Liquid Repellency Research Articles

Use of the droplet convergence effect of under-medium superlyophilic membranes in designing a system for on-demand separations of oil-in-water and water-in-oil emulsions

Separation using superwetting membranes that have discrepant interactions with water and oil, primarily those that display extreme liquid repellence, is a facile approach for oily wastewater treatment and purification of water-containing oil. However, these kinds of membranes suffer from size-sieving limitation. Owing to greater affinity toward dispersed droplets over liquid media, under-medium superlyophilic membranes have greater flexibility in the design of superwetting interfaces for oil–water separation. Herein, two membranes with completely opposite superwettabilities both in air and under oil/water media were utilized to create an integrated system for effective, on-demand separation of oil-in-water and water-in-oil emulsions. At superwetting interfaces, the under-medium superlyophilic membrane facilitates convergence of emulsion droplets while the other membrane intercepts converged droplets. As a result, the integrated membranes exhibit high purification capabilities of water and oil in surfactant-stabilized emulsions (e.g., > 99.97 % oil purification under gravity). The viscosity-dependent fluxes are > 550 L m−2h−1 when the viscosities of the liquid media are ≤ 1 mPa s. In contrast, an integrated system in which conventional in-air superhydrophilic membranes are utilized in place of the under-medium superlyophilic membranes does not efficiently separate the emulsions. The unique affinity profiles will endow under-medium superlyophilic membranes with a high potential for liquid–liquid separation.

Significantly enhanced corrosion resistance for Fe-based amorphous coatings via sealing treatment: Based on hybridisation and superhydrophobicity strategy

Based on the synergistic effect of hybridisation-superhydrophobicity, a simple and facile spraying method was used to achieve efficient sealing of Fe-based amorphous metallic coatings. In this paper, we employed rare-earth neodymium salts as inorganic sealant raw materials and loaded low surface energy fluorosilanes into epoxy resins to act as organic sealant raw materials. The surface structure and chemical composition of the sealing coatings were systematically characterised. The sealing mechanism as well as the anti-corrosion mechanism of the coating were investigated intensively. The results indicate that the superior corrosion resistance and self-cleaning ability of the sealed coating stems from the inorganic–organic-complex trinity effect: the corrosion inhibition effect of Nd oxide deposited during the inorganic sealing process, the shielding effect of the resin in the organic sealing, and the cross-linking and superhydrophobicity behaviour (liquid repellency effect) of the FDTES-Nd3+-Fe2+ complexes formed on the surface of the coating. This work provides valuable guidelines and insights for the design of subsequent corrosion-resistant and sealing coating.

Fluorine-free Liquid Repellent Coatings with Fully Self-Healing and Robust Adhesion Abilities

Fluorine-free Liquid Repellent Coatings with Fully Self-Healing and Robust Adhesion Abilities

Multi‐Scenario Applications of Fluoro‐Free Super Liquid‐Repellent Particles Prepared Through Excluded Volume Effect

AbstractSuperhydrophobic surfaces garner tremendous research attention due to their potential applications in the fields of oil–water separation membrane, self‐cleaning, and anti‐icing systems. However, the reported superhydrophobic materials that achieve low‐surface‐tension (<60 mN m−1) liquid repellency are typically prepared using perfluorinated compounds (PFCs), which pose significant risks to the natural environment and human health. Here a concept based on the excluded volume effect in polymer dilute solutions is explored to achieve a hydrophobic flexible polymer‐chain wrapping of multidimensional particles, which forms a nonadherent soft‐shell‐hard‐core structure and maintains the original structural integrity of particles. The prepared fluoro‐free super‐repellent multidimensional particles can be spray‐coated and dip‐coated on different substrates to prepare large‐scale superhydrophobic coatings, which exhibit excellent low‐surface‐tension (42.6−50 mN m−1) liquid repellency superior to the reported fluoro‐free superhydrophobic materials. Benefiting from the strong interaction of super‐repellent particles with flexible polymer chains, the superhydrophobic coatings show unexpected wear resistance and durability. This first demonstration of hydrophobic polymer‐wrapped particles for repelling low‐surface‐tension liquids provides insights into next‐generation fluoro‐free superhydrophobic materials.

