in fields such as 3D displays, biological probes, and anti-counterfeiting encryption, becoming a cutting-edge hot topic in the field of optical materials.

[0003] Polymer matrices are widely considered ideal carriers for achieving circularly polarized room-temperature phosphorescence due to their high molecular structure designability, excellent film-forming and processing properties, and ease of functionalization through doping / grafting. By controlling the spatial conformation of polymer chains and optimizing intermolecular interactions, nonradiative transitions of phosphorescent chromophores can be effectively suppressed, while simultaneously transmitting chiral signals to induce circularly polarized luminescence. However, there is a significant technical contradiction between the performance realization and biodegradability of existing polymer-based circularly polarized room-temperature phosphorescent materials, and performance control faces multiple technical challenges. On the one hand, existing systems generally rely on traditional polymer matrices such as polystyrene, polymethyl methacrylate, and polyvinyl alcohol. Although these materials can stabilize triplet excitons and construct chiral microenvironments through rigid frameworks or hydrogen bonding, the waste is difficult to degrade naturally after use, which easily leads to plastic pollution and microplastic accumulation. This is especially true in non-persistent application scenarios such as disposable advertising signs, short-term information encryption carriers, and temporary biomedical probes, which is seriously out of touch with the global circular economy strategy and the development needs of environmentally friendly materials.

[0004] On the other hand, to achieve the synergy between biodegradability and circularly polarized room temperature phosphorescence performance, the following multiple technical bottlenecks need to be overcome: (1) Biodegradable polymers (such as polylactic acid and polyhydroxy fatty acid esters) are mostly flexible chain structures with violent molecular chain movement, making it difficult to form a stable rigid microenvironment to suppress triplet exciton quenching, resulting in a significant reduction in phosphorescence efficiency; (2) Most biodegradable polymers lack inherent chiral structures and need to construct chiral microenvironments by introducing chiral units (such as chiral side chains and chiral dopants). However, the introduction of chiral units can easily damage the crystallinity and degradation performance of the polymer, and the efficient transmission of chiral signals to phosphorescent chromophores is difficult to achieve; (3) In the existing preparation process, the compatibility between biodegradable polymers and phosphorescent chromophores is poor, and phase separation is likely to occur, resulting in a weakening or even disappearance of the circularly polarized luminescence signal. Furthermore, it is difficult to accurately control the microstructure and molecular arrangement of the film during the film formation process, further restricting the stability of performance.

[0005] The aforementioned technical challenges have slowed the progress of research on biodegradable circularly polarized room-temperature phosphorescent materials, failing to meet the comprehensive demands of practical applications for high performance, environmental friendliness, and controllability. Therefore, developing a novel polymer system that simultaneously addresses the contradiction between material performance and degradability, as well as the challenge of performance control, to construct materials that possess both biodegradability and highly efficient circularly polarized room-temperature phosphorescent properties with controllable performance, has become a crucial technological direction urgently needing breakthroughs. This is of great significance for promoting the green application and industrialization of circularly polarized room-temperature phosphorescent materials. Summary of the Invention

[0006] The purpose of this invention is to provide a biodegradable polypeptide-based circularly polarized room-temperature phosphorescent material and its preparation method, so as to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is to provide a chiral polypeptide with the structure shown below: ; In the formula, C It is an L-type chiral carbon or a D-type chiral carbon; n is a positive integer from 25 to 300; R is selected from one of the following groups: The wavy line represents the group connection site.

