“…Alternative low-cost materials that present similar conductive and chemo-mechanical properties as the PFSI membranes are continuously searched for. Different crystalline-amorphous polymer architectures and the interrelation of their properties with the microphase separation structures, such as crystalline domains, the formation of conducting regions, and the distribution of ionic groups and water in the conducting regions were extensively studied in recent years [13,14,15,16,17,18,19,20].…”
Membranes based on sulfonated synditoactic polystyrene (s-sPS) were thoroughly characterized by contrast variation small-angle neutron scattering (SANS) over a wide Q-range in dry and hydrated states. Following special sulfonation and treatment procedures, s-sPS is an attractive material for fuel cells and energy storage applications. The film samples were prepared by solid-state sulfonation, resulting in uniform sulfonation of only the amorphous phase while preserving the crystallinity of the membrane. Fullerenes, which improve the resistance to oxidation decomposition, were incorporated in the membranes. The fullerenes seem to be chiefly located in the amorphous regions of the samples, and do not influence the formation and evolution of the morphologies in the polymer films, as no significant differences were observed in the SANS patterns compared to the fullerenes-free s-sPS membranes, which were investigated in a previous study. The use of uniaxially deformed film samples, and neutron contrast variation allowed for the identification and characterization of different structural levels with sizes between nm and μm, which form and evolve in both the dry and hydrated states. The scattering length density of the crystalline regions was varied using the guest exchange procedure between different toluene isotopologues incorporated into the sPS lattice, while the variation of the scattering properties of the hydrated amorphous regions was achieved using different H2O/D2O mixtures. Due to the deformation of the films, the scattering characteristics of different structures can be distinguished on specific detection sectors and at different detection distances after the sample, depending on their size and orientation.
“…Alternative low-cost materials that present similar conductive and chemo-mechanical properties as the PFSI membranes are continuously searched for. Different crystalline-amorphous polymer architectures and the interrelation of their properties with the microphase separation structures, such as crystalline domains, the formation of conducting regions, and the distribution of ionic groups and water in the conducting regions were extensively studied in recent years [13,14,15,16,17,18,19,20].…”
Membranes based on sulfonated synditoactic polystyrene (s-sPS) were thoroughly characterized by contrast variation small-angle neutron scattering (SANS) over a wide Q-range in dry and hydrated states. Following special sulfonation and treatment procedures, s-sPS is an attractive material for fuel cells and energy storage applications. The film samples were prepared by solid-state sulfonation, resulting in uniform sulfonation of only the amorphous phase while preserving the crystallinity of the membrane. Fullerenes, which improve the resistance to oxidation decomposition, were incorporated in the membranes. The fullerenes seem to be chiefly located in the amorphous regions of the samples, and do not influence the formation and evolution of the morphologies in the polymer films, as no significant differences were observed in the SANS patterns compared to the fullerenes-free s-sPS membranes, which were investigated in a previous study. The use of uniaxially deformed film samples, and neutron contrast variation allowed for the identification and characterization of different structural levels with sizes between nm and μm, which form and evolve in both the dry and hydrated states. The scattering length density of the crystalline regions was varied using the guest exchange procedure between different toluene isotopologues incorporated into the sPS lattice, while the variation of the scattering properties of the hydrated amorphous regions was achieved using different H2O/D2O mixtures. Due to the deformation of the films, the scattering characteristics of different structures can be distinguished on specific detection sectors and at different detection distances after the sample, depending on their size and orientation.
“… Fig. 2 Job plot of SPI/PE membranes before (open circle) [3] and after (solid circle) heat treatment calculated from normalized absorbance at 530 nm. …”
Section: Experimental Design Materials and Methodsmentioning
confidence: 99%
“…Through-plane proton conductivities of all membranes were measured by a membrane test system (MTS-740, Scribner) under different temperatures and humidities [3] . The proton conductivity (σ) was calculated as below ( Fig.…”
Section: Experimental Design Materials and Methodsmentioning
confidence: 99%
“…A membrane-electrode assembly (MEA) was fabricated from the CT blend membrane and Nafion 212, and a single cell test was performed following the Ref. [3] . The overvoltage was calculated based on polarization curve and cell impedance according to NEDO (New Energy and Industrial Technology Development Organization, Japan) protocol [4] ( Fig.…”
Section: Experimental Design Materials and Methodsmentioning
The data presented in this article are related to polymer-polymer type charge-transfer blend membranes for fuel cell application. The visible spectra of the charge-transfer (CT) blend membranes indicated formation of CT complex in the blend membranes, and behavior of CT complex formation by polymers was clarified by Job plot of the visible spectra. The effect of fluorine for membrane property and fuel cell performance of CT blend membranes were evaluated by 19F NMR and overvoltage analysis, respectively.
“…Therefore, improvements in the Nafion properties by incorporating inorganic fillers (such as titania, zirconia, and silica) or carbon-based nanomaterials (carbon nanotubes, fullerenes, etc.) into the membranes [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ] and alternative low-cost materials that present similar conductive and chemo-mechanical properties, such as the Nafion membranes [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ], are continuously searched for. Given the recent developments, which enable a controlled sulfonation of only the amorphous phase [ 26 ], preserving thus the crystallinity of the material, and an improved resistance to oxidation decomposition when fullerenes are added [ 27 ], the sulfonated syndiotactic polystyrene (s–sPS) is a good potential candidate for some PEMFC applications, as it presents a high proton conductivity comparable to Nafion [ 28 ], high chemical and thermomechanical stability, and a low cost.…”
Polymeric membranes based on the semi-crystalline syndiotactic–polystyrene (sPS) become hydrophilic, and therefore conductive, following the functionalization of the amorphous phase by the solid-state sulfonation procedure. Because the crystallinity of the material, and thus the mechanical strength of the membranes, is maintained and the resistance to oxidation decomposition can be improved by doping the membranes with fullerenes, the sPS becomes attractive for proton-exchange membranes fuel cells (PEMFC) and energy storage applications. In the current work we report the micro-structural characterization by small-angle neutron scattering (SANS) method of sulfonated sPS films and sPS–fullerene composite membranes at different temperatures between 20 °C and 80 °C, under the relative humidity (RH) level from 10% to 70%. Complementary characterization of membranes was carried out by FTIR, UV-Vis spectroscopy and prompt–γ neutron activation analysis in terms of composition, following the specific preparation and functionalization procedure, and by XRD with respect to crystallinity. The hydrated ionic clusters are formed in the hydrated membrane and shrink slightly with the increasing temperature, which leads to a slight desorption of water at high temperatures. However, it seems that the conductive properties of the membranes do not deteriorate with the increasing temperature and that all membranes equilibrated in liquid water show an increased conductivity at 80 °C compared to the room temperature. The presence of fullerenes in the composite membrane induces a tremendous increase in the conductivity at high temperatures compared to fullerenes-free membranes. Apparently, the observed effects may be related to the formation of additional hydrated pathways in the composite membrane in conjunction with changes in the dynamics of water and polymer.
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