Aramid nanofiber (ANF)-coated separators were successfully prepared by the dip-coating of a cationized polypropylene (PP) porous separator in an ANF dispersion in DMSO. The ANFs were successfully coated onto the surface of the cationized PP separator as demonstrated by FT-IR and XPS measurements and the ANFs could be directly observed on the surface of the composite separator via SEM and AFM. The ANF-based coating layers became more uniform and denser as more dip-coating cycles were employed. The gas permeabilities of the separators were strongly influenced by the concentrations of the ANF dispersion and the number of dip-coating cycles. The porosity decreased and a narrower pore size distribution was obtained after the ANFs were coated onto the cationized PP separator. The ANF-coated separators were found to exhibit higher dimensional stabilities than the pristine PP separator. The separators exhibited almost identical endothermic peaks in the DSC experiment and a similar shrink temperature in the DMA experiment but the ANF-coated separator exhibited a higher rupture temperature. The ANF-coated separator retained a comparable mechanical strength with that of the pristine PP separator. The ANF coating layer was mechanically stable and durable in the electrolyte. The ANF-coated separator exhibited comparable C-rate performance and cycling performance in LMO/Li cell systems to that of the PDA–PP separator, and showed significantly better C-rate performance and cycling performance than that of the pristine PP separator. The ANF-coated PP separators exhibited improved safety in a hot oven test in comparison with the pristine PP separator. Thus the ANF-coated separators have great potential for use in lithium ion batteries.

We report here a simple and reproducible strategy for fabricating highly durable and robust superhydrophobic cotton fabrics (SCFs) from a series of functional diblock copolymers. These diblock copolymers consisted of both poly(glycidyl methacrylate) (PGMA) and poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) blocks that were synthesized via sequential atom transfer radical polymerization (ATRP). While the PTFEMA block provides the low surface free energy, the PGMA block serves as an anchor and forms covalent bonds with the surfaces of cotton fibers. These covalent bonds are formed via the epoxy ring-opening reaction between the epoxy groups of the PGMA block and the hydroxyl groups on the surface of the cotton fiber, and self-crosslinking of epoxy groups from PGMA chains. Structures exhibiting nano- and microscale roughness were created in one-step by combining copolymer-based nanobumps onto surfaces of micro-sized fibers of the cotton fabric, as confirmed by SEM and AFM analysis. The modified cotton fabrics show excellent water repellency with water contact angles (WCAs) of ∼163° and water sliding angles (WSAs) of ∼3° under optimized conditions. Since the low-fluorinated PTFEMA chains are chemically bound to the cotton fibers, the SCFs possess long-term stability, ultra-high durability and robustness. In particular, these SCFs withstood mechanical abrasion by sandpaper, strong laundering conditions, ultrasonication treatment in tetrahydrofuran (THF) or trifluorotoluene (TFT), soaking in a wide range of organic solvents, as well as acidic and basic aqueous solutions, exposure to UV-irradiation and even refluxing in TFT or THF.

Random bi-functional copolymers bearing fluorinated units and sol–gel forming units were prepared and used together with silica particles in a one-pot process for preparing superamphiphobic coatings. The copolymers P(FOEA-r-IPSMA) were prepared by atom transfer radical polymerization (ATRP) of 2-(perfluorooctyl)ethyl acrylate (FOEA) and 3-(triisopropyloxy)silylpropyl methacrylate (IPSMA). The uniform silica particles were prepared using a modified Stöber process. Stirring P(FOEA-r-IPSMA), silica, water, and HCl together with substrates triggered the sol–gel reactions of the IPSMA units. These involved first the hydrolysis of IPSMA to yield silanol groups and then the condensation of the IPSMA silanol groups among themselves, and with silanol groups on silica or glass surfaces or with hydroxyl groups on cotton or filter paper. At optimized mass ratios of P(FOEA-r-IPSMA) to silica, the resultant coatings consisted of lightly covered silica particles that were embedded in a crosslinked P(FOEA-r-IPSMA) film. By optimizing the molar ratio between FOEA and IPSMA in P(FOEA-r-IPSMA), the rough particulate coatings on cotton, filter paper, and glass plates exhibited superamphiphobicity. More importantly, the particulate coatings were resistant to solvent extraction and NaOH etching.