[0008] Polypeptides are formed by amide bonds connecting their molecular chains. Their chemical structure is homologous to that of natural proteins, making them inherently biodegradable. They can be gradually hydrolyzed into amino acid molecules by microorganisms or enzymes, completely avoiding the risks of plastic waste and microplastic pollution caused by traditional materials. This perfectly meets the environmental protection needs of non-permanent scenarios such as disposable optical labels and short-term information encryption. More importantly, the amide bonds on the polypeptide molecular chains can form a dense network of intermolecular hydrogen bonds. This network can effectively restrict the molecular vibration and rotation of phosphorescent units and suppress the nonradiative transition of triplet excitons. The stable existence of triplet excitons is the key to room temperature phosphorescence. Traditional materials often require low temperatures or complex doping to achieve this effect. This invention achieves the stability of triplet excitons at room temperature through the inherent hydrogen bonding of the polypeptide matrix, greatly simplifying the preparation process and endowing the material with excellent room temperature phosphorescence performance.

[0009] The second technical solution of the present invention provides a method for preparing the above-mentioned chiral polypeptide, comprising the following steps: The chiral polypeptide was obtained by ring-opening polymerization using L-glutamic acid-N-carboxycyclic anhydride (L-Glu NCA) or D-glutamic acid-N-carboxycyclic anhydride (D-GluNCA) as monomers under the action of an initiator. The initiator used in this invention is a small molecule with a room-temperature phosphorescence unit, specifically any one of the following structural compounds: .

[0010] The structure of the L-type glutamic acid-N-carboxyl ring anhydride is shown below: ; The structure of the D-type glutamic acid-N-carboxyl ring anhydride is shown below: .

[0011] Furthermore, the ring-opening polymerization reaction is carried out at a temperature of 25-45°C and for a duration of 24-72 hours.

[0012] The ring-opening polymerization reaction was carried out under a protective atmosphere.

[0013] Further, the molar ratio of the initiator to the L-type glutamic acid-N-carboxylic acid anhydride is 1:25 to 1:300; or, the molar ratio of the initiator to the D-type glutamic acid-N-carboxylic acid anhydride is 1:25 to 1:300.

[0014] The third technical solution of the present invention provides the application of the above-mentioned chiral polypeptide in the preparation of biodegradable circularly polarized room temperature phosphorescent materials.

[0015] Fourth technical solution of the present invention: A method for preparing a biodegradable polypeptide-based circularly polarized room-temperature phosphorescent material, using a high-temperature drop casting method, comprising the following steps: The chiral polypeptide was dissolved in an organic solvent, and the resulting chiral polypeptide solution was dropped onto the surface of a carrier. After annealing, a film material was obtained, which is the biodegradable polypeptide-based circularly polarized room temperature phosphorescent material.

[0016] Furthermore, the organic solvent may be N,N-dimethylformamide.

[0017] Furthermore, the annealing temperature is 120-160℃; the annealing time is 50 min to 150 min.

[0018] Furthermore, the carrier is quartz, silicon wafer, glass, or metal.

[0019] Furthermore, the carrier is preheated at a temperature of 90 ℃ to 120 ℃.

[0020] Furthermore, the carrier can be a cuboid or a cylinder; preferably, the length, width, and height of the cuboid are independently selected from 1 mm to 50 mm, and the diameter and height of the cylinder are independently selected from 1 mm to 50 mm.

[0021] Furthermore, the concentration of the chiral polypeptide solution is 10 mg / mL to 50 mg / mL, and the dissolution temperature is 50℃ to 100℃.

[0022] Furthermore, the solvent used to prepare the chiral polypeptide solution may be N,N-dimethylformamide.

[0023] Furthermore, the 0.1 mL to 1 mL chiral polypeptide solution was drop-cast within 10 min to 60 min.

[0024] In this invention, the film thickness of the biodegradable polypeptide-based circularly polarized room temperature phosphorescent material is 0.01 mm to 0.1 mm.

[0025] Fifth technical solution of the present invention: providing a biodegradable polypeptide-based circularly polarized room temperature phosphorescent material prepared by the above preparation method.

