阅读说明：本技术 掺杂磺化聚芳醚砜复合材料及其制备方法和应用 (Doped sulfonated polyarylethersulfone composite material and preparation method and application thereof ) 是由 瓦黑德·玛兹那尼 王安闽 姚文东 于 2020-06-04 设计创作，主要内容包括：本发明公开了一种掺杂磺化聚芳醚砜复合材料及其的制备方法和应用。一种掺杂磺化聚芳醚砜复合材料,包括磺化聚芳醚砜以及掺杂在所述磺化聚芳醚砜中的改性纳米碳材料,所述改性纳米碳材料为改性剂处理过的纳米碳材料,并且所述改性剂氨基酸。这种掺杂磺化聚芳醚砜复合材料包括磺化聚芳醚砜以及掺杂在所述磺化聚芳醚砜中的改性纳米碳材料,氨基酸对纳米碳材料改性处理时,氨基酸可以与纳米碳材料上自带的羧基(-COOH)等基团结合,从而使得得到的改性纳米碳材料的表面带有额外的离子基团,从而可以通过提高离子团密度来提高质子电导率,通过重组聚合物链来提高机械完整性,从而使得掺杂磺化聚芳醚砜复合材料具有较高的质子电导率。(The invention discloses a doped sulfonated polyarylethersulfone composite material and a preparation method and application thereof. The sulfonated polyarylethersulfone-doped composite material comprises sulfonated polyarylethersulfone and a modified nano carbon material doped in the sulfonated polyarylethersulfone, wherein the modified nano carbon material is a nano carbon material treated by a modifier, and the modifier is amino acid. The sulfonated polyarylether sulfone-doped composite material comprises sulfonated polyarylether sulfone and a modified nanocarbon material doped in the sulfonated polyarylether sulfone, wherein when amino acid is used for modifying the nanocarbon material, the amino acid can be combined with carboxyl (-COOH) and other groups carried by the nanocarbon material, so that the surface of the obtained modified nanocarbon material is provided with additional ionic groups, the proton conductivity can be improved by improving the density of the ionic groups, and the mechanical integrity is improved by recombining a polymer chain, so that the sulfonated polyarylether sulfone-doped composite material has higher proton conductivity.)

1. The sulfonated poly (aryl ether sulfone) -doped composite material is characterized by comprising sulfonated poly (aryl ether sulfone) and a modified nano-carbon material doped in the sulfonated poly (aryl ether sulfone), wherein the modified nano-carbon material is a nano-carbon material treated by a modifier, and the modifier is amino acid.

2. The doped sulfonated polyarylethersulfone composite of claim 1, wherein the nanocarbon material comprises at least one of carbon nanotubes, carbon nanofibers, and nanocarbon spheres;

the mass ratio of the modified nano carbon material to the sulfonated polyarylethersulfone is (0.25-6): 100.

3. the doped sulfonated polyarylethersulfone composite of claim 1, wherein the modifier is histidine.

4. The preparation method of the doped sulfonated polyarylethersulfone composite material according to any one of claims 1 to 3, characterized by comprising the following steps:

pretreating a nano carbon material, and then modifying the pretreated nano carbon material by using an improver solution to obtain a modified nano carbon material; and

and uniformly mixing the modified nano carbon material and the sulfonated polyarylether sulfone under a liquid phase condition, and drying to obtain the doped sulfonated polyarylether sulfone composite material.

5. The doped sulfonated polyarylethersulfone composite material according to claim 4, wherein the pretreatment of the nanocarbon material comprises: dispersing the nano carbon material into a mixed solution of N, N-dimethylformamide and thionyl chloride, carrying out heat treatment for 8-48 h at the temperature of 60-85 ℃, and then cleaning and drying to obtain the pretreated nano carbon material.

6. The doped sulfonated polyarylethersulfone composite material according to claim 5, wherein in the mixed solution of N, N-dimethylformamide and thionyl chloride, the volume ratio of N, N-dimethylformamide to thionyl chloride is 2.5 to 10: 100.

7. the doped sulfonated polyarylethersulfone composite material according to claim 4, wherein the mass percentage concentration of the modifier solution is 0.5g/L to 4 g/L;

the solid-to-liquid ratio of the nano carbon material to the modifier solution is 0.1 g-4 g: 100 mL.

