Heat release at the wetting front during capillary filling of cellulosic micro-substrates

Spontaneous imbibition in cellulosic materials is an expanding field of research due to the direct applicability in paper-based microfluidics. Here, we show experimentally, using simultaneous thermal and optical imaging that the temperature at the wetting front during capillary filling of paper is temporarily increased, even if the imbibed fluid and the cellulosic substrate are initially at isothermal conditions. Several liquids and two types of filter paper, characterised by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, were investigated demonstrating a significant temperature rise at the wetting front that cannot be neglected form the process. The temperature rise is found to be related to the energetics of imbibition compounds, including acid-base contributions, that result in electrostatic attractions as the liquid molecules are adhered on the fiber surfaces upon capillary contact.

Facile construction of gemini-like surfactants at the interface and their effects on the interfacial tension of a water/model oil system

Gemini-like surfactants were fabricated by combining sodium dodecyl benzene sulfonate and butane-1,4-bis(methylimidazolium bromide) at the interface and evaluated for their ability to reduce the interfacial tension between water and a model oil.

DNA action on the growth and habit modification of NaCl crystals

{100} hopper-like NaCl crystals were prepared upon the action of DNA by the solvent evaporation method.

Biomimetic synthesis of novel calcium carbonate heterogeneous dendrites

Three-dimensional dendrites of calcium carbonate were successfully synthesized via a nonclassical crystallization pathway by combining two different functional additives. They showed fascinating heterogeneous superstructures made up of calcite scaffolding, aragonite shells, and an external amorphous coating.

Morphology and size control of calcium carbonate crystallized in a reverse micelle system with switchable surfactants

Sub-micron CaCO₃ particles with different morphologies were prepared in reverse micelles based on a CO₂/N₂ switchable surfactant (N′-dodecyl-N,N-dimethyl acetamidine bicarbonate).