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CN-122006517-A - Preparation method of Schiff base two-dimensional polymer/cellulose nanofiber heterogeneous ion channel membrane based on interface super-assembly strategy

CN122006517ACN 122006517 ACN122006517 ACN 122006517ACN-122006517-A

Abstract

The invention discloses a preparation method of a Schiff base two-dimensional polymer/cellulose nanofiber heterogeneous ion channel membrane based on an interface super-assembly strategy. According to the invention, melamine (MA) and trimesic aldehyde (BTCA) are used as raw materials, two-dimensional polyimide (2 DPI) is synthesized through Schiff base reaction, then the two-dimensional polyimide is peeled into a nano-sheet dispersion with the assistance of trifluoroacetic acid (TFA), then the nano-sheet dispersion is mixed with a DMSO dispersion of cellulose nano-fibers (CNF), and the mixture is subjected to vacuum assisted filtration and super-assembly on a nylon membrane to obtain a 2DPI/CNF composite membrane. The composite membrane prepared by the invention has good flexibility, water stability and cation selectivity, and the content of 2DPI is adjustable, so that the composite membrane is suitable for nano fluid devices. The invention has simple operation and low cost, and provides a novel ion channel material for the fields of osmotic energy conversion and the like.

Inventors

  • KONG BIAO
  • Abdulhei Rehmu Avati
  • HU CHENGMIN
  • ZENG JIE

Assignees

  • 光华创芯智能科技(杭州)有限公司

Dates

Publication Date
20260512
Application Date
20260306

Claims (9)

  1. 1. The preparation method of the Schiff base two-dimensional polymer/cellulose nanofiber heterogeneous ion channel membrane based on the interface super-assembly strategy is characterized by comprising the following steps of: 1) Preparing two-dimensional polyimide 2DPI powder by taking melamine MA and trimesic aldehyde BTCA as raw materials, and synthesizing the two-dimensional polyimide 2DPI powder under the heating condition through Schiff base reaction; 2) Stripping 2DPI nano-sheets, namely dispersing the 2DPI nano-sheets in an organic solvent, adding trifluoroacetic acid TFA, stirring at room temperature, and stripping into a dispersion of the 2DPI nano-sheets; 3) Preparing a CNF dispersion, namely stirring and carrying out ultrasonic treatment on TEMPO oxidized cellulose nanofiber in an organic solvent to obtain the CNF dispersion; 4) And (3) super-assembling the composite membrane, namely mixing the dispersion of the 2DPI nano-sheets and the dispersion of the CNF, and performing vacuum-assisted filtration and super-assembling to obtain the Schiff base two-dimensional polymer/cellulose nanofiber heterogeneous ion channel membrane.
  2. 2. The preparation method according to claim 1, wherein in the schiff base reaction in the step 1), the reaction solvent is N-methylpyrrolidone NMP, the catalyst is pyridine, a water removing agent calcium chloride is added, the reaction temperature is 100-160 ℃, and the reaction time is 30-50 h.
  3. 3. The preparation method according to claim 2, wherein the molar ratio of melamine MA to trimesic aldehyde BTCA is 1:1, the feeding ratio of melamine MA to N-methylpyrrolidone NMP is 1g:20 mL-1g:100 mL, and the volume ratio of N-methylpyrrolidone NMP to pyridine is 15:1-10:1.
  4. 4. The method according to claim 1, wherein in step 2), the organic solvent is dimethyl sulfoxide DMSO and the mass volume concentration of the dispersion of 2DPI nanoplatelets is 0.8 to 1.2 mg/mL.
  5. 5. The method according to claim 4, wherein in the stripping process, the volume ratio of trifluoroacetic acid TFA to the organic solvent is 1:40-1:50, the stirring speed is 200-400 rpm, and the stirring time is 5-8d.
  6. 6. The method according to claim 1, wherein in the step 3), the organic solvent is dimethyl sulfoxide DMSO and the mass-volume concentration of the CNF dispersion is 0.4-1.0 mg/mL.
  7. 7. The preparation method according to claim 1, wherein the step 4) is specifically that 2DPI and CNF dispersoid are mixed, distilled water is added for protonation, after stirring and ultrasonic treatment, the mixture is assembled on a nylon membrane through vacuum auxiliary filtration, and after drying, the mixture is peeled off to obtain the self-supporting 2DPI/CNF composite membrane.
  8. 8. The method of claim 7, wherein in step 4) the mass ratio of 2DPI in the dispersion of 2DPI nanoplatelets to CNF in the dispersion of CNF is from 5:3 to 10:1.
  9. 9. A Schiff base two-dimensional polymer/cellulose nanofiber heterogeneous ion channel membrane prepared by the preparation method of any one of claims 1-8.