8. The doped sulfonated polyarylethersulfone composite material according to claim 7, wherein the modifying of the pretreated nanocarbon material with an improver solution to obtain a modified nanocarbon material comprises the following operations: and soaking the pretreated nano carbon material in the improver solution for 10-80 min, heating the whole system to reflux and keeping for 24-96 h, and then cleaning and drying to obtain the modified nano carbon material.

9. The doped sulfonated polyarylethersulfone composite material according to claim 4, wherein the solvent is dimethylacetamide in the operation of uniformly mixing the modified nanocarbon material and the sulfonated polyarylethersulfone under the liquid phase condition.

10. The use of the doped sulfonated polyarylethersulfone composite material according to any one of claims 1 to 3 in the field of polymer electrolyte membrane preparation.

Technical Field

The invention relates to the field of polymer composite materials, in particular to a doped sulfonated polyarylethersulfone composite material and a preparation method and application thereof.

Background

Polymer Electrolyte Fuel Cells (PEFCs) have received a great deal of attention as clean and efficient electrochemical energy carriers due to their unique energy density, undetectable pollutant emissions, and system simplicity. Applications of PEFCs range from stationary electrical equipment to automobiles, and although receiving widespread attention, have been limited in ubiquitous commercial applications due to a number of key issues, such as poor performance at low Relative Humidity (RH), poor durability, and high cost. Therefore, research has been directed to improving performance at low relative humidity to reduce the use of expensive ancillary components (e.g., humidifiers).

One key component of PEFCs in terms of performance and production cost is their Polymer Electrolyte Membrane (PEM), which functions as both the positive and negative proton transporters and separators. Key characteristics of an ideal PEM include high proton conductivity, good water transport, low electron crossover, thermo-mechanical stability, low fuel permeability, and durability under various operating conditions. To date, the most advanced PEM for PEFCs is Nafion, dupont, which has excellent proton conductivity, low electron conductivity, and good chemical-mechanical stability. However, the widespread use of Nafion in PEFCs is hampered by the high cost, loss of proton conductivity at RHs below 20%, and environmental and mental incompatibility. There have been some efforts to develop alternative PEMs for petrochemical companies.

Hydrocarbon-based aromatic polymers are a material of great interest because of their low cost, flexibility in synthesis and molecular design, film forming tendency, and thermo-mechanical properties, which enable their use in a variety of applications, including rechargeable batteries, fuel cells, and separation science, among others. Sulfonated forms of polyimines, aromatic polymers such as Polyetheretherketones (PEEK), polyaryl ether sulfones, polyetherketones, and polybenzimidazoles have been extensively studied as base backbones for PEM preparation. Among them, polyarylethersulfone (SPAES) is a polymer having proton conductivity in nature, and the proton conductivity and thermo-mechanical properties thereof can be adjusted by sulfonation (DS) to various degrees. Thus, the utilization of SPAES for PEM applications has been increasing. In the plasma atomic emission spectrum, each proton carries several water molecules, which are transported through the PEM by electroosmotic resistance. Thus, the proton conductivity of the PEM is directly dependent on the presence of water molecules to dissolve the protons of the sulfonic acid groups. Unfortunately, electroosmotic drugs in low RH operation can cause dehydration of the anode, resulting in reduced performance of PEFCs. Furthermore, drying the anode catalyst layer can result in a reduction in current density, particularly when using thicker PEMs. Overall, low relative humidity (< 20%) and high temperature (>90C) can hinder the operation of PEFCs with SPAES, thus preserving the properties of bare SPAES.

These low RH problems have been overcome by the integration of hygroscopic inorganic fillers in the PEM, such as zeolites, zirconium phosphates, CeO₂、SiO₂、ZrO₂And TiO₂They can improve proton conductivity in low RH. The combination of the inorganic filler with the SPAES matrix results in the recombination of ion channels including intercalation of the inorganic filler and sulfonic acid (-SO)₃H) And (4) recombining the groups. Such a minute hygroscopic filler plays an important role in the moisture retention and proton transfer of the mixed film. Improving water retention and efficient water diffusion should reduce the ohmic resistance of the PEM and the cathode catalyst utilization. However, in different cases, the proton conductivity decreases with the addition of the inorganic filler, due to the lower proton conductivity of the filler itself, and the effect of dilution on the proton exchange primer in the base polymer. Furthermore, the weak interaction between the inorganic filler and the polymer matrix may prevent a homogeneous distribution of the filler in the polymer.

