An asymmetric polydopamine / carbon fiber water-vapor power generation film coupled with photothermal and wetness and a preparation method thereof
Patent Information
- Application Number
- CN202611124640.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-28
- Publication Date
- 2026-10-20
AI Technical Summary
[0003]本发明的目的在于提供一种光热与润湿耦合的非对称性聚多巴胺/碳纤维水伏发电膜及其制备方法，旨在通过聚多巴胺改性碳纤维膜使膜表面呈负电，并构建非对称性结构增大离子浓度梯度，吸引反离子形成双电层，为提高水伏发电膜性能提供新思路。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of hydroelectric power generation. Background Technology
[0002] Currently, the world faces severe shortages of freshwater and energy resources. Solar energy, as an inexhaustible and clean energy source, has extremely broad application prospects. Solar-driven interfacial evaporation (SDIE) technology can produce freshwater in a green and sustainable way, effectively avoiding the high energy consumption and pollution problems associated with traditional seawater desalination technologies. During seawater evaporation, ions migrate directionally with the water flow, forming an electric double layer and generating a potential difference. This phenomenon makes evaporation-induced power generation a reality. Hydrovoltaic power generation technology has attracted widespread attention due to its unique energy conversion mechanism. It utilizes the interaction between water and nanostructured functional materials to directly convert water energy into electrical energy. Combining solar-driven interfacial evaporation with evaporation-induced hydropower technology holds promise for achieving zero-carbon cogeneration, possessing potential advantages such as environmental friendliness, sustainable development, and applicability to distributed micropower systems. Summary of the Invention
[0003] The purpose of this invention is to provide an asymmetric polydopamine / carbon fiber hydrovoltaic membrane coupled with photothermal and wetting properties and its preparation method. The aim is to modify the carbon fiber membrane with polydopamine to make the membrane surface negatively charged and to construct an asymmetric structure to increase the ion concentration gradient, attracting counterions to form an electric double layer, thus providing a new approach to improving the performance of hydrovoltaic membranes.
[0004] The steps of this invention are: An asymmetric polydopamine / carbon fiber hydrovoltaic film coupled with photothermal and wetting properties, and its preparation method, characterized by the following specific steps: (1) Weigh a certain amount of dopamine monomer and dissolve it in deionized water; (2) Prepare a buffer solution by adding anhydrous ethanol and deionized water to a beaker and adjusting the pH with ammonia. (3) Add the dissolved dopamine solution to the buffer solution, and suspend the cleaned membrane (10 cm * 3 cm) in the middle of the beaker. Stir the reaction at room temperature in the dark to allow dopamine to polymerize at one end of the membrane. (4) The rate of dopamine polymerization and particle size can be controlled by controlling the pH of the buffer solution; In step (1), the mass of dopamine is 0.5 g; In step (2), the volumes of anhydrous ethanol and deionized water are 40 mL and 90 mL, respectively, and the pH range of the buffer solution is 9.87 to 11.17. In step (3), the length of the carbon fiber membrane immersed in the buffer solution is 5 cm; The reaction time in step (4) is 3 hours; (5) After a certain reaction time, the asymmetric polydopamine / carbon fiber photovoltaic membrane with photothermal and wetting coupling is thoroughly cleaned with deionized water, and then dried at 40 °C.
[0005] The formation principle of an asymmetric polydopamine / carbon fiber hydrovoltaic film coupled with photothermal and wetting processes: In a weakly alkaline alcohol-water mixed solvent, dopamine is oxidized by oxygen, which then undergoes intermolecular cross-linking to form polydopamine (PDA). Ammonia is mild and volatile, which is conducive to the formation of a more uniform coating. The ethanol-water mixed solvent can better dissolve dopamine and its oxidation intermediates, control the reaction rate, and avoid excessively rapid precipitation.
[0006] This invention employs an oxidative self-polymerization method, a simple preparation process that forms a dense polydopamine coating on carbon fibers. The polydopamine selectively modifies the carbon fiber membrane, constructing an asymmetric surface structure with both hydrophilic and hydrophobic regions. This asymmetry between photothermal and wettability induces directional capillary flow from the hydrophilic to the hydrophobic regions in an aqueous environment, driving directional ion transport. Based on this, the structure not only maintains the overall high-efficiency photothermal evaporation performance of the material but also converts the flow potential during evaporation into electrical energy through a continuous water-voltaic effect, thus simultaneously achieving efficient seawater desalination and hydropower generation in an integrated device, achieving combined hydropower. Attached Figure Description
[0007] Appendix Figure 1 SEM image of an asymmetric polydopamine / carbon fiber hydrovoltaic film coupled with photothermal and wetting effects.