Hard transparent nanogradient coating for ultradurable omniphobic liquid-like surface

Omniphobic liquid-like surface (LLS) offers excellent dynamic liquid repellency owing to the highly mobile polymer chains mediating at the solid–liquid interface. These polymer chains, often achieved by surface grafting, are not durable against abrasion or oxidation, which seriously hinders their practical application. Here we report a new vapor-based approach to create transparent nanogradient coating for LLSs with unprecedented mechanical strength and durability. The nanogradient coating is composed of a sandwich structure with an ultrathin primer, a rigid bulk, and a nanocomposite surface with abundant polydimethylsiloxane-like chains, all of which achieved via sequential plasma polymerization of a linear and a cyclic siloxane. The plasma-polymerized cyclic siloxane enables coating good mechanical strength while the plasma-polymerized linear siloxane confers coating sub-nanometer roughness and excellent dynamic liquid repellency. The resultant coating exhibits contact angle hysteresis < 5° towards many low-surface-energy liquids, as well as good mechanical strength with the hardness exceeding 1 GPa and superior durability enduring 100,000 cycles of abrasion. The coating also survived industrial standard thermal and accelerated UV-aging tests without losing its liquid repellency and transparency. The reported method is facile, scalable, and substrate-independent, offering exciting new opportunities towards industrial fabrication and real-world application of LLS.

Unconventional Dually-Mobile Superrepellent Surfaces.

The ability of water droplets to move freely on superrepellent surfaces is a crucial feature that enables effective liquid repellency. Common superrepellent surfaces allow free motion of droplets in the Cassie state, with the liquid resting on the surface textures. However, liquid impalement into the textures generally leads to a wetting transition to the Wenzel state and droplet immobilization on the surface, thereby destroying the liquid repellency. This study reports the creation of a novel type of superrepellent surface through rational structural control combined with liquid-like surface chemistry, which allows for the free movement of water droplets and effective repellency in both the Cassie and Wenzel states. Theoretical guidelines for designing such surfaces are provided, and experimental results are consistent with theoretical analysis. Furthermore, this work demonstrates the enhanced ice resistance of the dually-mobile superrepellent surfaces, along with their distinctive self-cleaning capability to eliminate internal contaminants. This study expands the understanding of superrepellency and offers new possibilities for the development of repellent surfaces with exceptional anti-wetting properties.

Multifunctional Superamphiphobic Coating Based on Fluorinated TiO2 toward Effective Anti-Corrosion.

The application of superamphiphobic coatings improves the surface's ability to repel fluids, thereby greatly enhancing its various functions, including anti-fouling, anti-corrosion, anti-icing, anti-bacterial, and self-cleaning properties. This maximizes the material's potential for industrial applications. This work utilized the agglomeration phenomenon exhibited by nano-spherical titanium dioxide (TiO2) particles to fabricate 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) modified TiO2 (TiO2@fluoroPOS) fillers with low surface energy. This was achieved through the in-situ formation of protective armor on the surface of the agglomerates using the sol-gel method and fluorination modification. Polyvinylidene fluoride-tetrafluoropropylene (PVDF-HFP) and TiO2@fluoroPOS fillers were combined using a spraying technique to prepare P/TiO2@fluoroPOS coatings with superamphiphobicity. Relying on the abundance of papillae, micropores, and other tiny spaces on the surface, the coating can capture a stable air film and reject a variety of liquids. When the coatings were immersed in solutions of 2 mol/L HCl, NaCl, and NaOH for a duration of 12 h, they retained their exceptional superamphiphobic properties. Owing to the combined influence of the armor structure and the organic binder, the coating exhibited good liquid repellency during water jetting and sandpaper abrasion tests. Furthermore, the coating has shown exceptional efficacy in terms of its ability to be anti-icing, anti-waxing, and self-cleaning.

