Stable and Durable Superhydrophobic Cotton Fabrics Prepared via a Simple 1,4-Conjugate Addition Reaction for Ultrahigh Efficient Oil-Water Separation.

Superhydrophobic materials used for oil-water separation have received wide attention. However, the simple and low-cost strategy for making durable superhydrophobic materials remains a major challenge. Here, this work reports that stable and durable superhydrophobic cotton fabrics can be prepared using a simple two-step impregnation process. Silica nanoparticles are surface modified by hydrolysis condensation of 3-aminopropyltrimethoxysilane (APTMS). 1,4-conjugate addition reaction between the acrylic group of cross-linking agent pentaerythritol triacrylate (PETA) and the amino group of octadecylamine (ODA) forms a covalent cross-linked rough network structure. The long hydrophobic chain of ODA makes the cotton fabric exhibit excellent superhydrophobic properties, and the water contact angle (WCA) of the fabric surface reaches 158°. The modified cotton fabric has good physical and chemical stability, self-cleaning, and anti-fouling. At the same time, the modified fabric shows excellent oil/water separation efficiency (98.16% after 20 cycles) and ultrahigh separation flux (15413.63 L m-2 h-1) due to its superhydrophobicity, superoleophilicity, and inherent porous structure. The method provides a broad prospect in the future diversification applications of oil/water separation and oil spill cleaning.

Hydrophobic Mn-Doped Solid-State Red-Emitting Carbon Nanodots with AIE Effect and Their Hydrogel Composites for Color-Changing Anticounterfeiting.

The aggregation-caused quenching has always limited the high concentration and solid-state applications of carbon nanodots. While the aggregation-induced emission effect, dominated by intramolecular motion, may be an effective means to solve this problem. Here, hydrophobic solid-state red-light carbon nanodots (M-CDs) with 95% yield are synthesized by a one-step hydrothermal method using 2,2'-dithiodibenzoic acid as the carbon source and manganese acetate as the dopant source. The disulfide bond of 2,2'-dithiodibenzoic acid serves as the symmetry center of molecular rotation and Mn catalyzes the synthesis of M-CDs, which promotes the formation of the central graphitic carbon structure. The M-CDs/agar hydrogel composites can achieve fluorescence transition behavior because of the special fluorescence transition properties of M-CDs. When this composite hydrogel is placed in water, water molecules contact with M-CDs through the network structure of the hydrogels, making the aggregated hydrogels of M-CDs fluorescence orange-red under 365 nm excitation. While in dimethyl sulfoxide, water molecules in the hydrogels network are replaced and the M-CDs fluoresce blue when dispersed, providing a potential application in information encryption. In addition, high-performance monochromatic light-emitting diode (LED) devices are prepared by compounding M-CDs with epoxy resin and coating them on 365 nm LED chips.

Photothermal Superhydrophobic Cotton Fabric Based on Silver Nanoparticles Cross-Linked by Polydopamine and Polyethylenimide.

Photothermal materials that can convert solar energy into heat energy through photothermal conversion have attracted extensive attention, but these materials are easily polluted by the environment. Here, we propose a simple and effective strategy for constructing photothermal superhydrophobic cotton fabrics with self-cleaning ability. The PDA@PEI@GA@Ag@PDMS-coated cotton fabric can achieve good superhydrophobicity (water contact angle: 159.6°) by a simple dipping method and mussel-inspired dopamine surface modification, which is regulated by the mass of dopamine, the mass of silver nitrate, and the concentration of polydimethylsiloxane (PDMS). The coated cotton fabric has good physical and chemical stability. Meanwhile, the coated cotton fabric has excellent self-cleaning and antifouling properties. The superhydrophobic PDA@PEI@GA@Ag@PDMS fabric exhibits excellent and stable photothermal properties, with the surface temperature reaching 70.4 °C under simulated sunlight with a current of 20 A. This photothermal superhydrophobic fabric with self-cleaning properties is expected to be applied in the field of photothermal conversion.