scholarly journals Durable Superhydrophobic Coating for Efficient Microplastic Removal

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1258
Author(s):  
Oriol Rius-Ayra ◽  
Alisiya Biserova-Tahchieva ◽  
Nuria Llorca-Isern
Keyword(s):  
Electron Microscopy ◽  
Contact Angle ◽  
Chemical Composition ◽  
High Resolution ◽  
Hierarchical Structure ◽  
Photoelectron Spectroscopy ◽  
Contact Angle Hysteresis ◽  
Superhydrophobic Coating ◽  
Static Contact ◽  
The Hierarchical Structure

The pollution caused by microplastics around the world is an increasingly significant issue that has to be tackled with different methods and technologies. Here, we report a straightforward and rapid process combining electrodeposition and electrophoresis to produce a durable superhydrophobic coating on an aluminum substrate (UNS A91070) that has a static contact angle (153°), sliding angle (1°), and contact angle hysteresis (1°). Field emission scanning electron microscopy and high-resolution transmission electron microscopy showed the presence of a hierarchical structure with nanolayers that were 70 nm thick. The chemical composition was also analyzed using attenuated total reflectance-Fourier transform infrared spectroscopy and high-resolution X-ray photoelectron spectroscopy, which revealed that the hierarchical structure was composed of zinc laurate (Zn(C11H20COO)2) that decreased the surface free energy of the system. Moreover, the coating showed high durability against abrasion caused by the P1200 SiC paper due to the presence of TiO2 particles in the upper layers as well as the homogeneous chemical composition of the hierarchical structure. Finally, taking advantage of the superoleophilic properties of superhydrophobic surfaces, the ability of the coating to remove high-density polyethylene microplastics from water was studied.

A SUPERHYDROPHOBIC COATING ON TITANIUM ALLOYS BY SIMPLE CHEMICAL ETCHING

2021 ◽  
pp. 2150027
Author(s):  
YUFENG ZHANG ◽  
GUOLIANG CHEN ◽  
YAMING WANG ◽  
YONGCHUN ZOU
Keyword(s):  
Contact Angle ◽  
Titanium Alloy ◽  
Electrochemical Impedance ◽  
Contact Angle Hysteresis ◽  
Manufacturing Strategy ◽  
Superhydrophobic Coating ◽  
Sliding Angle ◽  
The Hierarchical Structure ◽  
Silane Modification ◽  
Self Cleaning

In the present study, a scalable-manufactured and environmental-friendly method was proposed to fabricate the superhydrophobic coating on titanium alloy. The hierarchical binary surface structures were obtained by hydrothermal treatment of titanium alloy with oxalic acid and sodium hydroxide solutions successively. The hierarchical structure surfaces after fluoroalkyl-silane modification possessed a maximum contact angle of 158.7° and a sliding angle of 4.3°. The low contact angle hysteresis surface can lead to efficient self-cleaning performance, which was confirmed by the bounce and roll off of water droplet on the surface. Furthermore, the anticorrosion behaviors of the superhydrophobic coating in 3.5[Formula: see text]wt.% NaCl solution was evaluated by the electrochemical impedance spectroscopy (EIS). It was found that the superhydrophobic coating can maintain its superhydrophobic state (150°) within 48 h, thereby effectively preventing the corrosive medium from penetrating into the coating. This simple yet fast anti-corrosion/self-cleaning superhydrophobic coating manufacturing strategy will enlighten its potential application in the engineering fields.

