Highly Hydrophobic, Homogeneous Suspension and Resin by Graft Copolymerization Modification of Cellulose Nanocrystal (CNC)

Cellulose nanocrystal (CNC) is a nanoscale colloid with superior potential for coatings, liquid crystal displays, and optoelectronics. However, to date, the presence of hydrophilicity still limits its application. Multifunction via graft copolymerization modification of CNC appears to be breaking into a new direction. In this study, we used the residual hydroxyl groups on the CNC to react with 2-bromoisobu-tyryl bromide, and the initiator was therefore anchored on the CNC surface. Through atom transfer radical polymerization (ATRP), CNC was successfully grafted to azobenzene monomer, i.e., 9-[4-[2-[4-(trifluorometh) phenyl] diazenyl] phenoxy] nonayl acrylate (FAZO). After a series of characterization methods, such as FTIR, NMR and XRD, it was found that the surface water contact angle of the CNC-PFAZO prepared by the modification was as high as 134.4°, and the high hydrophilicity of this material could be maintained for up to one month, even longer.

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Vertical Orientation of Liquid Crystal on Polystyrene Substituted with n-Alkylbenzoate-p-oxymethyl Pendant Group as a Liquid Crystal Precursor

Polymers ◽

10.3390/polym13132058 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2058

Author(s):

Kyutae Seo ◽

Hyo Kang

Keyword(s):

Contact Angle ◽

Liquid Crystal ◽

Water Contact Angle ◽

Polymer Films ◽

Molar Fraction ◽

Side Chain ◽

Pendant Group ◽

Polymer Modification ◽

Vertical Orientation ◽

Water Contact

We synthesized a series of polystyrene derivatives modified with precursors of liquid crystal (LC) molecules via polymer modification reactions. Thereafter, the orientation of the LC molecules on the polymer films, which possess part of the corresponding LC molecular structure, was investigated systematically. The precursors and the corresponding derivatives used in this study include ethyl-p-hydroxybenzoate (homopolymer P2BO and copolymer P2BO#, where # indicates the molar fraction of ethylbenzoate-p-oxymethyl in the side chain (# = 20, 40, 60, and 80)), n-butyl-p-hydroxybenzoate (P4BO), n-hexyl-p-hydroxybenzoate (P6BO), and n-octyl-p-hydroxybenzoate (P8BO). A stable and uniform vertical orientation of LC molecules was observed in LC cells fabricated with P2BO#, with 40 mol% or more ethylbenzoate-p-oxymethyl side groups. In addition, the LC molecules were oriented vertically in LC cells fabricated with homopolymers of P2BO, P4BO, P6BO, and P8BO. The water contact angle on the polymer films can be associated with the vertical orientation of the LC molecules in the LC cells fabricated with the polymer films. For example, vertical LC orientation was observed when the water contact angle of the polymer films was greater than ~86°. Good orientation stability was observed at 150 °C and with 20 J/cm2 of UV irradiation for LC cells fabricated with the P2BO film.

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The Surface Hydrophilicity of Polypropylene Non-Woven Treated by Atmospheric Glow Plasma

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.328-330.1413 ◽

2011 ◽

Vol 328-330 ◽

pp. 1413-1416

Author(s):

Yan Zhang ◽

Rui Juan Liu ◽

Zhong Xuan Shang ◽

Yin Ding Lv ◽

Biao Gu

Keyword(s):

Contact Angle ◽

Surface Water ◽

Glow Discharge ◽

Water Contact Angle ◽

Discharge Plasma ◽

Woven Fabric ◽

Glow Discharge Plasma ◽

Sharp Decline ◽

Water Contact ◽

Glow Plasma

In this paper, polypropylene (PP) melt blown non-woven fabric is treated by atmospheric He, He/O2 or He/CO2 glow discharge plasma. The variation of the surface hidrophilicity of PP sample is experimentally investigated by the surface water contact angle. The results show that the surface water contact angle firstly has a sharp decline and then up to saturation. It is worth noting that the time the water contact angle is up to saturation greatly shortens when a spot of O2 or CO2 are added into the atmospheric He. In addition, when the PP samples are treated by the atmospheric glow discharge plasma, it is necessary of selecting a right applied voltage.

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Reconfigurable Hydrophobic/Hydrophilic Surfaces Based on Self-Assembled Monolayers

MRS Proceedings ◽

10.1557/proc-774-o5.8 ◽

2003 ◽

Vol 774 ◽

Cited By ~ 4

Author(s):

Joanne Deval ◽

Teodoro A. Umali ◽

Brandee L. Spencer ◽

Esther H. Lan ◽

Bruce Dunn ◽

...

