Electroactive Polymers: Developments of and Perspectives for Dielectric Elastomers

We present the development and applications of dielectric elastomers. For the last 10 years the significance of this class of polymers has risen as more applications seem possible and first products have been commercialized.     

Micro-structure evolution of wall based crystals after casting of model suspensions as obtained from Bragg microscopy

Growth of heterogeneously nucleated, wall based crystals plays a major role in determining the micro-structure during melt casting. This issue is here addressed using a model system of charged colloidal spheres in deionized aqueous suspension observed by Bragg microscopy which is a combination of light scattering and microscopy. We examine the evolution of the three-dimensional size, shape, and orientation of twin domains in monolithic crystals growing from two opposing planar walls into a meta-stable (shear-) melt. At each wall crystal orientation and twinning emerges during nucleation with small domains. During growth these widen and merge. From image analysis we observe the lateral coarsening velocities to follow a power law behaviour L(XY) ∝ t(1∕2) as long as the vertical growth continues at constant speed. Lateral coarsening terminates upon intersection of the two solids and hardly any further ripening is seen. Initial lateral coarsening velocities show a Wilson Frenkel type dependence on the melt meta-stability.     

Schatten properties,nuclearity and minimality of phase shift invariant spaces

We extend Feichtinger's minimality property on the smallest non-trivial time-frequency shift invariant Banach space, to the quasi-Banach case. Analogous properties are deduced for certain matrix spaces.We use these results to prove that the pseudo-differential operator $\mathrm{Op}(a)$ is a Schatten-q operator from $M^{\infty }$ to $M^p$ and r-nuclear operator from $M^{\infty }$ to $M^r$ when $a\in M^r$ for suitable p, q and r in $(0,\infty ]$.     

α-Diphenylphosphino-N-(pyrazin-2-yl)glycine as a ligand in Ni-catalyzed ethylene oligomerization

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The Reactivity of Hexafluorothioacetone and Hexafluoroacetone versus Phosphites

Abstract

The dimer of hexafluorothioacetone reacted with various phosphites to form thiophosphates and bis(trifluoromethyl)methylenphosphoranes, being unstable in the case of (Me₃SiO) P(OMe)_3-n, (n=1?3), where phosphonates (Me₃SiO)_n-1(MeO)_3-nP(O)[C(CF₃)=CF₂] (n=1-3) and Me₃SiF were observed. In general, cyclic phosphites behaved similar to acyclic ones. The resulting bis(trifluoromethyl)methylenphosphoranes were thermally stable except compound A, because of a new intramolecular fluorine transfer to phosphorus forming fluorophosphorane B.