Thermodynamic analysis and injection molding of hierarchical superhydrophobic polypropylene surfaces

2019 ◽  
Vol 40 (1) ◽  
pp. 86-97
Author(s):  
Can Weng ◽  
Jin Yang ◽  
Fei Wang ◽  
Tao Ding ◽  
Zhanyu Zhai
Keyword(s):  
Contact Angle ◽  
Injection Molding ◽  
Thermodynamic Analysis ◽  
Hierarchical Structure ◽  
Hierarchical Structures ◽  
Equilibrium Contact Angle ◽  
Surface Model ◽  
Textured Surface ◽  
Static Contact ◽  
The Hierarchical Structure

Abstract In this study, thermodynamic analysis of the hierarchical structure of the 3D cylinder-textured surface model was performed. The wetting states at different penetration depths, the effects of three components on the wetting properties, and all equilibrium contact angle of the hierarchical structure were investigated. It was found that the interaction between micropillars and nanopillars can affect the transition energy barrier and the transition pitch in the wetting-state transition process. This showed that all components would play a key role in enhancing the surface hydrophobicity. Polypropylene (PP) surfaces with mono micropillars and hierarchical structures were both fabricated by injection molding. Mold inserts for hierarchical structures were obtained by the combination of a punching plate and an anodized aluminum alloy plate. The static contact angle (CA) and the roll-off angle of injection-molded PP surfaces were measured and analyzed from the perspective of thermodynamic analysis. With the hierarchical structures, a static CA of about 163° as well as a roll-off angle of about 5° was approached. Compared with a mono micropillar-structured PP surface, the hierarchical-structured PP surface has a larger static CA and a smaller roll-off angle. The work demonstrates an inexpensive and reproducible technique to fabricate function-designed controlled hierarchical structures on PP material.

scholarly journals Cu–MoS2 Superhydrophobic Coating by Composite Electrodeposition

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 238 ◽  
Author(s):  
Lucia Helena Prado ◽  
Sannakaisa Virtanen
Keyword(s):  
Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Secondary Ion Mass Spectrometry ◽  
Contact Angle Hysteresis ◽  
Copper Matrix ◽  
Superhydrophobic Coating ◽  
Operational Parameters ◽  
Aisi 316L Stainless Steel ◽  
X Ray ◽  
Composite Electrodeposition

In this work, a superhydrophobic coating was developed by composite electrodeposition of MoS2 particles in a copper matrix. AISI 316L stainless steel and N80 carbon steel, with a thin electrodeposited Ni layer to improve adherence of the coating, were used as substrates. Different operational parameters of electrodeposition were studied in order to produce the highest possible contact angle. We demonstrate that, using this method, a coating with a hierarchical structure with feature dimensions in the range of µm to nm is obtained, with advancing contact angle values up to 158.2° and a contact angle hysteresis equal to 1.8°. To study the coating composition energy dispersive X-ray, X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were performed. Moreover, potentiodynamic polarizations were performed in H2SO4, NaCl and NaOH solutions to study the corrosion behavior of the coating. As a control, a sample coated only with MoS2 particles by means of electrophoretic deposition was produced. The results show that the composite coating can be used in applications where copper is used for corrosion protection, with the addition of the desirable effects of its superhydrophobicity.

scholarly journals Biomimetic Approach for the Elaboration of Highly Hydrophobic Surfaces: Study of the Links between Morphology and Wettability

Biomimetics ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 38
Author(s):  
Quentin Legrand ◽  
Stephane Benayoun ◽  
Stephane Valette
Keyword(s):  
Contact Angle ◽  
Ginkgo Biloba ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Textured Surfaces ◽  
Replication Process ◽  
Wetting Behavior ◽  
Static Contact ◽  
Biomimetic Approach ◽  
Highly Hydrophobic

This investigation of morphology-wetting links was performed using a biomimetic approach. Three natural leaves’ surfaces were studied: two bamboo varieties and Ginkgo Biloba. Multiscale surface topographies were analyzed by SEM observations, FFT, and Gaussian filtering. A PDMS replicating protocol of natural surfaces was proposed in order to study the purely morphological contribution to wetting. High static contact angles, close to 135∘, were measured on PDMS replicated surfaces. Compared to flat PDMS, the increase in static contact angle due to purely morphological contribution was around 20∘. Such an increase in contact angle was obtained despite loss of the nanometric scale during the replication process. Moreover, a significant decrease of the hysteresis contact angle was measured on PDMS replicas. The value of the contact angle hysteresis moved from 40∘ for flat PDMS to less than 10∘ for textured replicated surfaces. The wetting behavior of multiscale textured surfaces was then studied in the frame of the Wenzel and Cassie–Baxter models. Whereas the classical laws made it possible to describe the wetting behavior of the ginkgo biloba replications, a hierarchical model was developed to depict the wetting behavior of both bamboo species.