[0026] This invention utilizes the chiral characteristics of polypeptides and the functional integration of phosphorescent units to achieve controllable regulation of circularly polarized luminescence performance, overcoming the limitations of traditional materials with single performance and limited regulation methods. The polypeptide is formed by ring-opening polymerization of L-type or D-type glutamic acid anhydride monomers within an N-carboxyl ring. Its molecular chains naturally possess chirality, and during film formation, they self-assemble into chiral secondary structures such as α-helices and β-sheets. This chiral structure is transferred to the chemically bonded phosphorescent units through intermolecular forces (hydrogen bonds, van der Waals forces), causing the emission dipole moments of the phosphorescent units to align orderly along the chiral direction, thereby inducing a strong and stable circularly polarized room-temperature phosphorescent signal.

[0027] More importantly, this invention achieves precise control in two dimensions: on the one hand, by adjusting the molar ratio of initiator to monomer (1:25~1:300), the chain length of the polypeptide (number of repeating units n=25~300) is controlled. The longer the chain length, the denser the intermolecular hydrogen bond network, the higher the chiral transfer efficiency, and the more significant the intensity of the circularly polarized room-temperature phosphorescent signal, thus achieving gradient amplification of signal intensity; on the other hand, by converting the chirality of the monomer (interchange of L-type and D-type), the chirality of the secondary structure of the polypeptide is reversed, thereby inducing a complete reversal of the circularly polarized signal direction of the phosphorescent unit (interchange of left-handed and right-handed). This dual controllability of chain length-intensity and chirality-direction is difficult to achieve with traditional materials, providing possibilities for customized applications in different scenarios.

[0028] During ring-opening polymerization, the small-molecule initiator containing phosphorescent units not only initiates the growth of polypeptide chains but also chemically bonds phosphorescent functional units to the polypeptide molecular chains. This avoids the performance instability caused by the easy aggregation and migration of phosphorescent units in traditional doping processes, ensuring the uniform dispersion and stable existence of phosphorescent units in the matrix. The high-temperature drop casting and annealing processes further optimize the microstructure of the film: the high-temperature environment promotes rapid solvent evaporation, avoiding structural defects caused by slow solvent evaporation during film formation; the annealing treatment induces the polypeptide molecular chains to form more regular chiral secondary structures, strengthens the intermolecular hydrogen bond network, and further improves the stability of triplet excitons and chiral transfer efficiency, ultimately obtaining a CP-RTP film with uniform thickness and stable performance.

[0029] The preparation process of this invention does not require complex equipment, the reaction conditions are mild, and it is easy to scale up production. Compared with the complex processes such as vacuum coating and photolithography that traditional materials rely on, it significantly reduces production costs and is expected to promote the innovation of green technologies such as biodegradable optoelectronic devices and transient information encryption systems.

[0030] The material of this invention shows broad application prospects in multiple fields: in information encryption and security anti-counterfeiting, the unidirectionality of its circularly polarized light can be used to construct high-security optical tags; in the biomedical field, it can be designed as a metabolizable in vivo imaging probe; in the field of green optical devices, it can replace traditional materials in disposable displays, environmentally friendly sensors, etc., reducing resource waste.

[0031] The present invention discloses the following technical effects: This invention provides a polypeptide-based circularly polarized room-temperature phosphorescent material that combines high-performance optoelectronic functions with biodegradability. It uses L-type or D-type glutamic acid-N-carboxylic acid anhydride as a monomer and utilizes a small molecule initiator containing phosphorescent motifs to directly initiate ring-opening polymerization, thereby forming chemical bonds between the phosphorescent functional groups and the polymer backbone. This overcomes the technical bottleneck of performance degradation caused by phase separation in traditional doping methods.

[0032] This invention not only achieves uniform distribution of phosphorescent building blocks in the material, but also significantly improves the photoelectric properties of the material through the synergistic effect of the natural chiral structure of the polypeptide backbone and the hydrogen bond network. Furthermore, the emission direction of left-handed or right-handed circularly polarized light can be flexibly switched by adjusting the chirality (L / D type) of the monomers. At the same time, by adjusting the polymer chain length, the emission intensity and wavelength can be further optimized to meet the customized needs of different application scenarios.

