Branched and hyperbranched ionomeric polymers and uses thereof

Abstract

Described herein are branched and hyperbranched anionic phenylene polymers prepared with controlled anionic substituents. Applications of such branched ionomeric polymers are also described. The branched ionomeric polymers are made in a convenient and well-controlled manner, allowing for tailored properties in catalyst ink formulations, ionomeric polymer membranes, and other applications. Such branched ionomeric polymers find applications in water purification, fuel cell, and battery products.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 327,479, filed April 5, 2022, the contents of which are expressly incorporated by reference in their entirety. [Background technology]

[0002] Hydrocarbon-based proton exchange membranes (PEMs) and ionomers for electrochemical applications (e.g., fuel cells, electrolyzers, water treatment) are being actively pursued as an alternative to traditional perfluorosulfonic acid (PFSA)-based ionomers due to their ease of synthesis, low cost, reduced gas crossover, high Tg, and fewer environmental concerns. Many ion-containing polymers have been investigated, with much attention being paid to polymers incorporating aromatic groups in the polymer backbone, such as poly(arylene ethers), poly(arylene ether ketones), poly(arylene sulfones), poly(imides), and sulfonated derivatives of poly(benzimidazoles). However, previous hydrocarbon-based ionomers have often been hampered by their high susceptibility to oxidative degradation ex situ (e.g., Fenton's reagent test) and / or in situ (e.g., within PEM fuel cells). For this reason, recent attention has focused on the rational design of hydrocarbon-based ionomers with improved chemical and mechanical stability.

[0003] Polyphenylenes, such as those reported by Stille and Mullen, have inherent chemical stability and mechanical strength. Sulfonated phenylated polyphenylenes (sPPPs) have been of particular interest as PEMs due to their inherent chemical and mechanical stability due to their fully aromatic backbone. Sulfonated polyphenylenes are usually prepared by post-sulfonation of polyphenylenes and have recently been explored for use in polymer electrolyte fuel cells (PEMFCs).

[0004] However, research in this field has been limited by the challenge of synthesizing well-defined polymer backbones composed of sterically hindered rigid aryl-aryl bonds, with controllable sulfonation, and exhibiting high molecular weights. Additionally, limited solubility in polar solvents is a challenge. Functionalization of polyphenylenes (e.g., sulfonation) results in a random distribution of functional groups among the monomer units and throughout the macroscopic polymer structure, resulting in polymers with poorly defined structures (see, e.g., Fujimoto, CH; Hickner, MA; Cornelius, CJ; Loy, DA Macromolecules 2005, 38, 5010).

[0005] Precise control of polymer architecture and precise placement of ionic functional groups along the polymer backbone can improve the short- and long-range order of ion channels and enhance ionic conductivity. Polymer properties can be tuned by controlling the incorporation, placement, and sequence of sulfonic acid groups in the polymer. Such sequence is influenced by the polymer backbone structure itself, which can be linear, branched, hyperbranched, or have other higher order structures. Such polymer architecture and resulting properties impact the use of such polymers in end applications.

[0006] Hydrogen-related fuel cell technologies aim at environmentally friendly and sustainable energy systems. Among the various types of fuel cells, polymer electrolyte fuel cells are considered economically viable, but the manufacturing and capital costs remain high. For example, the membrane electrode assembly (MEA) accounts for up to 50% of the capital cost of a PEMFC stack, of which more than 80% is related to the platinum group metal (PGM) catalysts used. For this reason, significant efforts have been made to reduce the PGM content, but progress is slowed by the increasing mass transport resistance, which strongly depends on the catalyst layer (CL) morphology.

[0007] Fuel cell catalyst layers are typically prepared from catalyst inks, in which Pt-loaded carbon catalyst particles aggregate into agglomerates that then coalesce into larger aggregates to form larger secondary pores. These secondary pores facilitate gas diffusion and water transport within the CL, as explained by the agglomerate model. Polyelectrolytes, such as perfluorosulfonic acid (PFSA) ionomers, commonly referred to by the trademarks Nafion® or Aquivion®, can be included in the ink dispersion to encapsulate and bind the Pt / C agglomerates and provide proton conducting pathways within the CL. The content and type of ionomer in the catalyst ink can have a significant effect on the mass transport resistance within the resulting CL.

[0008] There are significant drawbacks to the use of PFSA ionomers. Despite intense research into PFSA ionomers, concerns are growing over the use of potentially hazardous chemical raw materials. Furthermore, the complex synthesis of PFSA ionomers limits production and increases costs, as very few chemical manufacturers have the capacity to produce such PFSA ionomers. Furthermore, the 2030 goal of operating PEMFCs at high temperatures of 120 °C may be limited by the relatively low thermal transition of PFSA, around 100 °C.

[0009] To address the shortcomings of PFSA-based ionomers, there is a need for thermochemically stable fluorine-free hydrocarbon ionomers. The main parameters of performance degradation of proton exchange membrane fuel cells (PEMFCs) using hydrocarbon-based proton-conducting ionomers include characteristically low electrochemical reaction rates, high ionic resistance, and high mass transport resistance within the catalyst layer. Furthermore, there is a need for a strategy for the controlled synthesis of oligophenylenes and polymers, including control of the incorporation, position, and frequency of anionic (e.g., sulfonated) functional groups in such fluorine-free hydrocarbon ionomers. The present disclosure seeks to meet these needs and provides further advantages. Summary of the Invention

[0010] This Summary is provided to introduce some concepts in a simplified form that are described below in the Detailed Description. This Summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0011] In one aspect, the disclosure features a branched ionomeric polymer that includes an anionic comonomer and a branching comonomer. Such branched ionomeric polymer includes a repeat unit of formula (I): [ka] (In the formula, R 1A , R 1B , R 1C , R 1D , R 1E , and R 1F are independently aryl or heteroaryl, each of 1~6 Alkyl, halo, nitro, cyano, SO3 - X + , PO3 2- X + 2, and COO - X + 1, 2, 3, 4, or 5 substituents (X + H + or a cation), R 1A , R 1B , R 1C , R 1D , R 1E , and R 1F At least two of them are independently SO3 - X + , PO3 2- X + 2, and COO - X + 1, 2, 3, 4, or 5 substituents (X + H +or a cation), R 1G and R 1H is independently 1~6 Alkyl, halo, nitro, cyano, SO3 - X + , PO3 2- X + 2, and COO - X + 1, 2, 3, 4, or 5 substituents (X + H + or a cation), or H; A1 is arylene, heteroarylene, aralkylene, or heteroaralkylene, each optionally substituted with 1, 2, 3, or 4 substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl; A2 is absent, arylene or heteroarylene, each of which is optionally substituted with 1, 2, 3, or 4 substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl; B is a branching comonomer; R 2A is a bond, The first repeat unit of formula (I) is R 2A and a repeating unit of the second formula (I) to form a branched structure.

[0012] The branching comonomer (B) comprises a structure of formula (II). [ka] (wherein L3 at each occurrence is an optionally substituted polyvalent heteroatom (e.g., N, P, B), a polyvalent aryl, a polyvalent heteroaryl, a polyvalent aralkyl, or a polyvalent heteroaralkyl, wherein the polyvalent aryl, the polyvalent heteroaryl, the polyvalent aralkyl, and the polyvalent heteroaralkyl are each selected from the group consisting of C 1~6optionally substituted with 1, 2, or 3 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl; L2 does not exist or C 1~6 an arylene or heteroarylene optionally substituted with 1, 2, 3, or 4 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl; L1 is not present or C 1~6 and arylene or heteroarylene, optionally substituted with 1, 2, 3, or 4 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl.

[0013] The disclosure further features methods of making the branched ionomeric polymers of the disclosure.

[0014] In another aspect, the disclosure features a catalyst ink formulation that includes the branched ionomeric polymer of the disclosure.

[0015] In a further aspect, the disclosure features an ionomeric polymer membrane that includes the branched ionomeric polymer of the disclosure. [Brief description of the drawings]

[0016] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, in which:

[0017] [Figure 1A] FIG. 1A shows a 3D representation of the chemical structure of HB-sPPT-H+.

[0018] [Figure 1B] FIG. 1B shows an example of HB-sPPT-H+ (a hyperbranched ionomeric polymer) prior to mechanical polishing, as viewable under a UV-filtered optical microscope.

[0019] [Figure 1C]FIG. 1C shows an example of HB-sPPT-H+ after mechanical polishing, as visible under a UV-filtered optical microscope.

[0020] [Figure 1D] FIG. 1D shows the measured water absorption properties of HB-sPPT-H+ and linear sPPB-H+ polymers at 80±0.5° C.

[0021] [Figure 1E] FIG. 1E shows an image of HB-sPPT-H+ in water.

[0022] [Figure 1F] FIG. 1F shows the chemical structure of the hyperbranched sulfonated phenylated poly(phenylene) terphenyl (HB-sPPT-H+) used as the catalyst layer binder.

[0023] [Figure 2A] Figure 2A shows the polarization and power curves for CCMs made with catalyst layers containing 15 wt% Linear sPPB-H+, 5 wt% HB-sPPT-H++10 wt% Linear sPPB-H+, 7.5 wt% HB-sPPT-H++7.5 wt% Linear sPPB-H+, and 10 wt% HB-sPPT-H++5 wt% Linear sPPB-H+. Data were obtained at 80 °C, 100% RH, 1 atm, H2 / O2 operation.

[0024] [Figure 2B] Figure 2B shows the polarization and power curves for CCMs made using catalyst layers containing 15 wt% linear sPPB-H+, 5 wt% HB-sPPT-H++10 wt% linear sPPB-H+, 7.5 wt% HB-sPPT-H++7.5 wt% linear sPPB-H+, and 10 wt% HB-sPPT-H++5 wt% linear sPPB-H+. Data was obtained at 80 °C, 100% RH, 1 atm, H2 / air operation with a film thickness of 35 ± 5 μm (sPPB-H+).

[0025] [Figure 3A]Figure 3A shows polarization and power curves for CCMs made with catalyst layers containing 30 wt% Nafion®, 25 wt% HB+5 wt% Nafion®, 20 wt% HB+10 wt% Nafion®, 15 wt% HB+15 wt% Nafion®, 10 wt% HB+20 wt% Nafion®, and 5 wt% HB+25 wt% Nafion®. Data was obtained at 80°C, 100% RH, 1 atm, H2 / O2 operation.

[0026] [Figure 3B] Figure 3B shows polarization and power curves for CCMs made with catalyst layers containing 30 wt% Nafion®, 25 wt% HB + 5 wt% Nafion®, 20 wt% HB + 10 wt% Nafion®, 15 wt% HB + 15 wt% Nafion®, 10 wt% HB + 20 wt% Nafion®, and 5 wt% HB + 25 wt% Nafion®. Data was obtained at 80°C, 100% RH, 1 atm, H2 / air operation with a membrane thickness of 25 ± 5 μm (Nafion® NR-211).

[0027] [Figure 4A] Figure 4A shows the polarization and power curves of CCMs prepared using catalyst layers containing linear sPPB-H+, 5 wt% HB+10 wt% linear sPPB-H+, and 10 wt% linear sPPB-H+ obtained at 80 °C, 100% RH, 1 atm, and film thickness: 33 ± 5 μm (sPPB-H+) with a constant H2 / O2 flow rate of 1 slpm.

[0028] [Figure 4B]FIG. 4B shows the polarization and power curves of CCMs prepared using catalyst layers containing linear sPPB-H+, 5 wt% HB+10 wt% linear sPPB-H+, and 10 wt% linear sPPB-H+ obtained at 80 °C, 100% RH, 1 atm, and film thickness: 33 ± 5 μm (sPPB-H+) in H2 / air operation.

[0029] [Figure 4C] FIG. 4C shows the Tafel relationship obtained at 80° C., 100% RH, 1 atm, and film thickness: 33±5 μm (sPPB-H+), and the inset shows the linearized region where the Tafel equation holds.

[0030] [Figure 4D] FIG. 4D shows a Nyquist plot using 0.5 slpm H2 / 1.0 slpm O2 at 0.8 V obtained at 80° C., 100% RH, 1 atm, and film thickness: 33±5 μm (sPPB-H+).

[0031] [Figure 4E] Figure 4E shows the CV scan obtained at 80 °C, 100% RH, 1 atm, film thickness: 33 ± 5 μm (sPPB-H+) with catalyst loading: 0.4 mgPt·cm-2 in 0.5 slpm H2 / 0 slpm N2 and scan rate: 50 mV·s-1.

[0032] [Figure 4F] FIG. 4F shows a Nyquist plot at 0.5 slpm H2 / 0.5 slpm N2 obtained at 80° C., 100% RH, 1 atm, and film thickness: 33±5 μm (sPPB-H+), with the inset showing the expansion of the high frequency region.

[0033] [Figure 5A]FIG. 5A shows the polarization and power curves of CCMs made with catalyst layers containing 30 wt% Nafion®, 5 wt% HB-sPPT-H++25 wt% Nafion®, and 25 wt% Nafion® obtained at 80° C., 100% RH, 1 atm, and membrane thickness: 25±5 μm (Nafion® NR-N211) with a constant H2 / O2 flow rate of 1 slpm.

[0034] [Figure 5B] FIG. 5B shows the polarization and power curves of CCMs made with catalyst layers containing 30 wt% Nafion®, 5 wt% HB-sPPT-H++25 wt% Nafion®, and 25 wt% Nafion®, obtained at 80° C., 100% RH, 1 atm, and membrane thickness: 25±5 μm (Nafion® NR-N211) in H2 / air operation.

[0035] [Figure 5C] FIG. 5C shows the Tafel relationship obtained at 80° C., 100% RH, 1 atm, and film thickness: 25±5 μm (Nafion® NR-N211), and the inset shows the linearized region where the Tafel equation holds.

[0036] [Figure 5D] FIG. 5D shows a Nyquist plot at 0.8 V, 0.5 slpm H2 / 1.0 slpm O2 obtained at 80° C., 100% RH, 1 atm, and film thickness: 25±5 μm (Nafion® NR-N211).

[0037] [Figure 5E] Figure 5E shows the CV scan of catalyst loading: 0.4 mg Pt / cm2 at 0.5 slpm H2 / 0 slpm N2, scan rate: 50 mV·s-1, 80 °C, 100% RH, 1 atm, and film thickness 25 ± 5 μm (Nafion® NR-N211).

[0038] [Figure 5F] FIG. 5F shows a Nyquist plot at 0.5 slpm H2 / 0.5 slpm N2 obtained at 80° C., 100% RH, 1 atm, and film thickness 25±5 μm (Nafion® NR-N211), with the inset showing the expansion of the high frequency region.

[0039] [Figure 6A] Figure 6A shows the polarization and power curves of CCMs made with catalyst layers containing CL of 15 wt% Linear sPPB-H+ (CCM1), 5 wt% HB-sPPT-H++10 wt% Linear sPPB-H+ (CCM2), 30 wt% Nafion® (CCM3), and 5 wt% HB-sPPT-H++25 wt% Nafion® (CCM4) obtained at 80 °C, 100% RH, and 1 atm with constant H2 / O2 flow rate of 1 slpm. The membrane thickness is 33 ± 5 μm for CCM1 and CCM2 (sPPB-H+) and 25 ± 5 μm for CCM3 and CCM4 (Nafion® NR-N211).

[0040] [Figure 6B] Figure 6B shows the polarization and power curves of CCMs made with catalyst layers containing CL of 15 wt% Linear sPPB-H+ (CCM1), 5 wt% HB-sPPT-H++10 wt% Linear sPPB-H+ (CCM2), 30 wt% Nafion® (CCM3), and 5 wt% HB-sPPT-H++25 wt% Nafion® (CCM4) at 80 °C, 100% RH, and 1 atm with constant H2 / air flow rate of 1 slpm. The membrane thickness is 33 ± 5 μm for CCM1 and CCM2 (sPPB-H+) and 25 ± 5 μm for CCM3 and CCM4 (Nafion® NR-N211).

[0041] [Figure 6C]Figure 6C shows the Tafel relationships obtained at 80 °C, 100% RH, 1 atm, and the inset shows the linearized region where the Tafel equation holds. The film thicknesses are 33 ± 5 μm (sPPB-H+) for CCM1 and CCM2, and 25 ± 5 μm (Nafion® NR-N211) for CCM3 and CCM4.

