Superhydrophobic Nanocoatings Research Articles

Superhydrophobic Nanocoatings on Galvanized Steel and Aluminum: Enhancing Oil & Gas Sustainability

Superhydrophobic Nanocoatings on Galvanized Steel and Aluminum: Enhancing Oil & Gas Sustainability

Effects of nanocoatings on the temperature-dependent cell parameters and power generation of photovoltaic panels.

Operational requirements of photovoltaic (PV) modules result in their inherent exposure to harsh environmental conditions. The performance of solar cells decreases with increasing temperature, with both efficiency and power output getting affected. High ambient temperature coupled with irradiance absorption leads to an elevated photovoltaic cell operating temperature, adversely affecting the panels' lifespan. Superhydrophobic nanocoatings are the preferred solution to reduce the accumulation of dust (soiling) over the surface of the panels. This article aims to study the effects of nanocoatings on module operating temperature and temperature-dependent cell parameters, such as open-circuit voltage ({V}_{mathrm{oc}}), short-circuit current ({I}_{mathrm{sc}}) and power generation. The application of nanocoating over the surface of solar panels reduces the operating temperatures while improving power generation in a temperate location with high annual atmospheric temperatures.

Superhydrophobic Nanocoatings as Intervention against Biofilm-Associated Bacterial Infections.

Biofilm formation represents a significant cause of concern as it has been associated with increased morbidity and mortality, thereby imposing a huge burden on public healthcare system throughout the world. As biofilms are usually resistant to various conventional antimicrobial interventions, they may result in severe and persistent infections, which necessitates the development of novel therapeutic strategies to combat biofilm-based infections. Physicochemical modification of the biomaterials utilized in medical devices to mitigate initial microbial attachment has been proposed as a promising strategy in combating polymicrobial infections, as the adhesion of microorganisms is typically the first step for the formation of biofilms. For instance, superhydrophobic surfaces have been shown to possess substantial anti-biofilm properties attributed to the presence of nanostructures. In this article, we provide an insight into the mechanisms underlying biofilm formation and their composition, as well as the applications of nanomaterials as superhydrophobic nanocoatings for the development of novel anti-biofilm therapies.

Preparation of Poly styrene coated nano silica superhydrophobic coating and evaluation of stability for optical purposes

Super-hydrophobic nanocoatings are having enormous applications in various fields. In this paper, an attempt was made to prepare the adhesive transparent superhydrophobic coating for optical applications. Nano-silica based coatings were prepared by using tetraethoxyorthosilicate (TEOS) as a silica precursor. Hexamethyldisilazane (HMDS) and Polystyrene were used to make coatings superhydrophobic, transparent, and durable. To evaluate the coating properties, contact angle, and transparency were observed. A tape test was performed to determine coating stability. It was found that the HMDS is responsible for hydrophobicity and Poly-styrene is for adhesion. Poly-Styrene based coatings were more stable compared to only HMDS based coatings.

Research on the pollution performance and degradation of superhydrophobic nano-coatings for toughened glass insulators

Most of the research efforts to enhance the pollution performance of glass insulators have been focused on room temperature vulcanizing (RTV) silicone rubber coatings to cover the original hydrophilic surface of glass with a hydrophobic polymeric one. However, in recent years, advanced superhydrophobic nano-coatings, with intrinsic self-cleaning properties, have been developed as a possible alternative to silicone. This paper presents a research carried out in an outdoor test station, where one insulator string composed of nano-coated glass insulators was monitored for over two years and its performance compared with other identical insulator strings, but composed by RTV silicone-coated and non-coated glass insulators. The test station was located in a heavily polluted area of France and the insulator strings were energized at transmission voltage level to represent real operational conditions. The pollution performance and degradation were investigated through leakage current analyses and quarterly visual inspections of the superhydrophobic surface. The results showed that the superhydrophobic nano-coating was only effective when it was new and during a short period of time. Later on, it was subjected to a gradual degradation resulting in a loss of hydrophobicity until reaching a steady hydrophilic condition.

A facile strategy to form three-dimensional network structure for mechanically robust superhydrophobic nanocoatings with enhanced transmittance

The mechanically robust nanocoatings with high transmittance and superhydrophobic self-cleaning are widely desired in daily-life and industry. However, to the state-of-art, it is still a great challenge to develop a simple and cost-effective approach to construct a multifunctional nanocoating due to structural confliction and technical limitation. In this work, we successfully fabricated such a multifunctional nanocoating through dip-coating a mixed suspension composed of acid-catalyzed silica sol (ACSS) as binder and hydrophobic silica nanoparticles (HSNs) as building block onto the glass substrate without any post-treatments. The introduction of ACSS highly crosslinked the HSNs and formed three-dimensional network structure, which enhanced the adhesion between HSNs and substrate, and thus significantly improved mechanical robustness of the nanocoatings. Moreover, it also retained enough porosity and surface roughness, thus achieving high transmittance and superhydrophobicity. The optimized nanocoating deposited on the glass slide had high transmittance of 96.17% and superhydrophobic self-cleaning property. It also showed highly mechanical robustness (3H pencil scratching test), enhanced adhesion (class of 4B for tape adhesion test), weatherable, and acidic (pH 5.0)/alkaline (pH 10.0) and thermal (250 °C) stability. The multifunctional nanocoating with the comprehensive performance has great potentials in practical applications.

