Method for manufacturing a reinforced composite film and a reinforced composite film manufactured thereby

Abstract

The present invention relates to a method for manufacturing a reinforced composite film and a reinforced composite film manufactured thereby. The method for manufacturing a reinforced composite film according to the present invention can minimize the difference in hydrophilic and hydrophobic properties between a porous support and a polymer electrolyte, while simultaneously improving the impregnation properties of the polymer electrolyte. [Solution] A method for manufacturing a reinforced composite film includes (A) a step of pre-treating a porous support; and (B) a step of impregnating the pre-treated porous support with a polymer electrolyte solution containing a solvent and a hydrocarbon polymer electrolyte. The polymer electrolyte solution further selectively contains a surfactant. The pre-treatment is carried out by one or more methods of either immersing the porous support in a pre-treatment solution containing one or more of K2Cr2O7 and KClO4, or by plasma treatment.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a reinforced composite film and a reinforced composite film manufactured thereby. [Background technology]

[0002] In recent years, much effort has been made to improve the performance and stability of fuel cells, particularly the electrolyte membrane, which is a core component of fuel cells. In particular, reducing resistance by thinning the polymer electrolyte membrane is crucial for improving fuel cell performance.

[0003] Meanwhile, there is active development of hydrocarbon polymers in block copolymer form, comparable to Nafion, a fluorine-based polymer that has recently been commercialized. Compared to fluorine-based polymer electrolyte membranes, hydrocarbon polymers have a higher volume expansion ratio with water and a lower elongation rate. Therefore, manufacturing technology for electrolyte membranes in the form of reinforced composite membranes that have a thin thickness and can complement the mechanical properties is essential. Furthermore, while hydrocarbon polymer electrolytes have ion transfer groups and are hydrophilic, the porous supports used for manufacturing reinforced composite membranes are usually highly hydrophobic, which presents a limitation in that it is difficult to manufacture uniform reinforced composite membranes. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Korean Published Patent No. 10-2023-0160510 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention was devised to solve the above-mentioned problems, and the present invention aims to provide a method for manufacturing a reinforced composite film, comprising the steps of (A) pre-treating a porous support; and (B) impregnating the pre-treated porous support with a polymer electrolyte solution containing a solvent, a surfactant, and a hydrocarbon polymer electrolyte, wherein the pre-treatment is carried out by one or more methods of either immersing the porous support in a pre-treatment solution containing one or more of K2Cr2O7 and KClO4, or by plasma treatment.

[0006] Furthermore, the present invention aims to provide a reinforced composite film manufactured by the method for manufacturing the reinforced composite film described above.

[0007] Furthermore, the present invention aims to provide a water electrolytic cell containing the reinforced composite membrane.

[0008] Furthermore, the present invention aims to provide a fuel cell including the reinforced composite membrane.

[0009] Furthermore, the present invention aims to provide a device that includes the fuel cell, wherein the device is one selected from a communication device, a transport device, and an energy storage device. [Means for solving the problem]

[0010] One aspect of the present invention provides a method for producing a reinforced composite film, comprising the steps of (A) pre-treating a porous support; and (B) impregnating the pre-treated porous support with a polymer electrolyte solution containing a solvent, a surfactant, and a hydrocarbon polymer electrolyte, wherein the pre-treatment is carried out by one or more methods of either immersing the porous support in a pre-treatment solution containing one or more of K2Cr2O7 and KClO4, or by plasma treatment.

[0011] Another aspect of the present invention is to provide a reinforced composite film manufactured by the method for manufacturing the reinforced composite film.

[0012] Still another aspect of the present invention provides a water electrolysis cell including the reinforced composite membrane.

[0013] Still another aspect of the present invention provides a fuel cell including the reinforced composite membrane.

[0014] Still another aspect of the present invention provides an apparatus including the fuel cell, wherein the apparatus is any one selected from a communication apparatus, a transportation apparatus, and an energy storage apparatus.

Advantages of the Invention

[0015] The method for manufacturing the reinforced composite membrane according to the present invention can minimize the difference in hydrophilic and hydrophobic properties between the porous support and the hydrocarbon-based polymer electrolyte, and at the same time improve the impregnation property of the polymer electrolyte.

[0016] The effects of the present invention are not limited to the effects mentioned above. The effects of the present invention should be understood to include any effects inferable from the following description.