Judiciously designed dual cross-linked networks for highly transparency, robustness and flexibility in liquid-repellent coatings

Highly transparent, durable, and flexible liquid-repellent coatings are urgently needed in the realm of transparent materials, such as car windows, optical lenses, solar panels, and flexible screen materials. However, it has been difficult to strike a balance between the robustness and flexibility of coatings constructed by a single cross-linked network design. To overcome the conundrum, this innovative approach effectively combines two distinct cross-linked networks with unique functions, thus overcoming the challenge. Through a tightly interwoven structure comprised of added crosslinking sites, the coating achieves improved liquid repellency (WCA>100°, OSA<10°), increased durability (withstands 2,000 cycles of cotton wear), enhanced flexibility (endures 5,000 cycles of bending with a bending radius of 1 mm), and maintains high transparency (over 98 % in the range of 410 nm to 760 nm). Additionally, the coating with remarkable adhesion can be applied to multiple substrates, enabling large-scale preparation and easy cycling coating, thus expanding its potential applications. The architecture of this fluoride-free dual cross-linked network not only advances liquid-repellent surfaces but also provides valuable insights for the development of eco-friendly materials in the future.

Long‐Term Immersion Study for Durability of Interconnected Micropatterned Surfaces with Sustained Water Repellency

AbstractThe sustained water repellency of interconnected micropatterned surfaces is explored over an extended duration, with a focus on their resilience during a 90‐day water‐immersion test. Initially, the microstructure surfaces exhibit high water repellency, a characteristic of the Cassie–Baxter state. However, subsequent detailed temporal analyses reveal varying responses depending on the structural topology. The interconnected micropatterned surfaces exhibit remarkable long‐term resistance to water; this is attributed to the formation of large and stable air pockets enabled by their unique microcavity structures. In comparison, hierarchical microcavity surfaces with micropillars exhibit a notable decrease in water repellency, as evidenced by reduced contact angles, suggesting a transition to a wetting state owing to the emergence of surface hydrophilicity during long‐term water exposure. This study demonstrates the importance of stable air‐pocket effects, particularly in applications where the long‐term stability of liquid repellency is critical, and suggests the role of interconnected structures in maintaining water repellency over time.

Abstract 7023: Application of exclusive liquid repellency for low input CUT&amp;Tag histone analyses in prostate cancer spheroids

Abstract Introduction/Background: Epigenetic alterations, including histone modifications and DNA methylation, drive treatment resistance and lethal prostate cancer. However, epigenetic assays typically require thousands of cells and are difficult to scale for patient tumor biopsies. While identifying these alterations is possible in cell lines, these analytes are more difficult to follow in clinical settings. Patient-derived organoids have emerged as viable intermediaries to investigate the changing chromatin landscape during the progression toward treatment-emergent prostate cancer. This report seeks to adapt the Cleavage Under Targets and Tagmentation (CUT&amp;Tag) assay for use on a microfluidic technology to eliminate cell loss associated with complex, multi-step epigenetic assays to facilitate analysis of low input prostate cancer spheroids. Methods: The Oil Immersed Lossless Total Analysis System (OIL-TAS) is an exclusive liquid repellency (ELR) platform that passes magnetic bead-bound analytes through immiscible phases to separate and extract analytes of interest while eliminating traditional centrifugation and wash steps that lead to sample loss. This platform enables adaptation of complex molecular assays such as CUT&amp;Tag for lossless sample manipulation. We focus on the analysis of histone modifications in rare cells utilizing antibodies for H3K27 acetylation and methylation. Comparison of LNCaP prostate cancer cell lines harvested from either 2D cell culture or 3D spheroids was performed to evaluate the sensitivity and specificity of this integrated assay. Results: The macroscale CUT&amp;Tag assay has been performed with inputs of 25,000 nuclei from LNCaP spheroids with greater yields than similar inputs from 2D LNCaP cell culture. Yield increases have also been seen when performing the assay with inputs &amp;lt;10,000 nuclei in microscale on the OIL-TAS relative to the macroscale. Utilizing the OIL-TAS platform with spheroid inputs will allow for more sensitive investigation of histone modifications. Conclusions: Integration of 3D, humanized models of tumor growth into the CUT&amp;Tag assay will enable discovery of differential epigenetic regulation within patient-derived organoids or complex co-culture studies. Establishing baseline epigenetic landscapes among these intermediary models will enable a new platform for drug testing. Utilization of the OIL-TAS platform will allow for miniaturization of the assay down to 1,000 cell inputs and enable multiparametric RNA-seq, EM-seq, and CUT&amp;Tag-seq of the same patient samples for longitudinal study. Citation Format: Zachary J. Kauffman, Kevin Koesser, Kyle T. Helzer, Jamie M. Sperger, Marina N. Sharifi, Chao Li, Erika Heninger, Xavier Hazelberg, Cole Gilsdorf, Shuang G. Zhao, Duane S. Juang, David J. Beebe, Joshua M. Lang. Application of exclusive liquid repellency for low input CUT&amp;Tag histone analyses in prostate cancer spheroids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7023.

