Triphenylchloromethane polymer with photochromic characteristic
By preparing triphenylchloromethane-based polymers, the problem of performance degradation of photochromic polymers in the solid state was solved, and significant, rapid, and reversible photochromic properties were achieved, which are suitable for functional fluorescent materials.
Patent Information
- Application Number
- CN202511805329.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-01-23
AI Technical Summary
Existing photochromic polymers exhibit performance degradation, slower response speed, and even loss of color-changing ability in the solid state, making it difficult to meet the needs of practical applications.
Triphenylchloromethane-based polymers were prepared through a simple one-step post-modification reaction. The polymers reacted with acetyl chloride in dichloromethane solvent to form polymers with photochromic properties, specifically PTPMC, HPTPMC, and PVTPMC.
It exhibits significant, rapid, and reversible photochromic properties in the solid state, with color changes ranging from yellow-green to orange-red or from blue to purple-red. The photoluminescence properties can still be recovered after multiple cycles. The synthesis method is simple and the conditions are mild.
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Figure CN121378680A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of functional polymer material synthesis, and particularly relates to a photochromic polymer with excellent performance. BACKGROUND
[0002] Photochromic polymers refer to a series of materials based on photochromic units on polymer chains, which produce reversible color changes under irradiation of specific wavelengths of light. Photochromic polymers are of great interest due to their fast and convenient response, such as reversibility, controllability, accessibility and non-destructive characteristics of light stimulus response. They also show promising performance in a series of applications, such as photoactuators, photochromism, drug delivery, and molecular switches. The current mainstream preparation strategy has inherent defects. The physical blending method is simple, but the small molecule photochromic compound is prone to migration and crystallization, resulting in performance degradation and poor durability. Although the chemical bonding method can improve stability, it usually needs to design and synthesize photochromic monomers with specific polymerization functional groups, and the synthesis route is complicated, and the polymerization process may have irreversible effects on sensitive photochromic groups. More importantly, many small molecule photochromic systems with excellent performance or partially polymerized systems perform well in solution, but once in solid state, due to the close molecular packing and limited movement, the photochromic efficiency will decrease sharply, the response speed will slow down, and even the color changing ability will be completely lost. This "solid-state quenching" phenomenon greatly limits its application in most practical scenarios (such as thin films, coatings, solid devices). Developing a photochromic polymer material that can simultaneously meet the three major demands of high performance in solid state, high stability, and simple synthesis has always been a technical bottleneck that researchers in this field strive to break through. Therefore, there is an urgent need in the art for a new polymer structure that does not require complex post-processing or doping, and can directly exhibit strong, fast and reversible photochromic behavior in solid state, while also considering good processing stability. SUMMARY
[0003] The present application aims to provide a triphenylchloromethane polymer with significant, fast and reversible photochromic performance in solid state, overcoming the deficiencies of existing photochromic materials in solid state applications.
[0004] The purpose of the present application is achieved by the following scheme: A photochromic polymer is a triphenylchloromethane polymer, and the structural general formula is as follows:
[0005] wherein the molecular weight is 1000 g / mol-100000 g / mol, the molecular weight distribution is 1-2.3, m is 5-200; n is 5-200; and the polymer has an aggregation-induced emission effect.
[0006] When the polymer is irradiated with 365 nm ultraviolet light, its solid-state fluorescence emission wavelength can undergo a red shift, specifically from yellow-green (550 nm) to orange-red (680 nm), or from blue (450 nm) to purple-red (670 nm). It can reversibly return to its original state after the ultraviolet light source is turned off.
[0007] The polymer can be prepared by a simple one-step post-modification reaction, namely, by reacting a triphenylmethanol-based polymer with acetyl chloride in a dichloromethane solvent, including the following steps: Three different types of poly(triphenylmethanol) were dissolved in dichloromethane and placed in a dry reaction tube. The mixture was then reacted with acetyl chloride at room temperature for 3 hours. After the reaction was completed, the mixture was filtered, washed, and vacuum dried. The reaction solution was then poured into a poor solvent to precipitate the polymer, thus obtaining the photochromic polymer.