[0042] [Figure 6D] Figure 6D shows Nyquist plots obtained at 80 °C, 100% RH, 1 atm, with 0.5 slpm H2 / 1.0 slpm O2 at 0.8 V. The film thicknesses are 33 ± 5 μm (sPPB-H+) for CCM1 and CCM2, and 25 ± 5 μm (Nafion® NR-N211) for CCM3 and CCM4.

[0043] [Figure 6E] Figure 6E shows CV scans obtained at 80 °C, 100% RH, 1 atm, with catalyst loading of 0.4 mg Pt cm-2 in 0.5 slpm H2 / 0 slpm N2 and scan rate of 50 mV s-1. The film thicknesses are 33 ± 5 μm for CCM1 and CCM2 (sPPB-H+) and 25 ± 5 μm for CCM3 and CCM4 (Nafion® NR-N211).

[0044] [Figure 6F] Figure 6F shows the Nyquist plots for 0.5 slpm H2 / 0.5 slpm N2 obtained at 80 °C, 100% RH, 1 atm, with the inset showing the expansion of the high frequency region. The film thicknesses are 33 ± 5 μm for CCM1 and CCM2 (sPPB-H+) and 25 ± 5 μm for CCM3 and CCM4 (Nafion® NR-N211).

[0045] [Figure 7A] FIG. 7A shows a cross-sectional SEM of 15 wt % linear sPPB-H+ ionomer (CCM1).

[0046] [Figure 7B] FIG. 7B shows a cross-sectional SEM of 5 wt% HB-sPPT-H++10 wt% linear sPPB-H+(CCM2).

[0047] [Figure 7C] FIG. 7C shows a cross-sectional SEM of 30 wt% Nafion® ionomer (CCM3).

[0048] [Figure 7D] FIG. 7D shows a cross-sectional SEM of 5 wt% HB-sPPT-H++25 wt% Nafion® (CCM4).

[0049] [Figure 7E] FIG. 7E shows cross-sectional SEMs of N2 adsorption isotherms (converted to STP and relative to the mass of carbon) Vads versus relative pressure / saturation pressure (P / P0) for the compared CCMs.

[0050] [Figure 7F] FIG. 7F shows a cross-sectional SEM of the pore size distribution determined from the adsorption isotherm.

[0051] [Figure 8] Figure 8 shows the t-plot from which the micropore volume (pores < 2 nm) and mesopore + macropore volume (2-50 nm + > 50 nm) were determined.

[0052] [Figure 9A] FIG. 9A is a schematic diagram of the catalyst layer structure when Nafion® is present in a PEMFC CL.

[0053] [Figure 9B] FIG. 9B is a schematic diagram of the catalyst layer structure when linear sPPB-H+ ionomer is present in a PEMFC CL.

[0054] [Figure 9C]FIG. 9C is a schematic diagram of the catalyst layer structure when HB-sPPT-H+ particles are present in a PEMFC CL.

[0055] [Figure 10A] FIG. 10A and FIG. 10B (continuation of FIG. 10A) show the synthetic route to hyperbranched sulfonated phenylated poly(phenylene) homopolymer (HB-sPPT-H+). [Figure 10B] FIG. 10A and FIG. 10B (continuation of FIG. 10A) show the synthetic route to hyperbranched sulfonated phenylated poly(phenylene) homopolymer (HB-sPPT-H+).

[0056] [Figure 11A] FIG. 11A is a SEM micrograph showing the surface roughness of 5 wt% HB-sPPT-H++10 wt% Linear sPPB-H+ at 1000x magnification.

[0057] [Figure 11B] FIG. 11B is a SEM micrograph showing the surface roughness of 7.5 wt% HB-sPPT-H++7.5 wt% Linear sPPB-H+ at 1000x magnification.

[0058] [Figure 11C] FIG. 11C is an SEM micrograph showing the surface roughness of 10 wt % HB-sPPT-H++5 wt % Linear sPPB-H+ at 1000x magnification.

[0059] [Figure 11D] FIG. 11D is a SEM micrograph showing the thickness of the catalyst coating film made from 5 wt% HB-sPPT-H++10 wt% linear sPPB-H+ at 1000x magnification.

[0060] [Figure 11E] FIG. 11E is a SEM micrograph showing the thickness of the catalyst coating film made from 7.5 wt% HB-sPPT-H++7.5 wt% Linear sPPB-H+ at 1000x magnification.

[0061] [Figure 11F] FIG. 11F is a SEM micrograph showing the thickness of the catalyst coating film made from 10 wt% HB-sPPT-H++5 wt% Linear sPPB-H+ at 1000x magnification.

[0062] [Figure 12A] FIG. 12A shows plots of mass and specific activity of CCMs made from 15 wt % sPPB-H+, 5 wt % HB-sPPT-H++10 wt % linear sPPB-H+, and 10 wt % sPPB-H+ obtained at 80° C., 100% RH, and 1 atm.

[0063] [Figure 12B] FIG. 12B shows plots of mass and specific activity for CCMs made from 30 wt% Nafion®, 5 wt% HB-sPPT-H++25 wt% Nafion®, and 30 wt% Nafion® obtained at 80° C., 100% RH, 1 atm.

[0064] [Figure 13A] FIG. 13A shows the performance plots of the MEA showing polarization and power curves under H2 / O2 with anode and cathode Pt catalyst loading of 0.4 mgPt / cm2 and operating conditions of 80° C., 100% RH, 1 atm.

[0065] [Figure 13B] FIG. 13B shows a performance plot of the MEA showing polarization and power curves for H2 / air operation with anode and cathode Pt catalyst loading of 0.4 mgPt / cm2 and operating conditions of 80° C., 100% RH, 1 atm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] Although particular embodiments of the present disclosure have been described herein for purposes of illustration, it will be understood that various modifications can be made without departing from the spirit and scope of the disclosure.

[0067] Sulfonated poly(arylene ether)s and sulfophenylated polyphenylene ionomers can exhibit improved chemical stability compared to PFSAs. In an illustrative example, biphenyl comonomers (sPPB-H + ) improves stability at the expense of lowering ionic conductivity.

[0068] Additionally, molecular branching of the ionomeric polymers was explored to reduce dimensional swelling and improve the mechanical integrity of this class of hydrocarbon ionomers when cast as PEMs. Of note, the electrical conductivity was improved when the branched ionomeric polymers described herein absorbed less water.

[0069] Herein, we present a novel method for the preparation of non-dimensionally swellable, non-coherent, hyperbranched sulfo-phenylated poly(phenylene) ionomer particles (HB-sPPT-HBs) to introduce a direct pathway for proton conduction in a hydrocarbon ionomer-based catalyst layer (CL). + The design and addition of a phosphodiesterase inhibitor (PDI) is reported.

[0070] definition

[0071] At various places in the present specification, substituents of compounds of the present disclosure are disclosed in groups or in ranges. It is specifically intended that the present disclosure include each individual subcombination of parts of such groups and ranges. Specifically, for example, "C 1~6 The term "alkyl" is intended to individually disclose methyl, ethyl, C3 alkyl, C4 alkyl, C5 alkyl, and C6 alkyl. As an example, the term "optionally substituted with 1, 2, 3, 4, or 5" is intended to individually disclose optional substitution with 1, 2, 3, or 4; 1, 2, or 3; 1 or 2; or 1 substituent.

[0072] Additionally, the compounds of the present disclosure are intended to be stable. As used herein, "stable" refers to a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture.

[0073] It will be further understood that certain features of the disclosure that are, for clarity, described in the context of separate embodiments, can also be provided in combination in a single embodiment. Conversely, various features of the disclosure that are, for brevity, described in the context of a single embodiment, can also be provided separately or in any suitable subcombination.

[0074] It is intended that a divalent group, such as a linking group (e.g., alkylene, arylene, etc.) between a first moiety and a second moiety, may be oriented in both a forward and reverse direction relative to the first and second moieties, unless otherwise specified.

[0075] An "optionally substituted" group can refer to a functional group that may or may not be substituted, for example, with an additional functional group. For example, if the group is unsubstituted, it can be referred to by the group name, such as alkyl or aryl. If the group is substituted with an additional functional group, it can be more generally referred to as a substituted alkyl or substituted aryl.

[0076] As used herein, the term "substituted" or "substitution" refers to the replacement of a hydrogen atom with a substituent other than H. For example, "N-substituted piperidin-4-yl" refers to the replacement of the H atom from the NH of piperidinyl with a non-hydrogen substituent, such as, for example, alkyl.

[0077] As used herein, the term "about" can be understood to include values ​​within 10% of the stated value.

[0078] As used herein, the term "alkyl" refers to a straight or branched chain hydrocarbon group. In some embodiments, an alkyl has 1-10 carbon atoms, 1-8 carbon atoms, 1-6 carbon atoms, 1-3 carbon atoms, 1 or 2 carbon atoms, or 1 carbon atom. Representative alkyl groups include methyl, ethyl, propyl (e.g., n-propyl, isopropyl), butyl (e.g., n-butyl, sec-butyl, and tert-butyl), pentyl (e.g., n-pentyl, tert-pentyl, neopentyl, isopentyl, pentan-2-yl, pentan-3-yl), and hexyl (e.g., n-hexyl and isomers).

[0079] As used herein, the term "alkylene" refers to a linking alkyl group.

[0080] As used herein, the term "cycloalkyl" refers to non-aromatic carbocycles, including cyclized alkyl, alkenyl, and alkynyl groups. Cycloalkyl groups can include monocyclic or polycyclic (e.g., having 2, 3, or 4 fused rings) ring systems, including spirocycles. In some embodiments, cycloalkyl groups can have 3 to about 20 carbon atoms, 3 to about 14 carbon atoms, 3 to about 10 carbon atoms, or 3 to 7 carbon atoms. Cycloalkyl groups can further have 0, 1, 2, or 3 double bonds and / or 0, 1, or 2 triple bonds. Also included in the definition of cycloalkyl are moieties that have one or more aromatic rings fused to the cycloalkyl ring (i.e., having a bond in common with the cycloalkyl ring), e.g., benzo derivatives such as pentane, pentene, hexane, and the like. Cycloalkyl groups with one or more fused aromatic rings can be attached through either the aromatic or non-aromatic moiety. One or more ring-forming carbon atoms of a cycloalkyl group can be oxidized, e.g., by having an oxo or sulfido substituent. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclopentenyl, cyclohexenyl, cyclohexadienyl, cycloheptatrienyl, norbornyl, norpinyl, norcamyl, adamantyl, and the like.

[0081] As used herein, the term "cycloalkylene" refers to a linking cycloalkyl group.

[0082] As used herein, the term "perfluoroalkyl" refers to a linear or branched fluorocarbon chain. In some embodiments, perfluoroalkyl has 1 to 10 carbon atoms (e.g., 1 to 8 carbon atoms, 1 to 6 carbon atoms, 1 to 3 carbon atoms, 1 or 2 carbon atoms, or 1 carbon atom). Representative alkyl groups include trifluoromethyl, pentafluoroethyl, and the like.

[0083] As used herein, the term "perfluoroalkylene" refers to a linking perfluoroalkyl group.

[0084] As used herein, the term "heteroalkyl" refers to a straight or branched chain alkyl group in which one or more carbon atoms are replaced with a heteroatom selected from O, N, or S. In some embodiments, a heteroalkylalkyl has 1-10 carbon atoms (e.g., 1-8 carbon atoms, 1-6 carbon atoms, 1-3 carbon atoms, 1 or 2 carbon atoms, or 1 carbon atom).

[0085] As used herein, the term "heteroalkylene" refers to a linking heteroalkyl group.

[0086] As used herein, the term "alkoxy" refers to an alkyl or cycloalkyl group, as described herein, attached to an oxygen atom. In some embodiments, an alkoxy has 1-10 carbon atoms (e.g., 1-8 carbon atoms, 1-6 carbon atoms, 1-3 carbon atoms, 1 or 2 carbon atoms, or 1 carbon atom). Representative alkoxy groups include methoxy, ethoxy, propoxy, and isopropoxy groups.

[0087] As used herein, the term "perfluoroalkoxy" refers to a perfluoroalkyl group or cyclic perfluoroalkyl group, as described herein, attached to an oxygen atom. In some embodiments, the perfluoroalkoxy has 1-10 carbon atoms (e.g., 1-8 carbon atoms, 1-6 carbon atoms, 1-3 carbon atoms, 1 or 2 carbon atoms, or 1 carbon atom). Representative perfluoroalkoxy groups include trifluoromethoxy, pentafluoroethoxy, and the like.

[0088] As used herein, the term "aryl" refers to an aromatic hydrocarbon group having 6 to 10 carbon atoms. Representative aryl groups include phenyl groups. In some embodiments, the term "aryl" includes monocyclic or polycyclic (e.g., having 2, 3, or 4 fused rings) aromatic hydrocarbons, such as, for example, phenyl, naphthyl, anthracenyl, phenanthrenyl, indanyl, and indenyl.

[0089] As used herein, the term "arylene" refers to linking aryl groups. For example, the term "phenylene" refers to linking phenyl groups.

[0090] As used herein, the term "aralkyl" refers to an alkyl or cycloalkyl group, as defined herein, in which one of the alkyl hydrogen atoms is replaced by an aryl group, as defined herein. A representative aralkyl group is a benzyl group.

[0091] As used herein, the term "aralkylene" refers to a linking aralkyl group.

[0092] As used herein, the term "heteroaryl" refers to a 5-10 membered aromatic monocyclic or bicyclic ring containing 1-4 heteroatoms selected from O, S, and N. Representative 5- or 6-membered aromatic monocyclic ring groups include pyridine, pyrimidine, pyridazine, furan, thiophene, thiazole, oxazole, and isoxazole. Representative 9- or 10-membered aromatic bicyclic ring groups include benzofuran, benzothiophene, indole, pyranopyrrole, benzopyran, quinoline, benzocyclohexyl, and naphthyridine.

[0093] As used herein, the term "heteroarylene" refers to a linking heteroaryl group.

[0094] As used herein, the term "heteroaralkyl" refers to an alkyl or cycloalkyl group, as defined herein, in which one of the hydrogen atoms of the alkyl is replaced with an aryl or heteroaryl group, as defined herein. For example, a representative aralkyl group is a benzyl group.

[0095] As used herein, the term "heteroaralkylene" refers to a linking heteroaralkyl group.

[0096] As used herein, the term "halogen" or "halo" refers to fluoro, chloro, bromo, and iodo groups.

[0097] As used herein, the term "copolymer" refers to a polymer that is the result of polymerization of two or more different monomers. The number and nature of each constitutional unit can be controlled separately in a copolymer. The constitutional units can be arranged in the following configurations: pure random, alternating random, regular alternating, regular block, or random block, unless otherwise specified. Pure random configurations can include, for example, xxyzxyyzyzz z... or yzxyzyzx x.... Alternating random configurations can be xyxzyxzyx z... and regular alternating configurations can be xyzxyzxy z.... Regular block configurations (i.e., block copolymers) have the following general configuration: ...xxyyzzzx x.... Meanwhile, random block configurations have, for example, the following general configuration: ...xxzzzxxyyzzzzxzzz... or, for example, ...xxxyyyxxyyyxxxxyy....

[0098] As used herein, the term "building block" of a polymer refers to an atom or group of atoms in the polymer, including a portion of the chain and its pendant atoms or groups of atoms, if any. A building block may be a repeating unit. A building block may also refer to an end group of a polymer chain. For example, the building block of polyethylene glycol is -CH2CH2O-, which corresponds to the repeating unit, or -CH2CH2OH, which corresponds to the end group.

[0099] As used herein, the term "repeating unit" corresponds to the smallest building block, the repetition of which constitutes a polymer (or an oligomeric molecule or block).

[0100] As used herein, the term "end group" refers to a unit that is located at the end of a polymer and is only attached to a polymer chain. For example, an end group may come from a monomer unit at the end of a polymer when the monomer unit is polymerized. As another example, an end group may be part of a chain transfer agent or initiator used to synthesize the polymer.

[0101] As used herein, the term "end" of a polymer refers to a constitutional unit of the polymer that is located at the end of the polymer backbone.

[0102] As used herein, the term "end group" refers to a functional group located at the end of a polymer backbone.

[0103] As used herein, the term "cationic" refers to a positively charged moiety or a moiety that can be ionized to a positively charged moiety under physiological conditions. Examples of cationic moieties include, for example, amino groups, ammonium groups, pyridinium groups, imino groups, sulfonium groups, quaternary phosphonium groups, and the like.