Biomimetic and Durably Superhydrophobic Nanofibrous Membranes for High‐Performance Waterproof and Breathable Textiles

AbstractMan‐made superhydrophobic membranes are of interest for various applications in energy, environment, and medical fields. However, simultaneously achieving durable superhydrophobicity, robust waterproofness, and high breathability of the membranes is still challenging. Herein, an efficient and powerful strategy is reported to create superhydrophobic membranes with perdurable liquid repellency and robust breathability via combining humidity‐induced electrospinning with coat‐crosslinking technology. The micro/nano rough structure is in situ constructed based on manipulating the phase separation of electrospun jets; meanwhile, the waterborne acrylic resins are bridged to the surface of nanofiber to endow the membranes with stable low surface energy via coating and crosslinking treatment. Eventually, the resultant membranes present superhydrophobicity with a water contact angle of ≈154°, good self‐cleaning and anti‐icing properties, robust waterproofness of 83.4 kPa, and high breathability of 3.71 kg m−2 d−1. More interestingly, the nanomaterials can maintain durable superhydrophobicity even after exposure to various severe conditions. The successful creation of high‐performance superhydrophobic membranes opens a new avenue for synthesizing advanced functional materials for application in a variety of fields.

Engineering PVDF omniphobic membranes with flower-like micro-nano structures for robust membrane distillation

Conventional PVDF membranes are easily wetted and contaminated in membrane distillation (MD) process, especially when used in separating high-salinity water and oil-contained saline water. To address these issues, an omniphobic membrane was fabricated in this work. ZnO micro-flowers with a rough structure were successfully deposited onto the PVDF membrane with the assistance of polydopamine assistance. After undergoing a fluorination process, the omniphobic membranes were prepared by the synergistic effect of surface microstructure and free energy. The effects of varying Zn(NO3)2 concentrations and deposition times on morphology, pore size and separation efficiency were comprehensively examined. It was demonstrated that at a Zn(NO3)2 concentration of 50 mM and a deposition time of 0.5 h, the resulting PVDF composite membrane exhibited high liquid repellency towards all the test liquids, such as water, ethanol solution, paraffin oil, and etc. Furthermore, the membrane consistently exhibited impressive salt rejection behavior (99.99%) and maintained an average flux (15.54 kg·m−2·h−1) when exposed to high-salinity solution (up to 20 wt%-NaCl). Meanwhile, during treating an oil-contained saline water emulsion with the oil content of 200 ppm, the membrane also displayed high resistance to wetting and fouling during the continuously 24 h tests. The membrane displayed a rejection rate of 99.99 % with an average vapor flux of 18.60 kg·m−2·h−1. In summary, this omniphobic membranes demonstrated a great potential in MD for practical challenging wastewater treatment.