[0008] Specifically, the method for preparing the above-mentioned triphenylchloromethane polymer with photochromic properties is characterized by comprising the following preparation steps:
[0009] Starting with linear triphenylmethanol polymer (PTPM), under anhydrous and oxygen-free conditions at room temperature, acetyl chloride was reacted with dichloromethane (DCM) as solvent for 3 hours. After the reaction was complete, the reaction solution was poured into a poor solvent to precipitate the polymer. The precipitate was then filtered, washed, and vacuum dried to obtain the photochromic polymer (PTPMC). Alternatively, starting with hyperbranched triphenylmethanol polymer (HPTPM), under anhydrous and oxygen-free conditions at room temperature, acetyl chloride was reacted with dichloromethane (THF) as solvent for 3 hours. The precipitate was then poured into a poor solvent to precipitate the polymer. The precipitate was then filtered, washed, and vacuum dried to obtain the photochromic polymer (PTPMC). Photochromic polymers are phenyl polymers (HPTPMC) that exhibit yellow fluorescence in the solid state, with the fluorescence shifting red with the duration of ultraviolet irradiation. Alternatively, starting with a side-chain triphenylmethanol polymer (PVTPM), the reaction is carried out under anhydrous and oxygen-free conditions at room temperature with dichloromethane (THF) as the solvent and acetyl chloride for 3 hours. The reaction solution is then poured into a poor solvent to precipitate the polymer. After filtration, washing, and vacuum drying, a photochromic polymer (PVTPMC) is obtained, which exhibits blue fluorescence in the solid state, with the fluorescence shifting red with the duration of ultraviolet irradiation.
[0010] Furthermore, the unsuitable solvent is petroleum ether.
[0011] The triphenylchloromethane polymer with photochromic properties prepared by the above-described preparation method of the present invention is characterized in that, under ultraviolet light irradiation at a wavelength of 365 nm, the solid of the synthesized triphenylchloromethane polymer exhibits a red shift as the duration of ultraviolet light irradiation, changing from yellow-green to orange-red, with the emission wavelength changing from 550 nm to 660 nm, or changing from blue fluorescence to purplish-red, with the emission wavelength changing from 440 nm to 670 nm. After the ultraviolet light is turned off, it can reversibly return to its original fluorescence.
[0012] Compared with existing polymer fluorescence modulation techniques, this invention has the following advantages: This invention relates to a photochromic polymer. The polymer exhibits a significant redshift in fluorescence even in the solid state, with a color change range covering the visible light region from yellow-green to orange-red or from blue to violet-red. Its color-changing behavior is rapid and significant, and it can reversibly recover after multiple light-dark cycles. Furthermore, due to the polymer's unique AIE properties, its photoluminescence performance is not weakened in the solid state but rather enhanced, completely overturning the traditional understanding that "the performance of photochromic materials inevitably degrades in the solid state." Moreover, the synthesis method is simple and the conditions are mild. Based on its excellent solid-state photochromic properties, it is highly suitable as a functional fluorescent material. Attached Figure Description
[0013] Figure 1 The figures show the 1H NMR spectra of the monomer and polymer of the side-chain triphenylmethanol polymer. In the figures: (A) 1H NMR spectrum of the triphenylmethanol monomer; (B) 1H NMR spectrum of the side-chain triphenylmethanol polymer PVTPM. Figure 2 The emission spectra and corresponding CIE coordinate diagrams of photochromic triphenylchloromethane polymers (PTPMC, HPTPMC, and PVTPMC) as a function of illumination time are shown in the figure. In the figure: (A) 1H NMR spectrum of PTPMC; (B) 1H NMR spectrum of HPTPMC; (C) 1H NMR spectrum of PVTPMC. Figure 3 Emission spectra and digital images of PTPMC (A), HPTPMC (B), and PVPTMC (C) over time. CIE coordinate plots of PTPMC (D), HPTPMC (E), and PVPTMC (F). Detailed Implementation
[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the embodiments described herein are merely illustrative and not intended to limit the invention.
