Protection of Urban Art Painting: A Laboratory Study

Urban art is a form of artistic visual expression and communication that is created in the street and generally in the public dimension of urban spaces. Often these kinds of artworks are in outdoor environments, and they usually suffer from atmospheric weathering and anthropic vandalism. Recently, several strategies have been used to limit or remove the effects of such vandalism. Currently, the use of quartz paints is growing among artists; such paints after setting are more porous and rough on the surface with respect to regular paints. The aim of the study is to assess the performance of anti-graffiti coatings on quartz artworks paints. Two anti-graffiti products were chosen, and their behaviors were assessed in the laboratory by means of contact angle measurement, water capillary test, colorimetric analysis, and optical and electron microscopy. Results showed good water repellence efficacy of the tested products, demonstrating that they are suitable for the protection of urban art, but at least two applications on the surface are needed to achieve good performance.

Evaluation of the Durability of Slippery, Liquid-Infused Porous Surfaces in Different Aggressive Environments: Influence of the Chemical-Physical Properties of Lubricants

Liquid-repellent surfaces have been extensively investigated due to their potential application in several fields. Superhydrophobic surfaces achieve outstanding water repellence, however their limited durability in severe operational conditions hinders their large-scale application. The Slippery, Liquid-Infused Porous Surface (SLIPS) approach solves many of the durability problems shown by superhydrophobic surfaces due to the presence of an infused liquid layer. Moreover, SLIPS show enhanced repellence towards low surface tension liquids that superhydrophobic surfaces cannot repel. In this perspective, SLIPS assume significant potential for application in harsh environments; however, a systematic evaluation of their durability in different conditions is still lacking in the literature. In this work, we report the fabrication of SLIPS based on a ceramic porous layer infused with different lubricants, namely perfluoropolyethers with variable viscosity and n-hexadecane; we investigate the durability of these surfaces by monitoring the evolution of their wetting behavior after exposure to severe environmental conditions like UV irradiation, chemically aggressive solutions (acidic, alkaline, and saline), and abrasion. Chemical composition and viscosity of the infused liquids prove decisive in determining SLIPS durability; especially highly viscous infused liquids deliver enhanced resistance to abrasion stress and chemical attack, making them candidates for applicable, long-lasting liquid-repellent surfaces.

Laser fabrication of modular superhydrophobic chips for reconfigurable assembly and self-propelled droplet manipulation

Natural creatures that enables controllable liquid transport provides the inspiration for developing novel microfluidic devices by engineering functional surfaces with superwettability. However, towards microfluidic applications, the strict requirements of sophisticated droplet manipulation make it challenging to reach this end. In this work, we report a conceptually new self-propelled droplet manipulation strategy based on reconfigurable superhydrophobic chips. The modular droplet chip (MDC) is developed by laser embossing a series of superhydrophobic structures on elastomer jigsaws that act as functional units. MDC is potable since only gravity is used as the driving force for dynamic manipulation of liquid droplets, including droplets transporting, splitting, merging and bouncing without mass loss. The MDC demonstrated reasonable anti-cross-contamination property due to the water repellence of the superhydrophobicity. Modular assembly of MDC enables different chip functions including solution dilution, SERS detection, cell labeling and chemical synthesis. As a miniature and portable experimental platform, the MDC is promising for next-generation lab-on-a-chip systems.

Fluorine-free superhydrophobic characterized coatings: A mini review

The scientific fraternity and coating companies have researched and developed coatings with superhydrophobic features for a wide range of applications, varying from automotive, oceanic, pharmaceutical, and thermal and power sectors, over the preceding few years. The self-cleaning features of superhydrophobic surfaces exhibit pronounced dust repelling and lower dust adhesiveness qualities, along with incomparable water repellence for maritime, automotive, and pharmaceutical applications. The advancement of super-hydrophobic surfaces for averting the accrual of impurities on surfaces is an active space of exploration globally. A lesser hysteresis of contact angle leads to drops of water sliding effortlessly on such surfaces. The solid surfaces’ surface energy can be weakened by fixing materials of lesser surface energy on the exterior, which can be performed by the following dual methods; either by fixing materials of reduced surface energy straight onto the exterior of a substrate in the form of a coating of that material, or by fixing materials of less surface energy on the exterior of nano-architectural structures and then dropping the coating of those nanoscale materials on the exterior of the substrate. The generation of nanoscale irregularities on substrates by dropping nanostructure layers on surfaces makes it an attractive option since, usually, nanomaterials have a minimum of one dimension, ranging from 1 - 100 nm. The nanostructures’ sizes unveil exceptional physical and chemical characteristics, principally owing to their greater specific surface area to volume quotient. This review encompasses the non-fluorinated superhydrophobic coatings developed to date.