[0008] Appendix Figure 2 XPS image of an asymmetric polydopamine / carbon fiber hydrovoltaic film coupled with photothermal and wetting effects. Detailed Implementation
[0009] To better illustrate the present invention, the following description, in conjunction with the accompanying drawings, uses an asymmetric polydopamine / carbon fiber hydrovoltaic film with photothermal and wetting coupling as an example.
[0010] Preparations before the experiment: 1. Preparation of asymmetric polydopamine / carbon fiber hydrovoltaic films coupled with photothermal and wetting processes: (1) Add 0.5g of dopamine hydrochloride to 8 ml of deionized water and stir at room temperature until fully dissolved; (2) Prepare a buffer solution by mixing anhydrous ethanol and deionized water and adjusting the pH with ammonia. (3) Add the dissolved hydrochloric acid dopamine solution to the buffer solution, and place the carbon fiber membrane into the mixed solution and stir for 3 hours at room temperature in the dark. (4) The asymmetric polydopamine / carbon fiber photovoltaic membrane with photothermal and wetting coupling after the reaction is completed is washed in deionized water, and then dried in an oven at 40 ℃.
[0011] Figure 1 and Figure 2 The images show the SEM and XPS images of the asymmetric polydopamine / carbon fiber hydrovoltaic film with photothermal and wetting coupling, respectively. The SEM image clearly shows polydopamine nanoparticles adsorbed on the film surface, while the XPS image reveals characteristic peaks for C, N, and O, effectively demonstrating the successful fabrication of the photothermal and wetting-coupled asymmetric polydopamine / carbon fiber hydrovoltaic film.
[0012] 2. Experimental Procedure: The effective membrane area prepared above is 15 cm². 2 An asymmetric polydopamine / carbon fiber hydrovoltaic membrane with photothermal and wetting coupling was placed on an evaporation power generation device containing a 3.5 wt% NaCl solution and irradiated with simulated sunlight at an intensity of 1 sun. The initial and final weights of the device were recorded, and the vapor permeability was calculated. The open-circuit voltage and short-circuit current of the asymmetric polydopamine / carbon fiber hydrovoltaic membrane with photothermal and wetting coupling were measured using an electrochemical workstation.
[0013] Example 1 0.5 g of dopamine hydrochloride was dissolved in 8 ml of deionized water; a buffer solution was prepared by mixing 40 ml of anhydrous ethanol and 90 ml of deionized water, and the pH was adjusted to 9.87 with ammonia; the dopamine hydrochloride solution was mixed with the buffer solution, and half of the carbon fiber membrane was immersed in the buffer solution and stirred at room temperature in the dark for 3 hours; the asymmetric polydopamine / carbon fiber photovoltaic membrane with photothermal and wetting coupling after the reaction was completed was thoroughly washed with deionized water, removed and dried at 40 °C. Placed on an evaporative power generation device under 1 sun of light, the photo-to-steam energy conversion efficiency was 92.5%, and the steam permeability was 2.83 kg / m³. 2 • h; The open-circuit voltage was measured to be 0.83 V and the current density was 0.14 mA / cm² when tested using an electrochemical workstation. 2 .
[0014] Example 2 0.5 g of dopamine hydrochloride was dissolved in 8 ml of deionized water; a buffer solution was prepared by mixing 40 ml of anhydrous ethanol and 90 ml of deionized water, and the pH was adjusted to 10 with ammonia; the dopamine hydrochloride solution was mixed with the buffer solution, and half of the carbon fiber membrane was immersed in the buffer solution and stirred at room temperature in the dark for 3 hours; the asymmetric polydopamine / carbon fiber hydrovoltaic membrane with photothermal and wetting coupling after the reaction was completed was thoroughly washed with deionized water, removed and dried at 40 °C. Placed on an evaporative power generation device under 1 day of sunlight, the photo-to-steam energy conversion efficiency was 94.9%, and the steam permeability was 2.97 kg / m³. 2 • h; The open-circuit voltage was measured to be 0.9 V and the current density was 0.24 mA / cm² when tested using an electrochemical workstation. 2 .
[0015] Example 3 0.5 g of dopamine hydrochloride was dissolved in 8 ml of deionized water; a buffer solution was prepared by mixing 40 ml of anhydrous ethanol and 90 ml of deionized water, and the pH was adjusted to 10.63 with ammonia; the dopamine hydrochloride solution was mixed with the buffer solution, and half of the carbon fiber membrane was immersed in the buffer solution and stirred at room temperature in the dark for 3 hours; the asymmetric polydopamine / carbon fiber photovoltaic membrane with photothermal and wetting coupling after the reaction was completed was thoroughly washed with deionized water, removed and dried at 40 °C. Placed on an evaporative power generation device under 1 day of sunlight, the photo-to-steam energy conversion efficiency was 97.02%, and the steam permeability was 3.18 kg / m³. 2 • h; The open-circuit voltage was measured to be 1 V and the current density to be 0.42 mA / cm² using an electrochemical workstation. 2 .
