STUDY OF WATER MANAGEMENT IN SOLID POLYMER ELECTROLYTES

• DOI: https://doi.org/10.22533/at.ed.11532225300410

• Palavras-chave: Polystyrene membranes; water management; solid electrolyte; Fuel cells

• Keywords: Polystyrene membranes; water management; solid electrolyte; Fuel cells

• Abstract: The variety of polymeric materials with distinct chemical structures that precisely control the molecular architecture underlies the numerous industrial uses of polymers over the past few decades. Polymer electrolytes or gel-type polymer electrolytes, for example, are interesting alternatives to substitute liquid electrolytes in different systems such as fuel cells (FC) and dye-sensitized solar cells (DSSC). For application in FC, the Nafion electrolyte is the most widely studied. However, this material is highly dependent on hydration and operating temperature. To a certain extent, concepts and models of proton conductivity in bulk water carry over to proton conductivity in Nafion and other polymer electrolyte membranes. To understand how water acts on these systems, in this work we conducted a study to identify the kind of interaction between the adsorbed water and the electrolyte structure of membrane. Differents copolymers were synthesized from styrene as the main comonomer and characterized chemically and thermally. Membranes were prepared by casting, hydrated and the Water Uptake (WU) and Water Content (WC) were determined. Differential Scaning Calorimetry (DSC) was used to determine the kinds of present water. We observed that several compositions absorb a lot of water and do not showed conductivity because it is basically free water and does not interact with the copolymer. For other side, when the copolymer structure allows strong interaction with water, the kind of water present also changes and this is reflected in the ionic properties of the membrane.