The use of nanoparticles to enhance Performance in the Textile Industry – A Concise Review

: Nanotechnology in the textile industry has gained popularity in the commercial market over the years. It involves utilizing the characteristic properties of nanomaterials to improve the functionality of the textile. The present article focuses on different types of nano moieties, their properties (such as water repellence, self-cleaning, UV-protection, anti-microbial and flame retardancy), and their applications in various sectors. We also discuss smart textiles, operating mechanisms, and their economic importance. We conclude that the successful application of nanotechnology in the textile industry lies in producing sustainable and multifunctional fabrics to meet the increasing customer demand.

Dodecyl Mercaptan Functionalized Copper Mesh for Water Repellence and Oil-water Separation

Reckless discharge of industrial wastewater and domestic sewage as well as frequent leakage of crude oil have caused serious environmental problems and posed severe threat to human survival. Various nature inspired superhy-drophobic surfaces have been successfully applied in oily water remediation. However, further improvements are still urgently needed for practical application in terms of facile synthesis process and long-term durability towards harsh environment. Herein, we propose a simple one-step dodecyl mercaptan functionalization method to fabricate Super-hydrophobic-Superoleophilic Copper Mesh (SSCM). The prepared SSCM possesses excellent water repellence and oil affinity, enabling it to successfully separate various oil-water mixtures with high separation efficiency (e.g., > 99% for hexadecane-water mixture). The SSCM retains high separating ability when hot water and strong corrosive aqueous solutions are used to simulate oil-water mixtures, indicating remarkable chemical durability of the dodecyl mercaptan functionalized copper mesh. Additionally, the efficiency can be well maintained during 50 cycles of separation, and the water repellence is even stable after storage in air for 120 days, demonstrating the reusability and long-term stability of the SSCM. Furthermore, the functionalized mesh also shows good mechanical robustness towards abrasion by sandpaper, and oil-water separation efficiency of > 96% can be obtained after 10 cycles of abrasion. The reported one-step dodecyl mercaptan functionalization could be a simple method for increasing the water repellence of copper mesh, and thereby be a great candidate for treating large-scale oily wastewater in harsh environments.

Characterization of PVDF/Graphene Nanocomposite Membranes for Water Desalination with Enhanced Antifungal Activity

Seawater desalination is a worldwide concern for the sustainable production of drinking water. In this regard, membrane distillation (MD) has shown the potential for effective brine treatment. However, the lack of appropriate MD membranes limits its industrial expansion since they experience fouling and wetting issues. Therefore, hydrophobic membranes are promising candidates to successfully deal with such phenomena that are typical for commercially available membranes. Here, several graphene/polyvinylidene (PVDF_G) membranes with different graphene loading (0–10 wt%) were prepared through a phase inversion method. After full characterization of the resulting membranes, the surface revealed that the well-dispersed graphene in the polymer matrix (0.33 and 0.5 wt% graphene loading) led to excellent water repellence together with a rough structure, and a large effective surface area. Importantly, antifungal activity tests of films indicated an increase in the inhibition percentage for PVDF_G membranes against the Curvularia sp. fungal strain. However, the antifungal surface properties were found to be the synergistic result of graphene toxicity and surface topography.

Recent Progresses of Superhydrophobic Coatings in Different Application Fields: An Overview

With the development of material engineering and coating industries, superhydrophobic coatings with exceptional water repellence have increasingly come into researchers’ horizons. The superhydrophobic coatings with corrosion resistance, self-cleaning, anti-fogging, drag-reduction, anti-icing properties, etc., meet the featured requirements from different application fields. In addition, endowing superhydrophobic coatings with essential performance conformities, such as transparency, UV resistance, anti-reflection, water-penetration resistance, thermal insulation, flame retardancy, etc. plays a remarkable role in broadening their application scope. Various superhydrophobic coatings were fabricated by diverse technologies resulting from the fundamental demands of different fields. Most past reviews, however, provided only limited information, and lacked detailed classification and presentation on the application of superhydrophobic coatings in different sectors. In the current review, we will highlight the recent progresses on superhydrophobic coatings in automobile, marine, aircraft, solar energy and architecture-buildings fields, and discuss the requirement of prominent functionalities and performance conformities in these vital fields. Poor durability of superhydrophobic coating remains a practical challenge that needs to be addressed through real-world application. This review serves as a good reference source and provides insight into the design and optimization of superhydrophobic coatings for different applications.