Surface functionalization of acidic or basic fillers is an effective way to solve the above problems. Acidic groups such as sulfonic acid, phosphoric acid, and carboxylic acid or amino groups (-NH) have been reported₂) And the functionalization of basic groups such as nitrogen heterocyclic rings can increase the density of PEM ionic groups and promote the proton conductivity of PEM. Although acidic groups have been widely used to modify fillers, acidic groups often reduce proton conductivity under low RH conditions due to high sensitivity to water molecules. In fact, the basic groups, due to their self-ionizing and self-dehydrating properties, have a sustained proton conductivity under low RH conditions, and are more suitable for modifying fillers under low RH conditions. The acidic groups in the polymer matrix interact with the basic groups in the filler through hydrogen bonding bridges and electrostatic forces. Thereby producingThe raw acid-base PEM is expected to have lower water absorption, lower fuel permeability, higher proton conductivity, good thermo-mechanical properties and flexibility.

That is, a polymer composite having high proton conductivity is currently lacking.

Disclosure of Invention

Based on this, there is a need to provide a doped sulfonated polyarylethersulfone composite material, which has higher proton conductivity.

In addition, a preparation method of the doped sulfonated polyarylethersulfone composite material and an application of the doped sulfonated polyarylethersulfone composite material are also necessarily provided.

The sulfonated polyarylethersulfone-doped composite material comprises sulfonated polyarylethersulfone and a modified nano carbon material doped in the sulfonated polyarylethersulfone, wherein the modified nano carbon material is a nano carbon material treated by a modifier, and the modifier is amino acid.

The preparation method of the doped sulfonated polyarylethersulfone composite material comprises the following steps:

pretreating a nano carbon material, and then modifying the pretreated nano carbon material by using an improver solution to obtain a modified nano carbon material; and

and uniformly mixing the modified nano carbon material and the sulfonated polyarylether sulfone under a liquid phase condition, and drying to obtain the doped sulfonated polyarylether sulfone composite material.

The doped sulfonated polyarylethersulfone composite material is applied to the field of preparing polymer electrolyte membranes.

The sulfonated polyarylether sulfone-doped composite material comprises sulfonated polyarylether sulfone and a modified nanocarbon material doped in the sulfonated polyarylether sulfone, wherein when the nanocarbon material is modified by amino acid, the amino acid can be combined with carboxyl (-COOH) and other groups carried by the nanocarbon material, so that the surface of the obtained modified nanocarbon material is provided with additional ionic groups, the proton conductivity can be improved by improving the density of the ionic groups, and the mechanical integrity is improved by recombining a polymer chain, so that the sulfonated polyarylether sulfone-doped composite material has higher proton conductivity.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without any creative effort.

Wherein:

FIG. 1 is a diagram of the mechanism of synthesis of sulfonated polyarylethersulfones.

FIG. 2 is a schematic diagram of the preparation scheme of SPAES/HCNT in example 1.

FIG. 3a is an FE-SEM image of CNTs according to example 1.

FIG. 3b is a FE-SEM picture of HCNT from example 1.

FIG. 3c is a FE-SEM image of CNTs according to example 2.

FIG. 3d is a FE-SEM picture of HCNT from example 2.

Figure 3e is an SEM image of CNTs from example 1.

Figure 3f is an SEM image of HCNT from example 1.

FIG. 4a is an SEM photograph of SPAES in example 3.

FIG. 4b is an SEM picture of SPAES/HCNT 1.5 from example 3.

FIG. 4c is the EDAX spectrum of SPAES from example 3.

FIG. 4d is the EDAX spectrum of SPAES/HCNT 1.5 from example 3.

FIG. 5a is an SEM picture (scale bar 10 μm) of the cross section of SPAES in example 3.

FIG. 5b is an SEM picture (scale bar 10 μm) of the cross-section of SPAES/HCNT 1.5 from example 3.

FIG. 5c is an SEM image of the cross section of SPAES in example 3 (scale bar 2 μm).

FIG. 5d is an SEM picture (scale bar 2 μm) of the cross-section of SPAES/HCNT 1.5 from example 3.

FIG. 5e is an SEM picture (scale bar 100nm) of the cross section of SPAES in example 3.

FIG. 5f is an SEM picture (200 nm on a scale) of the cross-section of SPAES/HCNT 1.5 from example 3.

FIG. 6 is a comparison of AFM of SPAES and SPAES/HCNT 1.5 in example 3, where a and c are AFM maps of SPAES and b and c are AFM maps of SPAES/HCNT 1.5.

FIG. 7 is a FT-IR spectrum of CNT and HCNT of example 1.