Sprayable Superoleophobic Coatings for Pumpless Handling of Low‐Surface‐Tension Liquids

AbstractLimited attention has been paid to repellency and wettability‐confined transport of low‐surface‐tension liquids, such as oils, alcohols, and hydrocarbons. This is because repellency becomes very difficult for fluids with surface tension below 30 mN m−1. This situation is encountered in many engineering applications using organic liquids and thus, oleophobic surfaces are of high technological importance. In this work, a nanocomposite coating comprising of fluorinated silica micro‐ and nanoparticles (filler), a copolymer (binder), and traces of fluorinated polyhedral oligomeric silsesquioxane (additive, lowest surface‐energy crystalline material reported to date) is spray‐deposited on a surface pretextured by laser etching, a technique that requires no lithographic processing. The approach results in surfaces that can repel liquid hydrocarbons with surface tension as low as 21.14 mN m−1 and also hinder the spreading of heptane (19.74 mN m−1) at room temperature. The repellency of several organic liquids with surface tensions in the range of 19.7 – 27 mN m−1 is experimentally investigated and compared with water (baseline case). To study the effect of fluid properties, comparisons are performed between the distances traveled and the velocities of microliter droplets transported pumplessly on wedge‐shaped wettability‐patterned tracks that confine the liquids by the superoleophobic background surrounding the wettable tracks.

Droplet impact on doubly re-entrant structures

Doubly re-entrant pillars have been demonstrated to possess superior static and dynamic liquid repellency against highly wettable liquids compared to straight or re-entrant pillars. Nevertheless, there has been little insight into how the key structural parameters of doubly re-entrant pillars influence the hydrodynamics of impacting droplets. In this work, we carried out numerical simulations and experimental studies to portray the fundamental physical phenomena that can explain the alteration of the surface wettability from adjusting the design parameters of the doubly re-entrant pillars. On the one hand, three-dimensional multiphase flow simulations of droplet impact were conducted to probe the predominance of the overhang structure in dynamic liquid repellency. On the other hand, the numerical results of droplet impact behaviours are agreed by the experimental results for different pitch sizes and contact angles. Furthermore, the dimensions of the doubly re-entrant pillars, including the height, diameter, overhang length and overhang thickness, were altered to establish their effect on droplet repellency. These findings present the opportunity for manipulations of droplet behaviours by means of improving the critical dimensional parameters of doubly re-entrant structures.

Solvent-free polyurethane coatings based on an in-situ curing strategy at room temperature with self-cleaning, anti-corrosion and anti-graffiti properties

Anti-smudge coatings have attracted extensive attention in recent years owing to their hydrophobic, self-cleaning, anti-graffiti properties and so on. However, most of the anti-smudge coatings are solvent-based and cured at high temperature or using special curing equipment, which negatively impacts the environment and limits their large-scale application in daily life. Herein, we report a solvent-free anti-smudge coating with potential for large-scale and green manufacturing. In detail, polydimethylsiloxane (PDMS) was used as the hydrophobic component, (3-aminopropyl)triethoxysilane (APTES) and 3-glycidoxypropyltrimethoxysilane (GPTMS) were used as the cross-linking agent, and a solvent-free polyurethane (SFPU) anti-smudge coating was in-situ constructed at room temperature for 24 h without any curing equipment. Due to the enrichment of PDMS chains on the surface and the dense cross-linked network of the coating, the as-prepared coating not only exhibited a high contact angle for water (99.3 ± 1.5°) and diiodomethane (69.5 ± 0.9°), but also excellent anti-smudge to contaminants, with both water and oily liquids were easy to slide off the surface of the coating without leaving any traces. Even after writing with an oil-based marker, the ink on the coated surface could be easily wiped off. Further study reveals that the coating surface maintained its original liquid repellency and stain resistance even after 10 d immersion in a 10 wt% NaCl solution, showing durable anti-corrosion properties. In addition, pigments did not affect the anti-graffiti performance of the coating, providing a multi-color scheme for practical application. This convenient, low-energy, environmentally friendly anti-smudge coating has great potential for widespread application in industry and daily life.