Description

Preparation method of Schiff base two-dimensional polymer/cellulose nanofiber heterogeneous ion channel membrane based on interface super-assembly strategy Technical Field The invention belongs to the technical field of ion channel materials, and particularly relates to a Schiff base two-dimensional polymer/cellulose nanofiber heterogeneous ion channel membrane based on an interface super-assembly strategy and a preparation method thereof. Background The two-dimensional polymer (2 DP) has great potential in the fields of energy sources, catalysis, separation and the like due to the high specific surface area, the definite pore structure and the excellent stability. However, the inherent rigidity and poor dispersion in solvents severely limit their processing into films and their use in devices. Although 2DP has been studied using trifluoroacetic acid (TFA) to assist in stripping imine bond linkages, how to effectively complex it with other nanomaterials to build macroscopic membrane materials with specific functions remains a challenge. Cellulose Nanofiber (CNF) is used as a natural polymer nanomaterial and has rich surface functional groups (-OH, -COOH), good biocompatibility and film forming property. The 2DP and the CNF are compounded, and the advantages of the two are hopefully combined, but a universal and efficient interface super-assembly method is lacking at present to realize the compounding, and the nano channel structure is accurately regulated and controlled to optimize the performance. On the other hand, bio-based nanomaterials such as Cellulose Nanofibers (CNF) are widely used for the construction of composite films due to their abundant surface functional groups (-OH, -COOH), excellent mechanical properties, good film forming properties and environmental friendliness. CNF can not only act as a structure-enhancing framework, but also impart cation selectivity to the composite membrane with its negative surface charge. By compounding 2DPI with CNF, the advantages of regular pore canal of 2DPI and the film forming and charge regulating capability of CNF can be cooperatively exerted theoretically. However, the existing composite method depends on physical blending or layer-by-layer self-assembly, and is difficult to realize ordered arrangement of molecular levels on an interface scale, so that the channel connectivity is poor and the ion transmission efficiency is low. Therefore, development of a universal and controllable interface super-assembly strategy is needed to realize accurate combination of 2DPI nanosheets and CNF on nanometer scale, so as to construct a novel ion channel membrane with high ion conductivity, excellent selectivity and long-term water stability, and provide a key material foundation for high-performance osmotic energy conversion and other applications. Disclosure of Invention The invention aims to solve the problems that a two-dimensional polymer is difficult to form a film and has single function in the prior art, and provides an interface super-assembled ion channel composite film based on a Schiff base two-dimensional polymer and cellulose nanofiber and a simple and efficient preparation method thereof. The composite membrane has excellent flexibility, water stability and adjustable nano channel structure, and provides an ideal material platform for high-performance ion transmission and osmotic energy conversion. The technical scheme of the invention is as follows. The invention provides a preparation method of a Schiff base two-dimensional polymer/cellulose nanofiber heterogeneous ion channel membrane based on an interface super-assembly strategy, which comprises the following steps: 1) Preparing two-dimensional polyimide 2DPI powder, namely synthesizing the two-dimensional polyimide 2DPI (2D polyimine, 2 DPI) powder by taking melamine MA and trimesic aldehyde BTCA as raw materials through Schiff base reaction under the heating condition; 2) Stripping 2DPI nano-sheets, namely dispersing the 2DPI nano-sheets in an organic solvent, adding trifluoroacetic acid TFA, stirring at room temperature, and stripping into a dispersion of the 2DPI nano-sheets; 3) Preparing a CNF dispersion, namely stirring and carrying out ultrasonic treatment on TEMPO oxidized cellulose nanofiber in an organic solvent to obtain the CNF dispersion; 4) And (3) super-assembling the composite membrane, namely mixing the dispersion of the 2DPI nano-sheets and the dispersion of the CNF, and performing vacuum-assisted filtration and super-assembling to obtain the Schiff base two-dimensional polymer/cellulose nanofiber heterogeneous ion channel membrane. In the invention, in the step 1), in the Schiff base reaction, the reaction solvent is N-methylpyrrolidone NMP, the catalyst is pyridine, the water-removing agent calcium chloride is added, the reaction temperature is 100-160 ℃, the reaction time is 30-50 h, the mole ratio of melamine MA to trimesic aldehyde BTCA is 1:1, the feeding ratio of the melamine