[0015] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.
[0016] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents and materials used in the following examples are commercially available.
[0017] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0018] This invention discloses a photochromic polymer.
[0019] Example 1 Synthesize main-chain linear triphenylmethanol polymer (PTPM), hyperbranched triphenylmethanol polymer (HPTPM), and side-chain triphenylmethanol polymer (PVTPM).
[0020] 1) The synthesis of PTPM was performed as follows: A 25 mL Schlenk tube was used. Fresh magnesium shavings (1.2 eq) were placed in the Schlenk tube and dried under vacuum. The Schlenk tube reaction system was then purged with a nitrogen atmosphere, and a nitrogen balloon was added to maintain a continuous inert environment. Subsequently, a monomer (selected from 4-chlorobenzophenone, 4-bromobenzophenone, or 4-fluorobenzophenone, 1.0 eq) dissolved in THF and preheated to 45°C was added to the reaction system via a syringe. After stirring for 5 minutes, a small amount of 1,2-dibromoethane was injected into the reaction system. The reaction was carried out under reflux for 24 hours. The Schlenk tube was then cooled to room temperature, and quenched and hydrolyzed by adding a saturated ammonium chloride aqueous solution. The resulting organic phase was filtered, extracted with dichloromethane / water, dried with anhydrous MgSO4, and concentrated under reduced pressure. The concentrate was added dropwise to excess petroleum ether to precipitate the product. After 2–3 purifications, the product was filtered under vacuum and dried to obtain the target polymer—linear triphenylmethanol polymer (PTPM).
[0021] 2) The synthesis steps of HPTPM are similar to those described above, except for the amount of reactants and the type of monomer: Take 2.5 eq of fresh magnesium shavings, and 1.0 eq of 4,4-dichlorobenzophenone, 4,4-dibromobenzophenone, or 4,4-difluorobenzophenone, dissolved in THF and preheated to 45°C before injecting into the reaction system. The remaining operations, including nitrogen protection, addition of 1,2-dibromoethane, reflux reaction for 24 hours, quenching, extraction, drying, concentration, and petroleum ether precipitation purification, are consistent with the PTPM synthesis process, yielding the target polymer—hyperbranched triphenylmethanol polymer (HPTPM).
[0022] 3) The synthesis of PVTPM mainly includes two stages: monomer preparation and RAFT polymerization. First, 4-bromostyrene (1 mmol) was dissolved in dry tetrahydrofuran and reacted with magnesium shavings (1.5 mmol) under a nitrogen atmosphere for 1.5 to 2.5 hours to prepare the corresponding Grignard reagent. This Grignard reagent was then reacted with benzophenone (1 mmol) in dry tetrahydrofuran for 12 hours. After the reaction, the organic phase was extracted with dichloromethane, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. The crude product was separated by column chromatography using petroleum ether / ethyl acetate (25:1 v / v), concentrated by rotary evaporation, and dried under vacuum to obtain a white powdery solid monomer, triphenylmethanol. Its NMR spectrum is shown in the appendix. Figure 1 (A) in the middle.
[0023] Subsequently, the above-mentioned triphenylmethanol monomer, chain transfer agent (trithiocarbonate), and initiator (azobisisobutyronitrile) were dissolved in 2 mL of dry tetrahydrofuran at a mass ratio of 1000:5:1, and a RAFT polymerization reaction was carried out. After the reaction was completed, the mixture was precipitated in petroleum ether to obtain the pure side-chain type polytriphenylmethanol polymer compound PVTPM, the NMR spectrum of which is attached. Figure 1 (B) in the middle.