Amphiphobic PTFE membrane as functional covering membrane to hinder ammonia emission during the composting process

Composting is a process of converting potentially harmful organic matter into harmless organic fertilizer through microbial fermentation. This process enables the rational use of resources and represents an embraced technology marked with sustainable development features. Hindering ammonia emissions during composting is vital, as ammonia is a valuable resource and harmful if emitted excessively. Polytetrafluoroethylene (PTFE) membranes are often used as functional covering membranes to prevent ammonia produced by composting from releasing due to its hydrophobicity. However, they are susceptible to oily aerosols in oily composting, which affects microbial decomposition in aerobic composting. Thus, the development of amphiphobic PTFE membrane is necessary and meaningful. For the amphiphobic PTFE membrane, an important issue is the amphiphobic stability of the membrane, especially in the special alkaline environment of composting. Herein, we suggest the use of the polymer to wrap around nanoparticles and PTFE membrane fibers to prepare stable amphiphobic membranes as functional covering membranes for oil-containing composting. Poly(methyl-3,3,3-trifluoropropylsiloxane) (PTFPMS) and 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFTS) entangled with each other and then wrapped the nanoparticles and membrane fibers to form stable amphiphobic membranes with high roughness and low surface energy. The prepared membrane had high liquid repellency to water (～152.8°), diiodomethane (～127.5°), and n-hexadecane (～127.0°). This membrane also possessed a high anti-oil fouling. Moreover, the membrane amphiphobicity exhibited a high stability. This is attributed to the stable fixation of nanoparticles on PTFE membrane fibers with PFTS/PTFPMS. Therefore, the amphiphobicity of the membrane was not affected by ammonia. As for the ammonia filtration efficiency, the amphiphobic membrane had a filtration efficiency of 77.4 % within 10 min, an increase of 6.8 % compared to the PTFE membrane, demonstrating the potential of the membrane we developed toward hindering ammonia emission. This work provides a new way of developing high-performance membrane for the oily composting process.

Design of functional coating with superior liquid repellency, self-cleaning, photodegradation and thermal insulation properties for building protection

A super-hydrophobic multifunctional coating (SMC) was designed and fabricated by combining commercial TiO2 with polydimethylsiloxane and perfluorodecyltrichlorosilane. The main objective of this research is to enhance the feasibility and effectiveness of SMC coating for building protection. After optimization, the comprehensive performance was significantly improved. The SMC not only significantly improves the water repellency of concrete (decreasing the capillary water absorption by 92.91 %), but also endows concrete with great self-cleaning and photodegradation properties. Additionally, ultraviolet–simulated (90 d) and practical environment (150 d) irradiation tests demonstrate the superior radiative cooling properties of SMC. COMSOL finite element simulation indicates about 20 % of ultraviolet light absorbance and 80 % of visible and near-infrared light reflectance on the SMC. The multifunctional SMC coating not only enhances the water repellency and self-cleaning properties of concrete, but also demonstrates excellent radiative cooling capabilities. These findings highlight the potential of the SMC coating as a promising material for sustainable and energy-efficient building applications.

Stretchable Superhydrophobic Surfaces: From Basic Fabrication Strategies to Applications

Superhydrophobic surfaces find extensive applications in various fields, including self-cleaning, liquid manipulation, anti-icing, and water harvesting. To achieve superhydrophobicity, the surfaces are designed with hierarchical nano- and/or microscale protrusions. These structures result in a static contact angle above 150° and a sliding/rolling-off angle below 10° when water droplets deposit on the surface. The combination of hierarchical structures and low-surface energy materials contributes to this unique liquid-repellent property. In addition to liquid repellency, the durability of these surfaces is crucial for practical applications, which has prompted the exploration of stretchable superhydrophobic surfaces as a viable solution. The flexibility of these surfaces means that they are effectively safeguarded against mechanical damage and can withstand daily wear and tear. Over the last decade, considerable research has been dedicated to developing stretchable superhydrophobic surfaces to expand their potential applications. This review provides an overview of stretchable superhydrophobic surfaces, specifically emphasizing current processing strategies and their prospective applications. Additionally, we present a forward-looking perspective on future fabrication methods to create robust superhydrophobic surfaces, further enhancing their practicality and versatility.

