Thanks to the exceptional materials properties of silica aerogels, this fascinating highly porous material has found high-performance and real-life applications in various modern industries. However, a requirement for a broadening of these applications is based on the further improvement of the aerogel properties, especially with regard to mechanical strength and postsynthesis processability with minimum compromise to the other physical properties. Here, we report an entirely novel, simple, and aqueous-based synthesis approach to prepare mechanically robust aerogel hybrids by cogelation of silk fibroin (SF) biopolymer extracted from silkworm cocoons. The synthesis is based on sequential processes of acid catalyzed (physical) cross-linking of the SF biopolymer and simultaneous polycondensation of tetramethylorthosilicate (TMOS) in the presence of 5-(trimethoxysilyl)pentanoic acid (TMSPA) as a coupling agent and subsequent solvent exchange and supercritical drying. Extensive characterization by solid-state H NMR,Si NMR, and 2D H-Si heteronuclear correlation (HETCOR) MAS NMR spectroscopy as well as various microscopic techniques (SEM, TEM) and mechanical assessment confirmed the molecular-level homogeneity of the hybrid nanostructure. The developed silica-SF aerogel hybrids contained an improved set of material properties, such as low density (ρ = 0.11-0.2 g cm), high porosity (∼90%), high specific surface area (∼400-800 m g), and excellent flexibility in compression (up to 80% of strain) with three orders of magnitude improvement in the Young's modulus over that of pristine silica aerogels. In addition, the silica-SF hybrid aerogels are fire retardant and demonstrated excellent thermal insulation performance with thermal conductivities (λ) of 0.033-0.039 W m K. As a further advantage, the formulated hybrid silica-SF aerogel showed an excellent printability in the wet state using a microextrusion-based 3D printing approach. The printed structures had comparable properties to their monolith counterparts, improving postsynthesis processing or shaping of the silica aerogels significantly. Finally, the hybrid silica-SF aerogels reported here represent significant progress for a mechanically customized and robust aerogel for multipurpose applications, namely, as a customized thermal insulation material or as a dual porous open-cell biomaterial used in regenerative medicine.

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GaAs compound-based electronics attracted significant interest due to unique properties of GaAs like high electron mobility, high saturated electron velocity and low sensitivity to heat. However, GaAs compound-based electronics demand a significant decrease in their manufacturing costs to be a good competitor in the commercial markets. In this context, copper-based nanoparticle (NP) inks represent one of the most cost-effective metal inks as a proper candidate to be deposited as contact grids on GaAs. In addition, Inkjet-printing, as a low-cost back-end of the line process, is a flexible manufacturing method to deposit copper NP ink on GaAs. These printed copper NP structures need to be uncapped and fused via a sintering method in order to become conductive and form an ohmic contact with low contact resistivity. The main challenge for uncapping a copper-based NP ink is its rapid oxidation potential. Laser sintering, as a fast uncapping method for NPs, reduces the oxidation of uncapped copper. The critical point to combine these two well-known industrial methods of inkjet printing and laser sintering is to adjust the printing features and laser sintering power in a way that as much copper as possible is uncapped resulting in minimum contact resistivity and high conductivity. In this research, copper ink contact grids were deposited on n-doped GaAs by inkjet-printing. The printed copper ink was converted to a copper grid via applying the optimized settings of a picosecond laser. As a result, an ohmic copper on GaAs contact with a low contact resistivity (8 mΩ cm2) was realized successfully.

a Macroporous magnesium silicide monoliths were successfully prepared by a two-step synthesis procedure. The reaction of gaseous magnesium vapor with macro-/mesoporous silicon, which was generated from hierarchically organized meso-/macroporous silica by a magnesiothermic reduction reaction, resulted in monolithic magnesium silicide with a cellular, open macroporous structure. By adjusting the reaction conditions, such as experimental set-up, temperature and time, challenges namely loss of porosity or phase purity of Mg 2 Si were addressed and monolithic magnesium silicide with a cellular network builtup was obtained.