Form follows the ion: The morphogenesis of fluorapatite–gelatine nanocomposites is studied from both electron microscopy and atomistic simulation revealing ion impregnation effects on the growth mechanisms. Depending on the ionic species used for pre‐treatment of the organic component dramatic changes of the mesoscopic structuring are observed.

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Die Form folgt aus dem Ion: Die Auswirkungen von Ionenimprägnierung der organischen Komponente auf den Wachstumsmechanismus und die Morphogenese von Fluorapatit‐Gelatine‐Nanokompositen wurden durch Elektronenmikroskopie und atomistische Simulationen untersucht. In Abhängigkeit von der Ionensorte konnten dabei drastische Veränderungen der mesoskopischen Strukturierung beobachtet werden.

In this study, polyetheretherketone composites were compounded using a two-screw extruder followed by injection moulding. The effects of multi-fillers on the mechanical properties and crystallization performances were investigated. Differential scanning calorimetry results indicate that the addition of fillers slightly increases the crystallization temperature and crystallinity. Compared to neat polyetheretherketone, the incorporation of inorganic filler leads to a significant improvement in matrix hardness, matrix stiffness and a slight increase in tensile strength. However, the material ductility, the impact strength and the fracture toughness of polyetheretherketone composites decrease. Fractography analyses show that the addition of fillers restraints the ductile deformation of polymers, which is responsible for the reduction of material ductility, impact strength as well as fracture toughness of polyetheretherketone composites.

The mechanistic details of the pressure-induced B1-B2 phase transition of rubidium chloride are investigated in a series of transition path sampling molecular dynamics simulations. The B2→B1 transformation proceeds by nucleation and growth involving several, initially separated, nucleation centers. We show how independent and partially correlated nucleation events can function within a global mechanism and explore the evolution of phase domains during the transition. From this, the mechanisms of grain boundary formation are elaborated. The atomic structure of the domain-domain interfaces fully support the concept of Bernal polyhedra. Indeed, the manifold of different grain morphologies obtained from our simulations may be rationalized on the basis of essentially only two different kinds of Bernal polyhedra. The latter also play a crucial role for the B1→B2 transformation and specific grain boundary motifs are identified as preferred nucleation centers for this transition.

Platelets as fillers in polymer coatings contribute to corrosion resistance by increasing the diffusion path of gases. The authors demonstrate that the same platelets can improve tribological properties and, thus, open a new way to design multifunctional polymer coatings. Improved corrosion resistance, low friction, and low wear are reported for polyimide composite coatings filled with a combination of boron nitride, pigment platelets, perfluoropolyether, and Si 3 N 4 particles. Contributions of different fillers to the tribological performance are explored for coatings with different filling protocols. The synergy of four components leads to the excellent tribological performance of the fully formulated coatings, while they cannot impart significant improvement in friction and wear when used separately.

Form development during growth of fluorapatite-gelatine nanocomposites is effected by pre-structuring of gelatine matrices by ion impregnation. The cover picture shows the hierarchical fractal aggregate (background), structural details of a fanlike aggregate, and a simulation of the "stiffening" effect on a protein molecule of Ca 2þ ion incorporation. This effect is discussed by R. Kniep and co-workers in their Communication on page 1905 ff. A second paper on page 1911 ff. deals with the effect of intrinsic electric dipole fields on the form development of the nanocomposite materials. Reactivity and SelectivityIn their Minireview on page 1844 ff., H. Mayr and A. R. Ofial challenge the widely accepted reactivity-selectivity principle for organic reactions: Reactivity and selectivity of a species should exhibit opposite behavior-but its not as easy as it sounds! Nanoscience DNA molecules are excellent building blocks for the construction of complex superstructures. Construction principles as well as possible applications of such assemblies are described by U. Feldkamp and C. M. Niemeyer in their Review on page 1856 ff. Photoresponsive MaterialsA first step towards the design of intelligent delivery vehicles is presented by S. Hecht and co-workers in their communication on page 1878 ff., which describes the unfolding of the hollow helical secondary structure of a foldamer upon irradiation.