The Surface Modification with Fluorocarbon Thin Films for the Prevention of Stiction in Mems

1998 ◽  
Vol 518 ◽  
Author(s):  
Sang-Ho Lee ◽  
Myong-Jong Kwon ◽  
Jin-Goo Park ◽  
Yong-Kweon Kim ◽  
Hyung-Jae Shin
Keyword(s):  
Contact Angle ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Fluorocarbon Films ◽  
Perfluorodecanoic Acid ◽  
Large Hysteresis ◽  
Static Contact ◽  
Receding Contact ◽  
Highly Hydrophobic ◽  
Receding Contact Angle

AbstractHighly hydrophobic fluorocarbon films were prepared by the vapor phase (VP) deposition method in a vacuum chamber using both liquid (3M's FC40, FC722) and solid sources (perfluorodecanoic acid (CF3(CF2)8COOH), perfluorododecane (C12F26)) on Al, Si and oxide coated wafers. The highest static contact angles of water were measured on films deposited on aluminum substrate. But relatively lower contact angles were obtained on the films on Si and oxide wafers. The advancing and receding contact angle analysis using a captive drop method showed a large contact angle hysteresis (ΔH) on the VP deposited fluorocarbon films. AFM study showed poor film coverage on the surface with large hysteresis. FTIR-ATR analysis positively revealed the stretching band of CF2 groups on the VP deposited substrates. The thermal stability of films was measured at 150°C in air and nitrogen atmospheres as a function of time. The rapid decrease of contact angles was observed on VP deposited FC and PFDA films in air. However, no decrease of contact angle on them was observed in N2.

scholarly journals A Simple Method to Create Superhydrophobic Aluminium Surfaces

2012 ◽  
Vol 706-709 ◽  
pp. 2874-2879 ◽  
Author(s):  
R. Jafari ◽  
Masoud Farzaneh
Keyword(s):  
Contact Angle ◽  
Stearic Acid ◽  
Synergistic Effects ◽  
Low Cost ◽  
Contact Angle Hysteresis ◽  
Spray Coating ◽  
Superhydrophobic Surfaces ◽  
Water Contact ◽  
Simple Method ◽  
Static Contact

Superhydrophobic surfaces were prepared using a very simple and low-cost method by spray coating. A high static water contact angle of about 154° was obtained by deposition of stearic acid on an aluminium alloy. However, this coating demonstrated a high contact angle hysteresis (~ 30º). On the other hand, superhydrophobic surfaces with a static contact angle of about 162º and 158º, and a low contact angle hysteresis of about 3º and 5º were respectively obtained by incorporating nanoparticles of SiO2and CaCO3in stearic acid. The excellent resulting hydrophobicity is attributed to the synergistic effects of micro/nanoroughness and low surface energy. A study of the wettability of these surfaces at temperatures ranging from 20 to-10 °C showed that the superhydrophobic surface becomes rather hydrophobic at supercooled temperatures.

Zooming in on surface chemical composition of soil microaggregates – Is there an effect of plants (Festuca)?

2021 ◽  
Author(s):  
Susanne K Woche ◽  
Stefan Dultz ◽  
Robert Mikutta ◽  
Klaus Kaiser ◽  
Georg Guggenberger
Keyword(s):  
Contact Angle ◽  
Organic Matter ◽  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Bare Soil ◽  
Organic N ◽  
Initial Contact ◽  
Surface Chemical ◽  
Surface Chemical Composition ◽  
Fresh Organic Matter