[0033] This invention employs a simple process combining high-temperature drop casting and annealing, enabling molecules to form a highly ordered arrangement on the carrier surface, effectively suppressing non-radiative transitions. Furthermore, the entire process requires no special equipment or toxic solvents, offering both high efficiency and environmental benefits. In addition, the material's polypeptide backbone is composed of biocompatible amino acids, and its amide bonds can be gradually degraded by enzymes in the natural environment, ultimately transforming into harmless small molecules, fully meeting biodegradability standards and significantly reducing the environmental pollution problems associated with traditional phosphorescent materials.

[0034] This invention achieves synergistic optimization of high-performance optoelectronic functions, complete biodegradability, and low-cost preparation through material design, process innovation, and functional integration. It not only breaks through the functional limitations of traditional materials but also aligns with the global trend of green and sustainable development, demonstrating significant technological advancement and market application potential. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1The following is a room-temperature phosphorescence spectrum of the polypeptide-based circularly polarized room-temperature phosphorescent thin film prepared in Example 5 of the present invention: (A) is the steady-state emission spectrum of L-polypeptide-1 and D-polypeptide-1, (B) is the time-resolved emission lifetime curve of L-polypeptide-1 and D-polypeptide-1 at the long-wavelength emission peak, (C) is the steady-state emission spectrum of L-polypeptide-2 and D-polypeptide-2, and (D) is the time-resolved emission lifetime curve of L-polypeptide-2 and D-polypeptide-2 at the long-wavelength emission peak.

[0037] Figure 2 shows the circularly polarized emission correlation spectrum of the polypeptide-based circularly polarized room temperature phosphorescent thin film prepared in Example 5 of the present invention; (A) is the circular dichroism spectrum of L-polypeptide-1 and D-polypeptide-1 in the characteristic absorption band, (B) is the circularly polarized emission spectrum of L-polypeptide-1 and D-polypeptide-1 in the characteristic emission band, (C) is the emission asymmetry factor spectrum of L-polypeptide-1 and D-polypeptide-1 in the characteristic emission band, (D) is the circular dichroism spectrum of L-polypeptide-2 and D-polypeptide-2 in the characteristic absorption band, (E) is the circularly polarized emission spectrum of L-polypeptide-2 and D-polypeptide-2 in the characteristic emission band, and (F) is the emission asymmetry factor spectrum of L-polypeptide-2 and D-polypeptide-2 in the characteristic emission band.

[0038] Figure 3 The images show the circularly polarized emission spectra of the polypeptide-based circularly polarized room-temperature phosphorescent films with different degrees of polymerization prepared in Example 5 of this invention; (A) shows L-polypeptide-2 and L-polypeptide-2. And L-polypeptide-2 The steady-state emission spectra of (B) are for L-polypeptide-2 and L-polypeptide-2. And L-polypeptide-2 Time-resolved emission lifetime curves at the long-wavelength emission peak, (C) represents L-polypeptide-2 and L-polypeptide-2. And L-polypeptide-2 The circularly polarized emission spectrum, (D) is for L-polypeptide-2, L-polypeptide-2 And L-polypeptide-2 The luminescence asymmetry factor spectrum. Detailed Implementation

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0041] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0042] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0043] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0044] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0045] Example 1: Preparation of chiral polypeptides The synthetic route of the chiral polypeptide in this embodiment is as follows: The preparation steps are as follows: Initiator BrBPhA (0.1 mmol) and L-Glu NCA (20 mmol) were added to a 25 mL single-necked round-bottom flask, followed by 5 mL of anhydrous N,N-dimethylformamide. The mixture was then reacted at 25 °C under a nitrogen atmosphere for 48 h. Afterward, the product was precipitated in 100 mL of diethyl ether, centrifuged to obtain a solid, and the precipitation and centrifugation were repeated three times. The solid was then dried in a vacuum oven to obtain the chiral polypeptide BrBPh-PLGA (n = 123).