Keyword(s):

Contact Angle ◽

Surface Water ◽

Water Contact Angle ◽

Self Assembled Monolayers ◽

Ionic Surfactant ◽

Initial Surface ◽

Lauryl Sulfate ◽

Water Contact ◽

Assembled Monolayers ◽

Self Assembled

AbstractThe fabrication of micron-scale channels and reaction chambers using micromachining techniques has created devices with large surface to volume ratios. As a result, surface properties play a major role in determining the behavior of micromachined devices. In this work, we present strategies that can be used to reconfigure surfaces from hydrophobic to hydrophilic or from hydrophilic to hydrophobic. The reversible nature of the surface is made possible by using deposition and removal of biomolecules or amphiphiles on self-assembled monolayers (SAMs). When the initial surface was hydrophobic (using a CH3-terminated SAM on the surface, water contact angle ∼100), it was rendered hydrophilic (water contact angle ≤60°) using monolayer adsorption of avidin protein. To retrieve the hydrophobicity, the avidin was subsequently removed using non-ionic surfactant octyl-β-D-glucopyranoside. Moreover, by incorporating a biotinylated poly(ethyleneglycol), the avidin-coated surface was resistant to further non-specific adsorption. If the initial surface was hydrophilic (using a CO2H-terminated SAM on the surface, water contact angle ≤20°), it was rendered hydrophobic (water contact angle >90°) using monolayer amphiphilic octadecylamine adsorption. The hydrophilicity was restored after subsequently removing the amphiphile using anionic surfactant sodium lauryl sulfate. Both types of surfaces showed excellent reversibility and demonstrated the ability to control surface wettability.

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Preparation and Characterization of Plasma-Treated Porous Poly(glycerol sebacate) Scaffolds

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.747.182 ◽

2013 ◽

Vol 747 ◽

pp. 182-185

Author(s):

Tharinee Theerathanagorn ◽

Boonlom Thavornyutikarn ◽

Wanida Janvikul

Keyword(s):

Contact Angle ◽

Water Contact Angle ◽

Photoelectron Spectroscopy ◽

Average Molecular Weight ◽

Sebacic Acid ◽

Angle Measurement ◽

Porous Scaffolds ◽

Hydroxyl Groups ◽

Condensation Polymerization ◽

Water Contact

In this study, poly (glycerol sebacate) (PGS) was initially synthesized via condensation polymerization of glycerol and sebacic acid at equimolar ratio (1:1) at 130°C for 24 h. The number average molecular weight (Mn) of the resulting polymer determined by gel permeation chromatography (GPC) was about 2800 g/mol. Porous PGS scaffolds were subsequently prepared by a particle-leaching technique. NaCl was added into the polymer at 60-90% w/w; the mixtures were cured in Teflon molds at 140°C for 16 h. The porous scaffolds were further subjected to surface treatment with low pressure oxygen plasma to increase surface carboxyl and hydroxyl groups and thereby enhance hydrophilicity of PGS scaffold surface. The surface morphology and wettability of both untreated PGS and plasma-treated PGS scaffolds were comparatively determined by scanning electron microscopy (SEM) and water contact angle measurement, respectively. A considerable decrease in water contact angle was observed on the PGS scaffolds after the plasma treatment. The surface chemistry, mechanical strength and degree of swelling of the PGS scaffolds were also assessed by X-ray photoelectron spectroscopy (XPS), dynamic mechanical analysis (DMA) and swelling measurement, respectively.

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High Stability Performance of Superhydrophobic Modified Fluorinated Graphene Films on Copper Alloy Substrates

Advances in Materials Science and Engineering ◽

10.1155/2017/6197872 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Rafik Abbas ◽

N. Elkhoshkhany ◽

Ahmed Hefnawy ◽

Shaker Ebrahim ◽

Aya Rahal

Keyword(s):

Contact Angle ◽

Water Contact Angle ◽

Sliding Angle ◽

Water Contact ◽

Stability Performance ◽

Graphene Films ◽

Superhydrophobic Property ◽

Self Cleaning ◽

Fluorinated Graphene ◽

Highly Hydrophobic

A stable self-cleaning superhydrophobic modified fluorinated graphene surface with micro/nanostructure was successfully fabricated on copper substrates via drop coating process. Irregularly stacked island-like multilayered fluorinated graphene nanoflakes comprised the microstructure. The fabricated films exhibited outstanding superhydrophobic property with a water contact angle 167° and water sliding angle lower than 4°. The developed superhydrophobic surface showed excellent corrosion resistance with insignificant decrease of water contact angle 166° in 3.5 wt.% NaCl solution. This stable highly hydrophobic performance of the fluorinated graphene films could be useful in self-cleaning, antifogging, corrosion resistive coatings and microfluidic devices.