Brief Description of the Drawings

[0017] [Figure 1] It is a diagram schematically showing a method for manufacturing a reinforced composite membrane according to an embodiment of the present invention. [Figure 2] It is a graph showing the water (WATER) contact angle over time of PTFE without any treatment, the pretreated porous support (PTFE-A) manufactured in Example 1 of the present invention, and the pretreated porous support (PTFE-A) manufactured in Example 2. [Figure 3] It is an image for measuring the water (WATER) contact angle at the initial stage (0 min) and after 60 minutes of PTFE without any treatment, the pretreated porous support (PTFE-A) manufactured in Example 1 of the present invention, and the pretreated porous support (PTFE-A) manufactured in Example 2. [Figure 4] It is a diagram showing the photographic images and haze of the reinforced composite membranes manufactured in Comparative Example 1, Comparative Example 2, and Examples 1 to 4 of the present invention. [Figure 5] This figure shows photographic images and haziness of the reinforced composite films produced in Comparative Example 3, Example 5, and Example 6 of the present invention. [Figure 6] This figure shows the results of contact angle measurements performed to confirm the PTFE wettability of the polymer solutions produced in Examples 5 and 6 of the present invention. [Figure 7] These are photographic images of the polymer electrolyte solutions of Examples 7 to 10 of the present invention. [Figure 8] This figure shows photographic images and haze of the reinforced composite films of Examples 7-10 and Comparative Example 4 of the present invention. [Figure 9] These are scanning electron microscope (SEM) images of the reinforced composite film and PTFE manufactured in Example 6 and Comparative Example 1 of the present invention. [Modes for carrying out the invention]

[0018] The advantages and features of the present invention, as well as methods for achieving them, will become clearer with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be embodied in various other forms, and these embodiments are provided only to complete the disclosure of the present invention and to fully inform those who are ordinary skill in the art to which the present invention pertains, and the present invention is defined only by the scope of the claims.

[0019] In describing the present invention, if a detailed explanation of related prior art is deemed to obscure the gist of the invention, such detailed explanation will be omitted. Where "includes," "has," "consists of," etc. are used in this specification, other parts may be added unless "only" is used. Furthermore, terms such as "includes" or "has" are intended to specify the existence of features, numbers, stages, components, or combinations thereof described in the specification, and should not be understood as excluding the possibility of the existence or addition of one or more other features, numbers, stages, components, or combinations thereof. Also, when a component is expressed singly, unless otherwise explicitly stated, the expression includes the case where it includes multiple components.

[0020] One aspect of the present invention provides a method for producing a reinforced composite film, comprising the steps of (A) pre-treating a porous support; and (B) impregnating the pre-treated porous support with a polymer electrolyte solution containing a solvent, a surfactant, and a hydrocarbon polymer electrolyte, wherein the pre-treatment is carried out by one or more methods of either immersing the porous support in a pre-treatment solution containing one or more of K2Cr2O7 and KClO4, or by plasma treatment.

[0021] (A) Pretreatment of the porous support Step (A) above is a step of pre-treating the porous support.

[0022] The porous support may contain one or more selected from the group consisting of polysulfone, polyarylene ethersulfone, polyarylene ether ketone, polybenzimidazole, polybenzoxazole, polybenzthiazole, polypyrrolone, polyether ether ketone, polyphosphazene, polytetrafluoroethylene (PTFE), polyethylene (PE), polyvinylidene fluoride (PVdF), polyethylene terephthalate (PET), polyimide (PI), polypropylene (PP), cellulose, and nylon, and is preferably polytetrafluoroethylene (PTFE).

[0023] The porous support layer may have a thickness of 5 to 30 μm, preferably 5 to 20 μm.

[0024] If the thickness of the porous support layer is less than the lower limit, the mechanical strength may decrease. Conversely, if it exceeds the upper limit, the polymer electrolyte may not be uniformly impregnated, and the ionic conductivity may decrease.

[0025] The porous support layer may have a porosity of 40 to 90%, preferably 40 to 85%.

[0026] If the porosity of the porous support layer is below the lower limit, the ionic conductivity may decrease, and conversely, if it exceeds the upper limit, the dimensional stability and durability may decrease.

[0027] The porous support layer may have a pore size of 0.02 to 0.80 μm, preferably 0.02 to 0.50 μm.

[0028] If the pore size of the porous support layer is below the lower limit, electrolyte impregnation may not be easy, and conversely, if it exceeds the upper limit, dimensional stability and durability may decrease.

[0029] The aforementioned pretreatment may be carried out by one or more methods, such as immersing the porous support in a pretreatment solution containing one or more of K2Cr2O7 and KClO4, or by plasma treatment.

[0030] The aforementioned pretreatment solution may contain one or more of K2Cr2O7 and KClO4, and preferably contains both K2Cr2O7 and KClO4.

[0031] In particular, when the pretreatment is performed by immersing the porous support in a pretreatment solution containing K2Cr2O7 and KClO4, it was confirmed that the porous support is not damaged at all, and the hydrophilicity is maximized while maintaining the porous properties at the same level as the initial state.

[0032] With respect to 100% by weight of the entire pretreatment solution, one or more of the K2Cr2O7 and KClO4 may be included in an amount of 0.5 to 10.0% by weight, preferably 1.0 to 5.0% by weight.