FIG. 8a is a TGA plot of CNT, HCNT, and SPAES/HCNT 0.5 of example 1, SPAES/HCNT1 of example 2, and SPAES/HCNT 1.5 of example 3.

FIG. 8b is a UTM chart of SPAES/HCNT 0.5 of example 1, SPAES/HCNT1 of example 2, and SPAES/HCNT 1.5 of example 3.

FIG. 8c is a DSC scan of SPAES/HCNT 0.5 of example 1, SPAES/HCNT1 of example 2, and SPAES/HCNT 1.5 of example 3.

FIG. 8d is a DSC two-pass scan of SPAES/HCNT 0.5 of example 1, SPAES/HCNT1 of example 2, and SPAES/HCNT 1.5 of example 3.

FIG. 9 is the water contact angle measurement plots of SPAES/HCNT 0.5 of example 1, SPAES/HCNT1 of example 2, and SPAES/HCNT 1.5 of example 3, where a is SPAES, b is SPAES/HCNT 0.5, c is SPAES/HCNT1, and d is SPAES/HCNT 1.5.

FIGS. 10a and 10b are graphs showing the change in mass of SPAES/HCNT 0.5 of example 1, SPAES/HCNT1 of example 2, and SPAES/HCNT 1.5 of example 3 at different relative humidities.

FIG. 10c is a graph showing the proton conductivity changes at different temperatures for SPAES/HCNT 0.5 of example 1, SPAES/HCNT1 of example 2, and SPAES/HCNT 1.5 of example 3 at a relative humidity of 100%.

FIG. 10d is a graph showing the proton conductivity changes at different relative humidities of SPAES/HCNT 0.5 of example 1, SPAES/HCNT1 of example 2, and SPAES/HCNT 1.5 of example 3 at a temperature of 80 ℃.

FIG. 10e is a graph showing the proton conductivity change of Nafion-115, SPAES/CNT 1.5 of example 3, and SPAES/HCNT 1.5 at different temperatures under the relative humidity of 100%.

FIG. 10f is a graph showing the proton conductivity change of Nafion-115, SPAES/CNT 1.5 of example 3, and SPAES/HCNT 1.5 at different relative humidities at a temperature of 80 ℃.

FIG. 11a is a plot of the polarization and power density of PEMFCs integrating SPAES, SPAES/CNT (1.5 wt%), SPAES/HCNT (1.5 wt%) and Nafion-115 membranes at 60 ℃ and 100% relative humidity.

FIG. 11b is a graph of the polarization and power density of PEMFCs integrating SPAES, SPAES/CNT (1.5 wt%), SPAES/HCNT (1.5 wt%) and Nafion-115 membranes at 60 ℃ and 20% relative humidity.

FIG. 11c is a graph showing the durability test of PEMFCs integrating SPAES, SPAES/CNT (1.5 wt%), SPAES/HCNT (1.5 wt%) and Nafion-115 membranes under the conditions of a temperature of 60 ℃ and a relative humidity of 100%.

FIG. 11d is a graph showing the durability test of PEMFCs integrating SPAES, SPAES/CNT (1.5 wt%), SPAES/HCNT (1.5 wt%) and Nafion-115 membranes under the conditions of temperature of 60 ℃ and relative humidity of 20%.

Figure 12a is an SEM image of SPAES prior to MEA durability testing.

Figure 12b is an SEM image of SPAES after MEA durability testing.

FIG. 12c is an SEM image of SPAES/HCNT (1.5 wt%) prior to MEA durability testing.

FIG. 12d is an SEM image of SPAES/HCNT (1.5 wt%) after MEA durability testing.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention discloses a sulfonated polyarylethersulfone-doped composite material, which comprises Sulfonated Polyarylethersulfone (SPAES) and a modified nano carbon material doped in the sulfonated polyarylethersulfone, wherein the modified nano carbon material is a nano carbon material treated by a modifier, and the modifier is amino acid.

The nano carbon material is a carbon material with at least one dimension of a disperse phase dimension less than 100 nm. The dispersed phase may consist of carbon atoms, or of heterogeneous (non-carbon) atoms, or even nanopores.

In the present embodiment, the nanocarbon material includes at least one of Carbon Nanotubes (CNTs), carbon nanofibers, and nanocarbon spheres.

The nano carbon material has higher specific surface area and better mechanical property, and is suitable to be used as a doping material.