[0046] Example 2 Preparation of chiral polypeptides The synthetic route of the chiral polypeptide in this embodiment is as follows: The preparation steps are as follows: Initiator BrBPhA (0.1 mmol) and D-Glu NCA (20 mmol) were added to a 25 mL single-necked round-bottom flask, followed by 5 mL of anhydrous N,N-dimethylformamide. The mixture was then reacted at 25 °C under a nitrogen atmosphere for 48 h. Afterward, the mixture was precipitated in 100 mL of diethyl ether, centrifuged to obtain a solid, and the precipitation and centrifugation were repeated three times. The solid was then dried in a vacuum oven to obtain the chiral polypeptide BrBPh-PDGA (n = 189).

[0047] Example 3 The synthetic route of the chiral polypeptide in this embodiment is as follows: The preparation steps are as follows: Initiator BrNIA (0.1 mmol) and L-Glu NCA (20 mmol) were added to a 25 mL single-necked round-bottom flask, followed by 5 mL of anhydrous N,N-dimethylformamide. The mixture was then reacted at 25 °C under a nitrogen atmosphere for 48 h. Afterward, the product was precipitated in 100 mL of diethyl ether, centrifuged to obtain a solid, and the precipitation and centrifugation were repeated three times. The solid was then dried in a vacuum oven to obtain the chiral polypeptide BrNI-PLGA (n = 119).

[0048] Furthermore, by controlling the initiator content to be 0.05 mmol and 0.025 mmol respectively and using the same reaction conditions as described above, two other chiral polypeptides with decreasing degrees of polymerization, BrNI-PLGA, can be obtained. (n = 78), BrNI-PLGA (n = 29).

[0049] Example 4 The synthetic route of the chiral polypeptide in this embodiment is as follows: The preparation steps are as follows: Initiator BrNIA (0.1 mmol) and D-Glu NCA (20 mmol) were added to a 25 mL single-necked round-bottom flask, followed by 5 mL of anhydrous N,N-dimethylformamide. The mixture was then reacted at 25 °C under a nitrogen atmosphere for 48 h. Afterward, the product was precipitated in 100 mL of diethyl ether, centrifuged to obtain a solid, and the precipitation and centrifugation were repeated three times. The solid was then dried in a vacuum oven to obtain the chiral polypeptide BrNI-PDGA (n = 125).

[0050] Example 5: Preparation of Polypeptide-based Circularly Polarized Room Temperature Phosphorescent Thin Films The chiral polypeptides prepared in Examples 1-4 were respectively used to prepare polypeptide-based circularly polarized room-temperature phosphorescent thin films. The specific steps are as follows: The chiral polypeptides (25 mg) prepared in Examples 1-4 were dissolved in N,N-dimethylformamide to prepare a solution of 25 mg / mL at a dissolution temperature of 50°C. The solution was then heated at 80°C for 30 min to obtain a chiral polypeptide solution. 100 μL of the above chiral polypeptide solution was then dropped onto a quartz plate (length × width × height: 10 × 10 × 1 mm) preheated at 120°C and spread evenly. The casting was completed in 5 min, and heating was stopped after 55 min. After cooling, a circularly polarized room temperature phosphorescent film with a thickness of 0.1 mm was obtained.

[0051] The polypeptide-based circularly polarized room-temperature phosphorescent films prepared using the chiral polypeptides of Examples 1 and 2 were labeled as L-polypeptide-1 and D-polypeptide-1, respectively; the chiral polypeptides BrNI-PLGA and BrNI-PLGA prepared using the chiral polypeptides of Example 3 were labeled as L-polypeptide-1 and D-polypeptide-1, respectively. and BrNI-PLGA The polypeptide-based circularly polarized room-temperature phosphorescent thin films prepared using the chiral polypeptide in Example 4 are labeled L-polypeptide-2 and L-polypeptide-2. L-Polypeptide-2 And D-polypeptide-2.