[0033] If the content of one or more of K2Cr2O7 and KClO4 in the pretreatment solution is below the lower limit, the chemical reaction that changes the chemical structure of the porous support may not occur. Conversely, if it exceeds the upper limit, a large number of defects may occur in the mechanical properties and porosity structure of the porous support.

[0034] When the pretreatment is carried out by immersion in a pretreatment solution, the immersion may be performed at 60-85°C for 2-4 hours, preferably at 63-80°C for 2.2-3.7 hours, more preferably at 65-75°C for 2.3-3.5 hours, and most preferably at 68-73°C for 2.5-3.2 hours.

[0035] If either the immersion temperature or time is below the lower limit, the chemical reaction that changes the chemical structure of the porous support may not occur. Conversely, if it exceeds the upper limit, a large number of defects may occur in the mechanical properties and porosity structure of the porous support.

[0036] The plasma treatment may be performed at a power of 30 to 100 kW for 30 seconds to 30 minutes, preferably at a power of 30 to 100 kW for 30 seconds to 5 minutes.

[0037] If either the plasma processing power or time is below the lower limit, the chemical reaction that changes the chemical structure of the porous support may not occur. Conversely, if it exceeds the upper limit, a large number of defects may occur in the mechanical properties and porosity structure of the porous support.

[0038] The aforementioned pretreatment may be carried out by one or more methods of either immersing the porous support in a pretreatment solution or by plasma treatment, and preferably both methods can be performed. In particular, performing both methods is preferable because it allows for hydrophilic modification without loss of the mechanical properties and ionic conductivity of the support. Furthermore, when plasma treatment is performed after chemical treatment, hydrophilic substances produced by the chemical treatment may be destroyed by the plasma, so it is preferable to perform the pretreatment in the order of primary plasma treatment oxidation of the support followed by secondary chemical treatment modification to hydrophilic active groups.

[0039] (B) The step of impregnating the pre-treated porous support with a polymer electrolyte solution containing a solvent, a surfactant, and a hydrocarbon polymer electrolyte. Step (B) is a step of impregnating the pre-treated porous support with a polymer electrolyte solution containing a solvent, a surfactant, and a hydrocarbon-based polymer electrolyte.

[0040] The solvent may be one or more organic solvents selected from alcohols, cycloalkanes, methylpyrrolidone (NMP), dimethylacetamide (DMAC), dimethoxyethane (DME), dimethyl sulfoxide (DMSO), and dimethylformamide (DMF), and preferably contains methylpyrrolidone (NMP).

[0041] Furthermore, the solvent may further contain cyclohexane, which is preferable in that it improves the wettability of the porous support.

[0042] When the solvent further contains cyclohexane, the cyclohexane may be present in an amount of 10 to 30% by weight, preferably 13 to 27% by weight, more preferably 15 to 25% by weight, and most preferably 17 to 23% by weight, relative to 100% by weight of the total solvent.

[0043] If the cyclohexane content in the solvent is below the lower limit, the impregnation properties may decrease; conversely, if it exceeds the upper limit, the solubility of the polymer solution may decrease.

[0044] According to a preferred embodiment of the present invention, (1) The porous support layer has a thickness of 5 to 12 μm, a porosity of 40 to 85%, and a pore size of 0.02 to 0.5 μm. (2) The pretreatment is carried out by both immersing the porous support in a pretreatment solution containing one or more of K2Cr2O7 and KClO4 and by plasma treatment. (3) The immersion is carried out at 68-73°C for 2.5-3.2 hours. (4) The plasma treatment is performed at a power of 1 to 100 kW for 1 to 30 minutes. (5) The solvent may further contain cyclohexane, with the cyclohexane present in an amount of 17 to 23% by weight relative to 100% by weight of the total solvent.

[0045] When all the conditions for the above-described preferred embodiment are met, the uniformity and mechanical properties (expansion suppression rate, mechanical strength, and elongation rate) of the final reinforced composite film are all within an excellent range, making it particularly preferable. However, if any one of the conditions (1) to (5) above is not met, it has been confirmed that at least one of the uniformity and mechanical properties (expansion suppression rate, mechanical strength, and elongation rate) decreases sharply.

[0046] The surfactant may include one or more of the following: anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants.

[0047] The anionic surfactant can be one or more selected from the group consisting of linear alkylbenzene sulfonates, fatty alcohol ether sulfates, and sulfo succinate esters, preferably a compound represented by the following chemical formula 1, more preferably C 12 H 25 C6H4SO3Na can be used.

[0048] [Chemical Formula 1]

Chem.