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The Synthesis of Nonionic Hyperbranched Organosilicone Surfactant and Characterization of Its Wetting Ability

Coatings ◽

10.3390/coatings11010032 ◽

2020 ◽

Vol 11 (1) ◽

pp. 32

Author(s):

Jie Liu ◽

Feifei Zhang ◽

Yinghu Song ◽

Kun Lv ◽

Ni Zhang ◽

...

Keyword(s):

Contact Angle ◽

Silicone Oil ◽

Water Solution ◽

Gel Permeation Chromatography ◽

Waterborne Polyurethane ◽

Hydroxyl Groups ◽

Water Contact ◽

Wetting Ability ◽

Ft Ir ◽

Organosilicone Surfactant

In this research, the epoxy silicone oil and self-made hydroxyl-terminated hyperbranched polymer (HBP-OH) were used to synthesis the nonionic hyperbranched organosilicone surfactant (NHSi). The molar rate of hydroxyl groups of HBP-OH and epoxy groups of epoxy silicon oil (n-OH: n-epoxy) was adjusted from 5:1~60:1 to prepare a series of NHSi. The Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FT-IR), contact angle measuring instrument, surface tensiometer and Scanning Electron Microscope (SEM) were employed to characterize the structure and property of HBP-OH and NHSi. GPC analysis indicated that the Mn of HBP-OH was 340.5. FT-IR analysis showed that with the increase of molar rate of n-OH:n-epoxy, the peak intensity of –OH increased. The prepared NHSi was then used to prepare the water solution. The lowest surface tension of NHSi solution was 24.71 mN·m−1 when the n-OH:n-epoxy was 30:1 in the preparation process. The minimum water contact angle of waterborne polyurethane (WPU) emulsion by adding 2% of NHSi was 14.85° on the surface of glass. The wetting experiments showed that the NHSi has good wetting ability to fixed sea-island superfine fiber synthetic material.

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Removal of Oily Contaminants from Water by Using the Hydrophobic Ag Nanoparticles Incorporated Dopamine Modified Cellulose Foam

Polymers ◽

10.3390/polym13183163 ◽

2021 ◽

Vol 13 (18) ◽

pp. 3163

Author(s):

Nadeem Baig ◽

Irshad Kammakakam

Keyword(s):

Contact Angle ◽

Separation Efficiency ◽

Environmentally Friendly ◽

Water Mixture ◽

Ag Nanoparticle ◽

Water Contact ◽

Functionalized Surfaces ◽

Highly Hydrophobic ◽

Modified Cellulose ◽

Excellent Selectivity

The presence of oil-related contaminants in water has emerged as a severe threat to the environment. The separation of these contaminants from water has become a great challenge, and extensive efforts are being made to develop suitable, environmentally friendly materials. Highly hydrophobic materials are effective in the selective separation of oil from water. In this work, silver (Ag)-incorporated, highly hydrophobic dopamine-modified cellulose sponge was prepared by functionalizing with the range of alkyl silanes. The Ag nanoparticle-incorporated dopamine provided the appropriate roughness, whereas the alkyl component provided the low surface energy that made it selective towards oil. It was found that the alkyl groups with a longer chain length were more effective in enhancing the hydrophobicity of the Ag nanoparticle-incorporated, dopamine-modified cellulose. The developed materials were characterized by Fourier transform infrared spectroscopy (FTIR), field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, and contact angle goniometry. The maximum water contact angle on the functionalized surfaces was observed at 148.4°. The surface of the C18s-Ag-DA-Cell-F showed excellent selectivity towards the oily component that rapidly permeated, and water was rejected wholly. The developed material showed a separation efficiency of 96.2% for the oil/water mixture. The C18s-Ag-DA-Cell-F material showed excellent reusability. Due to their environmentally friendly nature, excellent selectivity, and good separation efficiency, the functionalized cellulose materials can be used to separate oil and water effectively.

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Ecological drivers of eggshell wettability in birds

Journal of The Royal Society Interface ◽

10.1098/rsif.2021.0488 ◽

2021 ◽

Vol 18 (183) ◽

Author(s):

Marie R. G. Attard ◽

James Bowen ◽

René Corado ◽

Linnea S. Hall ◽

Robert A. Dorey ◽

...

