An environmentally friendly fluorine-free sandwich coating based on a nonwoven fabric for efficient unidirectional water transport

Designing a superhydrophobic cotton fiber coating exploiting TiO2@g-C3N4 layered structure for augmented photocatalysis and efficient water-oil separation

This study introduces a novel approach to develop a multifunctional coating on cotton fabric, emphasizing the utilization of cotton fiber as a biological macromolecule, by integrating a TiO2@g-C3N4 layered structure to confer superhydrophobic properties and multiple functionalities. The engineered structure not only enhances fabric roughness but also incorporates non-fluoro hydrophobic agents, thereby imparting diverse capabilities such as photocatalysis, oil-water separation, and self-cleaning to the cotton substrate. Fabrication of the TiO2@g-C3N4 layered structure involved ultrasonic dispersion of TiO2 and g-C3N4, subsequently deposited onto cotton fabric. Sequential hydrophobic treatment with polydimethylsiloxane (PDMS) and isophorone diisocyanate (IPDI) achieved superhydrophobicity, exhibiting an exceptional water contact angle (WCA) of 157.9°. Comprehensive characterization via scanning electron microscopy (SEM), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric validated the composite's structural and chemical properties. The introduced TiO2@g-C3N4 structure significantly enhanced fabric roughness, while PDMS treatment lowered surface energy and IPDI hydrolysis facilitated cross-linking, ensuring durability. The resultant TiO2@g-C3N4/PDMS cotton exhibited outstanding self-cleaning properties and demonstrated oil adsorption capacity, accommodating both heavy and light oils. Notably, this superhydrophobic cotton efficiently separated water-oil mixtures, achieving 96.8 % efficiency even after 10 cycles. Moreover, under simulated light, it displayed outstanding photocatalytic degradation (93.2 %) of methylene blue while maintaining a WCA of 150° post-degradation, highlighting sustained functionality. This innovation holds promise for sustainable applications, offering robust physical and chemical durability within the realm of biological macromolecules. The amalgamation of TiO2@g-C3N4 layered structure and PDMS treatment on cotton fabric underscores a sustainable approach to address water-oil separation challenges and enable efficient self-cleaning. This research demonstrates a significant step towards sustainable material applications and addresses pertinent real-world challenges in diverse technological domains.

Bioinspired Green Fabricating Design of Multidimensional Surfaces for Atmospheric Water Harvesting

Across the globe, the quest for clean water is escalating for both households as well as agricultural exigencies. With the industrial revolution and swift population growth, the contamination of natural water bodies has impacted the lives of more than two billion people around the world. A spectrum of water-saving solutions has been examined. Nonetheless, most of them are either energy-inefficient or limited to only a particular region. Thus, the pursuit of clean and potable drinking water is an assignment that invites collective discourse from scientists, policymakers, and innovators. In this connection, the presence of moisture in the atmosphere is considered one of the major sources of potential freshwater. Thus, fishing in atmospheric water is a mammoth opportunity. Atmospheric water harvesting (AWH) by some plants and animals in nature (particularly in deserts or arid regions) at low humidity serves as an inspiration for crafting state-of-the-art water harvesting structures and surfaces to buffer the menace of acute water scarcity. Though a lot of research articles and reviews have been reported on bioinspired structures with applications in water and energy harvesting, the area is still open for significant improvisation. This work will address the multidimensional-based AWH ability of natural surfaces or fabricated structures without the involvement of toxic chemicals. Moreover, the review will discuss the availability of clean technologies for emulating fascinating natural surfaces on an industrial scale. In the end, the current challenges and the future scope of bioinspired water harvesters will be discussed for pushing greener technologies to confront climate change.