[0049] Particularly, in the compound represented by the above Chemical Formula 1, when the R is a perfluoroalkyl group (Linear alkyl benzene sulfonates) of C 10 -C 13 , the impregnation effect of the hydrocarbon-based polymer electrolyte is maximized, so it is most preferable.)

[0050] AsForAny one or more selected from the group consisting of tetraalkylammonium salts, alkylpyridinium salts, and imidazolium quaternary ammonium salts can be used as the cationic surfactant. In terms of further increasing the polymer electrolyte impregnation effect, preferably, a compound represented by the following Chemical Formula 2 can be used. More preferably, C6H5CH2N + (CH3)2RCl -1 can be used.)

[0051] [Chemical Formula 2]

Chem.

[0052] The nonionic surfactant can be one or more selected from the group consisting of alkylphenol ethoxylates, fatty acid ethoxylates, and alcohol ethoxylates. Preferably, a compound represented by the following chemical formula 3 can be used, in that it further increases the polymer electrolyte impregnation effect, and more preferably, (C2H4O) n C 15 H 24 O· n You can use =9-10.

[0053] [Chemical formula 3] [ka] (In chemical formula 3, R is C8-C) 12 It is an alkyl group, and n is an integer between 3 and 40.

[0054] The aforementioned amphoteric surfactant can be one or more selected from the group consisting of alkylbetaine, alkyldimethyamine N-oxide, and zwitterion. Preferably, the compound represented by the following chemical formula 4 can be used, in that it further increases the polymer electrolyte impregnation effect, and more preferably C 21 H 37 NO4S can be used.

[0055] [Chemical formula 4] [ka] (In chemical formula 4, R is C 13 -C 19 It is an alkyl group.

[0056] The surfactant may be present in an amount of 0.3 to 5% by weight, preferably 0.5 to 4.5% by weight, more preferably 0.7 to 4% by weight, and most preferably 0.9 to 3.5% by weight, relative to 100% by weight of the entire polymer electrolyte solution.

[0057] If the amount of surfactant in the polymer electrolyte solution is below the lower limit, the degree of impregnation uniformity of the polymer electrolyte may not meet expectations. Conversely, if it exceeds the upper limit, the mechanical properties and ionic conductivity of the electrolyte membrane may decrease.

[0058] The hydrocarbon polymer electrolyte may contain one or more selected from the group consisting of sulfonated polyphenylene, sulfonated polyimide, sulfonated polyphenylene oxide, sulfonated polyether ether ketone, and sulfonated poly(ethter sulfone) (SPES, Sulfonated poly(ethter sulfone)), and preferably sulfonated poly(ethter sulfone) (SPES, Sulfonated poly(ethter sulfone)).

[0059] The hydrocarbon-based polymer electrolyte may be present in an amount of 1 to 25% by weight, preferably 3 to 23% by weight, more preferably 5 to 23% by weight, and most preferably 8 to 22% by weight, relative to 100% by weight of the entire polymer electrolyte solution.

[0060] If the content of the hydrocarbon polymer in the polymer electrolyte solution is below the lower limit or exceeds the upper limit, the polymer electrolyte impregnation process cannot be controlled, the impregnation rate decreases, and it may not be possible to manufacture a uniform reinforced composite film.

[0061] The impregnation in step (B) above may be carried out by one or more methods selected from the group consisting of doctor blade, roll coating, bar coating, slot die coating, comma coating, knife coating, gravure coating, micro-gravure coating, dip coating, flow coating, spin coating, and spray coating.

[0062] Step (B) may include (B1) a step of primary impregnating the pre-treated porous support with the polymer electrolyte solution; and (B2) a step of secondary impregnation of the primary impregnated porous support with the polymer electrolyte solution.

[0063] The primary impregnation may be carried out at 43-60°C for 2-7 hours, preferably at 44-57°C for 2.2-6.5 hours, more preferably at 46-55°C for 2.3-6.2 hours, and most preferably at 48-52°C for 3-6 hours.

[0064] If either the temperature or time of the primary impregnation is below the lower limit or exceeds the upper limit, the impregnation rate of the polymer electrolyte will decrease, and it may not be possible to manufacture a uniform reinforced composite film.

[0065] The secondary impregnation may be carried out at 60-80°C for 8-20 hours, preferably at 63-77°C for 8-18 hours, more preferably at 65-75°C for 9-16 hours, and most preferably at 67-73°C for 10-15 hours.

[0066] If either the temperature or time of the secondary impregnation is below the lower limit or exceeds the upper limit, the impregnation rate of the polymer electrolyte may decrease or deteriorate, making it impossible to manufacture a uniform reinforced composite film.

[0067] In particular, when step (B) is carried out under conditions that satisfy all of the above-described temperature and time conditions for primary impregnation and secondary impregnation, it was confirmed that the distribution characteristics and uniformity of the polymer electrolyte are maintained at the same level as the initial state even when the finally manufactured reinforced composite membrane is used in a fuel cell or water electrolytic cell for three days or more, which is particularly preferable.

