Abstract:
A method for preparing a membrane to be assembled in a membrane electrode assembly is disclosed, comprising the steps of : a) irradiating sections (4) of a polymer film (2) with electromagnetic and/or particle radiation with a predetermined irradiation profile in order to both define irradiated sections (4) and to form reactive centers, i.e. radicals, in said irradiated sections (4) of the membrane; thereby separating the irradiated sections (4) from each other by separation bands (6) of un-irradiated membrane sections; b) exposing the film (2) comprising the irradiated sections (4) to a monomer or a mixture of monomers amenable to radical polymerization in order to achieve the formation of a graft copolymer in said irradiated sections (4). This method and the respective assembly yield a membrane that has, due to the profile of the irradiation, separated regions of distinct and appropriate properties to serve as a fuel cell electrolyte. It is therefore possible to generate within the same membrane layer or membrane film sections which have in its swollen state pro ton- conductive properties adjacent to the separation band sections which are the remaining original insulating starting material. This allows to generate within a single layer a plurality of separate fuel cells. Furthermore, this method allows to achieve additional property gradients, such as conductivity, water uptake, etc., within the same "activated" section and also over the thickness of the membrane for the purpose of asymmetric grafting.
Abstract:
A method for making a composite ion exchange membrane including fabricating a layered membrane precursor including a microporous support of highly fluorinated nonionic polymer adhered to a layer of highly fluorinated sulfonyl halide polymer, hydrolizing the layered membrane precursor to convert the highly fluorinated sulfonyl halide polymer to highly fluorinated sulfonate polymer, impregnating the microporous support with a dispersion of highly fluorinated sulfonate polymer or precursor thereof in a polar liquid medium after hydrolyzing, removing the polar liquid medium, and heating to coalesce the highly fluorinated sulfonated polymer in the support.
Abstract:
A low electrical resistance bipolar membrane formed by the conjoining of treated anion and cation exchange membranes is disclosed. The treatment comprises contacting the membranes with an aqueous solution of at least one cation prior to conjoining and contacting at least one face of the membranes with an aqueous alkaline solution. A process for the preparation of acid and alkali using these bipolar membranes is also disclosed.
Abstract:
The present invention relates to a process for the preparation of films of conductive polymers, by the technique so-called roll-to-roll, which allows to obtain free¬ standing films having advantageous features such as toughness, flexibility, ability to adhere to different substrates, a submicron thickness and a very high ratio surface area/thickness; the present films are suitable for use in several technological applications, in particular for the development of biosensors, and in the production of flexible electronic components with large surface, suitable for wearable devices and also intended for contacting skin.
Abstract:
An ion exchange membrane (52) for a fuel cell comprises a polymer having an acid functional group normally including protons, and having alkali metal ions partially ion-exchanged with the protons of the acid functional group of the membrane. The partial ion exchange of alkali metal ions into the membrane relates either to patterning of the exchanged ion make-up of the membrane, with some being ion exchanged and some not, or to the extent or concentration of the ion exchange in any particular location, or to both.
Abstract:
PFSAs having CO tolerances greater than 500 ppm at temperatures above 100°C are provided by decreasing the equivalent weight and thickness of the membrane and impregnating the membrane pores with an oxide, e.g., a hydrophilic siloxane polymer or TiO 2 . This was accomplished by either impregnating an extruded PFSA film via sol-gel processing of tetraethoxysilane, or by preparing a recast film, using solubilized PFSA and an oxide source.
Abstract:
The present invention relates to methods of fabricating composite membranes wherein at least one of the components is initially provided in the form of a precursor. The composite material comprising the precursor is processed to transform the precursor and obtain a membrane having a desired property. Including a thermoplastic precursor to a desired component, which itself is less thermoplastic, permits separate pieces of the membrane to be joined by welding or other thermal processes relying on the meltability of the components to achieve a bond. The invention also encompasses fabricating a reinforced ion conducting membrane by melting and mixing a non ion-conducting precursor to an ion-conducting polymer with an essentially inert polymer. The composite material is then processed to transform the non-ion conducting polymer into the ion-conducting form. The mixing of the precursor and the inert polymer may also be achieved by co-precipitating a solution of the precursor and a suspension of the inert polymer; impregnating the precursor onto the walls of the pores of a porous, essentially inert polymer; filling the pores of a porous, essentially inert polymer with a solution of comprising a non-ion conducting precursor to an ion conducting precursor and evacuating the solvent to substantially fill the pores of a porous, essentially inert polymer with the precursor; or melting the precursor, filling the pores of a porous essentially inert polymer with the melted precursor and cooling the precursor to form an essentially pore free composite membrane.
Abstract:
Die Erfindung betrifft ein Verfahren zur Herstellung von Polyarylenether-Perlen aus einer Polyarylenetherlösung umfassend die Schritte i) Vereinzelung der Polyarylenetherlösung in einer Vereinzelungsvorrichtung, die in eine Schwingung mit einer Frequenz im Bereich von 10 bis 1400 Hz versetzt wird, unter Erhalt von Tropfen, ii) Überführen der Tropfen in ein Fällbad unter Ausbildung von Polyarylenether- Perlen in dem Fällbad, wobei das Fällbad (A) mindestens ein aprotisches Lösungsmittel (Komponente (1)) und mindestens ein protisches Lösungsmittel (Komponente (2)) enthält, (B) eine Temperatur von 0°C bis T c aufweist, wobei die kritische Temperatur T c in [°C] sich mit der Zahlenwertgleichung T c = (77- c) / 0,58 bestimmen lässt, in der c die Konzentration der Komponente (1) im Fällbad in [Gew.-%] ist und (C) die Komponente (1) in Konzentrationen von 5 Gew.-% bis c c aufweist, wobei die kritische Konzentration c c in [Gew.-%] sich mit der Zahlenwertgleichung c c = 77-0, 58*T bestimmen lässt, in der T die Temperatur im Fällbad in [°C] ist, wobei die Gew.-% jeweils bezogen sind auf die Summe der Gew.-% der Komponente (1 ) und der Komponente (2) im Fällbad.
Abstract:
A proton (H+)-conducting hydrocarbon (HC)-based polymer electrolyte membrane (PEM) having first and second oppositely facing surfaces comprises a HC-based membrane with at least one perfluoropolymer incorporated on or within at least the first and second surfaces. A method for fabricating the PEM comprises surface treating a HC-based polymeric membrane sheet via immersion in an aqueous solution or dispersion of said at least one perfluoropolymer, followed by drying of the surface treated polymeric membrane sheet.