Kolloide: Die Welt der vernachlässigten Dimensionen

Aquatic colloids are abundant in all natural aquatic systems. Aquatic colloids consist of clay minerals, micro‐organisms, humic substances, and anthropogenic colloids like soot and platinum (from catalysts in motor vehicles). Colloids may enhance contaminant transport due to sorption of hydrophobic organic compounds. They can have negative effects on water quality, especially micro‐organisms like pathogens or viruses. Colloids also can cause pore blocking and subsequent head loss in groundwater production wells. However, colloids can be useful in groundwater remediation or waster water treatment (e.g. tensides, flocculation, catalysts). The origin of colloids is due to weathering, degradation of organic compounds, dissolution or precipitation as well as hydrochemical or hydraulic gradients. Colloid stability is dominated by surface properties. New analytical tools like field flow fractionation, laser induced breakdown detection and scanning x‐ray microscopy will provide new insight into the behaviour of aquatic colloids.     

Harnessing Colloidal Crack Formation by Flow‐Enabled Self‐Assembly

Self‐assembly of nanomaterials to yield a wide diversity of high‐order structures, materials, and devices promises new opportunities for various technological applications. Herein, we report that crack formation can be effectively harnessed by elaborately restricting the drying of colloidal suspension using a flow‐enabled self‐assembly (FESA) strategy to yield large‐area periodic cracks (i.e., microchannels) with tunable spacing. These uniform microchannels can be utilized as a template to guide the assembly of Au nanoparticles, forming intriguing nanoparticle threads. This strategy is simple and convenient. As such, it opens the possibility for large‐scale manufacturing of crack‐based or crack‐derived assemblies and materials for use in optics, electronics, optoelectronics, photonics, magnetic device, nanotechnology, and biotechnology.