[0024] Example 2 Synthesis of photochromic polymers (PTPMC, HPTPMC, and PVTPMC) 1) The specific steps for synthesizing PTPMC are as follows: Take a 50 mL Schlenk tube, stopper the branch end with a glass stopper, and secure it with a metal spring and clamps to ensure good airtightness. Place the linear poly(triphenylmethanol) synthesized in Example 1 (also known as main-chain linear triphenylmethanol polymer, abbreviated as PTPM, 1 g) into the dried Schlenk tube, and fill the entire Schlenk tube with nitrogen gas. Finally, connect the entire apparatus to a nitrogen balloon for protection to ensure a nitrogen atmosphere. Then, add 2 mL of dichloromethane (DCM) through a syringe to dissolve the PTPM, and then slowly add excess acetyl chloride (6 mL) to the reaction tube. After refluxing for 3 hours, cool the solution to room temperature. After dichloromethane / water extraction, the organic solution is dried with anhydrous MgSO4 and concentrated under reduced pressure. The product is precipitated in excess petroleum ether, purified 2-3 times, vacuum filtered and dried to obtain the photochromic polymer (PTPMC), see [link to relevant documentation]. Figure 2 (A) The proton nuclear magnetic resonance (¹H NMR) spectrum of the PTPMC.
[0025] 2) The specific steps for synthesizing HPTPMC are as follows: Take a 25 mL Schlenk tube, stopper the branch end with a glass stopper, and secure it with a metal spring and clamps to ensure good airtightness. Place the hyperbranched triphenylmethanol polymer (HPTPM, 1 g) synthesized in Example 1 into the dried Schlenk tube, and fill the entire Schlenk tube with nitrogen gas. Finally, connect the entire apparatus to a nitrogen balloon for protection to ensure a nitrogen atmosphere. Then, dissolve the hyperbranched triphenylmethanol polymer (HPTPM) by adding 2 mL of dichloromethane using a syringe, and then slowly add excess acetyl chloride (6 mL) to the reaction tube. After refluxing for 3 hours, cool the solution to room temperature. After dichloromethane / water extraction, the organic solution is dried with anhydrous MgSO4 and concentrated under reduced pressure. The product is precipitated in excess petroleum ether, purified 2-3 times, vacuum filtered and dried to obtain the photochromic polymer (HPTPMC), see [link to relevant documentation]. Figure 2 The (B)HPTPMC's 1H NMR spectrum.
[0026] 3) The specific steps for synthesizing PVTPMC are as follows: Take a 25 mL Schlenk tube, stopper the branch end with a glass stopper, and secure it with a metal spring and clamps to ensure good airtightness. Place the synthesized side-chain poly(triphenylmethanol) polymer (PVTPM, 1 g) into the dried Schlenk tube, filling the entire Schlenk tube with nitrogen gas. Finally, connect the entire apparatus to a nitrogen balloon for protection to ensure a nitrogen atmosphere. Then, dissolve the PVTPM by adding 2 mL of dichloromethane using a syringe, followed by slowly adding excess acetyl chloride (6 mL) to the reaction tube. After reflux for 3 hours, cool the solution to room temperature. After dichloromethane / water extraction, the organic solution is dried with anhydrous MgSO4 and concentrated under reduced pressure. The product is precipitated in excess petroleum ether, purified 2-3 times, vacuum filtered and dried to obtain the photochromic polymer (PVTPMC). See [link to relevant documentation]. Figure 2 The (C)PVTPMC 1H NMR spectrum (¹H NMR) of the image.
[0027] Example 3 The photochromic polymers were subjected to light irradiation, and their fluorescence spectra were measured.