[0104] As used herein, the term "anionic" refers to a negatively charged functional group or a functional group that can be ionized to a negatively charged site under physiological conditions. Examples of anionic groups include carboxylate, sulfate, sulfonate, phosphate, and the like.

[0105] As used herein, the term "branched" refers to a polymer that includes side chains or "branches" extending from a main polymer segment (e.g., polymer backbone). The branches are composed of the same repeating units as the main segment. A branched ionomeric polymer includes relatively less branching comonomer in the ionomeric polymer compared to a hyperbranched ionomeric polymer, which includes more branching comonomer in the ionomeric polymer. A branched ionomeric polymer can include a mixture of linear and branched segments.

[0106] As used herein, the term "hyperbranched" refers to a polymer that includes a three-dimensional polymer structure that differs from the normal dendrimer structure and may include a mixture of linear and branched segments. A hyperbranched ionomeric polymer includes relatively more branching comonomers in the ionomeric polymer than are present in the branched ionomeric polymer. For example, the polymer composition may include about 20 mol% to about 40 mol%, about 20 mol% to about 30 mol%, about 20 mol% to about 25 mol%, about 18 mol% to about 22 mol%, or about 20 mol% of the branched monomer. A hyperbranched ionomeric polymer typically includes little or no linear segments. The hyperbranched ionomeric polymers described herein include HB-sPPT-H + It can be expressed as:

[0107] Branched and hyperbranched ionomeric polymers are distinguished from crosslinked polymers in that branched or hyperbranched ionomeric polymers do not contain linkages between polymer chains or between existing polymer chains.

[0108] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. Additionally, the materials, methods, and examples are illustrative only and are not intended to be limiting.

[0109] Branched and Hyperbranched Ionomeric Polymers

[0110] The polymers of the present disclosure may be branched and / or hyperbranched. Without wishing to be bound by theory, in some embodiments, branched and / or hyperbranched ionomeric polymers may have improved properties over their linear polymer analogs. Branched and / or hyperbranched ionomeric polymers may include a branching comonomer (B) covalently bonded to at least three anionic comonomer units. Branched and / or hyperbranched ionomeric polymers can be synthesized by reacting a functionalized branching comonomer (e.g., a dienophile) having three or more reactive functional groups with a functionalized anionic comonomer (e.g., a diene) having two or more diene functional groups. Such compositions can provide branching via the dienophile comonomer. Additionally, branched and / or hyperbranched ionomeric polymers can be synthesized by reacting a functionalized anionic comonomer (e.g., a diene) having three or more reactive diene functional groups with a dienophile comonomer (e.g., an alkyne and / or ketone) having two or more functional groups. Such compositions can provide branching via the diene comonomer. Additionally, branched and / or hyperbranched ionomeric polymers can be synthesized by reacting functionalized anionic comonomers (e.g., dienes) having three or more reactive diene functional groups with dienophile comonomers having three or more functional groups (e.g., alkynes and / or ketones). Such compositions can provide branching through both diene and dienophile comonomers. Examples of branched dienophile comonomers and branched dienes include, but are not limited to, 3-, 4-, 5-, and / or 6-way functionality. Scheme 1 shows a branched ionomeric polymer containing a trifunctional branched dienophile monomer.

[0111] Polyvalent linkers (i.e., comonomers) can be incorporated into the polymer using polyfunctional aromatic systems terminated with alkynes or protected alkynes, which are then used in a reaction with a dienophile comonomer to generate branch points according to Schemes 1 and 2. The diene comonomers can be a mixture of anionic and hydrophobic uncharged comonomers. The functionalized branched aromatic systems can be small, such as 1,3,5-triethynylbenzene, or larger, with multiple aromatic groups.

[0112] Scheme 1: Synthesis of branched ionomeric polymers and exemplary sulfonated phenylated polyphenylene ionomers containing difunctional anionic monomer A and trifunctional monomer B to induce branching between linear segments of difunctional monomer C.

[0113] [ka]

[0114] Scheme 2: Hyperbranched ionomeric polymer (HB-sPPT-H + ) and the synthesis of an exemplary sulfonated phenylated polyphenylene ionomer. Scheme 2 can omit the difunctional monomer C entirely (as shown) or can include the difunctional monomer C.

[0115] [ka]

[0116] The polymers of the present disclosure include branched ionomeric polymers comprising repeat units of formula (I). [ka] (In the formula, R 1A , R 1B , R 1C , R 1D , R 1E , and R 1Fare each independently 1~6 Alkyl, halo, nitro, cyano, SO3-X + , PO3 2- X + 2, and COO - X + 1, 2, 3, 4, or 5 substituents (X + H + or a cation; R 1A , R 1B , R 1C , R 1D , R 1E , and R 1F At least two of them are independently SO3 - X + , PO3 2- X + 2, and COO - X + 1, 2, 3, 4, or 5 substituents (X + H + or a cation), R 1G and R 1H are each independently H, aryl, or heteroaryl, and the aryl and heteroaryl are each independently 1~6 Alkyl, halo, nitro, cyano, SO3 - X + , PO3 2- X + 2, and COO - X + 1, 2, 3, 4, or 5 substituents (X + H + or a cation), A1 is an arylene, heteroarylene, aralkylene, or heteroaralkylene, each of which is optionally substituted with 1, 2, 3, or 4 substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl; A2 is absent, arylene, or heteroarylene, each of which is optionally substituted with 1, 2, 3, or 4 substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl; B is a branched comonomer; R 2A is a bond, The first repeat unit of formula (I) is R 2A to the second repeat unit of formula (I) to form a branched structure.

[0117] Branched ionomeric polymers comprising repeat units of formula (I) can include anionic comonomer units and branched comonomer (B) units.

[0118] In some embodiments, the anionic comonomer comprises more than 1 aryl group, more than 6 aryl groups, less than 10 aryl groups, exactly 7 aryl groups, or exactly 9 aryl groups, and further comprises more than 1 anionic substituent (e.g., sulfonate, phosphonate, and / or carboxylate), 2 to 7 anionic substituents, 2 to 6 anionic substituents, 2 to 4 anionic substituents, 4 to 10 anionic substituents, at least 2 anionic substituents, or no more than 4 anionic substituents.

[0119] Anionic substituents can contain one or more groups, either identical or different, that are anionic at physiological pH, or that are neutral at physiological pH but become anionic at a pH higher than the pKa of the substituent. For example, anionic groups include sulfonates, phosphonates, carboxylates, or combinations thereof.

[0120] Each of the anionic substituents (e.g., sulfonate, phosphonate, and / or carboxylate) can be protonated or have a non-proton counterion. As described herein, X + is the counter ion, H +, cations, alkali metal ions (e.g., Li + , Na + , K + , Rb + , and / or Cs + ), ammonium, substituted ammonium such as alkyl-, aryl-, or heteroaryl-substituted ammonium, or combinations thereof. For example, ammonium can be represented by R 5A , R 5B , R 5C , and R 5D However, independently, H, C 1~6 [N(R 5A )(R 5B )(R 5C )(R 5D )] + It could be.

[0121] In an exemplary embodiment, the anionic comonomer unit comprises a structure according to formula (VII). [ka]

[0122] In some embodiments, the branching comonomer (B) units comprise a structure of formula (II): [ka] (wherein L3, at each occurrence, is an optionally substituted polyvalent heteroatom (e.g., N, P, B), a polyvalent aryl, a polyvalent heteroaryl, a polyvalent aralkyl, or a polyvalent heteroaralkyl, wherein the polyvalent aryl, the polyvalent heteroaryl, the polyvalent aralkyl, and the polyvalent heteroaralkyl are each selected from the group consisting of C 1~6 optionally substituted with 1, 2, or 3 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl; L2 is absent, arylene or heteroarylene, each of the arylene and heteroarylene being selected from the group consisting of C 1~6optionally substituted with 1, 2, 3, or 4 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl; L1 is absent, arylene or heteroarylene, and the arylene and heteroarylene are each selected from the group consisting of C 1~6 Optionally substituted with 1, 2, 3, or 4 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl.

[0123] In an illustrative example, the branched comonomer (B) can include a structure of formula (III): [ka]

[0124] A branched ionomeric polymer comprising repeat units of formula (I) can comprise anionic comonomer units having a frequency "Y" and branched comonomer (B) units having a frequency "Z".

[0125] In some embodiments, the molar ratio of Z:Y in the polymer is from about 1:3 to about 1:2, from about 1:4 to about 2:3, from about 1:5 to about 3:4, about 1:2, or about 1:3.

[0126] The relative molar composition of Z:Y can affect the degree of branching and the structural, material, and electronic properties of the resulting polymer, such that values ​​of molar ratios less than about 1:3 or greater than about 1:2, or less than about 1:3 or greater than about 2:3, or less than about 1:4 or greater than about 1:2, may result in too low or too high a degree of branching, respectively, for the polymer to exhibit the desired ionomeric performance, as described in Examples 1-4 below.

[0127] As described herein, the anionic comonomer and the branching comonomer (B) are covalently bonded.

[0128] In one embodiment, the repeat unit comprises the structure of formula (IV): [ka]

[0129] In some embodiments, the polymer is insoluble in a polar solvent. Polar solvents can include water, alcohol (e.g., methanol, ethanol, propanol, isopropanol, n-butanol, and / or tert-butanol). In some embodiments, the polymer is insoluble in a low boiling point alcohol. Low boiling points include boiling points below about 120°C, below about 100°C, below about 90°C, below about 85°C, below about 80°C, below about 70°C, from about 60°C to about 80°C, from about 60°C to about 85°C, or from about 60°C to about 120°C. Examples of low boiling point alcohols include methanol, ethanol, propanol, isopropanol, n-butanol, tert-butanol, and the like.

[0130] In some embodiments, the polar solvent comprises an alcohol, water, or a combination thereof. In some embodiments, the polar solvent comprises a combination of multiple components, such as alcohol and water, or multiple different alcohols and water. In embodiments where the polar solvent comprises alcohol and water, the composition of the polar solvent can be about 1:1 water to alcohol by volume, about 1:2 water to alcohol by volume, about 1:3 water to alcohol by volume, about 1:4 water to alcohol by volume, about 1:2.5 water to alcohol by volume, or about 1:3.5 water to alcohol by volume.

[0131] The branched ionomeric polymer of formula (I) can be formed by polymerization of a functionalized branching comonomer (B) and a functionalized anionic comonomer. The polymerization is carried out in a Diels-Alder addition reaction, Z m moles of functionalized comonomer (B) and Y m The polymerization of the functionalized anionic comonomer may include polymerization of moles of functionalized anionic comonomer.

[0132] In the polymer synthesis, the functionalized branched comonomer (B) is a dienophile and can contain more than one alkyne functional group, two or more alkyne functional groups, three or more alkyne functional groups, 2-4 alkyne functional groups, 2-6 alkyne functional groups, exactly 6 alkyne functional groups, exactly 5 alkyne functional groups, exactly 4 alkyne functional groups, or exactly 3 alkyne functional groups. For example, the functionalized branched comonomer (B) can be a trifunctional comonomer (B) containing three alkyne functional groups.

[0133] In polymer synthesis, the functionalized anionic comonomer is a diene. The functionalized anionic comonomer can include one diene, two dienes, three dienes, or four dienes in the functionalized anionic comonomer reagent.

[0134] The molar ratio of functionalized branched comonomer (B) to functionalized anionic comonomer in the polymer synthesis can be greater than about 0.2, greater than about 0.4, greater than about 0.5, greater than about 0.6, greater than about 0.7, from about 0.5 to about 0.7, or about 0.67.

[0135] The branched comonomer (B) can be formed from a functionalized comonomer (B), such as a trifunctional comonomer (B). Such a functionalized comonomer (B) plays the role of a dienophile in the Diels-Alder addition reaction. A representative trifunctional comonomer (B) dienophile is represented by formula (V): [ka] (wherein L3, at each occurrence, is an optionally substituted polyvalent heteroatom (e.g., N, P, B), a polyvalent aryl, a polyvalent heteroaryl, a polyvalent aralkyl, or a polyvalent heteroaralkyl, wherein the polyvalent aryl, the polyvalent heteroaryl, the polyvalent aralkyl, and the polyvalent heteroaralkyl are each selected from the group consisting of C 1~6optionally substituted with 1, 2, or 3 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl; L2 is absent, arylene or heteroarylene, each of the arylene and heteroarylene being selected from the group consisting of C 1~6 optionally substituted with 1, 2, 3, or 4 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl; L1 is absent, arylene or heteroarylene, and the arylene and heteroarylene are each selected from the group consisting of C 1~6 optionally substituted with 1, 2, 3, or 4 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl; D1, D2, and D3 are independently H, R 1G , R 1H , R 3G , R 3H or a protecting group (e.g., a silyl protecting group, a substituted silyl protecting group, a trialkylsilyl protecting group, a silyl ether protecting group, a trialkylsilyl ether protecting group, a trimethylsilyl ether); R 1G and R 1H are independently H, aryl, or heteroaryl, each of which is selected from the group consisting of C 1~6 Alkyl, halo, nitro, cyano, SO3 - X + , PO3 2- X + 2, and COO - X + 1, 2, 3, 4, or 5 substituents (X + H + or a cation), R 3G and R 3H is independently alkyl, aryl, or aralkyl.

[0136] The multivalent branched comonomers referred to herein, such as the branched comonomers (B), can be incorporated into the polymer via an alkyne functional group or a protected alkyne functional group. The alkyne functional group can be located at a central position in the molecule or at a terminal position in the molecule. The functionalized comonomers (B) can include a mixture of functionalized comonomers, or can include a pure composition of comonomers having substantially one molecular composition.

[0137] The functionalized comonomer (B) can be a relatively small molecule, such as 1,3,5-triethynylbenzene, or a relatively large molecule, such as a molecule containing more than one aromatic group and three alkyne functional groups. The functionalized comonomer (B) can contain one or more aromatic rings, one or more heteroaromatic rings, or a combination thereof. When the functionalized comonomer (B) contains one or more heteroaromatic rings, one or more heteroatoms can be present, and the one or more heteroatoms are selected from nitrogen, oxygen, and sulfur. The heteroaromatic ring can be pyridine or pyrazine. Representative trifunctional comonomers (B) can contain one or more of the following structures: [ka]

[0138] In some embodiments, the functionalized comonomer (B) can include a central atom, such as nitrogen or carbon, and can include one or more of the following structures: [ka]

[0139] In some embodiments, one or more of the terminal alkyne groups is substituted with H.

[0140] In some embodiments, the functionalized comonomer (B) can include 5 or 6 functional groups, such as 5 or 6 alkyne groups. The functionalized comonomer (B) can include 5 or 6 functionalized aromatic rings to form a hexa- or penta-phenylbenzene dienophile derivative. Representative hexa- or penta-phenylbenzene dienophiles can include the following: where the "R" substituents can be the same or different within the molecule and can include an alkyne functional group or hydrogen. [ka]

[0141] In one embodiment, the polyvalent comonomer has a structure according to the functionalized comonomers described herein, such as, for example, a trifunctional dienophile according to formula (VIII). [ka]

[0142] In one embodiment, the functionalized anionic comonomer has a structure according to formula (VI): [ka] (In the formula, R 1A , R 1B , R 1C , R 1D , R 1E , and R 1F are independently aryl or heteroaryl, each of 1~6 Alkyl, halo, SO3 - X + , PO3 2- X + 2, and COO - X + 1, 2, 3, 4, or 5 substituents (X + H + or a cation), R 1A , R 1B , R 1C , R1D , R 1E , and R 1F At least two of them are independently SO3 - X + , PO3 2- X + 2, and COO - X + 1, 2, 3, 4, or 5 substituents (X + H + or a cation), A1 is arylene, heteroarylene, aralkylene, or heteroaralkylene, each optionally substituted with 1, 2, 3, or 4 substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl; A2 is absent, arylene or heteroarylene, and the arylene and heteroarylene are each optionally substituted with 1, 2, 3, or 4 substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl.

[0143] As described herein, X + is the counter ion, H + , cations, alkali metal ions (e.g., Li + , Na + , K + , Rb + , and / or Cs + ), ammonium, substituted ammonium such as alkyl-, aryl-, or heteroaryl-substituted ammonium, or combinations thereof. For example, ammonium can be represented by the formula [N(R 5A )(R 5B )(R 5C )(R 5D )] + R 5A , R 5B , R 5C , and R 5D are independently H, C 1~6 It is alkyl, aryl, aralkyl, or heteroaryl.