The sulfonated polyarylether sulfone-doped composite material comprises sulfonated polyarylether sulfone and a modified nanocarbon material doped in the sulfonated polyarylether sulfone, wherein when the nanocarbon material is modified by amino acid, the amino acid can be combined with carboxyl (-COOH) and other groups carried by the nanocarbon material, so that the surface of the obtained modified nanocarbon material is provided with additional ionic groups, the proton conductivity can be improved by improving the density of the ionic groups, and the mechanical integrity is improved by recombining a polymer chain, so that the sulfonated polyarylether sulfone-doped composite material has higher proton conductivity.

Preferably, in the sulfonated polyarylether sulfone-doped composite material, the mass ratio of the modified nano carbon material to the sulfonated polyarylether sulfone is 0.25-6: 100.

specifically, in the sulfonated polyarylethersulfone-doped composite material, the mass ratio of the modified nanocarbon material to the sulfonated polyarylethersulfone may be 0.5: 100. 1: 100. 1.5: 100. 2: 100. 3: 100 or 4: 100.

in this embodiment, the modifier is histidine. The nano carbon material is modified by histidine, and can be combined with carboxyl (-COOH) and other groups carried by the nano carbon material, and the modified nano carbon material can provide additional ionic groups when being soaked in the SPAES matrix, so that sequential acid-base pairs generated along the SPAES/HCNT interface can be used as proton conduction sites, and the SPAES/HCNT composite membrane has enhanced proton conductivity.

Particularly preferably, the modified nanocarbon material is histidine-modified carbon nanotube (HCNT).

The invention also discloses a preparation method of the doped sulfonated polyarylether sulfone composite material, which comprises the following steps:

s10, pretreating the nano carbon material, and modifying the pretreated nano carbon material by using an improver solution to obtain the modified nano carbon material.

Preferably, the pretreatment of the nanocarbon material is performed by: dispersing the nano carbon material into a mixed solution of N, N-Dimethylformamide (DMF) and thionyl chloride, carrying out heat treatment for 8-48 h at the temperature of 60-85 ℃, and then cleaning and drying to obtain the pretreated nano carbon material.

The purpose of the pretreatment is to wash away some impurity groups on the surface of the nano carbon material, and to activate the groups on the surface of the nano carbon material to improve the binding rate of the next surface modification.

Preferably, in the mixed solution of N, N-dimethylformamide and thionyl chloride, the volume ratio of N, N-dimethylformamide to thionyl chloride is 2.5 to 10: 100.

specifically, in the mixed solution of N, N-dimethylformamide and thionyl chloride, the volume ratio of N, N-dimethylformamide to thionyl chloride may be 3: 100. 4: 100. 5: 100. 6: 100. 7: 100. 8: 100 or 9: 100.

specifically, the temperature of the heat treatment may be 70 ℃, the time of the heat treatment may be 24 hours, the detergent for cleaning may be Tetrahydrofuran (THF), and the drying may be vacuum drying.

Preferably, the mass percentage concentration of the modifier solution is 0.5 g/L-4 g/L.

Specifically, the mass percentage concentration of the modifier solution is 1g/L, 1.5g/L, 2g/L, 2.5g/L, 3g/L or 3.5 g/L.

Preferably, the solid-to-liquid ratio of the nanocarbon material to the modifier solution is 0.1g to 4 g: 100 mL.

Specifically, the solid-to-liquid ratio of the nanocarbon material to the modifier solution was 0.2 g: 100mL, 0.3 g: 100mL, 0.4 g: 100mL, 0.5 g: 100mL, 1 g: 100mL, 2 g: 100mL, 2.5 g: 100mL, 3 g: 100mL or 3.5 g: 100 mL.

Modifying the pretreated nano carbon material by using an improver solution to obtain a modified nano carbon material, wherein the operation comprises the following steps: and soaking the pretreated nano carbon material in an improver solution for 10-80 min, heating the whole system to reflux and keeping for 24-96 h, and then cleaning and drying to obtain the modified nano carbon material.

Specifically, the heating reflux can be completed in a reflux condenser, the drying is vacuum drying, and the cleaning agent for cleaning is ethanol.

And S20, uniformly mixing the modified nano-carbon material obtained in the step S10 and the sulfonated polyarylether sulfone under a liquid phase condition, and drying to obtain the doped sulfonated polyarylether sulfone composite material.

Preferably, the solvent is dimethylacetamide (DMAc) in the operation of uniformly mixing the modified nanocarbon material and the sulfonated polyarylethersulfone under the liquid phase condition.

