Recovery of the compromised antifouling property because of perturbation in the essential chemistry on top of the hierarchical topography of a superhydrophobic coating is commonly achieved through some stimuli (temperature, humidity, pH, etc.)-driven reassociation of the low surface energy molecules. However, self-healing of superhydrophobicity in physically damaged materials having inappropriate topography is difficult to achieveand extremely important for the practical utility of this bioinspired property. Recently, very few materials have been introducedthat are capable of recovering the hierarchical featuresbut only after the application of appropriate external stimuli. Further, the optimization of appropriate stimuli is likely to be a challenging problem in practical scenarios. Here, we have strategically exploited a simple and robust 1,4-conjugate addition reaction between aliphatic primary amine and aliphatic acrylate groups for appropriate and covalent integration of a modified-graphene oxide nanosheetwhich is well recognized for its exceptional mechanical properties. The synthesized material exhibited a remarkable ability to protect the antifouling property from various harsh physical insults, including physical erosion of the top surface of the polymeric coating and various physical manipulations etc. However, after application of pressure on the same polymeric coating, the bioinspired, nonadhesive (contact angle hysteresis <5°) superhydrophobicity was compromised, and the physically damaged polymeric coating became highly adhesive (contact angle hysteresis ∼50°) and superhydrophobic. But, after releasing the pressure, the native nonadhesive (contact angle hysteresis <5°) extreme wettability was self-restored in the polymeric coating through recovery of the essential hierarchical topographywithout requiring any external stimulus. This unique material, having impeccable durability and absolute self-healing capability, was further explored in (i) developing rewritable aqueous patterns on the extremely water-repellent surface and (ii) selective impregnation of water-soluble agents on the surface of polymeric coatingwithout any permanent change in the extreme water repellency property. The unique self-healing process eventually provided a superhydrophobic printthat was made out of hydrophilic small molecules. This printing was performed directly from an aqueous medium, which is extremely hard to achieve using the conventional superhydrophobic materials. Such multifunctional interfaces could be an important avenue for various smart applications, including delivery of hydrophilic small molecules, catalysis, self-assembly of colloids, reusable chemical sensing, etc.
Stretchable and nature inspired multilayers are developed through covalent and layer-by-layer integration of functional nanomaterials. These nanomaterials are amino graphene oxide and a chemically reactive polymeric nanocomplex, and the synthesized material is capable of sustaining various forms of severe physical damage and large tensile deformations simultaneously.
Bilayer membranes that can morph in a controlled manner were prepared by restacking exfoliated layers of clay and graphene oxide (GO) from their respective aqueous dispersions.
The electrokinetic streaming potential derived from the natural evaporation process through nanoscale capillary channels is gaining increasing attention for its potential to be a self-sufficient and maintenance-free energy resource. An evaporation-induced energy-harvesting device displaying energy density up to 40 mWm–2 was fabricated by exploiting atomically thin two-dimensional (2D) nanofluidic channels of a reconstructed V2O5 membrane. Systematic studies were also performed to uncover the effects of internal device parameters, like channel dimensions, membrane thickness, and electrode separation, and external environmental conditions such as relative humidity and atmospheric temperature on energy efficiency. Most importantly, physical damages to the V2O5 device can be healed just by adding a drop of water. The evaporation-induced nanogenerators can be connected to add up the voltage and current values generated by individual devices. Besides, two methods are proposed here to overcome practical hurdles associated with these kinds of devices. In the first method, secondary materials (like cloth and paper) are employed to draw water molecules from the reservoir and transfer it to surface-active nanofluidic channels. In the second method, a hydrophilic gel membrane of agar, LiCl, and glycerol is used to mimic the natural hydrological cycle for continuous power output even in low humid conditions.
Efficient harvesting of electrokinetic-streaming-potential requires a trade-off between high flow-rate and nanofluidic confinement. To attain the best out of these parameters, we have developed a periodic network of tetrahedral and octahedral voids interconnected through fine biconical nanofluidic channels by close-packing nearly monodisperse silica spheres of diameters 285, 620, 1000, 1750, and 2900 nm. The interstices of closepacked silica spheres (diameter 285 to 1750 nm) simultaneously exhibit surface-charge-governed ionic conductivity and fast flow of water. The power density harvested from streaming water was found to be increasing with increased diameter of the close-packed spheres up to 1750 nm (151 mWm −2 ), and to be decreasing with further rise in the sphere diameter. The power density was found to be dependent on the mass loading of the silica spheres, contact area of the electrodes, and pH of the streaming water. Pretreatment of the silica spheres with concentrated nitric acid further enhanced the efficiency of the energy harvesting through streaming potential. Harvesting of streaming potential from packed silica spheres was found to be a convenient way of obtaining energy from water flowing through the household water taps, as they can be connected in a series to add up energy generated in multiple devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.