Tunable dendrimer-like porous silica nanospheres: Effects of structures and stacking manners on surface wettability

Similar to raspberry-like particles with dual-size roughness, dendrimer-like porous silica nanospheres (DPSNs) have great potentials to fabricate superhydrophobic nano-coatings due to facile and controllable synthesis, center-radial large pores and interconnected wrinkles on particle surface. However, there are very limited reports about the effects of structures and stacking manners of DPSNs on wettability up to date. In this work, various nano-coatings with different particle stacking manner (i.e., micro- and/or nano-roughness) are successfully constructed by using a series of DPSNs with tunable particle sizes and surface pore sizes as building blocks, based on paint- and dip-coating methods. For relatively flat surface and compact sphere stacking manner obtained by paint-coating, compared with solid silica nanospheres (SSNs)-coated glass slides, DPSNs-coated glass slides possess more nano-roughness to allow air pockets to exist center-radial porous channels, thus enhancing the hydrophobicity. Moreover, dip-coating makes higher surface submicro- and nano-roughness than paint-coating due to loose and locally aggregated stacking manner, thus achieving superhydrophobicity for both small and large DPSNs. In addition, owing to lower light scattering, small DPSNs are more suitable to prepare the coated slide glass with superhydrophobicity and enhanced transmittance. These interesting findings are significant to guide the design and synthesis of functional nano-coatings.

Superhydrophobic nanocoatings prepared by a novel vacuum cold spray process

A superhydrophobic TiO2-oleic acid (OA) nanocomposite coating was fabricated by a novel vacuum cold spray (VCS) process at room temperature. The content of OA immobilized on TiO2 nanoparticles could influence the deposition effect during the VCS process, in turn controlling the wettability of nanocoatings acquired. The wettability of the nanocoatings could be adjusted by altering the content of OA in the starting nanocomposite powder. The maximum static water contact angle and the minimum sliding angle were obtained at 151.2°and 1.2°, respectively, with the molar ratio of OA to TiO2 at 1:10. Additionally, it was observed that the newly constructed superhydrophobic coatings display mechanical durability. This study presents a promising approach for fabricating inorganic-organic nanocomposite superhydrophobic coatings for long-term functional applications.

Silica Based Superhydrophobic Nanocoatings for Natural Rubber Surfaces

Silica based nonfluorinated superhydrophobic coatings for natural rubber surfaces have been developed. The coating was synthesized using nanosilica dispersion and a polychloroprene type binder as a compatibilizer. This nanocoating of silica was applied on to the surface of finished natural rubber gloves, by spray coating or dipped coating methods. The nanocoating demonstrates a water contact angle of more than 150° and sliding angle of 7°. The morphological features of the coating have been studied using scanning electron microscopy and atomic force microscopy while Fourier transform infrared spectroscopy was used to understand the nature of surface functional groups. Both imaging techniques provided evidence for the presence of nanosized particles in the coating. Coated gloves demonstrated comparable mechanical properties and significantly better alcohol resistivity when compared to those of the uncoated gloves.

Superhydrophobic nanocoatings: from materials to fabrications and to applications.

Superhydrophobic nanocoatings, a combination of nanotechnology and superhydrophobic surfaces, have received extraordinary attention recently, focusing both on novel preparation strategies and on investigations of their unique properties. In the past few decades, inspired by the lotus leaf, the discovery of nano- and micro-hierarchical structures has brought about great change in the superhydrophobic nanocoatings field. In this paper we review the contributions to this field reported in recent literature, mainly including materials, fabrication and applications. In order to facilitate comparison, materials are divided into 3 categories as follows: inorganic materials, organic materials, and inorganic-organic materials. Each kind of materials has itself merits and demerits, as well as fabrication techniques. The process of each technique is illustrated simply through a few classical examples. There is, to some extent, an association between various fabrication techniques, but many are different. So, it is important to choose appropriate preparation strategies, according to conditions and purposes. The peculiar properties of superhydrophobic nanocoatings, such as self-cleaning, anti-bacteria, anti-icing, corrosion resistance and so on, are the most dramatic. Not only do we introduce application examples, but also try to briefly discuss the principle behind the phenomenon. Finally, some challenges and potential promising breakthroughs in this field are also succinctly highlighted.

Stable superhydrophobic coatings from thiol-ligand nanocrystals and their application in oil/water separation

Stable superhydrophobic coatings were successfully achieved from thiol-ligand nanocrystals. Nanocrystals included VIII and IB metals and oxide nanoparticles, such as Fe, Co, Ni, Cu and Ag. We present a simple and available method that facilitates the synthesis of superhydrophobic textiles and sponges, in which the interaction between the nanocrystals and thiol plays a significant role in the formation of a special wetting surface. Meanwhile, the superhydrophobic textiles could also be endowed with new functionalities. For example, textiles with Fe3O4 nanocoatings possess magnetic properties, and Ag nanocrystals provide an antibacterial effect. If perfluoroalkyl thiol was used to replace alkyl thiol, the as-modified surfaces became oleophobic from superoleophilic. The proposed strategy was fit for various nanoparticles from as-established methods, including the preparation in different polar solvents, and the usage of surfactants as capping agents. As-prepared superhydrophobic nanocoatings show good durability towards hot water, surfactant aqueous solutions, and ultrasonic treatment in nonpolar solvents. The superhydrophobic and superoleophilic nanocoatings were effectively used for application in oil/water separation.