Specifically, the operation of uniformly mixing the modified nanocarbon material and the sulfonated polyarylethersulfone under the liquid phase condition may be: adding the modified nano carbon material into dimethyl acetamide, ultrasonically mixing uniformly, and adding sulfonated polyaryl ether sulfone to dissolve uniformly.

In the application, the sulfonated polyarylethersulfone can be directly purchased or can be prepared by self.

Referring to FIG. 1, the sulfonated polyarylethersulfone is prepared as follows: after preparing BP, DFDPS and SDFDPS monomers by polycondensation, K is added₂CO₃And an organic mixed solution (NMP/toluene-2/1 v/v) was added as an entrainer. The reaction mixture was refluxed at 150 ℃ for 5 hours to dehydrate the system, and after toluene removal, the reaction mixture was refluxed at 190 ℃ for polymerization. The viscous solution obtained after 48h of reaction was diluted with NMP and filtered to remove the salt. Precipitating in ethanol to obtain white powder, extracting with deionized water, and removing residual salts and low molecular weight oligomers.The product was dried in a vacuum oven at 80 ℃ for 24h and then 1.0M H was added₂SO₄(aq) stirring, adding-SO₃Conversion of Na to-SO₃And H, washing with distilled water for several times until residual sulfuric acid is removed. Finally drying for 24h at 80 ℃ under the vacuum condition to obtain the SPAES polymer.

The doped sulfonated polyarylethersulfone composite material has higher proton conductivity, and can be applied to the field of preparation of polymer electrolyte membranes.

The following are specific examples.

Experimental reagent: polyetheretherketone powder was purchased from Victrex, korea. Sulfuric acid (H2SO4, 95%) was purchased from Daejung Chemicals in korea. Multiwall CNTs (80% MWCNTs) and toluene in anhydrous solution (99.98%) were obtained from Sigma Aldrich, and 3-aminopropyl-triethoxysilane (99% APTES) was obtained from Acros organics. N, N-Dimethylformamide (DMF) was purchased from korea, chemical industry, sanchun.

Purification by recrystallization from toluene gave 4,4' -difluorodiphenyl sulfone (DFDPS, 99.0%, Aldrich). DFDPS was sulfonated with 65.0% fuming sulfuric acid to produce 3,3 '-disulfonic acid-4, 4' -difluorodiphenyl sulfone (SDFDPS) and purified according to Harrison et al (78% yield). 4,4' -dihydroxybiphenyl (BP, 97.0%, Aldrich) was purified by recrystallization from methanol. 3, 4-diaminobenzoic acid (DABA, 98.0%, TCI) was purified by recrystallization from deionized water. With potassium carbonate (K)₂CO₃99.0%, aldrich), sodium nitrate (NaNO3, 99.0%, aldrich), potassium permanganate (KMnO)₄99.0%, Aldrich), phosphorus pentoxide (P)₂O₅99.0%, Aldrich), sulfuric acid (H)₂SO₄95.0%, Daejung), hydrochloric acid (HCl, 35.0%, Daejung), hydrogen peroxide (H)₂O₂30.0%, Daejung) and poly (phosphoric acid) (PPA, 116.0%, Junsei) as starting materials. N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), toluene, and ethanol were stored over molecular sieves prior to use.

Experimental equipment: the surface and cross-sectional properties of the prepared samples were investigated using field emission scanning electron microscopy (FE-SEM, ZEISS, Supra 40VP), energy dispersive x-ray analysis (EDAX) and scanning electron microscopy (SEM, JEOL, JSM-6400). Sample preparation for this analysis was done by platinum sputtering. And (3) carrying out microstructure imaging on the prepared sample by adopting a transmission electron microscope (TEM, JEOL, JEM-2010) with an accelerating voltage of 80-200 kv. An atomic force microscope (AFM, Bruker, multilod-8) was used to capture topographical images and determine the surface roughness of the prepared samples. The functional groups and the crystalline properties of the prepared samples were investigated using Fourier transform infrared spectroscopy (FT-IR, PerkinElmer, Frontier) and X-ray diffraction (XRD, Panalytical, X' pert Pro Power). The ion cluster size of the prepared film was determined using small angle x-ray scattering method (SAXS, Empyrean, Panalyticl). Thermal properties such as thermal stability and glass transition temperature of the prepared film were evaluated by a thermogravimetric analyzer (TGA, TA instruments, Q400) and a differential scanning calorimeter (DSC, TA instruments, Q20). Tensile stress and strain of the film were tested using a universal tester.