Chemical composition of the renewed fire extinguishing powder and its physical characteristics

Water, foam, dry powder, carbon dioxide and liquid chemicals are used as fire extinguishers depending on the fire types. The fire classification of ABC type includes fires caused by paper, wood, dye, fuel, oil, lubricants and flammable gases. In this work, the investigation of the procedure for re-determining the composition of prepared fire extinguishers was carried out depending on the ratio of organic and inorganic substances, and their fire extinguishing activity was tested. The Sample-1 contains about 50% of ammonium dihydrophosphate (NH4H2PO4) which is taking into account the main component and the sum of ammonium sulphate (NH4)2SO4 and other inorganic and organic components by 50%. As a result of fire extinction tests, its fire extinguishing activity was higher than that of other Samples included different ratios of substances. Based on the thermogravimetric analysis of the Sample -1, the polymerization and water release process of NH4H2PO4 was detected as endothermic effect. The weight loss was occurred by 74% and 26% remained as P2O5 when temperature reached to highest degree. Some physical parameters such as moisture content, water repellence, density and particle size were analyzed according to ISO standard method and all these important parameters showed that it can meet the requirements for fire extinguishing powder standards. Гал унтраагч шинэчилсэн бэлдмэлийн найрлага, түүний физик шинж чанарын судалгаа Хураангуй: Ус, хөөс, хуурай нунтаг, нүүрс хүчлийн хий ба химийн шингэн бодис зэргийг галын төрлөөс хамааруулан гал унтраагчаар ашигладаг. Галын ABC ангилалд цаас, мод, будаг, шатахуун, тос, тосолгооны материал, шатамхай хий зэргээс үүдэлтэй гал хамаарна. Энэхүү ажлаар импортын гал унтраагч бодисын найрлагыг шинэчлэн тогтоох судалгааг органик ба органик бус химийн бодисуудын харьцаанаас хамааруулан явуулж, тэдгээрийн гал унтраах идэвхийг ABC ангиллын галд туршив. Үндсэн бүрдэл болох аммонийн дигидрофосфат (NH4H2PO4)-ыг 50%, (NH4)2SO4 ба бусад бүрэлдэхүүн бодисуудын нийлбэрийг мөн 50%-иар тооцоолон авсан. Бэлдмэл 1-ийн гал унтраах идэвх нь бусад бэлдмэлүүдийн идэвхээс өндөр байв. Бэлдмэлийн термографийн судалгаагаар NH4H2PO4-ын их хэмжээний дулаан шингээн полимержих, ус ялгаруулах процесс DTA-ийн муруйд эндо эффект хэлбэрээр илэрсэн ба температурын дээд утгад жингийн алдагдал 74%-д хүрч, 26% нь P2O5 хэлбэрээр үлдсэн. Гал унтраагч нунтгийн физик шинж чанарын гол үзүүлэлтүүд болох чийг, хувийн жин, ус үл нэвтрүүлэх чадвар, ширхэглэлийн хэмжээг тодорхойлсон ба эдгээр үзүүлэлтүүд нь стандартын шаардлагуудыг хангасан байна. Түлхүүр үг: Гал унтраагч нунтаг, идэвх, аммонийн дигидрофосфат, DTA/TG, физик үзүүлэлт

Soil Management Systems to Overcome Multiple Constraints for Dryland Crops on Deep Sands in a Water Limited Environment on the South Coast of Western Australia

Deep sands on the south coast sandplain of Western Australia (WA) have multiple soil constraints including water repellence, high soil strength, low nutrient levels and subsoil acidity. The aim of the study was to test contrasting methods of managing water repellence and to assess their impacts on one or more soil constraints to crop production. These methods included seeding tyne design (knife point, winged points, paired row), soil wetting agent addition, strategic inversion tillage (rotary spading, mouldboard ploughing to 0.35 m) and clay-rich subsoil addition (170 t ha−1 with incorporation by spading to 0.20 or 0.35 m). Limesand (2 t ha−1) was applied as a split plot treatment prior to tillage. Cumulative crop yields were increased by 2.1–2.6 t ha−1 over five years by the strategic deep tillage and clay application treatments compared to the control. Water repellence was reduced by the inversion ploughing and subsoil clay addition treatments only. The effect of water repellence on crop establishment was expressed only in low rainfall years (Decile < 4) and mitigated by the paired row, wetting agent, spader and clay-amended treatments. In all years, plant numbers were adequate to achieve yield potential regardless of treatment. Soil K and plant tissue K and B were increased where clay had been applied. Inversion tillage reduced soil pH, organic carbon (OC) and macro nutrients in the 0–0.1 m layer although in most years there was no significant decline in plant tissue macro nutrient levels. Soil strength was reduced as a result of the inversion tillage to a depth of 0.35 m. However, the alleviation of soil strength and the crop yield responses diminished with time due to re-compaction. No crop response to the applied lime was found over five years at this site since the soil pHCaCl2 exceeded 4.7 within the root zone. In terms of soil constraints, we conclude that compaction was the dominant constraint at this site followed by water repellence and K deficiency.