The proton exchange membrane (PEM) is a key element of a polymer electrolyte fuel cell, and radiation-grafting is an attractive option for the synthesis of PEMs. Via a systematic investigation of a well-defined model material, sulfonated polystyrene grafted poly(ethylene-alt-tetrafluoroethylene), ETFE-g-PS(SA), we show that the performance and stability of radiation-grafted PEMs in fuel cells strongly depends on the microstructure of the underlying base polymer. The nanoscale structure of the base polymers, grafted films, and membranes is probed by small-angle scattering, and the nanoscale proton dynamics is probed by quasi-elastic neutron scattering. The results of these techniques correlated with fuel cell relevant propertiesincluding proton conductivity and water uptakeand fuel cell performance clearly indicate that differences in the arrangement of the crystalline phase in the otherwise chemically identical semicrystalline base films can have considerable impact, representing an essential aspect to consider in the development of proton exchange membranes prepared via preirradiation grafting.

The polymer design concept of short versus long side chains was successfully adapted to radiation-grafted membranes, the fabrication of which is an easy and up-scalable process. This concept was investigated by the generation of two model membranes based on polystyrene sulfonic acid-grafted ethylene-alt-tetrafluoroethylene, prepared using a low versus high irradiation dose. It was shown to be essential to adjust the grafting parameters of both systems to obtain two membranes with similar composition in through-plane direction. In particular, the high-dose system showed pronounced grafting fronts. A structure-property correlation was found regarding the influence of the graft lengths on the performance characteristics of electron beam-grafted ethylene-alt-tetrafluoroethylene-based proton exchange membranes, e.g. the membrane type associated with a higher number density of short grafted chains showed higher water sorption behaviour as well as increased proton conductivity, especially in the lower relative humidity range.

Various energetic polynitro esters, carbamates, and nitrocarbamates that were derived from the amino acid glycine were fully characterized by single-crystal X-ray diffraction, vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Owing to their positive oxygen balance, the suitability of these compounds as potential oxidizers in energetic formulations was investigated and discussed. In addition, the heats of formation of the products were calculated by using the Gaussian 09 program package at the CBS-4M level of theory. From these values and the calculated densities (from the X-ray data), several detonation parameters, such as detonation pressure, velocity, energy, and temperature, were computed by using the EXPLO5 code. Furthermore, their sensitivities towards impact, friction, and electrostatic discharge were tested by using a drop hammer, a friction tester (both BAM certified), and a small-scale electrical-discharge device, respectively.

The energetic boron esters tris(1-ethyl-5-aminotetrazolyl) borate, tris(2-ethyl-5-aminotetrazolyl) borate, tris(1-ethyltetrazolyl) borate, tris(2-ethyltetrazolyl) borate, and tris(2-(3-nitro-1,2,4-triazolyl)ethyl) borate were synthesized and analyzed by NMR and IR spectroscopy, elemental analysis, and mass spectrometry. Two tetracoordinate borates potassium tetrakis(3-nitro-1,2,4-triazolyl)borate and potassium bis(4,4Ј,5,5Ј-tetranitro-2,2Ј-bisimidazolyl)borate were synthesized and fully characterized as well. Moreover, the energetic and * Prof. Dr. T. M. Klapötke

Swift heavy ions create tracks of activated material in a polymer film for subsequent modification to form proton conducting channels.