Functionalized silica nanoparticles with or without in situ surface modification are used to fabricate bijels via solvent transfer induced phase separation (STrIPS).

Ultrafiltration membranes are important porous materials to produce freshwater in an increasingly water-scarce world. A recent approach to generate porous membranes is solvent transfer induced phase separation (STrIPS). During STrIPS, the interplay of liquid−liquid phase separation and nanoparticle self-assembly results in hollow fibers with small surface pores, ideal structures for applications as filtration membranes. However, the underlying mechanisms of the membrane formation are still poorly understood, limiting the control over structure and properties. To address this knowledge gap, we study the nonequilibrium dynamics of hollow fiber structure evolution. Confocal microscopy reveals the distribution of nanoparticles and monomers during STrIPS. Diffusion simulations are combined with measurements of the interfacial elasticity to investigate the effect of the solvent concentration on nanoparticle stabilization. Furthermore, we demonstrate the separation performance of the membrane during ultrafiltration. To this end, polyelectrolyte multilayers are deposited on the membrane, leading to tunable pores that enable the removal of dextran molecules of different molecular weights (>360 kDa, >60 kDa, >18 kDa) from a feed water stream. The resulting understanding of STrIPS and the simplicity of the synthesis process open avenues to design novel membranes for advanced separation applications.

In a variety of applications metal matrix composites (MMC) show very beneficial properties. A well-known example are oxide dispersion strengthened (ODS) materials. Their high temperature mechanical properties can be noticeably improved by adding ceramic particles to a metal matrix. A similar approach was used for the development of wearresistant materials, e.g. silver-based contact materials for switches [1] or iridium-based electrode materials. [2] Both electrical contacts and electrodes are damaged by an arc discharge. The crater formation can be explained by the particle-ejection-model [3] which describes the loss of material as melting and splashing of electrode material.The wear resistance of contact materials is increased by the addition of particles like SnO 2 , CdO, In 2 O 3 to a silver matrix. In presence of such particles, electrical discharges cause smaller and flatter craters. [4,5] As a result of the increased viscosity of the molten material, less particles are ejected from the crater. [4] This effect can only operate if the melting point of the particles is higher than that of the matrix material.Furthermore, the wear resistance can be raised by the addition of particles with a sublimation temperature close to the melting point of the matrix material. The sublimation of the particles, e.g CdO consumes energy which cools the melt. This reduces the amount of molten material, thus leading to less erosion. [6] In order to improve the erosion resistance of electrode materials Al 2 O 3 , MgO, and rare earth metal oxides, especially Y 2 O 3 and La 2 O 3 have been added to iridium and ruthenium, respectively. [7,8] Two theories are discussed to explain the increase in wear resistance. On the one hand, these oxides impede oxidation of the electrode surface. [9,10] On the other hand, the large atomic weight of the oxides, especially of rare earth metals, leads to a reduced sputter rate during the glow discharge. [11] In a previous paper [12] we showed that oxidation plays a dominant role in the erosion of electrode materials. In the case of platinum, erosion stems from the plasma-assisted formation of volatile oxides in the cathode spot.In this paper, the fabrication, microstructural design and characterization of platinum composites with 14 vol.% ceramic dispersoids are presented. Metal oxides of different atomic weight and high melting points were chosen: MgO (M Mg = 24.3 g/mol), ZrO 2 (M Zr = 91.2 g/mol) and CeO 2 COMMUNICATIONS ADVANCED ENGINEERING MATERIALS 2006, 8, No. 1-2 a) b) Fig. 1. Metallographic cross sections of Pt/MgO samples after the second sintering at 1600°C: (a) mechanically alloyed and (b) chemically alloyed samples. The microstructure of the chemically alloyed sample is much more homogeneous.

The cover shows the the microstructure of a Pt/MgO composite which could be fully densified at sintering temperatures above 1700°C. More about platinum ceramic composites and their properties can be found in the article by J. Rager on page 81.

Throughout the course of one day, the human body goes through numerous mechanical activities. These activities, while usually not very powerful individually, produce an ample amount of energy collectively. This mechanical energy can be harvested into electrical energy via piezoelectricity. Recent research into piezoelectric nanocomposites has yielded techniques to foam the materials into softer, porous structures more suitable for human comfort. This study focuses on using a host polymer polydimethylsiloxane (PDMS) and citric acid to create foams. Citric acid, a common industrial chemical blowing agent (CBA), is used in this project due to its capabilities to produce foams with consistent pore sizes and distribution. These foams, coupled with piezoelectric nanoparticles, are fabricated, analyze, and tested. They are mechanically characterized using tensile testing. Electrical characterization is carried out using an integrated mechanical-electrical testing setup. These foams are lighter, softer, and can produce higher electrical output than non-porous counterparts. We believe that these foams have great potential in upcoming piezoelectric technology.