Profile of Acute Poisoning and Its Outcome in Children Admitted to a Tertiary Care Hospital in Northeast India: A Cohort Study

Introduction: Acute poisoning in children is an important public health problem. It is a significant paediatric emergency in both developing and developed countries, leading to preventable morbidity and mortality. While there is substantial research literature on acute childhood poisoning from developed countries, there is a lack of data from developing countries like India due to inadequate and poor surveillance of poisoning-related data. Aim: To investigate the clinical and epidemiological profile, as well as the outcome, of acute poisoning in children admitted to the paediatric emergency department of a tertiary care hospital in Northeast India. Materials and Methods: This prospective cohort study was conducted in the Paediatrics department of Assam Medical College and Hospital, Dibrugarh, Assam, India, from April 1, 2021, to March 31, 2022. All children under the age of 12 years who presented to the paediatric department with a history of exposure to toxic substances were included in the study. The admitted children were assessed in terms of demographic variables, type of poison, route of poisoning, time of presentation, circumstances of poisoning, storage place of poison, clinical presentation, and interventions provided. Data were presented as mean and frequency. Results: A total of 78 children under 12 years of age were enrolled in the study, with a mean age of three years and three months at presentation. The majority of cases (96.2%) involved accidental poisoning, while a small proportion (3.8%) was due to suicidal poisoning. Of the two reported cases of suicidal poisoning, one involved a male child and the other involved a female child. Both children were above six years of age. The most common causes of poisoning were kerosene (34.6%), organophosphorus compounds (10.3%), and liquid mosquito repellents (9.1%). Conclusion: This study revealed both unintentional and intentional poisoning cases, with a high prevalence of accidental poisoning observed in children below three years of age. Kerosene was identified as the most common cause of childhood poisoning.

Covalent crosslinking chemistry for controlled modulation of nanometric roughness and surface free energy.

Smooth interfaces embedded with low surface free energy allow effortless sliding of beaded droplets of selected liquids-with homogeneous wettability. Such slippery interfaces display low or moderate contact angles, unlike other extremely liquid repellent interfaces (e.g. superhydrophobic). These slippery interfaces emerged as a promising alternative to extremely liquid repellent hierarchically rough interfaces that generally suffer from instability under severe conditions, scattering of visible light because of the hierarchically rough interface, entrapment of fine solid particulates in their micro-grooves and so on. However, a controlled and precise modulation of surface free energy and nanometric roughness is essential for designing a more compelling solid and dry antifouling interface. Here, we have unprecedentedly demonstrated the ability of covalent cross-linking chemistry for precise and simultaneous modulation of both essential surface free energy (∼49 mN m-1 to ∼22 mN m-1) and roughness (root mean square roughness from 30 nm to 3 nm) of a solid interface for achieving liquid, substrate, and process independent, robust slippery properties. The strategic selection of β-amino-ester linkage through a 1,4-conjugated addition reaction between amine and acrylate groups of a three component reaction mixture (dominated by a 61% (w/w) crosslinker) under ambient conditions provided a facile basis for associating various important and relevant properties-including self-cleaning ability, anti-smudge properties (against both water and oil-based inks), thermal stability (>300 °C), chemical stability, physical durability, optical transparency (∼95%) and so on. The embedded slippery properties of the coating remained unaffected at both low (0 °C) and high (100 °C) temperatures. Thus, the prepared coating would be appropriate to maintain the unperturbed performance of commercially available solar cell modules and other relevant objects under outdoor conditions.