[0068] (C) A step of heat-treating the porous support impregnated with the polymer electrolyte solution. The method for producing a reinforced composite film of the present invention may further include, after step (B), a step of heat-treating a porous support impregnated with the polymer electrolyte solution;

[0069] The heat treatment may be carried out at 150-200°C for 0.5-5 hours, preferably at 155-190°C for 0.6-4 hours, more preferably at 160-180°C for 0.7-3 hours, and most preferably at 165-175°C for 0.8-1.5 hours.

[0070] If either the temperature or time of the heat treatment is below the lower limit or exceeds the upper limit, the impregnation rate of the polymer electrolyte may decrease or deteriorate, making it impossible to manufacture a uniform reinforced composite film.

[0071] In particular, although not explicitly described in the following examples and comparative examples, in the method for manufacturing a reinforced composite membrane of the present invention, reinforced composite membranes were manufactured under different conditions as described below, and these were used in a fuel cell to perform 300 water electrolysis reactions. The current density was measured, and the surface state of the reinforced composite membrane before and after the reaction was observed.

[0072] As a result, when all of the following conditions were met, no rapid decrease in current density was observed during the 300 water electrolysis reactions, and the thickness deviation of the reinforced composite film before and after the 300 water electrolysis reactions was maintained at the same level as the initial state.

[0073] However, if any of the following conditions were not met, a sharp decrease in current density was observed after 200 water electrolysis cycles, and after 300 water electrolysis cycles, the thickness deviation of the reinforced composite film increased compared to the initial stage.

[0074] 1) The surfactant is a compound represented by the following chemical formula 1, 2) The polymer electrolyte is sulfonated poly(ethersulfone) (SPES), 3) Step (B) includes (B1) a step of primary impregnating the pre-treated porous support with the polymer electrolyte solution; and (B2) a step of secondary impregnation of the primary impregnated porous support with the polymer electrolyte solution; 4) The primary impregnation is carried out at 48-52°C for 3-6 hours. 5) The secondary impregnation is carried out at 67-73°C for 10-15 hours. 6) The step after step (B) may further include heat treatment of the porous support impregnated with the polymer electrolyte solution at 165-175°C for 0.8-1.5 hours.

[0075] [Chemical formula 1] [ka]

[0076] (In chemical formula 1, R is C 10 -C 13 It is a perfluoroalkyl group.

[0077] Another aspect of the present invention is to provide a reinforced composite film manufactured by the manufacturing method described above.

[0078] The reinforced composite film may include a porous support pretreated by either immersion in a pretreatment solution containing one or more of K2Cr2O7 and KClO4, or by plasma treatment; and a polymer electrolyte solution containing a solvent, a surfactant, and a hydrocarbon polymer electrolyte impregnated on one or both sides of the porous support.

[0079] The reinforced composite film may have a thickness of 5 to 200 μm, preferably 5 to 100 μm.

[0080] If the thickness of the reinforced composite film is less than the lower limit, its mechanical properties may decrease; conversely, if it exceeds the upper limit, its electrochemical properties may decrease.

[0081] Another aspect of the present invention is to provide a water electrolytic cell including the reinforced composite membrane.

[0082] Another aspect of the present invention is to provide a fuel cell comprising the reinforced composite membrane.

[0083] A further aspect of the present invention is to provide an apparatus including a fuel cell, wherein the apparatus is one selected from a communication apparatus, a transport apparatus, and an energy storage apparatus.

[0084] The present invention will be described in more detail below using examples and other references. However, the scope and content of the present invention should not be narrowed or limited by the following examples and other references.

[0085] Example 1. Pretreatment A Pretreatment of porous support (A) A porous support made of polytetrafluoroethylene (PTFE) material (thickness: 6 μm, porosity: 80%, average pore diameter: 0.23 μm) was plasma-treated at 100 kW power for 1 minute to prepare a pre-treated porous support (PTFE-A).

[0086] Polyelectrolyte solution A sulfonated poly(ether sulfone) polymer electrolyte solution was obtained using dimethyl sulfoxide (DMSO) as the solvent, with SPES comprising 10% by weight relative to 100% by weight of the total polymer electrolyte solution.

[0087] Reinforced composite membrane manufacturing After positioning the porous support (PTFE-A) on a glass substrate, the porous support (PTFE-A) was first impregnated with the polymer electrolyte solution at 50°C for 6 hours using a doctor blade, then the polymer electrolyte solution was secondarily impregnated at 70°C for 12 hours using a doctor blade, and then heat-treated at 170°C for 1 hour to obtain a reinforced composite film with a thickness of 25 μm.

