A transparent superhydrophobic coating with mechanochemical robustness for anti-icing, photocatalysis and self-cleaning

A review on fundamentals, constraints and fabrication techniques of superhydrophobic coatings

Incidents of viral outbreaks have increased at an alarming rate over the past decades. The most recent human coronavirus known as COVID-19 (SARS-CoV-2) has already spread around the world and shown R0 values from 2.2 to 2.68. However, the ratio between mortality and number of infections seems to be lower in this case in comparison to other human coronaviruses (such as severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV)). These outbreaks have tested the limits of healthcare systems and have posed serious questions about management using conventional therapies and diagnostic tools. In this regard, the use of nanotechnology offers new opportunities for the development of novel strategies in terms of prevention, diagnosis and treatment of COVID-19 and other viral infections. In this review, we discuss the use of nanotechnology for COVID-19 virus management by the development of nano-based materials, such as disinfectants, personal protective equipment, diagnostic systems and nanocarrier systems, for treatments and vaccine development, as well as the challenges and drawbacks that need addressing.

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How can nanotechnology help to combat COVID-19? Opportunities and urgent need.

Wax-based artificial superhydrophobic surfaces and coatings

Nanofibers have attracted extensive attention and been applied in various fields due to their high aspect ratio, high specific surface area, flexibility, structural abundance, etc. The electrospinning method is one of the most promising and effective ways to produce nanofibers. The electrospun nanofibers-based films and membranes have already been demonstrated to possess small pore sizes, larges specific surface area, and can be grafted with different functionalities to adapt to various purposes. The environmental applications of nanofibers are one of the essential application fields, and great achievements have been made in this field. To well summarize the development of nanofibers and their environmental applications, we review the nanofiber fabrication methods, advanced fiber structures, and their applications in the field of air filtration, heavy metal removal, and self-cleaning surface. We hope this review and summary can provide readers a comprehensive understanding of the structural design and environmental applications of electrospun nanofibers.

Structural design and environmental applications of electrospun nanofibers.

Recent Advances in durability of superhydrophobic self-cleaning technology: A critical review

Nanocrystalline ferrite samples with composition NixZn1−xFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared by oxalate co-precipitation method. Thick film of ferrites was prepared by screen printing techniques on glass substrates. The ferrite samples were characterized by X-ray diffraction (XRD), thermo gravimetric and differential thermal analysis (TG–DTA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy and field emission scanning electron microscopy techniques. The TG–DTA and XRD confirms the formation of ferrite phase and cubic spinel structure. FT-IR spectra show two major absorption bands near 400 and 600 cm−1 corresponding to tetrahedral and octahedral sites respectively. The structural parameters like lattice constant, crystallite size, ionic radii, ionic bond lengths and force constants of ferrite powders were calculated. The grain size of the ferrite thick films was lies in the range 30–65 nm. Gas sensing properties of ZnFe2O4, NiFe2O4 and Ni0.6Zn0.4Fe2O4 thick films was studied for liquid petroleum gas (LPG), ethanol (C2H5OH) and chlorine (Cl2). Zinc ferrite thick film shows high sensitivity (82 %), good response (30 s) and recovery time (90 s) for ethanol as compared to LPG and Cl2. Nickel ferrite thick film shows good sensitivity (63 %), better response (30 s) and recovery time (70 s) for LPG. Ni0.6Zn0.4Fe2O4 is more sensitive for Cl2 followed by ethanol as compare to LPG. Among nickel, zinc and Ni0.6Zn0.4Fe2O4 thick films, zinc ferrite thick film is more sensitive for LPG, C2H5OH and Cl2.

Ni–Zn ferrite thick film gas sensors

Ferrites have emerged out as excellent material for a broad spectrum of applications. Thick films of these materials have great demand for energy and advanced electronics. This review highlights a brief overview of the spinel-type of ferrite thick films (S-FTFs) development right from their historical developments, preparation strategies and state of art applications. The fabrication of S-FTFs includes the discussion on screen-printing, doctor blade tape casting, plasma spray, and spin coating. The comparative analysis of the screen printing technique to the other methods is provided to assist the scientific community during the process of choosing the most suitable fabrication technique. The influence of the synthesis parameters such as temperatures (pre-sintering and final sintering), binders (organic and inorganic), sizes (crystallite, grain, and particle), substrate material and the final heat treatment process in S-FTFs, and the preparation of the ferrite powders and their fabrication technique are review and summarized. Moreover, this review provides a brief overview of the S-FTFs applications, which are classified into four broad categories: sensors, microwave, magnetic and advanced applications. This classification provides a deeper insight into the potential of the S-FTF applications. The motivation in materializing the review of S-FTFs technology is to inspire aspiring research candidates and boost their research interest in this particular field.

A review of spinel-type of ferrite thick film technology: fabrication and application

Cadmium ferrite was prepared by standard ceramic method and characterized by XRD, IR and SEM techniques. The X-ray analysis confirms the formation of single phase cubic spinel structure. The lattice constant decreases slightly and porosity increases with increase in sintering temperature. The crystallite size of the samples lies in the range of 22.83 to 24.44 nm. The IR study shows two absorption bands around 400 cm -1 and 600 cm -1 corresponding to octahedral and tetrahedral sites respectively. The grain size increases and switching field decreases with increases in sintering temperature. Copyright © 2013 VBRI press.

Effect Of Sintering Temperature On Structural And Electrical Switching Properties Of Cadmium Ferrite

Ferrite samples with composition, Cd
 $_{\emph{x}}$
 Co
 $_{1-\emph{x}}$
 Fe2O4 (x = 0·80, 0·85, 0·90, 0·95 and 1·0), were prepared by standard ceramic method and characterized by XRD, IR and SEM techniques. X-ray analysis confirms the formation of single phase cubic spinel structure. Lattice constant and grain size of the samples increase with increase in cadmium content. Bond length (A–O) and ionic radii (
 ${\emph{r}}_{\rm {A}})$
 on A-sites increase, whereas bond length (B–O) and ionic radii (
 ${\emph{r}}_{\rm{B}})$
 on B-site decrease. The crystallite sites of the samples lie in the range of 29·1–42·8 nm. IR study shows two absorption bands around 400 cm − 1 and 600 cm − 1 corresponding to tetrahedral and octahedral sites, respectively.

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S. P. Dalawai

Papers

Recent Advances in durability of superhydrophobic self-cleaning technology: A critical review

Ni–Zn ferrite thick film gas sensors

A review of spinel-type of ferrite thick film technology: fabrication and application

Effect Of Sintering Temperature On Structural And Electrical Switching Properties Of Cadmium Ferrite

Structural properties of Cd–Co ferrites