[0144] In an exemplary embodiment, the functionalized anionic comonomer of formula (VI) is represented by formula (XIV). [ka]

[0145] The branched ionomeric polymer of formula (I) can further include a bifunctional linker (C), as shown in Scheme 1. The bifunctional linker can include an aryl group or a heteroaryl group, and as used herein, is an arylene or a heteroarylene. In an embodiment, the arylene or heteroarylene can include one aryl group or a heteroaryl group, can include more than one aryl group or a heteroaryl group, or can include a combination of one or more aryl groups and heteroaryl groups. When the bifunctional linker (C) is present and includes one or more or more aryl groups or heteroaryl groups, the aryl groups or heteroaryl groups can be the same or different aryl groups or heteroaryl groups. For example, the one or more or more aryls or heteroaryls can include aryl and aryl (e.g., phenyl and phenyl to form a biphenyl, or phenyl and naphthyl), or can include aryl and heteroaryl (e.g., phenyl and pyridyl).

[0146] In one embodiment, the difunctional arylene can be phenyl, naphthyl, anthracenyl, biphenyl, terphenyl, and the like, or combinations thereof.

[0147] The functionalized comonomer (B), the difunctional comonomer C and the functionalized anionic comonomer described herein can be reacted together in a specific ratio to achieve a defined desired ratio in the branched ionomeric polymer composition. For example, the functionalized comonomer (B) can be present in an amount of 0.001 to 20 mol % relative to the combination of the anionic comonomer and the difunctional comonomer C. In the above, the difunctional comonomer C may be present or may not be present at all.

[0148] In contrast, hyperbranching results from a higher relative amount of functionalized comonomer (B) when used in a ratio of greater than about 20 mol%, greater than about 15 mol%, greater than about 13 mol%, greater than about 12 mol%, about 13.3 mol%, about 13.33 mol%, or about 13.333 mol% relative to the anionic comonomer (e.g., a relative amount of approximately 66-67 mol%). In one embodiment, the hyperbranched ionomeric polymer comprises functionalized comonomer (B) in an amount of about 13.3 mol% relative to the amount of anionic comonomer. In one embodiment, the hyperbranched ionomeric polymer comprises functionalized comonomer (B) in an amount of about 13.33 mol% relative to the amount of anionic comonomer. In one embodiment, the hyperbranched ionomeric polymer comprises functionalized comonomer (B) in an amount of about 13.33 mol% relative to the amount of anionic comonomer. In one embodiment, the hyperbranched ionomeric polymer comprises a functionalized comonomer (B) in an amount of about 20 mol% relative to the amount of the anionic comonomer. For example, to achieve hyperbranching, the molar ratio of the functionalized comonomer (B) to the difunctional comonomer C in the Diels-Alder synthesis reaction compared to the functionalized anionic comonomer can be greater than about 0.2 (corresponding to about 20 mol%), greater than about 0.3 (corresponding to about 30 mol%), greater than about 0.4 (corresponding to about 40 mol%), greater than about 0.5 (corresponding to about 50 mol%), greater than about 0.6 (corresponding to about 60 mol%), greater than about 0.7 (corresponding to about 70 mol%), from about 0.2 to about 0.8, from about 0.5 to about 0.75, from about 0.6 to about 0.7, or about 0.67 (corresponding to about 67 mol%). In the above, the difunctional comonomer C may be present or may not be present at all.

[0149] In one embodiment, the branched or hyperbranched ionomeric polymer of formula (I) is used in a catalyst ink formulation. The catalyst ink formulation can include (1) a polar solvent, (2) a branched and / or hyperbranched ionomeric polymer having the structure of formula (I) described herein, including any variations, (3) a branched and / or linear ionomeric polymer, and (4) a catalyst. The catalyst ink formulation can include (1) a polar solvent, (2) a hyperbranched ionomeric polymer having the structure of formula (I) described herein, including any variations, (3) a linear ionomeric polymer, and (4) a catalyst. The catalyst ink formulation can include (1) a polar solvent, (2) a branched ionomeric polymer having the structure of formula (I) described herein, including any variations, (3) a linear ionomeric polymer, and (4) a catalyst. The catalyst ink formulation can include (1) a polar solvent, (2) a hyperbranched ionomeric polymer having the structure of Formula (I) described herein, including all variations, (3) a branched and linear ionomeric polymer, and (4) a catalyst.

[0150] The catalysts of the catalyst ink formulation can include platinum on a carbon support (i.e., Pt / C) with various Pt particle sizes combined with carbon materials of various surface areas and sizes, Pt alloys on a carbon support with various precious metal alloy particle sizes and alloy ratios (e.g., PtCo / C) combined with carbon materials of various surface areas and sizes, or MNC catalysts incorporating non-precious metal ions (e.g., M is iron or cobalt) within a nitrogen-doped carbon support.

[0151] The amount of catalyst used may depend on the identity of the catalyst, the amount of solids in the catalyst ink, the ratio of ionomer to catalyst, and / or other factors.

[0152] As used herein, wt% of Pt / C catalyst refers to the total amount of Pt / C solids used, including the amount of both Pt and carbon. For example, the wt% of Pt / C remains the same relative to the total mass used whether the Pt / C is 40 wt% Pt and 60 wt% carbon or has a different relative composition.

[0153] In one embodiment, the amount of the catalyst used may be about 0.1 wt % to about 2.0 wt % calculated as solid content.

[0154] In one embodiment, the catalyst loading can be from about 0.1% w / v to about 25% w / v of catalyst (eg, Pt / C, PtCo / C, and MNC catalysts) relative to the amount of catalyst ink solvent.

[0155] In one embodiment, the catalyst ink composition can include, based on total solids, from about 1 wt % to about 30 wt % ionomeric polymer and from about 70 wt % to about 99 wt % supported catalyst.

[0156] In one embodiment, the catalyst ink composition can include, based on total solids, from about 10 wt % to about 30 wt % of the ionomeric polymer and from about 70 wt % to about 90 wt % of the supported catalyst.

[0157] In one embodiment, the catalyst layer can include from about 1 wt % to about 30 wt % ionomeric polymer and from about 70 wt % to about 99 wt % supported catalyst or solids.

[0158] The linear ionomeric polymer can include a structure of formula (IX): [ka]

[0159] This is a linear sulfonated phenylated poly(phenylene) biphenyl, sPPB-H + In another embodiment, the linear ionomeric polymer can comprise a structure of formula (X): [ka]

[0160] This is because sPPB-H + and a random copolymer containing hydrophobic units, RCP-sPPB-H +In one embodiment, the linear ionomeric polymer can include, but is not limited to, commercially available PFSA materials such as long side chain PFSA ionomers (e.g., Nafion®), short side chain PFSA ionomers (e.g., Aquivion®), and / or similar derivatives thereof (e.g., 3M ionomers). In one embodiment, the linear ionomeric polymer is any linear ionomeric polymer.

[0161] The branched or hyperbranched ionomeric polymer can be disposed in a polar solvent, and the branched or hyperbranched ionomeric polymer is disposed, introduced, or suspended in the polar solvent. The branched or hyperbranched ionomeric polymer can be dispersed in the polar solvent. The branched or hyperbranched ionomeric polymer can have a solubility in the polar solvent of about 0% to about 20%, about 0% to about 15%, about 0% to about 10%, or about 0% to about 5%. In one embodiment, the branched or hyperbranched ionomeric polymer has a solubility in the polar solvent of about 0% to about 20%. The branched or hyperbranched ionomeric polymer is substantially insoluble in the polar solvent.

[0162] A linear ionomeric polymer has a greater solubility in a polar solvent than a branched or hyperbranched ionomeric polymer. The polar solvent can be contacted with the linear ionomeric polymer, and the linear ionomeric polymer can be completely (e.g., about 90% to about 100%), substantially completely (e.g., at least about 97%), or predominantly (e.g., at least about 90%) dispersed in the polar solvent to form a solution of the linear ionomeric polymer dispersed in the polar solvent.

[0163] As used herein, "dispersed" means that the particles of the ionomeric polymer are fairly uniformly dispersed in the polar solvent, or that the ionomeric polymer is soluble in the polar solvent and capable of being uniformly dispersed in the polar solvent immediately after mixing.

[0164] In one embodiment, a linear ionomeric polymer (e.g., sPPB-H +) is at least about 97% dispersed in an alcohol (e.g., a low boiling alcohol as described herein). In one embodiment, the linear ionomeric polymer (e.g., sPPB-H + ) is at least about 97% dispersed in a combination of water and alcohol (eg, a low boiling alcohol as described herein).

[0165] In one embodiment, sPPB-H + The combination of sPPB-H and the branched and / or hyperbranched polymer is at least about 97% dispersed in an alcohol (e.g., a low boiling alcohol as described herein) or at least about 97% dispersed in a combination of an alcohol (e.g., a low boiling alcohol as described herein) and water, for example, when the amount of branching is about 0.5 mol %. In one embodiment, the sPPB-H + The combination of sPPB-H and the branched and / or hyperbranched polymer is at least about 90% dispersed in an alcohol (e.g., a low boiling alcohol as described herein) or at least about 90% dispersed in a combination of alcohol (e.g., a low boiling alcohol as described herein) and water, for example, when the amount of branching is about 1 mole %. In one embodiment, the sPPB-H +The combination of the branched and / or hyperbranched polymers is partially dispersed (e.g., less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 30%, or less than about 33%) in an alcohol (e.g., a low boiling alcohol as described herein) or in a combination of alcohol (e.g., a low boiling alcohol as described herein) and water, for example, when the amount of branching is about 2 mol % or more. In some embodiments, the polar solvent can include water, alcohol (e.g., methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol), ketone (acetone, methyl ethyl ketone, methyl isobutyl ketone). In some embodiments, the polar solvent is a low boiling alcohol. Low boiling alcohols can include those with boiling points below 120° C., below 100° C., below 90° C., below 85° C., below 80° C., below 70° C., from about 60° C. to about 80° C., or from about 60° C. to about 85° C. Examples of low boiling alcohols include methanol, ethanol, isopropanol, n-propanol, tert-butanol, n-butanol, etc. In a preferred embodiment, the alcohol is methanol or isopropanol.

[0166] In some embodiments, the polar solvent comprises an alcohol, a ketone, water, or a combination thereof. In some embodiments, the polar solvent comprises a combination of multiple components, such as alcohol and water; multiple different alcohols and water; or one or more of the same or different alcohols, one or more of the same or different ketones, and water. In embodiments in which the polar solvent comprises alcohol and water, the composition of the polar solvent may be about 1:1 by volume of water to alcohol(s), about 1:2 by volume of water to alcohol(s), about 1:3 by volume of water to alcohol(s), about 1:4 by volume of water to alcohol(s), about 1:2.5 by volume of water to alcohol(s), or about 1:3.5 by volume of water to alcohol(s).

[0167] In some embodiments, the amount of linear ionomeric polymer added is an amount that allows the branched or hyperbranched ionomeric polymer to be dispersed in a polar solvent.

[0168] In some embodiments, the branched or hyperbranched ionomeric polymer may be present in the catalyst ink formulation in an amount of from about 0.01 wt % to about 10 wt % of total solids.

[0169] The amount (mass) of linear ionomeric polymer can be less than, equal to, or greater than the amount of branched or hyperbranched ionomeric polymer used. For example, the ratio of the mass of linear ionomeric polymer to the mass of branched ionomeric polymer can be about 1:2 to about 3:1, about 1:1 to about 2:1, about 1.8:1 to about 2.2:1, about 1.9:1 to about 2.1:1, or about 2:1. In one embodiment, the ratio of the mass of linear ionomeric polymer to the mass of branched ionomeric polymer is about 2:1.

[0170] The branched or hyperbranched ionomeric polymer, in combination with the linear ionomeric polymer, can be present in the polar solvent at about 0.01% w / v to about 35% w / v, about 0.01% w / v to about 30% w / v, about 0.01% w / v to about 25% w / v, about 0.01% w / v to about 20% w / v, about 0.01% w / v to about 15% w / v, about 0.01% w / v to about 10% w / v, about 0.01% w / v to about 5% w / v, less than about 20% w / v, or less than about 10% w / v.

[0171] In one embodiment, the catalyst ink formulation comprises a branched or hyperbranched ionomeric polymer and a linear ionomeric polymer, and the total amount of branched, hyperbranched, and linear ionomeric polymer dispersed in a polar solvent is from about 0.1% w / v to about 25% w / v.

[0172] At concentrations higher than those stated above, the stability of the dispersion containing the insoluble branched or hyperbranched ionomeric polymer may be compromised, which may prevent the incorporation of the branched or hyperbranched ionomer into the catalyst ink formulation and prevent effective incorporation into the polymer film, resulting in reduced benefits to electrical properties and power density, as detailed in the examples below.

[0173] Examples of anionic polyphenylene monomers, oligomers, and polymers are provided below. Example 1 describes the controlled synthesis of sulfonated comonomers and the preparation of sulfonated branched oligophenylenes and hyperbranched ionomeric polymers (HB-sPPT-HB) with precisely controlled position and number of sulfonic acid groups. + The usefulness of this in the synthesis of

[0174] In one embodiment, the branched and / or hyperbranched ionomeric polymers described herein can be incorporated into an ionomeric polymer membrane.

[0175] The ionomeric polymer membrane can include a mechanical reinforcement and an ionomeric binder bonded to the mechanical reinforcement.

[0176] The ionomeric polymer membrane can include a substrate and an ionomeric binder that bonds to the substrate.

[0177] Ionomeric binders can bond directly or indirectly to mechanical reinforcements or substrates via covalent bonds, ionic bonds, hydrogen bonds, van der Waals forces, and / or metallic bonds.

[0178] The mechanical reinforcement or substrate may comprise a porous polymeric material. The porous polymeric material may be any polymeric material that contains pores. The porous polymeric material may be, for example, a linear sulfonated phenylated poly(phenylene) biphenyl (sPPB-H) of formula (IX): + The poly(phenylene) ionomer may be a linear sulfonated phenylated poly(phenylene) ionomer, such as a phenylene ionomer having a phenyl group and / or an expanded polyethylene (ePE).

[0179] In one embodiment, the ionomeric binder can include a branched ionomeric polymer of Formula (I) or a hyperbranched ionomeric polymer of Formula (I) and all repeats disclosed herein. The branched or hyperbranched ionomeric polymer of the ionomeric binder can include an amount of about 0.5 wt% to about 99 wt%, about 0.5 wt% to about 50 wt%, about 0.5 wt% to about 25 wt%, or about 0.5 wt% to about 15 wt%.

[0180] In one embodiment, the ionomeric binder can further comprise a linear ionomer. For example, the linear ionomeric polymer of the ionomeric binder can be a linear sulfonated phenylated poly(phenylene) biphenyl (sPPB-H + ) Ionomer, sPPB-H + and a random copolymer comprising hydrophobic units, a PFSA material, or a combination thereof.

[0181] In one embodiment, the amount (weight) of linear ionomer in the ionomeric binder can be less than, equal to, or greater than the amount of branched or hyperbranched ionomeric polymer used. For example, the ratio of the weight of linear ionomeric polymer to the weight of branched ionomeric polymer can be about 1:1 to about 3:1, about 1:1 to about 2:1, about 1.8:1 to about 2.2:1, about 1.9:1 to about 2.1:1, or about 2:1. In one embodiment, the ratio of the weight of linear ionomeric polymer to the weight of branched ionomeric polymer is about 2:1.

[0182] In one embodiment, the branched or hyperbranched ionomer of the ionomeric binder is present in an amount of about 0.5 wt % to about 10 wt %, and the linear sPPB-H of the ionomeric binder is present in an amount of about 0.5 wt % to about 10 wt %. + The ionomer is present in an amount about equal to or greater by weight than the branched or hyperbranched ionomer of the ionomeric binder.

[0183] The ionomeric binder can include a combination of branched ionomeric polymers and hyperbranched ionomeric polymers without any linear ionomeric polymers, a combination of linear ionomeric polymers and hyperbranched ionomeric polymers without any branched ionomeric polymers, or a combination of branched ionomeric polymers and linear ionomeric polymers without any hyperbranched ionomeric polymers.

[0184] The catalyst layer described herein can be applied to an ionomeric polymer membrane to form a catalyst-coated ionomeric polymer membrane.

[0185] In one embodiment, the ionomeric polymer membranes described herein can further include a catalyst layer to form a catalyst-coated ionomeric polymer membrane, where the catalyst layer is in contact with the ionomeric polymer membrane.

