Covalent organic frameworks (COFs) are an emergent class of crystalline porous polymers featuring a long-range regular pore structure, high porosity and excellent chemical stability. Bilayer COF membranes with tunable interfaces hold great promise in ionic and molecular separations. Herein, we designed a series of bilayer COF membranes with homointerface and heterointerface, which achieved efficient desalination performance through manipulating the interface confinement effect. COF membranes were prepared on a porous support through successively regulating the growth of imine-based 2D COF layers by in situ growth and counter-diffusion approach at ambient temperature. Narrowed sub-nanometer interlaced channels were created at the interface of the two adjacent COF layers. The rejection rate of homointerface COF membrane toward Na₂SO₄ was higher than that of heterointerface COF membranes, which was due to the synergistic enhancement of interface-confined size sieving and Donnan effect. The homointerface TpPa–SO₃H/TpPa–SO₃H/MPAN membrane exhibits a rejection rate of 98.3% for Na₂SO₄ and water flux of 13.1 L m⁻² h⁻¹ bar⁻¹, which is the highest performance among COF desalination membranes ever reported.

Some drawbacks such as lack of durability, requirement for high-cost fluorosilane modification, and complicated fabrication processes have limited the practical applications of superhydrophobic coatings for several years. In this work, we provide a novel method to fabricate a robust superhydrophobic coating without pre-modification by pressing ZnSn(OH)₆ (ZHS) particles into polydimethylsiloxane (PDMS) solution, and then curing. PDMS used in this work is not only a low surface energy material, but also an adhesive to enhance the bonding force between particles and substrates. The PDMS@ZHS coating (ZHS particles coated on PDMS) is also superhydrophobic when it is immersed into dodecane, and shows excellent self-cleaning in air and oil environments. After undergoing serious chemical corrosion and mechanical abrasion, the superhydrophobicity of the coating remained well. For different kinds of substrates, this coating can be covered and repels water as well. Owing to the excellent flame-retardancy of ZHS particles, PDMS@ZHS coated paper displays excellent flame retardancy in limiting oxygen index (LOI), vertical flame, and cone calorimeter tests. We believe that this simple, environmentally friendly, and versatile fabrication of the PDMS@ZHS coating has excellent real-life applications.

Superwetting has pronounced influences on membrane permeability, selectivity, and stability in diverse separation processes.

Reports about polyethylene terephthalate (PET) fabrics with durable superhydrophobicity and flame retardance are very limited. In this paper, durable superhydrophobic, photocatalytic, flame-retardant (FR) PET fabrics were fabricated for the first time by a green approach and further employed for various applications. Through layer-by-layer (LBL) alternate deposition of mixed polyelectrolytes, including branched poly(ethylenimine) (BPEI), phytic acid (PA), and ammonium polyphosphate (APP), the fabric obtained superior self-quenched flame retardance through deposition of only two bilayers (BL). The fire burned very slowly, and was self-extinguished after ignition for 8 s. The fabric was also anti-dripping. When the FR fabric was further coated with a layer of PDMS-grafted-TiO₂@PDMS coating, it presented excellent superhydrophobicity and self-cleaning properties both under air and water conditions. Moreover, the final fabric showed durable superhydrophobicity, which presented resistance to repeated rinsing treatments, repeated peeling by adhesive tape, and cyclic abrasion treatments. This fabric also showed superior photocatalysis capability and photocatalytically stable superhydrophobicity. The finally coated fabrics could selectively and highly efficiently remove polluted oils from water and separate oil–water mixtures. This multifunctional fabric is believed to show very promising application potential in the flame retardance, superhydrophobicity, self-cleaning, water purification, liquid separation, and photocatalysis fields.