[0052] Emission spectroscopy and luminescence lifetime tests at long-wavelength emission peaks were performed on the four types of polypeptide thin film materials under ultraviolet light excitation. Polypeptide 1 series was excited with 310 nm ultraviolet light, and polypeptide 2 series was excited with 330 nm ultraviolet light.

[0053] Figure 1The following is a room-temperature phosphorescence spectrum of the polypeptide-based circularly polarized room-temperature phosphorescent thin film prepared in Example 5 of the present invention: (A) is the steady-state emission spectrum of L-polypeptide-1 and D-polypeptide-1, with the curves clearly showing characteristic emission peaks, indicating that both films have luminescent properties; (B) is the time-resolved emission lifetime curve of L-polypeptide-1 and D-polypeptide-1 at the long-wavelength emission peak, and the test results show that both have millisecond-level emission lifetimes, which is consistent with the typical characteristics of room-temperature phosphorescence; (C) is the steady-state emission spectrum of L-polypeptide-2 and D-polypeptide-2, whose characteristic emission peaks correspond to those of L-polypeptide-1 and D-polypeptide-1, and the peak shapes are stable; (D) is the time-resolved emission lifetime curve of L-polypeptide-2 and D-polypeptide-2 at the long-wavelength emission peak, which also shows a stable millisecond-level lifetime. The test results in Figure 1 clearly show that the polypeptide-based circularly polarized room-temperature phosphorescent films prepared in this invention all exhibit significant room-temperature phosphorescence properties.

[0054] To further verify the chiral luminescence properties of the thin films, the chiral absorption signals of the four thin films were tested using a circular dichroism spectroscopy (CDS) instrument, and the chiral characteristics of their room-temperature phosphorescence emission were characterized using a circularly polarized emission spectrometer (CPE). Figure 2 shows the circularly polarized emission spectra of the polypeptide-based circularly polarized room-temperature phosphorescent thin films prepared in Example 5 of this invention: (A) shows the circular dichroism spectra of L-polypeptide-1 and D-polypeptide-1 in the characteristic absorption band, with the curves showing symmetrical and opposite chiral absorption signals, proving that the chirality of the polypeptides was successfully transferred to the entire film; (B) shows the circularly polarized emission spectra of L-polypeptide-1 and D-polypeptide-1 in the characteristic emission band, exhibiting obvious symmetrical circularly polarized room-temperature phosphorescence characteristics; (C) shows the emission asymmetry factor spectra of L-polypeptide-1 and D-polypeptide-1 in the characteristic emission band, with a value reaching 10 in the room-temperature phosphorescence emission band. -2 (A) shows strong circularly polarized room-temperature phosphorescence characteristics; (D) shows the circular dichroism spectra of L-polypeptide-2 and D-polypeptide-2 in the characteristic absorption band, which also show symmetrical and opposite chiral absorption peaks, consistent with the chiral absorption patterns of L-polypeptide-1 and D-polypeptide-1; (E) shows the circularly polarized emission spectra of L-polypeptide-2 and D-polypeptide-2 in the characteristic emission band, showing obvious symmetrical circularly polarized room-temperature phosphorescence characteristics; (F) shows the emission asymmetry factor spectrum of L-polypeptide-2 and D-polypeptide-2 in the characteristic emission band, which can also reach 10 in the room-temperature phosphorescence emission band. -2It exhibits strong circularly polarized room temperature phosphorescence characteristics.

