Non-fluorine surface modification of acetylated birch for improved water repellence

In this work, a non-fluorinated surface treatment, i.e., hydrophobized silicone nanofilaments, was applied on both birch and acetylated birch wood samples via a gas-phase based reaction. A superhydrophobic behavior was observed on both the surface-modified samples as revealed by the static water contact angles (CAs) greater than 160°, also valid for samples prepared with the shortest reaction time of 1 h. The dynamic wettability behavior of the samples was studied by a multicycle Wilhelmy plate method. The surface-modified acetylated birch exhibited a pronounced enhanced water resistance, resulting in very low water uptake of 3 ± 1 wt% after 100 cycles, which was not only about 29 and 5 times lower than that of the non-surface-modified birch and acetylated birch, respectively, but also three times lower than that of the surface-modified birch. Moreover, the aesthetic appearance of the acetylated wood was maintained as the surface modification only resulted in a small color change. This work shows the potential of preparing super water-repellent wood by non-fluorinated surface modification.

Tight bonding and high-efficiency utilization of S–S moieties to enable ultra-stable and high-capacity alkali-metal conversion batteries

The dual active-phase (FeS2@S) cathode with fluorinated surface and cross-linked carbon network enables the preservation and rational distribution of sulfur molecule interlayer sandwiched between FeS2 core and in situ derivative carbon shell.

Direct Fluorination as Method of Improvement of Operational Properties of Polymeric Materials

Direct fluorination of polymers is a widely utilized technique for chemical modification. Such introduction of fluorine into the chemical structure of polymeric materials leads to laminates with highly fluorinated surface layer. The physicochemical properties of this layer are similar to those of perfluorinated polymers that differ by a unique combination of chemical resistance, weak adhesion, low cohesion, and permittivity, often barrier properties, etc. Surface modification by elemental fluorine allows one to avoid laborious synthesis of perfluoropolymers and impart such properties to industrial polymeric materials. The current review is devoted to a detailed consideration of wetting by water, energy characteristics of surfaces, adhesion, mechanical and electrical properties of the polymers, and composites after the direct fluorination.