[0088] Example 2. Pretreatment B Pretreatment of porous support (B) A porous support made of polytetrafluoroethylene (PTFE) material (thickness: 6 μm, porosity: 80%, average pore diameter: 0.23 μm) was treated by a wet chemical process by immersing it in a pretreatment solution containing 3% by weight of KClO4 at 70°C for 3 hours to prepare a pretreated porous support (PTFE-B).

[0089] Subsequently, a 25 μm thick reinforced composite film was manufactured using the same method as in Example 1, except that a porous support (PTFE-B) was used instead of the porous support (PTFE-A) manufactured in Example 1.

[0090] Example 3. Pretreatment A + surfactant A reinforced composite film was manufactured in the same manner as in Example 1, except that 1.1% by weight of polyoxyethylene(9)nonylphenylether.branched(alkylphenolethoxylates) was added to the polymer electrolyte solution as a surfactant.

[0091] Example 4. Pretreatment B + Surfactant A reinforced composite film was manufactured in the same manner as in Example 2, except that 1.1% by weight of polyoxyethylene(9)nonylphenylether.branched(alkylphenolethoxylates) was added to the polymer electrolyte solution as a surfactant.

[0092] Example 5. Pretreatment A + Surfactant + Impregnation accelerator A reinforced composite film was manufactured in the same manner as in Example 3, except that a mixture of dimethyl sulfoxide (DMSO) and cyclohexane (n-cyclohexane) in a weight ratio of 8:2 was used as the solvent for the polymer electrolyte solution.

[0093] Example 6. Pretreatment B + Surfactant + Impregnation Accelerator A reinforced composite film was manufactured in the same manner as in Example 4, except that a mixture of dimethyl sulfoxide (DMSO) and cyclohexane (n-cyclohexane) in a weight ratio of 8:2 was used as the solvent for the polymer electrolyte solution.

[0094] Example 7. Pretreatment A + Anionic surfactant + NMP A reinforced composite film was manufactured in the same manner as in Example 3, except that N-methyl-2-pyrrolidone (NMP) was used as the solvent for the polymer electrolyte solution, and sodium dedecylbenzenesulfonate (linear alkylbenzene sulfonates) represented by the following chemical formula 5 was used as the surfactant.

[0095] [Chemical formula 5] C 12 H 25 C6H4SO3Na

[0096] Example 8. Pretreatment A + cationic surfactant + NMP A reinforced composite film was manufactured by the same method as in Example 7, except that benzalkonium chloride (tetraalkylammonium salts), represented by the following chemical formula 6, was used as a cationic surfactant instead of the anionic surfactant.

[0097] [Chemical formula 6] C6H5CH2N + (CH3)2RCl -1

[0098] Example 9. Pretreatment A + nonionic surfactant + NMP A reinforced composite film was manufactured by the same method as in Example 7, except that a nonionic surfactant, polyoxyethylene(9)nonylphenylether, branched (alkylphenolethoxylates), represented by the following chemical formula 7, was used instead of the anionic surfactant.

[0099] [Chemical formula 7] (C2H4O) n C 15 H 24 O·n = 9-10

[0100] Example 10. Pretreatment A + amphoteric surfactant + NMP A reinforced composite film was manufactured by the same method as in Example 7, except that 3-(4-Heptyl)phenyl-3-hydroxypropyl)dimethylammoniopropanesulfonate(zwitterion) (3-(4-Heptyl)phenyl-3-hydroxypropyl)dimethylammoniopropanesulfonate(zwitterion) of the following chemical formula 8 was used as an amphoteric surfactant instead of the anionic surfactant.

[0101] [Chemical formula 8] C 21 H 37 NO4S

[0102] Comparative Example 1 The same method as in Example 1 was used for the production, but no pretreatment was applied to the porous support made of polytetrafluoroethylene (PTFE) material (thickness: 6 μm, porosity: 80%, average pore diameter: 0.23 μm).

[0103] Comparative Example 2 The same procedure as in Comparative Example 1 was used to produce a reinforced composite film with a thickness of 25-30 μm, using 1.1% by weight of polyoxyethylene(9)nonylphenylether.branched(alkylphenolethoxylates) as a surfactant in the polymer electrolyte solution.

[0104] Comparative Example 3 The same procedure as in Comparative Example 2 was used to produce the reinforced composite film with a thickness of 25-30 μm, but a mixture of dimethyl sulfoxide (DMSO) and cyclohexane (n-cyclohexane) in a weight ratio of 8:2 was used as the solvent for the polymer electrolyte solution.

[0105] Comparative Example 4 The same procedure as in Comparative Example 1 was used to produce the reinforced composite film with a thickness of 25-30 μm, but N-methyl-2-pyrrolidone (NMP) was used as the solvent for the polymer electrolyte solution.