[0186] The catalyst layer, or a component of the catalyst layer, can be in contact with the mechanical reinforcement of the ionomeric polymer membrane, the ionomeric binder of the ionomeric polymer membrane, or both the mechanical reinforcement and the ionomeric binder of the ionomeric polymer membrane. The catalyst layer, or a component of the catalyst layer, can be in contact with the substrate of the ionomeric polymer membrane, the ionomeric binder of the ionomeric polymer membrane, or both the substrate and the ionomeric binder of the ionomeric polymer membrane.

[0187] The catalyst layer can be formed from a catalyst ink. The catalyst layer can be formed from a catalyst ink formulation as described herein above and below. Forming the catalyst layer can include applying the catalyst ink formulation and then removing the solvent. Forming the catalyst layer can include printing with the catalyst ink formulation.

[0188] The catalyst layer comprises a catalyst ink composition having at least about 90% of the solvent removed, at least about 95% of the solvent removed, at least about 97% of the solvent removed, at least about 99% of the solvent removed, substantially all detectable solvent removed, or about 97% of the solvent removed. In one embodiment, about 97% of the solvent from the catalyst ink formulation is removed in forming the catalyst layer.

[0189] The solvent of the catalyst ink formulation may be removed by solvent removal techniques known in the art (eg, ambient temperature and pressure evaporation, elevated or elevated pressure evaporation, solvent extraction, filtration, absorption, etc.).

[0190] The catalyst layer can include catalysts such as platinum on a carbon support with various Pt particle sizes combined with carbon materials of various surface areas and sizes (i.e., Pt / C); platinum alloys on a carbon support with various precious metal alloy particle sizes and alloy ratios combined with carbon materials of various surface areas and sizes (e.g., PtCo / C); or MNC catalysts incorporating non-precious metal ions (e.g., M is iron or cobalt) within a nitrogen-doped carbon support. The catalyst-coated ionomeric polymer membrane can include Pt / C, PtCo / C, MNC catalysts, or combinations thereof.

[0191] The catalyst layer may further include an additive.

[0192] The catalyst layer may include a combination of a catalyst, a branched ionomeric polymer, a hyperbranched ionomeric polymer, a linear ionomeric polymer, or a combination thereof, and an additive. The catalyst layer may further include residual solvent.

[0193] As used herein, the catalyst layer ionomeric polymer can include a branched ionomeric polymer, a hyperbranched ionomeric polymer, a linear ionomeric polymer, or a combination thereof.

[0194] The amount of catalyst, branched ionomeric polymer, hyperbranched ionomeric polymer, and linear ionomeric polymer in the catalyst layer comprises about 50 wt % to about 100 wt %, based on the total weight of the catalyst layer.

[0195] The catalyst layer catalyst and catalyst layer ionomeric polymer can comprise at least 90 wt% of the catalyst layer, the catalyst and ionomeric polymer can comprise at least 94 wt% of the catalyst layer, the catalyst and ionomeric polymer can comprise at least 95 wt% of the catalyst layer, the catalyst and ionomeric polymer can comprise at least 96 wt% of the catalyst layer, the catalyst and ionomeric polymer can comprise at least 97 wt% of the catalyst layer, or the catalyst and ionomeric polymer can comprise at least 98 wt% of the catalyst layer.

[0196] The catalyst layer can include about 10 wt % to about 30 wt % ionomeric polymer and about 70 wt % to about 90 wt % catalyst.

[0197] The ionomeric binder of the ionomeric polymer membrane can comprise at least 50 wt% of the weight of the ionomeric polymer membrane, at least 60 wt% of the weight of the ionomeric polymer membrane, at least 70 wt% of the weight of the ionomeric polymer membrane, at least 80 wt% of the weight of the ionomeric polymer membrane, at least 90 wt% of the weight of the ionomeric polymer membrane, or from about 60 wt% to about 90 wt% of the weight of the ionomeric polymer membrane.

[0198] The linear ionomer of the ionomeric binder can comprise about 0 wt%, about 1 wt%, about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, or about 30 wt%. In one embodiment, the linear sPPB-H of the ionomeric binder can comprise about 0 wt%, about 1 wt%, about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, or about 30 wt%. + The ionomer may comprise about 15 wt% of the weight of the ionomer binder.

[0199] The branched and / or hyperbranched ionomeric polymers of the ionomeric binder can comprise an amount of from about 0.5 wt % to about 25 wt % by weight of the ionomeric binder, or from about 0 wt % to about 25 wt % by weight of the ionomeric binder.

[0200] The linear ionomeric polymer of the ionomeric binder is present in an amount about equal to or greater than the amount of the branched or hyperbranched ionomeric polymer of the ionomeric binder.

[0201] Optimization of the wt% of linear ionomer is discussed in more detail in Examples 1-4. Thus, the composition of the ionomeric binder can be guided by the stability (e.g., reduced delamination of the catalyst layer from the substrate) of the ionomeric polymer membranes that contain branched or hyperbranched ionomeric polymers.

[0202] In one embodiment of the branched or hyperbranched ionomeric polymer membrane, the substrate or mechanical reinforcement, the ionomeric binder, and the catalyst layer are essentially free of halogen. As used herein, "essentially free" means that the branched or hyperbranched ionomeric polymer membrane, the ionomeric binder, and the catalyst layer each contain less than about 1% halogen, less than about 0.5% halogen, less than about 0.01% halogen, or less than about 0.001% halogen. Measurable levels of halogen may be introduced during operation, for example, as halide salts (e.g., NaCl), as synthesis or processing impurities, or as trace gases.

[0203] The ionomeric polymer membrane can have an upper surface and a lower surface, such as in a sheet-like configuration, including a rolled, folded, or otherwise distorted sheet.

[0204] The catalyst layer can contact only the top surface, only the bottom surface, or both the top and bottom surfaces of the ionomeric polymer membrane.

[0205] When the catalyst layer is in contact with only the top or bottom surface of the ionomeric polymer membrane, a bilayer is formed, which can be used as a bilayer membrane electrode assembly.

[0206] When a catalyst layer is in contact with both the top and bottom of the ionomeric polymer membrane, a triple layer is formed, which can be used as a triple layer membrane electrode assembly.

[0207] The bilayer or triple layer catalyst coated ionomeric polymer membrane can be in a planar form, such as a sheet. The sheet can be planar, rolled, folded, or otherwise distorted. For example, the catalyst coated ionomeric polymer membrane can be a sheet wound into a roll to form a roll that can have dimensions such as 30 cm wide and 1-1000 m long, or 10-100 m long.

[0208] In one embodiment, the catalyst layer of the catalyst-coated ionomeric polymer membrane can function as an anode or a cathode. When only one side of the ionomeric polymer membrane is in contact with a catalyst layer, the catalyst layer is either an anode or a cathode. When both sides of the ionomeric polymer membrane are in contact with a catalyst layer, one catalyst layer is an anode and the other catalyst layer is a cathode.

[0209] In general, the anode is the electrode where oxidation occurs during an electrochemical reaction, and the cathode is the electrode where reduction occurs during an electrochemical reaction.

[0210] Whether a catalyst layer is an anode or a cathode can be determined by the orientation of the catalyst layer in a product such as a fuel cell. Whether a catalyst layer is an anode or a cathode can be determined by a combination of the orientation of the catalyst layer in a fuel cell and the amount of catalyst present. In a fuel cell, the anode is the electrode where a fuel such as hydrogen (H2) is oxidized to produce electrons and protons (H + ) are then drawn into an external circuit to perform useful work, releasing protons (H + ) travels through the electrolyte to the cathode. In a fuel cell, the cathode is the electrode where oxygen (O2) is reduced and protons (H + ) to form water (H2O).

[0211] In an electrolysis device, the anode is where water (HO) is oxidized through an electrochemical reaction to produce oxygen (O) and protons (H + ) and electrons (e - ) is an electrode that generates

[0212] In an electrolyser, the cathode produces protons (H + ) is reduced to produce hydrogen gas (H2).

[0213] Branched or hyperbranched ionomeric polymer membranes have a dielectric constant of about 0.001 mS cm at 30% to 100% relative humidity when measured using AC impedance spectroscopy (electrochemical impedance spectroscopy) at temperatures between about 20 °C and about 90 °C or between about 50 °C and about 90 °C. ―1 ~Approx. 1000mS cm ―1 , about 0.001mS cm ―1 ~Approx. 750mS cm ―1 , about 0.001mS cm ―1 ~Approx. 450mS cm ―1 , about 1mS cm ―1 ~Approx. 1000mS cm ―1 , about 0.001mS cm ―1 Super, about 1mS cm ―1 More than or about 1000 mS cm ―1 The ionomeric polymer membrane can have a proton conductivity (e.g., ex situ conductivity, in-plane) of less than about 1 mS cm at about 80° C. in water, as measured using AC impedance spectroscopy (electrochemical impedance spectroscopy). -1 ~Approx. 1000mS cm -1 , or about 50 mS cm -1 ~Approx. 450mS cm -1 The nanotube can have a proton conductivity (e.g., ex situ conductivity, in-plane) of 0.1 to 0.5 μm.

[0214] The branched or hyperbranched ionomeric polymers described herein can be incorporated into a catalyst layer of a fuel cell, electrolyzer, or another electrochemical device. The fuel cell, electrolyzer, or another electrochemical device can include a catalyst layer.

[0215] For example, the branched or hyperbranched ionomeric polymers can be incorporated into a catalyst layer of a fuel cell, electrolyzer, or another electrochemical device in an amount of about 5 wt% to about 45 wt%, about 10 wt% to about 45 wt%, about 15 wt% to about 45 wt%, about 30 wt% to about 45 wt%, about 5 wt% to about 30 wt%, about 15 wt% to about 45 wt%, about 30 wt% to about 45 wt%, about 10 wt% to about 30 wt%, about 10 wt% to about 20 wt%, or about 15 wt% to about 30 wt% of the solids in the catalyst layer.

[0216] In some embodiments, the branched or hyperbranched ionomeric polymers of the present disclosure are incorporated into a cation exchange resin.

[0217] The branched or hyperbranched ionomeric polymers described herein may exhibit less than about 20% or less than about 10% mass loss when exposed to Fenton's reagent at a temperature of 80° C., 1 atm, for a time period of more than 0 minutes and less than or equal to 180 minutes, more than 0 minutes and less than or equal to 90 minutes, or more than 0 minutes and less than or equal to 60 minutes.

[0218] The branched or hyperbranched ionomeric polymers described herein can be prepared by, for example, soaking a sample in a 1 M NaCl solution at pH 7 for 48 hours and then titrating the acidic form to pH 7 with a standardized titrant (e.g., 0.01 M NaOH solution, Sigma Aldrich). - H + ) membrane with its conjugate base sodium counterpart (e.g., -SO3 - Na + ) is approximately 2 to 4.5 meq g -1 or about 2.9 to 3.7 meq g -1The IEC can be calculated using the volume and molar concentration of the titrant used and the dry mass of the sample being titrated. Those skilled in the art will appreciate that titrations can also be performed with other bases (such as KOH solutions) and that the counterion cations can be exchanged, for example, by exposing a sodium sulfonate salt to KCl to give a full or partial potassium salt (e.g., -SO3 - K + ) can be formed. EXAMPLES

[0219] Example 1

[0220] Nonconformal particles of hyperbranched sulfonated phenylated poly(phenylene) ionomers as proton conducting pathways in PEMFC catalyst layers

[0221] Characteristic low electrochemical reaction rates, high ionic resistance, and high mass transport resistance within the catalyst layer (CL) are the main parameters causing poor performance in polymer electrolyte fuel cells (PEMFCs) that utilize hydrocarbon-based proton-conducting ionomers.

[0222] In the catalyst ink, the Pt-loaded carbon catalyst particles aggregate into agglomerates containing primary pores with diameters of about 1 nm to about 30 nm. Upon deposition to form the anode and cathode CLs, the agglomerates aggregate into larger aggregates that form larger secondary pores with diameters of about 20 nm to about 200 nm. The secondary pores facilitate gas diffusion and water transport within the CLs, as described in the agglomerate model. A polyelectrolyte, such as perfluorosulfonic acid (PFSA) ionomer, commonly referred to by the trademark Nafion®, is also included in the ink dispersion to encapsulate and bind the Pt / C agglomerates and provide proton conducting pathways within the CLs.

[0223] A thin coating of ionomer can introduce an O2 permeation barrier between the interstitial spaces in the primary pores and on the surface of the secondary pore structure and the catalyst particles. This permeation barrier introduces a mass transport resistance that cannot be explained by the agglomerate model alone. As a result, intense research has been conducted to understand O2 permeation through ionomer thin films, the effect of ionomer chemistry, the effect of support porosity, and the effect of catalyst ink composition on mass transport limitations in CLs.

[0224] Herein, non-dimensionally swellable, non-conformal, hyperbranched sulfo-phenylated poly(phenylene) ionomer particles (HB-sPPT-HB) are described. + By designing and adding a new cation exchange copolymer (C1C1O2), a direct pathway for proton conduction was introduced into the hydrocarbon ionomer-based CLs, which resulted in an 8-fold reduction in the ionic resistance of the CLs, a 71% increase in the catalytic mass activity, and a more than 90% increase in the power output at 0.6 V (H2 / air) compared to the state-of-the-art hydrocarbon ionomer-based CLs.

[0225] HB-sPPT-H + The benefits of incorporating ionomer particles are also demonstrated when used in a PEMFC based on perfluorosulfonic acid (PFSA) ionomer. These results dispel the common notion that hydrocarbon ionomers have limited gas permeability and electrochemical activity, and open up previously unexplored avenues for the development of ionomers for non-fluorinated, all-hydrocarbon PEMFCs.

[0226] Hydrocarbon substitutes created to date contain aromatic units that are inherently thermochemically resilient. Unlike PFSAs, polyaromatic and polyheterocyclic polymers can be synthesized from readily available synthetic chemical feedstocks in a typical organic polymer chemistry laboratory. Hydrocarbon ion-conducting polymers have relatively low gas permeability compared to PFSAs, resulting in low gas crossover when used as proton exchange membranes (PEMs).

[0227] Sulfonated poly(arylene ether)s and sulfophenylated polyphenylene ionomers exhibit improved chemical stability towards PFSAs. In an illustrative example, biphenyl comonomers (sPPB-H + ) offers improved stability at the expense of reduced ionic conductivity.

[0228] sPPB-H + Crosslinking and molecular branching were also explored as a way to reduce dimensional swelling and improve the mechanical integrity of this class of hydrocarbon ionomers when cast as PEMs. A notable observation is that with low water uptake, these materials exhibit increased electrical conductivity, suggesting that the increase in proton concentration outweighed the decrease in proton mobility. However, too great a degree of branching renders the ionomers insoluble and unsuitable for PEM formation.

[0229] The fully hydrocarbon-based MEA uses linear sPPB-H as both the binder for the CL and the PEM. + Using 1.5W cm 2 A power output (H2 / O2, at atmospheric pressure) of over 10 ...

[0230] Inspired by the high anion exchange membrane fuel cell performance achievable with insoluble radiation grafted ETFE anion exchange materials used in the CL of anion exchange membrane fuel cells (AEMFC), we developed a novel terphenyl comonomer-containing hyperbranched sulfonated polyphenylene (HB-sPPT-H) with the aim of reducing the ionic resistance in the CL, as depicted in Figures 1A and 1F. + ) particles can be included in the CL.

[0231] HB-sPPT-H +was obtained by [4+2] Diels-Alder cycloaddition reaction of the difunctional diene comonomer TEAsBTC with the trifunctional dienophile comonomer 1,3,5-tris-(4-ethynyl-phenyl)-benzene (3), prepared as shown in Figure 10. The dienophile comonomer (3) was obtained by a three-step synthesis starting with the cyclotrimerization of 4-iodoacetophenone with paratoluenesulfonic acid in a solvent-free manner to give intermediate (1) in 82% yield. Sonogashira coupling of intermediate (1) with trimethylsilylacetylene gave the second intermediate product (2) in 92% yield after precipitation, which was used without further purification. A deprotection step of the silyl groups was carried out under mild conditions (MeOH / K2CO3) to give (3) in 73% yield after purification on a silica plug. TEAsBTC and (3) were reacted in Ar-degassed nitrobenzene with stirring at 170 °C for 5 days. After the polymerization was completed, the precipitate formed was filtered to obtain HB-sPPT-NEt3 + The synthesis scheme and subsequent proton form (HB-sPPT-H + The exchange of HB-sPPT-H + A 3D representation of the chemical structure is shown in FIG. 1A.

