Bacterial adhesion on silicone nano-and microstructures is investigated in stagnant and flow experiments. Static adhesion tests are performed in 0.9% NaCl solution. These experiments reveal that the number of Staphylococcus epidermidis (S. epidermidis) and Escherichia coli (E. coli) adhering to glass surfaces can significantly be reduced if silicone nanofilament and rod coatings are present. Further, flow experiments are conducted in a parallel-plate flow chamber using 0.9% NaCl solution and artificial urine as medium. Silicone nanofilament coated surfaces are compared to uncoated glass surfaces. E. coli colonisation on filament coated surfaces is reduced for at least 24 h in 0.9% NaCl solution, while in artificial urine no reduction is observed after 24 h. S. epidermidis shows converse adhesion behaviour. Here, initial adhesion on nanofilaments is promoted but the number of adherent S. epidermidis seems to decrease after extended contact time. The obtained results demonstrate that superhydrophobic silicone surfaces significantly reduce bacterial colonisation under stagnant and dynamic conditions. However, the bacterial adhesion behaviour depends on the architecture of the silicone nano-and microstructures and the bacterial species investigated.

The roughness of superhydrophobic silicone nanofilaments (SNFs) is exploited to enlarge the contact area of conventional filter material. As an efficient wetting of the filter material is crucial for water treatment, the wettability of SNFs is readily modified from superhydrophobic to hydrophilic during the functionalization process. SNFs are coated on glass beads and subsequently modified with biocidal silver nanoparticles (AgNPs). The enlarged surface area of SNFs allows a 30 times higher loading of AgNPs in comparison to glass beads without SNF coating. Thus, in column experiments, the AgNP-SNF-nanocomposite-modified glass beads exert superior antibacterial activity towards suspensions of E. coli K12 compared to AgNP functionalized glass beads without SNFs. Additionally, reusing the AgNP-SNF-nanocomposite-coated glass beads with fresh bacteria contaminated medium increases their efficacy and reduces the colony forming units by ≈6 log units. Thereby, the silver loss during percolation is below 0.1 μg mL . These results highlight, first, the potential of AgNP-SNF-nanocomposite-modified glass beads as an effective filter substrate for water disinfection, and second, the efficiency of SNF coating in increasing the contact area of conventional filter material.

Mixed transition metal nickel oxide materials (M-NiO; M = Co, Mn, Fe) supported on silicone nanofilaments (SNFs) were synthesized via precipitation reaction with urea. All materials were evaluated for their OER activity in 0.1 M KOH, of which the Fe-NiO/SNFs showed a notable improvement over NiO/SNFs and unsupported NiO. The results presented herein demonstrate the extension of our previously reported synthesis for NiO/SNFs to yield SNF-supported mixed transition metal-oxide materials. The versatility and scalability of the synthesis are particularly interesting for the facile preparation of three-dimensional, binderless electrodes for alkaline water electrolysis applications. The urgency for efficient large-scale energy storage and conversion systems continues to rise as the implementation of intermittent renewable energy sources, such as wind and solar energy harvesting plants, continues to become more prevalent. To meet this demand, the electrolytic splitting of water is expected to play a key role due to its ability to produce clean, carbon emission-free hydrogen fuel at high pressure.1-3 Typically, the choice of highly active and stable electrocatalysts for use in acid-based polymer electrolyte water electrolysis (PEWE) is restricted to the noble metal oxides (i.e. IrO 2 /RuO 2 ), the scarcity and high cost of which will largely impede widespread commercialization. In the past decade, however, alkaline water electrolysis has regained considerable attention as the development of alkaline anion exchange membranes with improved ionic conductivity and stability continues to show significant progress.4-7 Alkaline water electrolysis operates on the basis of the anodic oxygen evolution reaction (OER: 4OH − → 2H 2 O + O 2 + 4e − ) and concurrent cathodic hydrogen evolution reaction (HER:The high pH environment associated with alkaline water electrolysis greatly expands the repertoire of OER catalyst candidate materials due to the heightened stability and relatively high activity of transition metal oxides in basic media. To date, Ni-based oxides have perhaps been the most promising OER catalysts for alkaline water electrolysis in terms of cost, stability, and activity, especially those containing Fe. [8][9][10][11] Ni-based oxides have been widely explored as OER electrocatalysts for use in alkaline water electrolysis throughout the years and even commercial systems currently utilize Ni-coated steel electrodes. 9More recently, the mixed metal hydroxides containing both Ni and Fe represent some of the most widely investigated catalysts due to the low OER overpotentials encountered in alkaline electrolytes and also at near-neutral pH conditions. 8,[11][12][13][14][15][16][17] To date, however, most electrodes for alkaline electrolysis are prepared as thin films on a two dimensional (2D) substrate using methods such as electrodeposition, dip-coating, or spin-coating. As a result, many research efforts have been directed at developing three-dimensional (3D) electrode structures that offer much higher electrocatalytical...