[0106] [Table 1]

[0107] Experimental Example 1. Evaluation of physical properties by pretreatment of porous support. Porosity evaluation The pore sizes of untreated PTFE, the pre-treated porous support (PTFE-A) manufactured in Example 1, and the pre-treated porous support (PTFE-B) manufactured in Example 2 were measured and are shown in Table 2 below.

[0108] [Table 2]

[0109] As shown in Table 2 above, both pretreatment methods resulted in a reduction in porosity of approximately 10%, which was found to be not significantly different from the initial support.

[0110] Water Contact Angle Evaluation The water contact angles over time were measured for PTFE, the pre-treated porous support (PTFE-A) manufactured in Example 1, and the pre-treated porous support (PTFE-B) manufactured in Example 2, and the results are shown in Figures 2 to 4.

[0111] Figure 2 shows the time-series change in the water contact angle of untreated PTFE, a pre-treated porous support (PTFE-A) manufactured in Example 1 of the present invention, and a pre-treated porous support (PTFE-B) manufactured in Example 2.

[0112] Figure 3 shows images for measuring the water contact angle at initial (0 min) and 60 min for untreated PTFE, a pre-treated porous support (PTFE-A) manufactured in Example 1 of the present invention, and a pre-treated porous support (PTFE-B) manufactured in Example 2.

[0113] As shown in Figures 1 to 3, in the case of the PTFE support chemically pretreated in Examples 1 and 2, it was confirmed that the contact angle decreased significantly and hydrophilicity improved.

[0114] Experimental Example 2. Reinforced Composite Film Formation by Pretreatment of Porous Support and Use of Surfactants Figure 4 shows photographic images and haziness of the reinforced composite films produced in Comparative Example 1, Comparative Example 2, and Examples 1-4 of the present invention.

[0115] As shown in Figure 4, the reinforced composite films of Comparative Example 1, Example 1, and Example 2, which did not use surfactants in the polymer electrolyte solution, showed a haze value of 70% or higher, indicating low impregnation characteristics. In contrast, the reinforced composite films of Example 3 and Example 4, which used polymer electrolyte solutions with added surfactants, showed a haze value of less than 70%, indicating low turbidity / haze characteristics. Furthermore, compared to Comparative Example 2, where the porous support was not pretreated, which still showed a high haze value of 75%, the reinforced composite films of Example 3 and Example 4 showed lower haze values.

[0116] Experimental Example 3. Optimization of Polymer Solution Composition To confirm the impregnation characteristics depending on the type of polymer electrolyte solution, the macroscopic image and haze characteristics of reinforced composite films using an impregnation accelerator were analyzed and are shown in Figure 5.

[0117] Figure 5 shows photographic images and haziness of the reinforced composite films produced in Comparative Example 3, Example 5, and Example 6 of the present invention.

[0118] As shown in Figure 5, the reinforced composite films produced in Examples 5-6 and Comparative Example 3 showed significantly increased impregnation rates and low haze values ​​due to the use of an impregnation accelerator, which facilitated the impregnation of the polymer solution. Of these, only Examples 5 and 6, in which the porous support was pre-treated, showed remarkably low haze values ​​of 40% or less.

[0119] Figure 6 shows the results of contact angle measurements performed to confirm the PTFE wettability of the polymer solutions produced in Examples 5 and 6 of the present invention.

[0120] As shown in Figure 6, it can be confirmed that optimizing the composition of the polymer solution can reduce the contact angle, improve wettability to PTFE, and increase the polymer impregnation rate.

[0121] Experimental Example 4. Evaluation of Polymer Electrolyte Solution Properties Based on Surfactant Type Figure 7 shows photographic images of the polymer electrolyte solutions and reinforced composite membranes produced in Examples 7 to 10, where the type of surfactant and the content of the polymer electrolyte were varied. Figure 8 shows the reinforced composite membranes and their haze values.

[0122] Figure 7 is a photographic image of the polymer electrolyte solutions of Examples 7 to 10 of the present invention.

[0123] As shown in Figure 7, a comparison of the solubility of impregenation promoters in SPES 50 polymer solution revealed that the non-ionic promoter, in particular, exhibited the most uniform properties without phase separation.

[0124] Figure 8 shows photographic images and haze of the reinforced composite films of Examples 7-10 and Comparative Example 4 of the present invention.

[0125] As shown in Figure 8, when reinforced composite films were manufactured using different impregenation promoters, it was confirmed that the most uniform properties were observed without phase separation, particularly when a non-ionic promoter was used.

[0126] Experimental Example 5. Cross-sectional analysis and ionic conductivity measurement of reinforced composite films Figure 9 shows scanning electron microscope (SEM) images of the reinforced composite film and PTFE manufactured in Example 6 and Comparative Example 1 of the present invention.