<p>Formation of soil microaggregates (SMA) is a surface-driven process and depends on mineral cementing and organic gluing agents. Yet, the role of plants in soil microaggregation by input of fresh organic matter remains little understood. In a mesocosm experiment silty Luvisol topsoil (<250 µm; original soil material) was incubated in absence (bare soil) and presence of plants (Festuca) and water-stable free and occluded SMA were isolated after 4, 12, and 30 weeks and investigated for the surface chemical composition by X-ray photoelectron spectroscopy (XPS) and for wetting properties by contact angle determination.</p><p>Compared to the original soil, the surfaces of both free and occluded SMA tended to smaller O and larger C contents, thus a smaller O/C ratio, along with a slight increase in initial contact angle from about 10° (original soil) to about 20° (SMA). The O/C ratio decreased slightly further from 4 to 12 weeks, especially for bare soil without plants. Slightly greater C contents were detected for occluded than for free SMA, probably hinting at higher retention of organic matter on surfaces of microaggregates entrained in larger soil structures. For bare soil, a slightly greater N content was observed for free SMA while in the presence of Festuca free and occluded SMA had same N contents.</p><p>Regardless of the presence of Festuca, C speciation indicated a lower proportion (in % of total C) of C=O/O-C-O and a higher proportion of C - C/C -  H species for occluded than for free SMA, probably indicating less altered organic matter at the surfaces of occluded SMA. While the proportion of C=O/O-C-O species slightly decreased, that of C- C/C-H species slightly increased towards the end of the incubation. This may hint at some preferences in microbial respiration with respect to C compounds and formation of microbial metabolites. From N speciation a higher ratio between protonated and non-protonated organic N species (N<sub>p</sub>/N<sub>np</sub>) was indicated for Festuca than for bare soil after 4 and for 30 weeks of incubation, i.e., the presence of plants seems to impact N compounds present. The N<sub>p</sub>/N<sub>np </sub>ratio tended to decrease after 30 weeks compared to 4 weeks for both treatments, hinting on changes in N species present.</p><p>In summary, aside some effect on N species present, results indicate rather incubation and SMA origin (free, occluded) than the presence of plants (Festuca) to impact surface chemical composition of the tested SMA. This suggests no defined contribution of plants and their products to formation of 250-53 µm-sized SMA.</p>

scholarly journals Amphiphobic Nanostructured Coatings for Industrial Applications

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 787 ◽  
Author(s):  
Federico Veronesi ◽  
Giulio Boveri ◽  
Mariarosa Raimondo
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Friction Reduction ◽  
Hybrid Coatings ◽  
Wetting Behavior ◽  
Wide Range ◽  
Solid Liquid

The search for surfaces with non-wetting behavior towards water and low-surface tension liquids affects a wide range of industries. Surface wetting is regulated by morphological and chemical features interacting with liquid phases under different ambient conditions. Most of the approaches to the fabrication of liquid-repellent surfaces are inspired by living organisms and require the fabrication of hierarchically organized structures, coupled with low surface energy chemical composition. This paper deals with the design of amphiphobic metals (AM) and alloys by deposition of nano-oxides suspensions in alcoholic or aqueous media, coupled with perfluorinated compounds and optional infused lubricant liquids resulting in, respectively, solid–liquid–air and solid–liquid–liquid working interfaces. Nanostructured organic/inorganic hybrid coatings with contact angles against water above 170°, contact angle with n-hexadecane (surface tension γ = 27 mN/m at 20 °C) in the 140–150° range and contact angle hysteresis lower than 5° have been produced. A full characterization of surface chemistry has been undertaken by X-ray photoelectron spectroscopy (XPS) analyses, while field-emission scanning electron microscope (FE-SEM) observations allowed the estimation of coatings thicknesses (300–400 nm) and their morphological features. The durability of fabricated amphiphobic surfaces was also assessed with a wide range of tests that showed their remarkable resistance to chemically aggressive environments, mechanical stresses and ultraviolet (UV) radiation. Moreover, this work analyzes the behavior of amphiphobic surfaces in terms of anti-soiling, snow-repellent and friction-reduction properties—all originated from their non-wetting behavior. The achieved results make AM materials viable solutions to be applied in different sectors answering several and pressing technical needs.

Sign in / Sign up

Export Citation Format

Share Document