[0232] HB-sPPT-H + The powder exhibited sand-like properties and could be mechanically crushed, even after stirring in common laboratory polar protic solvents, as shown in Figure 1E. UV optical microscopy of the as-precipitated HB-sPPT-H + and HB-sPPT-H used for preparing the catalyst ink. + Photographs of both are shown in Figure 1B. + The size of the particles was measured using ImageJ processing software and was found to be in the range of 30-100 microns, but appears to be formed, at least in part, from agglomerates of smaller particles. Dispersion of the agglomerates (e.g., grinding, milling, etc.) revealed smaller particles with a mean particle size of 7.0 ± 2.1 µm, as shown in Figure 1C.

[0233] HB-sPPT-H at different relative humidity at 80℃ + The moisture absorption of the powder was measured by dynamic vapor sorption (DVS) measurement. + Compared with ionomer. sPPB-H + An exemplary structure of is shown in formula (IX). [ka]

[0234] The resulting absorption isotherm is shown in Figure 1D. At 75% RH, HB-sPPT-H + The water absorption of the linear sPPB-H was 32 wt%, + (40wt%). + The linear sPPB-H undergoes dimensional expansion (145% by volume). + Unlike the membranes of HB-sPPT-H, it does not exhibit dimensional swelling and remains sand-like in boiling water. The relatively low branching of the polymer (≦2 mol%) can reduce water absorption but increase proton conductivity when cast as a membrane, resulting in HB-sPPT-H. + The conductivity of the material can be increased.

[0235] In situ fuel cell electrochemical characterization was performed using HB-sPPT-H + The effect of HB-sPPT-H on hydrocarbon-based and PFSA-based catalyst-coated membranes (CCMs) was investigated. + Since ionomers are insoluble in alcohol, if they are used as the only ionomer in CL, the catalyst will rapidly peel off from the membrane and the CCM will fail. + Linear sPPB-H + Used in combination with ionomer or Nafion® ionomer. Linear sPPB-H + The ionomer content in CL is typically 15 wt%, whereas for Nafion® it is typically 30 wt%. Thus, the HB-sPPT-H for linear ionomers +The ratio of HB-sPPT-H to 5 wt% was adjusted to these total wt%. Figures 2A and 2B show the results of the 5 wt% HB-sPPT-H based on triplicate measurements of three samples. + +10wt% linear sPPB-H + This shows that the combination of these two produces optimal output performance.

[0236] In the PFSA-based CCM shown in Figures 3A and 3B, 5 wt% HB-sPPT-H + An improved composition of +25 wt% Nafion® ionomer was produced.

[0237] The performance improvement was not due to the mass reduction of the linear ionomer but due to the addition of additional HB-sPPT-H. + To demonstrate the contribution of the ionomer, a comparison with CL containing 10 wt% Linear sPPB-H+ and 25 wt% Nafion® ionomer is shown in Figures 4A-4F, Figures 5A-5F, and Tables 1 and 2 below.

[0238] [Table 1]

[0239] a = peak power density on the power density curve, b = power density corresponding to 0.6 V on the polarization curve, c = Tafel slope (mV / decade), d = mass activity obtained from effective current density at 0.9 V (corrected for H2 crossover and ohmic losses) and catalyst loading, e = specific activity obtained from effective current density at 0.9 V (corrected for H2 crossover and ohmic losses) and catalyst loading, f = ionic resistance in the CL obtained from the linear intercept of the low frequency resistance with the x-axis under equal H2 / N2, g = electrochemical surface area determined by cyclic voltammogram, h = intercept of the HFR with the x-axis under H2 / O2, I = charge transfer resistance, diameter of the semicircle of the Nyquist plot under H2.

[0240] [Table 2]

[0241] Improved CCM: 15wt% linear sPPB-H + Ionomer (hereafter referred to as CCM1), 5wt% HB-sPPT-H + +10wt% linear sPPB-H + (CCM2), 30wt% Nafion® ionomer (CCM3), and modified 5wt% HB-sPPT-H + A direct comparison is made between +25 wt% Nafion® ionomer based CCM (CCM4).

[0242] The polarization and power curves for H2 / O2 operation are shown in Figure 6A, and the extraction data listed in Table 3 are for CCM2 (1430 mW cm -2 ) has a peak power density of CCM1 (1240 mW cm -2 ), but 15% higher than the PFSA-based CCM3 (1470 mW cm -2 ) and CCM4 (1490 mW cm -2 ) is comparable to that of CCM2 (876 mW cm). In H2 / air operation, a significant improvement in output performance was observed (Figure 6B). -2 ) is CCM1 (655 mW cm -2 ) and the power density at 0.6 V increased by 92% (685 mW cm for CCM2). -2 , 356 mW cm for CCM1 -2 In H2 / air operation, the peak power density of CCM4 is also 11% higher than that of CCM3.

[0243] To better understand the differences in the obtained power density curves, the low current density region was further investigated by Tafel analysis. Ohmic losses and H2 crossover were corrected from the H2 / O2 polarization curves, and the mass activities and specific activities of the CCMs were calculated (Tables 3-4) from the data replotted in Figure 6C. The Tafel slopes of all CCMs were significantly higher than those of the sPPB-H for ORR catalyst on Pt. + The average was −73 mV·dec, similar to what was previously reported for the expected value of ionomers. -1As shown in Tables 3-4, the mass activities (I m(0.9V) ) were 17 mA mg for CCM1 and 17 mA mg for CCM2, respectively. -1 Pt , 29mA·mg -1 Pt and 54 mA mg for CCM3 and CCM4, respectively. -1 Pt , 70mA·mg -1 Pt Similarly, the specific activity (I s(0.9V) ) is 159 μA cm -2 Pt (CCM1), 283 μA cm -2 Pt (CCM2), 350 μA cm -2 Pt (CCM3), 424 μA cm -2 Pt It has been reported that the presence of HB-sPPT-H+ ionomer in the CL increases the specific activity of the hydrocarbon-based CCM by 78% and that of the PFSA-based CL by 21%. The calculated activities are the charge transfer resistance R at 0.8 V. ct(0.8V) This is consistent with the decrease in HB-sPPT-H, which is shown in the Nyquist plot in Figure 6D and reported in Tables 3-4. + The ECSA values ​​when is included in the CL are almost equal in both CCM1 and CCM2 (43m 2 ·g -1 Pt and 41m 2 ·g -1 Pt ), CCM3(62m 2 ·g -1 Pt ) and CCM4(60m 2 ·g -1 Pt The same is true when comparing HB-sPPT-H + Linear sPPB-H +This indicates that the ionomer content contributes to the overall activation of the Pt catalyst along with the Nafion® ionomer. As shown in Figures 4-5, the lower ECSA values ​​at lower ionomer contents may be due to the disconnection of the proton conduction pathway with the subcritical ionomer content. Since the ECSAs are similar, the I m(0.9V) and R ct(0.8V) The change in corresponds to the change in the intrinsic catalytic activity of the Pt surface, and the change in + is lower than that of Nafion®, but HB-sPPT-H + It is hypothesized that the adsorption of sulfonate and phenyl from the hydrocarbon ionomer is the primary cause of the decrease in specific activity.

[0244] From the H2 / O2 Nyquist plot (Figure 6D and Tables 3–4), the RHFR of the hydrocarbon-based CCM with a PEM thickness of 33 μm is approximately 70 mΩ·cm 2 and the RHFR of a Nafion®-based CCM with a PEM thickness of 25 μm is approximately 60 mΩ cm 2 As a result, it was found that the ohmic losses of the films of each CCM were very similar. 2 / HB-sPPT-H under air flow + It can be concluded that the significant increase in the power performance of is a result of the observed increase in catalytic activity, although the decrease in concentration resistance at higher current densities should play a larger role.

[0245] To investigate this, EIS measurements were carried out in a H2 / N2 environment, where the second linear region and the intercept of the real axis are R ionic-CL / 3 As shown in Figure 6F and the values ​​in Tables 3 to 4, HB-sPPT-H + CCM2, which contains 2 ) is 8 times lower than ionic-CL (73mΩ·cm 2 ) and HB-sPPT-H in CL. + As a result of the ionomer, it shows a significantly higher proton conductivity. PFSA-based CCM4 (98 mΩ cm 2) containing HB-sPPT-H + The improvement is all PFSA-based CCM3 (115 mΩ cm 2 Although this is lower than the enhancement observed for the hydrocarbon-based CCMs compared to the HB-sPPT-H, the Nafion®-based CCMs show an overall higher ionic conductivity, likely due to the adaptive network that the Nafion® ionomers are capable of forming. This adaptive network is expected to be the reason for the higher calculated ECSA for the PFSA-based CCMs compared to the hydrocarbon-based CCMs. Nevertheless, the HB-sPPT-H + provided much improved ionic conductivity, and the lowest ionic resistance among all samples was still the 5 wt% HB-sPPT-H + +10wt% linear sPPB-H+CCM2(73mΩ·cm 2 ) was.

[0246] [Table 3]

[0247] a = peak power density on the power density curve, b = power density corresponding to 0.6 V on the polarization curve, c = Tafel slope (mV / decade), d = mass activity obtained from effective current density at 0.9 V (corrected for H2 crossover and ohmic losses) and catalyst loading, e = specific activity obtained from effective current density at 0.9 V (corrected for H2 crossover and ohmic losses) and catalyst loading, f = ionic resistance in the CL obtained from the linear intercept of the low frequency resistance with the x-axis equal under H2 / N2, g = electrochemical surface area determined by cyclic voltammogram, h = intercept of the HFR with the x-axis under H2 / O2, I = charge transfer resistance, diameter of the semicircle of the Nyquist plot under H2 / O2.

[0248] [Table 4]

[0249] To further elucidate the cause of the improved high power performance at high current density, SEM micrographs of the compared CCMs are shown in Figures 7A-7D. + It has been shown that the addition of ionomer particles increased the thickness of the CCL. The CL thickness of CCM1 was ~10 μm, while that of HB-sPPT-H + The CL thickness of CCM2, which contained 5 wt% of HB-SPPT-H and 15 wt% of ionomer, was ~13 μm. For the PFSA-based CCMs shown in Figures 7C-7D, + A similar increase in CL thickness of ~3 μm in the presence of particles was observed. + The thicker CL observed in is attributed to the relatively large size of the individual particles on the micron scale, as shown in Figures 1B and 1C, potentially acting as pore-forming materials.

[0250] [Table 5]

[0251] i = BET SA, determined from the range of N2 partial pressures from 0.05 to 0.2; ii = mesopore SA, SA>2 nm, calculated from the slope of the t-plot; iii = micropore SA, SA<2 nm, calculated from the slope of the SA total and mesoporous SA>2 nm. iv = total pore volume, V total is calculated from the total adsorbed gas volume at a N2 partial pressure of 0.98. v = micropore volume, v < 2 nm is based on the intercept of the t-plot.

[0252] HB-sPPT-H +To investigate the effect of N2 on CL porosity, N2 porosimetry was performed. The adsorption and desorption isotherms of the compared CCMs are shown in Figure 7E. The observed isotherms are typical type II isotherms, which are known to have a high degree of microporosity and a steep increase in the isotherm when operated under low partial pressure conditions. As shown in Table 5, the BET surface areas (BET SA) of the CLs prepared from CCM1, CCM2, CCM3, and CCM4 were 633, 531, 174, and 261 m, respectively. 2 ·g -1 carbon The former is calculated as 639m for Pt / C. 2 ·g carbon -1 , 666m 2 ·g -1 carbon in) and sPPB-H + shows that Nafion® does not block the carbon pores as well as Nafion®. However, a dramatic reduction in CL porosity was observed for Nafion®-based CCMs, with the larger mesopore + macropore volume being 10 times lower than for the hydrocarbon-based CCMs. These results indicate that Nafion® ionomers coat the agglomerates of the carbon-supported catalyst and block the internal primary pore structure. Conversely, this is not the case for the hydrocarbon ionomers, which provide less inhibition of gas transport and, as a result, significantly improved power performance at high current densities when using air as the oxidant.

[0253] HB-sPPT-H on hydrocarbon-based CCMs + The addition of 0.1% results in a ~16% decrease in BET SA compared to CCM1, but with the addition of larger pores (0.53 cm) of the same volume, as seen by the similar slope of the t-plot in Figure 8 and the similarly large area under the pore size distribution curve shown in Figure 7F. 3 ·g -1 carbon) and considering the increased thickness of the CL, the significant improvement in power performance at high current densities cannot be explained by porosity measurements alone. Rather, it appears to be related to the 8-fold lower ionic resistance in the CL, i.e., the concentration resistance associated with proton transport. However, in the case of Nafion®-based CCMs, the HB-sPPT-H + The ionomer increases the BET SA by 50% compared to CCM4, likely due to a reduction in the Nafion® content, which is likely responsible for the improvement in the high current density region in Figure 6B, in addition to the improved ionic conductivity via CL.

[0254] Hyperbranched sulfonated phenylated poly(phenylene) (HB-sPPT-H + ) insoluble particles were synthesized. + Incorporation of the particles into the hydrocarbon- and PFSA-based CLs did not appear to impede gas transport and was shown to enhance the specific activity of the Pt / C catalyst. As shown in Figures 9A-9C, the HB-sPPT-H + The use of PFSA-based CLs (5wt%) can reduce the concentration resistance of PEMFCs, at least in part, by providing long-distance proton-conducting pathways with the ultrathin ionomer membrane located close to the electrochemical reaction sites. When combined with the high porosity of the hydrocarbon-based CLs, it has been shown that the power density of H2 / air operation is much improved compared to PFSA-based MEAs. Thus, the design of the hydrocarbon ionomers can take into account their impact on the macropores between the catalyst aggregates.

[0255] Example 2

[0256] Methods and materials for polymer and membrane synthesis

[0257] The reaction scheme for the synthesis of ionomers is shown in Figure 10. Linear sulfonated phenylated poly(phenylene) biphenyl (SPPB-H + ) and hyperbranched sulfonated phenylated poly(phenylene) terphenyl (HB-SPPT-H+ ) Ionomers were synthesized using the materials and methods described herein. Linear SPPB-H + The Diels-Alder (DA) polymerization reaction was used for the synthesis of PFSA-based catalyst coated membranes (CCMs). Perfluorosulfonic acid (PFSA) polymer; Nafion® NR-211 membrane (DuPont, TE143904, thickness 25 ± 5 μm) and Nafion® D520 dispersion (Ion Power, lot SGA-12-02CS) were used for the PFSA-based catalyst coated membranes (CCMs). Pt / C catalyst powder (TEC10E50E, lot 109-0111, 46.4% Pt) and PTFE-treated gas diffusion layers (GDLs) were purchased from FuelCellStore. Methanol (MeOH reagent grade ≥ 99.8%) was purchased from Fischer Scientific.

[0258] 1,3,5-Tris-(4-iodophenyl)-benzene (1)

[0259] Iodoacetophenone (15 g, 61 mmol) was reacted neat with paratoluenesulfonic acid (343 mg, 2.03 mmol) and stirred in a pressure vessel at 130 °C for 5 h. Upon completion, the product was dissolved in dichloromethane (20 mL) and precipitated with 95% ethanol. The precipitate was filtered and washed with ethanol to give 1,3,5-tris-(4-iodo-phenyl)-benzene as a yellow powder in 82% yield.

[0260] 1 H NMR(400MHz,CDCl3) δ=7.84~7.79(m,5H),7.68(s,3H),7.43~7.38(m,6H) Spectral data are from the literature.

[0261] 1,3,5-Tris-(4-trimethylsilylethynyl-phenyl)-benzene (2)

[0262] 1,3,5-Tris-(4-iodo-phenyl)-benzene (5 g, 7.31 mmol), triphenylphosphine (19 mg, 0.73 mmol), bis(triphenylphosphine)palladium(II) dichloride (46 mg, 0.73 mmol) and trimethylsilylacetylene (3.43 mL, 24 mmol) were dissolved in a mixture of THF (150 mL) and diisopropylamine (25 mL) under inert atmosphere. Then, copper(I) iodide (14 mg, 0.73 mmol) was slowly added to the reaction mixture and stirred at 50 °C for 5 h. The solution was poured with Et2O and the precipitate was filtered. The filtrate was evaporated, 200 mL of Et2O was added and washed with 1 M hydrochloric acid (200 mL). The organic phase was separated, washed with saturated aqueous ammonium chloride solution, water, dried over magnesium sulfate and concentrated in vacuum. The product was recovered as a pale orange powder (92% yield) and was used later without further purification.