[0127] As shown in Figure 9, untreated PTFE has a disordered pore network structure, but when impregnated with a polymer, a structure in which the pores are well filled can be observed. Furthermore, the cross-sectional image of Example 6, in which the polymer solution composition was optimized, can be seen to show a structure in which the pores are better filled with the polymer electrolyte.

[0128] On the other hand, the ionic conductivity of the reinforced composite films produced in Example 2, Example 6, and Comparative Example 1 was measured and is shown in Table 3 below.

[0129] [Table 3]

[0130] As shown in Table 3 above, it can be confirmed that the ionic conductivity of the reinforced composite film improves as the polymer impregnation rate is improved by optimizing the surfactant and polymer solution composition.

[0131] Although embodiments of the present invention have been described above, it is clear to any person with ordinary skill in the art that they can modify and change the present invention in various ways by adding, changing, deleting, or adding components, without departing from the spirit of the invention as described in the claims, and that these modifications are also included within the scope of the rights of the present invention.

Claims

1. (A) Pretreatment of the porous support; (B) The step of impregnating the pre-treated porous support with a polymer electrolyte solution containing a solvent and a hydrocarbon polymer electrolyte; The aforementioned polymer electrolyte solution further selectively contains a surfactant, The above pretreatment involves the porous support being K ２ Cr ２ O ７ and KClO ４ A method for producing a reinforced composite film, comprising immersion in a pretreatment solution containing one or more of the following and one or more plasma treatment methods.

2. The pretreatment in step (A) above involves K ２ Cr ２ O ７ and KClO ４ This is carried out by immersion in a pretreatment solution containing one or more of the following: The method for producing a reinforced composite film according to claim 1, characterized in that the immersion is carried out at 60 to 85°C for 2 to 4 hours.

3. The pretreatment in step (A) above is carried out by plasma treatment of the porous support, The method for manufacturing a reinforced composite film according to claim 1, characterized in that the plasma treatment is performed at a power of 30 to 100 kW for 30 seconds to 30 minutes.

4. The method for producing a reinforced composite film according to claim 1, characterized in that the solvent further comprises cyclohexane.

5. The method for producing a reinforced composite film according to claim 1, characterized in that the surfactant comprises one or more of anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants.

6. The method for producing a reinforced composite film according to claim 1, characterized in that the surfactant contains one or more compounds represented by the following chemical formulas 1 to 4. [Chemical formula 1] 【Chemistry 1】 (In Chemical Formula 1, R is an alkyl group of C １０ -C １３ or a perfluoroalkyl group of C １０ -C １３ .) [Chemical formula 2] 【Chemistry 2】 (In chemical formula 2, R １ C ８ -C １８ It is an alkyl group, R ２ CH ２ C ６ H ５ (And X is F, Cl, Br, I.) [Chemical formula 3] 【Transformation 3】 (In chemical formula 3, R is C) ８ -C １２ (It is an alkyl group, and n is an integer between 3 and 40.) [Chemical formula 4] 【Chemistry 4】 (In chemical formula 4, R is C １３ -C １９ It is an alkyl group.

7. The method for producing a reinforced composite film according to claim 1, characterized in that the surfactant is contained in an amount of 0.3 to 5% by weight with respect to 100% by weight of the entire polymer electrolyte solution.

8. The method for producing a reinforced composite film according to claim 1, characterized in that the polymer electrolyte includes one or more selected from the group consisting of sulfonated polyphenylene, sulfonated polyimide, sulfonated polyphenylene oxide, sulfonated polyether ketone, and sulfonated polyethersulfone (SPES, sulfonated poly(ether sulfone)).

9. The method for producing a reinforced composite film according to claim 1, characterized in that the hydrocarbon-based polymer electrolyte is contained in an amount of 1 to 25% by weight with respect to 100% by weight of the entire polymer electrolyte solution.

10. The aforementioned (B) stage is, (B1) The step of primary impregnating the pre-treated porous support with the polymer electrolyte solution; and (B2) A step of secondary impregnation of the primary impregnated porous support with the polymer electrolyte solution; a method for producing a reinforced composite film according to claim 1, characterized by comprising these steps.

11. A method for producing a reinforced composite film according to claim 1, further comprising the step of (C) heat-treating the porous support impregnated in the polymer electrolyte solution after step (B).

12. A method for manufacturing a water electrolytic cell, comprising the step of manufacturing a reinforced composite membrane by the manufacturing method described in any one of claims 1 to 11.

13. A method for manufacturing a fuel cell, comprising the step of manufacturing a reinforced composite membrane by the manufacturing method described in any one of claims 1 to 11.

14. A method for manufacturing any one device selected from a communication device, a transport device, and an energy storage device, comprising the step of manufacturing a fuel cell by the manufacturing method described in claim 13.

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