Keyword(s):

Contact Angle ◽

Extreme Environments ◽

Bird Species ◽

Microbial Colonization ◽

Initial Contact ◽

Water Contact ◽

Diverse Range ◽

External Threats ◽

Highly Hydrophobic ◽

The Relationship

Complex and at times extreme environments have pushed many bird species to develop unique eggshell surface properties to protect the embryo from external threats. Because microbes are usually transmitted into eggs by moisture, some species have evolved hydrophobic shell surfaces that resist water absorption, while also regulating heat loss and the exchange of gases. Here, we investigate the relationship between the wettability of eggshells from 441 bird species and their life-history traits. We measured the initial contact angle between sessile water droplets and the shell surface, and how far the droplet spread. Using phylogenetic comparative methods, we show that body mass, annual temperature and eggshell maculation primarily explained variance in water contact angle across eggshells. Species nesting in warm climates were more likely to exhibit highly hydrophobic eggshells than those nesting in cold climates, potentially to reduce microbial colonization. In non-passerines, immaculate eggs were found to have more hydrophobic surfaces than maculate eggshells. Droplets spread more quickly on eggshells incubated in open nests compared to domed nests, likely to decrease heat transfer from the egg. Here, we identify clear adaptations of eggshell wettability across a diverse range of nesting environments, driven by the need to retain heat and prevent microbial adhesion.

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Fabrication of a Simultaneous Highly Transparent and Highly Hydrophobic Fibrous Films

Applied Sciences ◽

10.3390/app11125565 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5565

Author(s):

Doo-Hyeb Youn ◽

Kyu-Sung Lee ◽

Sun-Kyu Jung ◽

Mangu Kang

Keyword(s):

Surface Roughness ◽

Contact Angle ◽

Water Contact Angle ◽

Electrospun Fiber ◽

Contact Angles ◽

Light Transmittance ◽

Electrospun Fibers ◽

Water Contact ◽

Aligned Fibers ◽

Highly Hydrophobic

This paper discusses the fabrication and characterization of electrospun nanofiber scaffolds made of polystyrene (PS). The scaffolds were characterized in terms of their basis material molecular weight, fiber diameter distribution, contact angles, contact angle hysteresis, and transmittance. We propose an aligned electrospun fiber scaffold using an alignment tool (alignment jig) for the fabrication of highly hydrophobic (θW > 125°) and highly transparent (T > 80.0%) films. We fabricated the alignment jig to align the electrospun fibers parallel to each other. The correlation between the water contact angles and surface roughness of the aligned electrospun fibers was investigated. We found that the water contact angle increased as the surface roughness was increased. Therefore, the hydrophobic properties of the aligned electrospun fibers were enhanced by increasing the surface roughness. With the change in the electrospinning mode to produce aligned fibers rather than randomly distributed fibers, the transmittance of the aligned electrospun fibers increased. The increase in the porous area, leading to better light transmittance in comparison to randomly distributed light scattering through the aligned electrospun fibers increased with the fibers. Through the above investigation of electrospinning parameters, we obtained the simultaneous transparent (>80%) and hydrophobic (θW > 140°) electrospun fiber scaffold. The aligned electrospun fibers of PS had a maximum transmittance of 91.8% at the electrospinning time of 10 s. The water contact angle (WCA) of the aligned electrospun fibers increased from 77° to 141° as the deposition time increased from 10 s to 40 s. The aligned fibers deposited at 40 s showed highly hydrophobic characteristics (θW > 140°).

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A Comparative Analysis on the Effect of Variety of Grape Pomace Extracts on the Ice-Templated 3D Cryogel Features

Gels ◽

10.3390/gels7030076 ◽

2021 ◽

Vol 7 (3) ◽

pp. 76

Author(s):

Irina Elena Raschip ◽

Nicusor Fifere ◽

Maria Valentina Dinu

Keyword(s):

Contact Angle ◽

Food Packaging ◽

Radical Scavenging ◽

Surface Hydrophobicity ◽

Grape Pomace ◽

Total Phenolic ◽

Water Contact ◽

Static Water ◽

Highly Hydrophobic ◽

Water Swelling

Nowadays, there is a growing interest in developing functional packaging materials from renewable resources containing bioactive compounds (such as polyphenols) in order to reduce the use of petroleum-based plastics and their impact on the environment. In this regard, the effect of a variety and concentration of grape pomace extracts (Feteasca Neagra or Merlot) incorporated within ice-templated 3D xanthan-based composites was evaluated by considering their water content, surface and texture properties, radical scavenging and microbiological activities. The embedding of Feteasca Neagra or Merlot grape pomace extracts was studied by static water swelling and contact angle measurements, and SEM, EDX, and TGA analyses. The water contact angle results showed an increase in the surface hydrophobicity of the extract-loaded cryogels with an increase in extract content from 10 to 40 v/v%. SEM micrographs indicated that the entrapment of grape pomace extracts affected the morphology of the pore walls and reduced the pore sizes. The antioxidant activity of grape pomace extract-loaded composite cryogels was closely related to the total phenolic content of grape variety and to their concentration into matrices. The highly hydrophobic character of composite cryogels containing Merlot grape pomace extract and their remarkable antimicrobial activity indicates a great potential of these materials for food packaging applications.

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