[0263] 1 H NMR (400MHz, acetone) δ = 7.99 (s, 3H), 7.92-7.88 (m, 6H), 7.64-7.57 (m, 6H), 0.26 (s, 27H) Spectral data are from the literature.

[0264] 1,3,5-Tris-(4-ethynyl-phenyl)-benzene (3)

[0265] 1,3,5-Tris-(4-trimethylsilylethynyl-phenyl)-benzene (2 g, 3.3 mmol) was dissolved in THF (20 mL) and methanol (80 mL). Potassium carbonate (2.79 g, 20 mmol) was added to the reaction and stirred at room temperature for 5 h, covered with aluminum foil to prevent sunlight. After completion, 300 mL of dichloromethane was added and the organic phase was washed with water, dried over magnesium sulfate and concentrated in vacuo. The crude product was purified on a silica gel plug using a mixture of hexane / dichloromethane 7:3 to give 1,3,5-tris-(4-ethynyl-phenyl)-benzene (460 mg, 73%) as a pale yellow powder.

[0266] 1H NMR (400MHz, acetone) δ = 8.00 (s, 3H), 7.95-7.87 (m, 6H), 7.67-7.60 (m, 6H), 3.74 (s, 3H) Spectral data are from the literature.

[0267] HB-sPPT-H +

[0268] In a 50 mL round bottom flask, nitrobenzene (14 mL) was degassed under argon for 1 h. TEAsBTC (700 mg, 0.497 mmol) and 1,3,5-tris-(4-ethynyl-phenyl)-benzene (127 mg, 0.335 equiv.) were added, the round bottom flask was covered with aluminum foil and stirred at 170 °C for 4 days. The polymer precipitate was washed with ethyl acetate (200 mL) to give an off-white powder. The polymer was then dispersed in MeOH (100 mL) and subsequently exchanged into the sodium form by the addition of 2 M NaOH (40 mL). The polymer was then filtered as a beige powder and was found to be insoluble in MeOH, EtOH, iPrOH, DMAc, DMF, DMSO, NMP, and boiling water. Acidification of the polymer was achieved by dispersion in deionized water (60 mL) and 2 M HCl (60 mL) and filtration to give the acidic polymer (503 mg) in 87% yield.

[0269] Preparation of catalyst-coated membranes

[0270] sPPB-H + Membrane: Acidified polymer sPPB-H + The solid polymer electrolyte membrane (SPE) was cast from a DMSO solution (7.5 wt%) at 85 °C. The fabrication process consisted of casting 10 g of sPPB-H +The procedure begins with dissolving sPPB-H in 133 g of DMSO at 80 °C and stirring continuously. The resulting polymer solution was vacuum filtered at room temperature through a glass fiber filter into a round bottom flask. The polymer solution was cast into a film by placing a flat glass plate, which had been washed with acid (1 M HCl solution), washed with distilled water, and dried with MeOH, on a casting table (RK PrintCoat Instrument K202 Control Coater casting table with doctor blade). The glass plate was immersed in distilled water to peel off the cast film. Residual DMSO was removed by immersing the cast film in 1 M H2SO4 solution for 24 h, extracting and replacing the acidified solution three times at 8 h intervals. The DMSO-free film was then vacuum dried overnight at 80 °C. These films were then either directly used to coat catalysts to make CCMs or dissolved in a solvent (e.g. MeOH) to prepare catalyst inks following the procedure described herein. + The membrane had a relatively moderate water content of 129 mS cm at 30 and 80 °C, respectively, which is higher than that of NR-211. -1 and 172 mS cm -1 The proton conductivity of the sPPB-H prepared by the above method is shown. + Characterization of the membranes is shown in Figures 2A, 2B, 4A-4F, 11B-11F, 12A, and 12B.

[0271] Preparation of catalyst ink

[0272] The following method was carried out to prepare the catalyst ink utilized in the preparation of catalyst-coated membranes for fuel cell characterization. The data can be seen in Figures 2A, 2B, 3A, 3B, 4A-4F, and 5A-5F. The catalyst-coated membranes were prepared using pure solid sulfonated phenylated poly(phenylene) biphenyl (sPPB-H + ) polymer electrolyte membrane and hyperbranched sulfonated phenylated poly(phenylene) terphenyl (HB-sPPT-H +) , sPPB-H +The catalyst inks were prepared using Nafion® D520 ionomer, either individually or in combination. + Both HB-sPPT-H and Nafion® D520 are soluble in alcohol solvents such as MeOH. + Because ionomers are insoluble in MeOH, a different method must be used to prepare the catalyst ink.

[0273] The catalyst ink (1 wt% solids in 1:3 v / v water / methanol) consisted of Pt / C and linear sPPB-H + A homogenous solution of ionomer (3 wt% ionomer in MeOH) or Nafion® D520 was first prepared. One-third of the water required for the Pt / C solids was first added and the slurry solution was sonicated for 10 minutes to ensure that the Pt / C particles were adequately wetted. This slurry solution was then placed on a stir plate in a fume hood and one-third of the methanol required was added dropwise and stirred for 15 minutes. The resulting mixture was mixed with linear sPPB-H + The ionomer or Nafion® D520 ionomer solution was added dropwise and the resulting ink was stirred for 10 minutes, after which the remaining methanol and water were added dropwise, respectively, to form the catalyst ink.

[0274] HB-sPPT-H + The ionomer-based catalyst ink was prepared by dissolving the appropriate solid HB-sPPT-H in the presence of MeOH. + The ionomer was prepared by grinding. Dried and ground HB-sPPT-H + The ionomer was prepared by dissolving the linear sPPB-H + or Nafion® D520 ionomer. + The base catalyst ink was sonicated for 2 hours.

[0275] Catalyst Coated Membrane

[0276] The following method was carried out to prepare the catalyst coated membranes used for fuel cell characterization. The data can be seen in Figures 2A, 2B, 3A, 3B, 4A-4F, 5A-5F, 6, 7A-7D, 8, 11, 12A, and 12B. The hydrocarbon-based electrodes were prepared by spray coating pure sPPB-H using a spray coater (Sono-tak ExactaCoat). + The ink was applied onto the membrane from an ultrasonic Accumist nozzle at 120 kHz with a diameter of 2–6 mm in a 2D path from left to right, then bottom to top, with a path speed of 75 mm s -1 The spray was performed at 0.8 shaping air, 0.5 W and 2 W generator power during idle and running, respectively, and 0.3 ml min−1 flow rate. -1 The catalyst loading was set at 5 cm 2 (2.24 × 2.24 cm) area, 0.4 mgPt cm -2 Using this method, a PFSA-based reference catalyst coated membrane (CCM) was also prepared, using a Nafion® D520 dispersion as the binder (ionomer) in the catalyst ink, which was then coated onto a Nafion® NR-211 membrane as a reference. The resulting catalyst coated membrane (CCM) was prepared by splitting two 7.6 cm 2 The electrodes were sandwiched between 2.76 x 2.76 cm PTFE-treated gas diffusion layers (Sigracet 29BC, FuelCellStore) and compressed in fuel cell hardware (AHNS). Three samples were made for each setup.

[0277] Electrochemical characterization

[0278] The following method was performed for fuel cell characterization. The data can be seen in Figures 2A, 2B, 3A, 3B, 4A-4F, 5A-5F, 6, 12A, 12B, and 13. The MEA was compressed between two single serpentine flow fields of the fuel cell hardware (AHNS) using a torque wrench. Fujifilm Prescale pressure paper was used to confirm proper compression. Different torques were applied in the range of 0.5-6.0 N m in increments of 0.5 N m to ensure even pressure distribution across the edges, and tests were performed on the fuel cell hardware secured with eight bolts. Optimal compression was obtained at 5.7 N m (50 in-lbs) using a 130 μm thick glass fiber reinforced PTFE gasket (Hightechflon GbR) and a 50 μm silicone subgasket. The resulting MEA was conditioned using a custom-designed accelerated conditioning procedure at fuel cell operating conditions of 80 °C, 100% relative humidity (RH), and inlet gas flows of H2 and O2 at the anode and cathode of 0.5 slpm and 1.0 slpm, respectively. The cells were equilibrated at open circuit voltage (OCV) before starting the electrochemical characterization. The electrochemical characterization began by performing polarization curves, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) analysis. Tafel analysis of the MEA was performed to determine the Tafel slope and exchange current density. The voltage and current density used in the Tafel plots were corrected for high frequency resistance and H2 crossover losses, respectively. Mass activity (I m(0.9V) ) and specific activity (I s(0.9V) ) is 0.9V HFR-free The effective current density at 1000 K, the electrochemical surface area, and the Pt loading of each sample were determined. For each electrochemical analysis performed, triplicate samples were tested. The precision of each electrochemical analysis performed is indicated by the associated standard deviation and, where appropriate, error bars.

[0279] Physical characterization

[0280] The ion exchange capacity (IEC) allows to measure the exchangeable protons in a polymeric material. Prior to the measurements, the polymer powder was dried under vacuum at 80 °C for 48 h. The IEC measurements were carried out in triplicate by immersing the powder in a 1 M NaCl solution for 48 h and then titrating the solution with 0.01 M NaOH (Sigma Aldrich) using an automatic titrator Metrohm 848 Titrino Plus. The experimental IEC is calculated according to equation (1):

[0281]

number

[0282] HB-sPPT-H + The water absorption of the powder was done by gravimetry between wet and dry samples and was performed in triplicate. Before measuring the water absorption, the samples were dried in a vacuum oven at 80 °C for 48 h and the dry mass of the polymer was measured. The powder was then immersed in deionized water and stirred for 48 h. The wet polymer was then filtered through a wet frit and the wet mass was measured before termination. Equations (2) and (3) were then used to calculate the water absorption and the number of water molecules per sulfonic acid group.

[0283]

number

[0284]

number

[0285] Before the DVS measurement, the samples were dried in vacuum at 80 °C. + and HB-sPPT-H + The isothermal water uptake / loss of was measured at 80 °C using a water vapor sorption analyzer (DVS-1000 Adventure) while changing the relative humidity (RH) from 0% to 75% in 10% increments (Figure 1D). Each step was equilibrated for 2 h.

[0286] The size of the insoluble HB-sPPT particles was examined using a Nikon Eclipse 50i equipped with a high-pressure mercury lamp and a Qimaging camera. The images obtained were calibrated using a 0.01 mm dot cross ruler for microscope calibration, and the particle size was determined using ImageJ software (developed by the National Institutes of Health, USA). The morphological details of the CL, such as roughness and thickness, were examined using an FEI Nova NanoSEM 430 scanning electron microscope (SEM). For thickness measurements, CCM samples were prepared by freezing each sample in liquid nitrogen and then fracturing it. The samples were typically imaged at an accelerating voltage of 15 kV. Images of the sample cross sections were taken to determine the thickness of the CCM, and high-magnification images of the sample surfaces were taken to measure the morphology and roughness of the CCM (Figure 1B).

[0287] N2 porosimetry analysis to probe the pore space within the CLs was performed using a Micrometrics ASAP2020 Accelerated Surface Area and Porosimetry System equipped with liquid N2. Ultra-high purity N2 gas (99.999%) was used for this analysis. Each investigated CCM (50 cm 2 ) were prepared using N211 substrates as detailed previously (the magnitude of N2 physisorption was measured to be negligible). The Pt loading on both electrodes was 0.4 mg cm -2 The CCM was cut into equal thin strips and degassed at 90 °C for 1 h and then at 105 °C for 12 h. Adsorption and desorption isotherms were measured immediately after degassing and replotted as a function of carbon volume and mass. Brunauer-Emmett-Teller surface area (BET SA) was determined over a range of N2 partial pressures from 0.05 to 0.2. The degree of microporosity within the CL was determined using t-plots in which the adsorption isotherms were plotted against the thickness of the adsorbed layer on the pore walls. This thickness, t, was calculated using the Harkins-Jura equation and the volume of the micropores was estimated from the intercept of the linear region with the y-axis. The aforementioned data are shown in Figures 7E, 7F and 8.

[0288] Example 3

[0289] Improving polymer composition of membranes and catalyst inks

[0290] Linear sPPB-H + Unlike HB-sPPT-H + The ionomer is insoluble in low boiling point protic alcohols such as MeOH. Therefore, the obtained HB-sPPT-H + The Pt / C catalyst ink was in a granular form rather than a dispersed form, which is due to the fact that the HB-sPPT-H + This indicates that the ionomer alone does not form a bond network with the Pt / C catalyst. + It was observed that the CCM made from the -Pt / C catalyst ink showed significant mechanical degradation with large pinholes forming in different parts of the CCM making it unsuitable for fuel cell operation. However, the linear sPPB-H + Ionomer HB-sPPT-H + When added to the ionomer in various ratios, a dispersion ink was formed that allowed bonding with the Pt / C on the membrane, enabling in-situ characterization of the fuel cell.

[0291] Linear sPPB-H in CL + and HB-sPPT-H + To determine the improved combination of ionomers, HB-sPPT-H was used as a control, as shown in Figures 6A-6F. + Ionomer and Linear sPPB-H + Various combinations of both types of ionomers with an ionomer content of 15 wt% were tested. From the physical characterization of the resulting CCMs in Figure 11A, SEM micrographs show that HB-sPPT-H + It was observed that the roughness of the CCM surface increased with increasing content. + and 10 wt% HB-sPPT-H +It is shown that the CCM containing HB-sPPT-H had the smoothest and roughest CL surfaces, respectively. Figures 11D-11F show the thickness of the CCMs, and the thickness of the catalyst layer on both the anode and cathode was 100%. + Note that the ionomer content decreases as it increases. + At the ionomer content, significant exfoliation of CL and reduction in CL size are observed.

[0292] Finally, the polarization curve analysis shown in Figures 7A to 7F shows that the 5 wt% HB-sPPT + 10 wt% linear sPPB-H + Ionomers have been identified as an advantageous combination for improved performance of hydrocarbon-based PEMFCs. Similarly, for Nafion®-based CCMs, the polarization curve analysis shown in Figures 12A-12B demonstrates that 5 wt% HB+25 wt% Nafion® ionomers is an advantageous combination for improved performance of Nafion®-based PEMFCs.

[0293] Effect of low ionomer loading

[0294] The in situ electrochemical data shown in Figures 4A-4C, 5A-5C and Tables 1-2 are + This helps to understand the effect of ionomer on CL and proves that the reported performance improvement is not due to the decrease in the linear ionomer content in the CL. The polarization and power curves under both H2 / O2 (Figures 4A and 5A) and H2 / air (Figures 4B and 4B) conditions for the hydrocarbon-based and PFSA-based CLs are shown and the extracted data are listed in Tables 1-2. For the hydrocarbon CCM, the 5 wt% HB-sPPT-H + +10wt% sPPB-H + The peak power density using 10wt% sPPB-H in CL was +The PFSA CCM was also shown to be 67% (53%) higher than the CCM using ionomer. + The peak power density with +25 wt% Nafion® was 10% (18%) higher than the CL with 25 wt% Nafion® ionomer. Thus, the IV data shown indicates that the HB-sPPT-H ionomers exhibited a high peak power density despite the assumption that the particle size is on the same order as the catalyst layer thickness shown in Figures 11D-11F. + It can be seen that plays a positive role in the performance of PEMFC.

[0295] Similarly, as shown in Tables 1-2, Figure 12A (hydrocarbons), and Figure 12B (PFSA), the mass activity (I m(0.9V) ) and specific activity (I s(0.9V) ) from the extracted value, HB-sPPT-H was found in CL. + It is seen that the presence of ionomers increases the previously low mass and specific activities of the hydrocarbon-based CCMs by more than 80%. For Nafion®-based CCMs, 5 wt% HB-sPPT-H in CL is sufficient to obtain the desired activity. + When ionomer was included, a >40% increase in specific activity was reported. This was seen in the case of 5 wt% HB-sPPT-H. + +10wt% HB-sPPB-H + Ionomer (839mΩ·cm 2 ) at 0.8 V. ct(0.8V) This is consistent with the decrease in + Ionomer (885mΩ·cm 2 ) and simply 10wt% sPPT-H + CCM containing ionomer (1297 mΩ cm 2 ) is in good agreement with both the Nyquist plots in Figure 4D. A similar trend is observed for R ct(0.8V) This was also observed in the 5wt% HB-sPPT-H +The response of the Nafion®-based CCM with +25 wt% Nafion® (Figure 5D) shows the lowest charge transfer resistance compared to both CCMs with 30 wt% Nafion® and 25 wt% Nafion® ionomer in the CL.

