A Critical Revision of the Nano‐Morphology of Proton Conducting Ionomers and Polyelectrolytes for Fuel Cell Applications

A few aspects of the nano‐morphology of hydrated Nafion and other ionomers and polyelectrolytes in their acid form are revisited by examining the evolution of small angle X‐ray scattering (SAXS) data which are recorded for a wide range of water volume fractions (Φ_water ≈ 7–56 vol%). A consistency check with the recent “parallel cylinder model” discloses that this is most likely biased by a large uncertainty of the experimentally determined water content. We rather find our data to be consistent with locally flat and narrow (around 1 nm) water domains . The formation of relatively thin water “films” is suggested to be a common feature of many ionomers and polyelectrolytes, and the underlying driving force is most likely electrostatics within these highly dissociated systems. The water films may act as a charged (e.g., with positive protonic charge carriers) “glue”, keeping together the oppositely charged polymer structures. While this interaction tends to produce flat morphologies, the formation process is suggested to be constraint by limited conformational degrees of freedom of the corresponding polymer and the interactions between polymer backbones. This may leave severe tortuosities on larger scales which depend on the sample history (including swelling, de‐swelling, aging, stretching, and pressing).     

Disperse Amphiphilic Submicron Particles as Non‐Covalent Supports for Cationic Homogeneous Catalysts

A simple method for the effective immobilization of homogeneous catalysts on polystyrene colloids via non‐covalent binding is demonstrated. Stable latices with sufficiently high loading of accessible borate anions are prepared via emulsion polymerization. Incorporation of cationic rhodium complexes, supported via their borate counter‐anion is efficient, and these supported homogeneous catalysts maintain constant catalytic activity for CC hydrogenation during several recycles, with very low metal leaching.     

Student and faculty inter-generational digital divide: Fact or fiction?

This article analyzes the digital native–digital immigrant dichotomy based on the results of a small-scale study conducted at the University of Toronto, Faculty of Dentistry, regarding students’ and faculty members’ perceptions toward the implementation of digital learning technologies in the curriculum. The first element chosen for measurement was user perception of the impact on learning of basic software such as email, web browsers, online e-texts as well as hardware devices such as personal computers, laptops and MP3 players. In addition, the study also evaluated Blackboard, the learning management system of choice introduced by the parent university in the academic year 2006–2007. The results of this study suggest that there exists a slight inter-generational difference at the Faculty in the perceived usefulness and importance of digital technologies for learning and teaching, but that this difference is minimal, with no universal applicability. The study concludes that the digital native–digital immigrant duality is a complex phenomenon which cannot always be described in these extreme terms.