[0016] Example 4 0.5 g of dopamine hydrochloride was dissolved in 8 ml of deionized water; a buffer solution was prepared by mixing 40 ml of anhydrous ethanol and 90 ml of deionized water, and the pH was adjusted to 11.17 with ammonia; the dopamine hydrochloride solution was mixed with the buffer solution, and half of the carbon fiber membrane was immersed in the buffer solution and stirred at room temperature in the dark for 3 hours; the asymmetric polydopamine / carbon fiber hydrovoltaic membrane with photothermal and wetting coupling after the reaction was completed was thoroughly washed with deionized water, removed and dried at 40 °C. Placed on an evaporative power generation device under 1 day of sunlight, the photo-to-steam energy conversion efficiency was 95.88%, and the steam permeability was 2.98 kg / m³. 2 • h; The open-circuit voltage was measured to be 1 V and the current density to be 0.26 mA / cm² using an electrochemical workstation. 2 .
[0017] Comparative Example 1: A carbon fiber membrane evaporation power generation device containing a 3.5 wt% NaCl solution was irradiated with simulated sunlight of intensity 1 sun. The initial and final weights of the device were recorded, and the light-to-steam energy conversion efficiency was calculated to be 45%, with a steam permeability of 0.5 kg / m³. 2 •h; The open-circuit voltage was measured to be 0.22 V using an electrochemical workstation.
[0018] Comparative Example 2: 0.5 g of dopamine hydrochloride was dissolved in 8 ml of deionized water; a buffer solution was prepared by mixing 40 ml of anhydrous ethanol and 90 ml of deionized water, and the pH was adjusted to 10.63 with ammonia; the dopamine hydrochloride solution was mixed with the buffer solution, and a 3*5 cm carbon fiber membrane was immersed in the buffer solution and stirred at room temperature in the dark for 3 hours; the symmetrical polydopamine / carbon fiber photovoltaic membrane after the reaction was completed was thoroughly washed with deionized water, removed, and dried at 40 °C. Placed on an evaporative power generation device under 1 day of sunlight, the light-to-steam energy conversion efficiency was 97.02%, and the steam permeability was 3.18 kg / m³. 2 •h; The open-circuit voltage was tested using an electrochemical workstation and found to be 0.78 V.
[0019] in conclusion: Compared to carbon fiber membranes and symmetrical polydopamine / carbon fiber membranes, the asymmetric polydopamine / carbon fiber hydrovoltaic membrane, which couples photothermal and wetting processes, promotes the increase of ion concentration gradient, exhibits good hydrovoltaic power generation capability, and demonstrates the highest photo-steam energy conversion efficiency, steam permeability, and open-circuit voltage at a reaction pH of 10.63.
Claims
1. An asymmetric polydopamine / carbon fiber hydrovoltaic film coupled with photothermal and wetting properties, and its preparation method, characterized in that, The main steps are as follows: (1) Weigh a certain amount of dopamine monomer and dissolve it in deionized water; (2) Prepare a buffer solution by adding anhydrous ethanol and deionized water to a beaker and adjusting the pH with ammonia. (3) Add the dissolved dopamine solution to the buffer solution, and suspend the cleaned carbon fiber membrane (10 cm * 3 cm) in the middle of the beaker. Stir the reaction at room temperature in the dark to allow dopamine to polymerize at one end of the membrane. (4) The rate of dopamine polymerization and particle size can be controlled by controlling the pH of the buffer solution; (5) After a certain reaction time, the asymmetric polydopamine / carbon fiber photovoltaic membrane coupled with photothermal and wetting is thoroughly cleaned with deionized water, and then dried at 40 °C.
2. The method for preparing the asymmetric polydopamine / carbon fiber hydrovoltaic film with photothermal and wetting coupling according to claim 1, characterized in that... Dopamine is selectively polymerized in regions on carbon fiber membranes; In step (1), the mass of dopamine is 0.5 g; In step (2), the volumes of anhydrous ethanol and deionized water are 40 mL and 90 mL, respectively, and the pH range of the buffer solution is 9.87 to 11.
17. In step (3), the length of the carbon fiber membrane immersed in the buffer solution is 5 cm; The reaction time in step (4) is 3 h.
3. The asymmetric polydopamine / carbon fiber hydrovoltaic film with photothermal and wetting coupling obtained by the preparation method according to claim 1 is characterized in that... The structure exhibits photothermal asymmetry and wetting asymmetry.
4. The asymmetric polydopamine / carbon fiber hydrovoltaic membrane with photothermal and wetting coupling obtained by the preparation method according to claim 1 can be applied to cogeneration and other water treatment applications.