[0028] In specific Example 2, the products (PTPMC and HPTPMC) exhibited a red shift in fluorescence after different periods of illumination (see attached figure). Figure 3 (A) and (B) in the appendix. Figure 3 As shown in (A) and (B), under light treatment for different durations, the fluorescence of the polymer gradually shifts to red, changing from yellow-green to orange-red with longer irradiation time. This change can also be observed in the CIE coordinate graph, as detailed in the appendix. Figure 3 (D) and (E) in the example. Similarly, the product (PVTPMC) in Specific Example 2 exhibits a red shift in fluorescence after different illumination times, as shown in the appendix. Figure 3 (C) in the appendix. Figure 3 As shown in (C), under light treatment for different durations, the fluorescence of the polymer gradually shifts to red, changing from blue to reddish-purple with longer irradiation time. This change can also be observed in the CIE coordinate graph, as detailed in the appendix. Figure 3 (F) In the figure. After the UV lamp was turned off, the fluorescence color of all samples gradually returned to the state before irradiation over time, indicating that their photochromic behavior has good reversibility.
Claims
1. A triphenylchloromethane polymer with photochromic properties, characterized in that: The structural formula of the triphenylchloromethane polymer is any one of the following three: ； The molecular weight of each of the three types is 1000-100000 g / mol, and the molecular weight distribution is 1.1-2.3; m is 5-200; n is 5-200.
2. The triphenylchloromethane polymer with photochromic properties as described in claim 1, characterized in that: The triphenylchloromethane polymer with photochromic properties is a fluorescent polymer under 365nm ultraviolet light irradiation. In the solid state, its fluorescence ranges from yellow to orange-red or from blue to purple-red, and its emission wavelength ranges from 550nm to 680nm or from 450nm to 680nm.
3. The triphenylchloromethane polymer with photochromic properties as described in claim 1 or 2, characterized in that: The triphenylchloromethane polymer with photochromic properties exhibits aggregation-induced emission.
4. A method for preparing the triphenylchloromethane polymer with photochromic properties according to any one of claims 1-3, characterized in that: The preparation steps include the following: ； Starting with linear triphenylmethanol polymer (PTPM), under anhydrous and oxygen-free conditions at room temperature, acetyl chloride was reacted with dichloromethane (DCM) as solvent for 3 hours. After the reaction was complete, the reaction solution was poured into a poor solvent to precipitate the polymer. The precipitate was then filtered, washed, and vacuum dried to obtain the photochromic polymer (PTPMC). Alternatively, starting with hyperbranched triphenylmethanol polymer (HPTPM), under anhydrous and oxygen-free conditions at room temperature, acetyl chloride was reacted with dichloromethane (THF) as solvent for 3 hours. The precipitate was then poured into a poor solvent to precipitate the polymer. The precipitate was then filtered, washed, and vacuum dried to obtain the photochromic polymer (PTPMC). Photochromic polymers are phenyl polymers (HPTPMC) that exhibit yellow fluorescence in the solid state, with the fluorescence shifting red with the duration of ultraviolet irradiation. Alternatively, starting with a side-chain triphenylmethanol polymer (PVTPM), the reaction is carried out under anhydrous and oxygen-free conditions at room temperature with dichloromethane (THF) as the solvent and acetyl chloride for 3 hours. The reaction solution is then poured into a poor solvent to precipitate the polymer. After filtration, washing, and vacuum drying, a photochromic polymer (PVTPMC) is obtained, which exhibits blue fluorescence in the solid state, with the fluorescence shifting red with the duration of ultraviolet irradiation.
5. The preparation method according to claim 4, characterized in that: The unsuitable solvent is petroleum ether.
6. A triphenylchloromethane polymer with photochromic properties prepared by the preparation method according to any one of claims 4-5, characterized in that: The synthesized triphenylchloromethane polymer with photochromic properties exhibits a red shift in its solid state under ultraviolet light irradiation at a wavelength of 365 nm, changing from yellow-green to orange-red with the duration of ultraviolet irradiation, and the emission wavelength changes from 550 nm to 660 nm. Alternatively, it can change from blue fluorescence to purple-red with the emission wavelength changing from 440 nm to 670 nm. After the ultraviolet light is turned off, it can reversibly return to its original fluorescence.