[0055] To further verify the tunability of chiral luminescence in thin films, emission spectroscopy, luminescence lifetime at long-wavelength emission peaks, and circularly polarized luminescence were performed on the same type of chiral polypeptide thin film materials with decreasing degree of polymerization. Figure 3 The room-temperature phosphorescence spectra and circularly polarized emission spectra of polypeptide-based circularly polarized room-temperature phosphorescent films with different degrees of polymerization prepared in Example 5 of the present invention are shown: where (A) represents L-polypeptide-2 and L-polypeptide-2. And L-polypeptide-2 The steady-state emission spectra of the three films clearly show the same characteristic emission peaks, indicating that all three films possess luminescent properties; (B) represents L-polypeptide-2 and L-polypeptide-2. And L-polypeptide-2 Time-resolved emission lifetime curves at the long-wavelength emission peak showed that both exhibited similar millisecond-level emission lifetimes, consistent with typical characteristics of room-temperature phosphorescence; (C) represents L-polypeptide-2 and L-polypeptide-2. And L-polypeptide-2 In the circularly polarized emission spectrum of the characteristic emission band, it exhibits a circularly polarized room-temperature phosphorescence signal that decreases with the degree of polymerization; (D) represents L-polypeptide-2 and L-polypeptide-2. And L-polypeptide-2 The luminescence asymmetry factor spectrum in the characteristic emission band shows values ​​ranging from 10 in the room temperature phosphorescent emission band. -2 As the phosphorus content gradually decreases to ~0, it exhibits a clear characteristic of circularly polarized room-temperature phosphorescence with adjustable polymerization degree. The test results in Figure 3 clearly demonstrate that the polypeptide-based thin film prepared in this invention possesses significantly tunable circularly polarized room-temperature phosphorescence properties.

[0056] The above test results fully demonstrate that the polypeptide-based circularly polarized room-temperature phosphorescent films prepared by this invention all possess significant chiral room-temperature phosphorescent emission performance. Not only can the direction of circularly polarized emission signals be precisely reversed by converting the chirality (L-type / D-type) of the polypeptide, but the intensity of chiral emission can also be controlled by utilizing the degree of polymerization of the chiral polypeptide.

[0057] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A chiral polypeptide, characterized in that, The structure is as follows: ； In the formula, C It is an L-type chiral carbon or a D-type chiral carbon; n is a positive integer from 25 to 300; R is selected from one of the following groups: 。 2. The method for preparing chiral polypeptides as described in claim 1, characterized in that, Includes the following steps: The chiral polypeptide was obtained by ring-opening polymerization using L-type glutamic acid-N-carboxylated intracyclic anhydride or D-type glutamic acid-N-carboxylated intracyclic anhydride as monomers, under the action of an initiator. The initiator is any one of the following structural compounds: 。 3. The preparation method according to claim 2, characterized in that, The ring-opening polymerization reaction is carried out at a temperature of 25-45℃ and for a duration of 24-72 hours.

4. The preparation method according to claim 3, characterized in that, The molar ratio of the initiator to the L-type glutamic acid-N-carboxylic acid anhydride is 1:25 to 1:300; or, the molar ratio of the initiator to the D-type glutamic acid-N-carboxylic acid anhydride is 1:25 to 1:

300.

5. The application of the chiral polypeptide as described in claim 1 in the preparation of biodegradable circularly polarized room temperature phosphorescent materials.

6. A method for preparing a biodegradable polypeptide-based circularly polarized room-temperature phosphorescent material, characterized in that, Includes the following steps: The chiral polypeptide of claim 1 is dissolved in an organic solvent, and the resulting chiral polypeptide solution is dropped onto the surface of a carrier, followed by annealing to obtain the biodegradable polypeptide-based circularly polarized room temperature phosphorescent material.

7. The preparation method according to claim 6, characterized in that, The annealing temperature is 120-160℃; the annealing time is 50 min to 150 min.

8. The preparation method according to claim 6, characterized in that, The carrier is quartz, silicon wafer, glass, or metal.

9. The biodegradable polypeptide-based circularly polarized room-temperature phosphorescent material prepared by the preparation method according to any one of claims 6-8.

Images