Enhancement of Anhydrous Proton Conductivity of Poly(vinylphosphonic acid)–Poly(2,5‐benzimidazole) Membranes via In Situ Polymerization

Abstract

Polymer electrolyte membranes (PEMs) are synthesized via in situ polymerization of vinylphosphonic acid (VPA) within a poly(2,5‐benzimidazole) (ABPBI) matrix. The characterization of the membranes is carried out by using Fourier transform infrared (FTIR) spectroscopy for the interpolymer interactions, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) for the thermal properties, and scanning electron microscopy (SEM) for the morphological properties. The physicochemical characterizations suggest the complexation between ABPBI and PVPA and the formation of homogeneous polymer blends. Proton conductivities in the anhydrous state (150 °C) measured by using impedance spectroscopy are considerable, at up to 0.001 and 0.002 S cm−1 for (1:1) and (1:2) molar ratios, respectively. These conductivities indicate significant improvements (>1000×) over the physically blended samples. The results shown here demonstrate the great potential of in situ preparation for the realization of new PEM materials in future high‐temperature and non‐humidified polymer electrolyte membrane fuel cell (PEMFC) applications.

Investigation of perfluorinated proton exchange membranes prepared via a facile strategy of chemically combining poly(vinylphosphonic acid) with PVDF by means of poly(glycidyl methacrylate) grafts

“…Recently, the development of proton exchange membranes (PEMs) has attracted significant interest among researchers since they play a critical role in the efficient operation of fuel cells by exchanging protons between anode and cathode [1][2][3][4][5][6][7][8]. The requirements for PEMs to be successfully employed in PEMFC include high proton conductivity, good mechanical properties, enhanced chemical stability, and low permeability [9][10][11].…”

A Solution‐Processable Liquid‐Crystalline Semiconductor for Low‐Temperature‐Annealed Air‐Stable N‐Channel Field‐Effect Transistors

“…[1,2] Small moleculeso ffer great benefits due to their limited p-extended core, which can be readily modified with av ariety of functional groups to fine-tune their optoelectronic and physicochemical properties. [5][6][7][8][9] To this end, numerous molecular semiconductors have been developed and characterized in aw ide range of optoelectronic applications, such as OFETs, [10] organic photovoltaics (OPVs), [11] and organic lightemitting diodes( OLEDs) [12] and transistors (OLETs). [5][6][7][8][9] To this end, numerous molecular semiconductors have been developed and characterized in aw ide range of optoelectronic applications, such as OFETs, [10] organic photovoltaics (OPVs), [11] and organic lightemitting diodes( OLEDs) [12] and transistors (OLETs).…”

“…[3,4] In addition, the solubility,s ynthetic reproducibility, and final purity levels of small molecules can be superiort ot hose of macromolecules and polymers, which is very crucial for the realization of low-cost and high-performance plastic optoelectronics. [5][6][7][8][9] To this end, numerous molecular semiconductors have been developed and characterized in aw ide range of optoelectronic applications, such as OFETs, [10] organic photovoltaics (OPVs), [11] and organic lightemitting diodes( OLEDs) [12] and transistors (OLETs). [13] It is worth notingt hat, among these applications, p-conjugated small molecules have been even commercialized in active-matrix OLED displays as emissive and hole/electron transporting/ blockingl ayers.…”

Dielectric relaxations in phosphoric acid‐doped poly(2,5‐benzimidazole) and its composite membranes

“…Since the optimal performance of a catalyst can only be achieved at higher temperature, a membrane with proton conductivity of 0.1 S cm −1 at 160 to 200 °C will be an ideal choice for PEM fuel cells . Hence, membranes for high‐temperature fuel cells have also been proposed, and among them, polybenzimidazole (PBI)‐based membranes operating at temperature above 160 °C have shown conductivity comparable to that of Nafion (at 90 °C and 98% relative humidity) . Unlike that with Nafion, the proton conduction in PBI membranes is not entirely water‐dependent; instead, the phosphoric acid content in the doped‐membranes provides the conduction path .…”

“…3 Hence, membranes for high-temperature fuel cells have also been proposed, and among them, polybenzimidazole (PBI)-based membranes operating at temperature above 160 8C have shown conductivity comparable to that of Nafion (at 90 8C and 98% relative humidity). [4][5][6][7][8][9][10] Unlike that with Nafion, the proton conduction in PBI membranes is not entirely water-dependent; instead, the phosphoric acid content in the doped-membranes provides the conduction path. [11][12][13][14][15] It has been established that the molecular weight, chain orientation/entanglements, and dielectric relaxation behavior of the polymer materials have a significant effect on the proton conduction of the membranes.…”