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The splashing of liquid drops onto a solid surface is important for a wide range of applications, including combustion and spray coating. As the drop hits the solid surface, the liquid is ejected into a thin horizontal sheet expanding radially over the substrate. Above a critical impact velocity, the liquid sheet is forced to separate from the solid surface by the ambient air, and breaks up into smaller droplets. Despite many applications involving complex fluids, their effects on splashing remain mostly unexplored. Here we show that the splashing of a nanoparticle dispersion can be suppressed at higher impact velocities by the interactions of the nanoparticles with the solid surface. Although the dispersion drop first shows the classical transition from deposition to splashing when increasing the impact velocity, no splashing is observed above a second higher critical impact velocity. This result goes against the commonly accepted understanding of splashing, that a higher impact velocity should lead to even more pronounced splashing. Our findings open new possibilities to deposit large amount of complex liquids at high speeds.

The splashing of liquid drops onto a solid surface is important for a wide range of applications, including combustion and spray coating. As the drop hits the solid surface, the liquid is ejected into a thin horizontal sheet expanding radially over the substrate. Above a critical impact velocity, the liquid sheet is forced to separate from the solid surface by the ambient air, and breaks up into smaller droplets. Despite many applications involving complex fluids, their effects on splashing remain mostly unexplored. Here we show that the splashing of a nanoparticle dispersion can be suppressed at higher impact velocities by the interactions of the nanoparticles with the solid surface. Although the dispersion drop first shows the classical transition from deposition to splashing when increasing the impact velocity, no splashing is observed above a second higher critical impact velocity. This result goes against the commonly accepted understanding of splashing, that a higher impact velocity should lead to even more pronounced splashing. Our findings open new possibilities to deposit large amount of complex liquids at high speeds.

Wood can be considered as a highly porous, three-dimensional organic scaffold. It can be mineralized to create hierarchically structured organic-inorganic hybrid materials with novel properties. In the present paper, the precipitation of CaCO3 mineral in Norway spruce and European beech wood has been studied by alternating impregnation with aqueous and alcoholic electrolyte solutions. Microstructural imaging by SEM and confocal Raman microscopy shows the distribution of calcite and vaterite as two CaCO3 polymorphs, which are deposited deep inside the cellular structure of the wood. The confined microenvironment of the wood cell wall seems to favor a formation of vaterite, as visible by XRD and Raman spectroscopy. In view of a practical application, the mineralization of wood opens up ways for sustainable wood-based hybrid materials with a significantly improved fire resistance, as proven via pyrolysis combustion flow calorimetry and cone calorimetry tests. Beyond that, this versatile solute-exchange approach provides an opportunity for the incorporation of a broad range of different mineral phases into wood for novel material property combinations.

Wood can be considered as a highly porous, three-dimensional organic scaffold. It can be mineralized to create hierarchically structured organic-inorganic hybrid materials with novel properties. In the present paper, the precipitation of CaCO3 mineral in Norway spruce and European beech wood has been studied by alternating impregnation with aqueous and alcoholic electrolyte solutions. Microstructural imaging by SEM and confocal Raman microscopy shows the distribution of calcite and vaterite as two CaCO3 polymorphs, which are deposited deep inside the cellular structure of the wood. The confined microenvironment of the wood cell wall seems to favor a formation of vaterite, as visible by XRD and Raman spectroscopy. In view of a practical application, the mineralization of wood opens up ways for sustainable wood-based hybrid materials with a significantly improved fire resistance, as proven via pyrolysis combustion flow calorimetry and cone calorimetry tests. Beyond that, this versatile solute-exchange approach provides an opportunity for the incorporation of a broad range of different mineral phases into wood for novel material property combinations.