[0296] As shown in Figures 4E and 5E, the CCM with a low linear ionomer content, i.e., 10 wt% HB-sPPB-H + Low ECSA values ​​were reported for CCMs with 0.1% Nafion® (Figure 4E) and 25 wt% Nafion® (Figure 5E). The reported lower ECSA values ​​may be due to the more disrupted proton conduction pathways caused by the subcritical ionomer content. These assertions are supported by EIS measurements in H2 / N2 environment (Figures 4F and 5F), which show that the reduced ionomer content results in a lower ionic conductivity of the catalyst layer (R ionic-CL =15wt% HB-sPPB-H + For 598 mΩ cm 2 , 10wt% HB-sPPB-H + For 1421 mΩ cm 2 HB-sPPT-H + The CCM containing 15wt% HB-sPPB-H + and 10wt% HB-sPPB-H + Significantly lower R than the base CCM ionic-CL (8-fold and 20-fold lower, respectively), and HB-sPPT-H in CL + As a result of the ionomer, it shows higher proton conductivity. In the Nafion®-based CCM, HB-sPPT-H + The presence of increases the proton conductivity in Nafion®-based CLs. However, this enhancement is less than that observed in the hydrocarbon-based CCMs, although Nafion®-based CCMs exhibit higher overall ionic conductivity, likely due to the adaptive network that Nafion® ionomers can form.

[0297] Example 4

[0298] Use of hyperbranched ionomers

[0299] The hyperbranched ionomer was used in conjunction with a third type of ionomer typically used in catalyst layers, and with an additional commercially available proton exchange membrane.

[0300] Experiments were carried out as described herein and a performance plot was generated for the MEA, which had a 0.4 mg Pt / cm2 anode and cathode. 2 Polarization and power curves under H2 / O2 when loaded with 0.4 mg Pt / cm2 Pt catalyst and operated at 80 °C, 100% RH, and 1 atm (Figure 13A). 2 The polarization and power curves (FIG. 13B) for H2 / air operation with a Pt catalyst loading of 100% and 1 atm at 80° C. are shown. The data in FIG. 13A and FIG. 13B were obtained from a membrane with PF1-HLF8-15-X Pemion® and a catalyst layer with 15 wt% PP1-HNN8-00-X, as shown by the data represented as circles; a membrane with PF1-HLF8-15-X Pemion® and a catalyst layer with 4.1 wt% HB-sPPT+8.4 wt% PP1-HNN8-00-X ionomer, as shown by the data represented as pentagons; and a membrane with DuPont Nafion® N211 and a catalyst layer with 30 wt% DuPont Nafion® D520, as shown by the data represented as hexagons. The peak power density obtained and the power density at 0.6 V are shown in Table 6.

[0301] These results demonstrate the state-of-the-art performance for a hydrogen PEM fuel cell operating under ambient conditions (air or oxygen).

[0302] [Table 6]

Claims

1. A branched or hyperbranched ionomer polymer comprising a repeating unit of formula (I), wherein the branched or hyperbranched ionomer polymer comprises an anionic comonomer and a branched comonomer (B). 【Chemistry 1】 (wherein, R ＋ , － , ＋ , ＋ , ２ , R １Ｂ , R １Ｃ , R １Ｄ , R １Ｅ , and R １Ｆ are each independently aryl or heteroaryl, each of which is C １～６ alkyl, halo, nitro, cyano, SO ３ － X ＋ , PO ３ ２－ X ＋ ２ , and COO － X ＋ selected independently from 1, 2, 3, 4, or 5 substituents (X ＋ is H ＋ or a cation), and at least two of said R １Ａ , R １Ｂ , R １Ｃ , R １Ｄ , R １Ｅ , and R １Ｆ are each independently aryl or heteroaryl substituted with 1, 2, 3, 4, or 5 substituents (X ３ － X ＋ , PO ３ ２－ X ＋ ２ , and COO － X ＋ selected independently from 1, 2, 3, 4, or 5 substituents (X ＋ is H ＋ or a cation). R １Ｇ and R １Ｈ Independently, C １～６ Alkyl, halo, nitro, cyano, SO ３ － X ＋ , PO ３ ２－ X ＋ ２ , and COO － X ＋ One, two, three, four, or five substituents (X) are independently selected from the above. ＋ H ＋ An aryl or heteroaryl, or H, which may be substituted with a cation. A １ is an arylene, heteroarylene, aralkylene, or heteroaralkylene, each of which may be substituted with one, two, three, or four substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl. A ２ is either absent or is an arylene or heteroarylene, and the arylene and heteroarylene may each be substituted with one, two, three, or four substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl. B is a branched comonomer, R ２Ａ It is a combination, The repeating unit of the first equation (I) is R ２Ａ It then combines with the repeating unit of the second equation (I) to form a branched structure.

2. The branched or superbranched ionomer polymer according to claim 1, wherein the polymer is insoluble in a polar solvent.

3. The branched or superbranched ionomer polymer according to claim 1, wherein the molar ratio of Z:Y in the polymer is 1:3 to 1:

2.

4. The branched or superbranched ionomer polymer according to claim 1, wherein the branched comonomer (B) comprises the structure of formula (II). 【Chemistry 2】 (In the formula, L ３ Each of these is a polyvalent heteroatom (e.g., N, P, B), polyvalent aryl, polyvalent heteroaryl, polyvalent aralkyl, or polyvalent heteroaralkyl, which may be substituted in each case. １～６ It may be substituted with one, two, or three substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl groups. L ２ Does not exist, or C １～６ Arylene or heteroarylene which may be substituted with 1, 2, 3, or 4 substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl, L １ Does not exist, or C １～６ Arylene or heteroarylene may be substituted with one, two, three, or four substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl groups.

5. The branched or superbranched ionomer polymer according to claim 1, wherein the branched comonomer (B) comprises the structure of formula (III). 【Transformation 3】

6. The branched or superbranched ionomer polymer according to claim 1, wherein the anionic comonomer comprises the structure of formula (VII). 【Transformation 7】

7. The branched or superbranched ionomer polymer according to claim 1, wherein the repeating unit comprises the structure of formula (IV). 【Chemistry 4】

8. A branched or superbranched ionomer polymer according to claim 1, The branched or superbranched ionomer polymer is formed by polymerization of a functionalized branched comonomer (B) and a functionalized anionic comonomer. A branched or hyperbranched ionomer polymer in which the molar ratio of the functionalized branched comonomer (B) to the functionalized anionic comonomer is greater than 0.

2.

9. The branched or superbranched ionomer polymer according to claim 8, wherein the molar ratio of the functionalized branched comonomer (B) to the functionalized anionic comonomer is about 0.

667.

10. The branched or superbranched ionomer polymer according to claim 1, further comprising a bifunctional monomer C.

11. A catalyst ink formulation, A branched or superbranched ionomer polymer according to any one of claims 1 to 10, Linear ionomer polymers and Polar solvents and A catalyst, and The linear ionomer polymer is dispersed in the polar solvent, A catalyst ink formulation in which an amount of the linear ionomer polymer is used that allows the branched or superbranched ionomer polymer to be dispersed in the polar solvent.

12. The catalyst ink formulation according to claim 11, wherein the polar solvent comprises an alcohol having a boiling point of less than 120°C.

13. The catalyst ink formulation according to claim 11, wherein the alcohol is methanol.

14. A catalyst ink formulation according to claim 11, The aforementioned polar solvent further contains water, A catalyst ink formulation in which the volume ratio of water to the aforementioned alcohol is approximately 1:3 to approximately 3:

1.

15. The catalyst ink formulation according to claim 11, wherein the branched or superbranched ionomer polymer is present in the formulation in an amount of about 0.01 wt% to about 10 wt% of the total solids.

16. The linear ionomer polymer is a linear sulfonated phenylated poly(phenylene)biphenyl (sPPB-H ＋ ) Ionomer polymer, sPPB-H ＋ The catalyst ink formulation according to claim 11, which is a random copolymer containing hydrophobic units, a PFSA material, or a combination thereof.

17. The catalyst ink formulation according to claim 11, wherein the amount of the linear ionomer polymer is approximately equal to or greater than the amount of the branched or superbranched ionomer polymer.

18. A catalyst ink formulation according to claim 11, The aforementioned formulation comprises a branched or superbranched ionomer polymer and a linear ionomer polymer. A catalyst ink formulation wherein the total amount of the branched, superbranched, and linear ionomer polymers dispersed in the polar solvent is about 0.1% w / v to about 25% w / v.

19. The catalyst ink formulation according to claim 11, wherein the catalyst is a Pt / C, PtCo / C, M-N-C catalyst, or a combination thereof.

20. The catalyst ink formulation according to claim 11, wherein the catalyst content is approximately 0.1% w / v to approximately 25% w / v.

21. An ionomer polymer film, Mechanical reinforcement and The mechanical reinforcing material comprises an ionomer binder bonded to the aforementioned mechanical reinforcing material, The ionomer binder comprises a branched or superbranched ionomer polymer according to any one of claims 1 to 10, wherein the ionomer binder is an ionomer polymer film.

22. A catalyst-coated ionomer polymer film, The ionomer polymer film according to claim 21, A catalyst-coated ionomer polymer film comprising a catalyst layer in contact with the ionomer polymer film.

23. A catalyst-coated ionomer polymer film according to claim 22, The catalyst layer is formed from a catalyst ink, The catalyst ink is a catalyst-coated ionomer polymer film, wherein the catalyst ink is the catalyst ink formulation described in claim 11.

24. The catalyst-coated ionomer polymer film according to claim 22, wherein the catalyst layer comprises a Pt / C, PtCo / C, M-N-C catalyst, or a combination thereof.

25. A catalyst-coated ionomer polymer film according to claim 22, The ionomer polymer film has an upper surface and a lower surface, The catalyst layer is in contact only with the upper surface of the ionomer polymer, only with the lower surface of the ionomer polymer, or with both the upper and lower surfaces of the ionomer polymer. If the catalyst layer is in contact only with the upper surface or only with the lower surface of the ionomer polymer film, a double layer is formed. A catalyst-coated ionomer polymer film in which a triple layer is formed when the catalyst layer is in contact with both the upper and lower surfaces of the ionomer polymer film.

26. A catalyst-coated ionomer polymer film according to claim 22, The catalyst layer on the upper surface of the ionomer polymer film and the catalyst layer on the lower surface of the ionomer polymer film are either anodes or cathodes. When only one side of the ionomer polymer is in contact with the catalyst layer, the catalyst layer is either an anode or a cathode. A catalyst-coated ionomer polymer film in which both sides of the ionomer polymer are in contact with the catalyst layer, one of the catalyst layers is the anode and the other catalyst layer is the cathode.

27. The ionomer polymer film according to claim 21, wherein the mechanical reinforcing material comprises a porous polymer material.

28. The catalyst-coated ionomer polymer film according to claim 22, wherein the mechanical reinforcing material comprises a porous polymer material.

29. The linear ionomer polymer of the ionomer binder is linear sulfonated phenylated poly(phenylene)biphenyl (sPPB-H ＋ ) Ionomer polymer, sPPB-H ＋ The ionomer polymer film according to claim 21, which is a random copolymer, PFSA material, or a combination thereof, containing hydrophobic units.

30. The catalyst-coated ionomer polymer film according to claim 22, wherein the linear ionomer polymer of the ionomer binder is a linear sulfonated phenylated poly(phenylene)biphenyl (sPPB-H+) ionomer polymer, a random copolymer comprising sPPB-H+ and hydrophobic units, a PFSA material, or a combination thereof.

31. A catalyst-coated ionomer polymer film according to claim 22, The catalyst layer contains an ionomer polymer, A catalyst-coated ionomer polymer film wherein the ionomer polymer comprises a branched or superbranched ionomer polymer according to any one of claims 1 to 10.

32. A catalyst-coated ionomer polymer film according to claim 22, The branched or superbranched ionomer polymer in the catalyst layer is present in an amount of about 0.5 wt% to about 25 wt% of the weight of the catalyst layer. A catalyst-coated ionomer polymer film in which the linear ionomer polymer in the catalyst layer is present in an amount approximately equal to or greater than the amount of the branched or superbranched ionomer polymer in the catalyst layer.

33. The ionomer polymer film according to claim 21, wherein the mechanical reinforcing material and the ionomer binder are substantially halogen-free.

34. The catalyst-coated ionomer polymer film according to claim 22, wherein the mechanical reinforcing material, the ionomer binder, and the catalyst layer are substantially halogen-free.

35. A method for synthesizing branched or superbranched ionomer polymers, Z ｍ Moles of functionalized branched comonomers (B) and Y ｍ The process includes polymerizing a molar functionalized anionic comonomer by a Diels-Alder addition reaction. The functionalized branched comonomer (B) is a dienophile, The functionalized anionic comonomer is a diene, Z ｍ : Y ｍ A method in which the molar ratio of is greater than 0.

2.

36. Said Z ｍ : Y ｍ The method according to claim 35, wherein the molar ratio of is approximately 0.

67.

37. The method according to claim 35 or claim 36, wherein the functionalized branched comonomer (B) has a structure according to formula (V). 【Transformation 5】 (In the formula, L ３ Each of these is a polyvalent heteroatom (e.g., N, P, B), polyvalent aryl, polyvalent heteroaryl, polyvalent aralkyl, or polyvalent heteroaralkyl, which may be substituted in each case. １～６ It may be substituted with one, two, or three substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl groups. L ２ It is either absent or is arylene or heteroarylene, and the arylene and heteroarylene are, respectively, C １～６ It may be substituted with one, two, three, or four substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl groups. L １ It is either absent or is arylene or heteroarylene, and the arylene and heteroarylene are, respectively, C １～６ It may be substituted with one, two, three, or four substituents independently selected from alkyl, halo, nitro, cyano, aryl, and heteroaryl groups. D １ , D ２ , and D ３ These are H and R, independently. １Ｇ , R １Ｈ , R ３Ｇ , R ３Ｈ , or protecting groups (e.g., silyl protecting group, substituted silyl protecting group, trialkylsilyl protecting group, silyl ether protecting group, trialkylsilyl ether protecting group, trimethylsilyl ether), R １Ｇ and R １Ｈ are each, independently, H, aryl, or heteroaryl, where the aryl and heteroaryl are each, independently, substituted with 1, 2, 3, 4, or 5 substituents independently selected from C １～６ alkyl, halo, nitro, cyano, SO ３ － X ＋ 、PO ３ ２－ X ＋ ２ 、and COO － X ＋ where X ＋ is H ＋ or a cation) and may be substituted, R ３Ｇ and R ３Ｈ are, independently, alkyl, aryl, or aralkyl.)

38. The method according to claim 35 or claim 36, wherein the functionalized branched comonomer (B) has a structure according to formula (VIII). 【Transformation 8】

39. The method according to claim 35 or claim 36, wherein the anionic comonomer has a structure according to formula (VI). 【Transformation 6】 (In the formula, R １Ａ , R １Ｂ , R １Ｃ , R １Ｄ , R １Ｅ , and R １Ｆ These are independently aryl or heteroaryl, and each is C １～６ alkyl, halo, SO ３ － X ＋ , PO ３ ２－ X ＋ ２ , and COO － X ＋ One, two, three, four, or five substituents (X) are independently selected from the above. ＋ H ＋ R may be substituted with a cation, １Ａ , R １Ｂ , R １Ｃ , R １Ｄ , R １Ｅ , and R １Ｆ At least two of them are, independently, SO ３ － X ＋ , PO ３ ２－ X ＋ ２ , and COO － X ＋ One, two, three, four, or five substituents (X) are independently selected from the above. ＋ H ＋ It is an aryl or heteroaryl substituted with (or a cation), A １ is an arylene, heteroarylene, aralkylene, or heteroaralkylene, each of which may be substituted with one, two, three, or four substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl. A ２ (either is absent, or is an arylene or heteroarylene, which may each be substituted with one, two, three, or four substituents independently selected from halo, nitro, cyano, aryl, and heteroaryl.)

40. The method according to claim 35 or claim 36, wherein the functionalized anionic comonomer is represented by formula (XIV). 【Chemistry 14】

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