Hydrophobicity of Teflon Coated Well-Ordered Silver Nanorod Arrays

2012 ◽  
Vol 1389 ◽  
Author(s):  
Arif S. Alagoz ◽  
Wisam J. Khudhayer ◽  
Tansel Karabacak
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Hierarchical Structures ◽  
Silicon Substrates ◽  
Nanorod Arrays ◽  
Water Contact ◽  
Glad Technique ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Angle Deposition

ABSTRACTFrom wings of flies to plant leafs, hydrophobic surfaces are well-common in nature. Many of these surfaces have micro and nano hierarchical structures coated with low surface energy layer. In this work, we mimicked similar structure by fabricating Teflon coated periodic and well-ordered silver nanorod arrays and investigated the effect of nanorod separation on water contact angle (WCA). The silver nanorod arrays were deposited on patterned and flat silicon substrates using glancing angle deposition (GLAD) technique. Then a thin layer of Teflon was deposited on the silver nanorods by small angle deposition (SAD) technique. A systematic increase in water contact angle was observed with increasing nanorod separation which is attributed to the decreased area fraction of solid-liquid interface.

Hydrophobic Metallic Nanorods coated with Teflon Nanopatches by Glancing Angle Deposition

2009 ◽  
Vol 1188 ◽  
Author(s):  
Wisam J Khudhayer ◽  
Rajesh Sharma ◽  
Tansel Karabacak
Keyword(s):  
Contact Angle ◽  
Normal Incidence ◽  
Glancing Angle Deposition ◽  
Nanorod Arrays ◽  
Hydrophobic Property ◽  
Glancing Angle ◽  
Shadowing Effect ◽  
Glad Technique ◽  
Metallic Nanorods ◽  
Angle Deposition

AbstractIntroducing a hydrophobic property to vertically aligned hydrophilic metallic nanorods was investigated experimentally and theoretically. First, platinum nanorod arrays were deposited on flat silicon substrates using a sputter Glancing Angle Deposition Technique (GLAD). Then a thin layer of Teflon (nanopatches) was partially deposited on the tips of platinum nanorod at a glancing angle of  = 85° as well as at normal incidence ( = 0°) for different deposition times. We show that GLAD technique is capable of depositing ultrathin isolated Teflon nanopatches on selective regions of nanorod arrays due to the shadowing effect during GLAD. Contact angle measurements on Pt/Teflon nano-composite have shown contact angle values as high as 138°, indicating a significant increase in the hydrophobicity of originally hydrophilic Pt nanostructures. Finally, a 2D simplified wetting model utilizing Cassie and Baxter theory of heterogeneous surfaces has been developed to explain the wetting behavior of Pt/Teflon nanocomposite.

scholarly journals Fabrication of Adhesive Resistance Surface with Low Wettability on Ti6Al4V Alloys by Electro-Brush Plating

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 64 ◽  
Author(s):  
Xiaojuan Dong ◽  
Jianbing Meng ◽  
Haian Zhou ◽  
Rufeng Xu ◽  
Xue Bai ◽  
...  
Keyword(s):  
Contact Angle ◽  
Chemical Compositions ◽  
Sliding Angle ◽  
Water Contact ◽  
Resistance Surface ◽  
Adhesive Surface ◽  
Plating Method ◽  
Brush Plating ◽  
Solid Liquid Interface ◽  
Solid Liquid

Anti-adhesive Ni coatings with low wettability were successfully fabricated on Ti6Al4V substrates via an electro-brush plating method, and subsequently modified with a fluoroalkylsilane (FAS) film. The surface morphology, chemical compositions, and wettability of the as-prepared coatings were measured using scanning electron microscopy (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrophotometry (FTIR), and contact angle measurements. The results showed that the surface of Ti6Al4V substrate was endowed with flower-like structures. Each flower-like cluster was constituted by a large number of Ni ions. After surface modification of FAS, the as-prepared Ti6Al4V surface had a water contact angle as high as 151.5°, a sliding angle close to 2.1°, and a solid surface energy as low as 0.97 mJ/m2. Potentiodynamic polarization tests showed that the Ni coating could provide a stable corrosion protection. In addition, the effects of processing conditions, such as working voltage, relative velocity, electrolyte concentration, and processing time, were investigated. The mechanism of the adhesive resistance was proposed, and the low wettability of Ti6Al4V surfaces was explained by Cassie–Baxter model. As a result, it was necessary to reduce the fraction of the solid–liquid interface in order to achieve anti-adhesive surface.

STICKY AND SLIPPY: TWO HYDROPHOBIC STATES TRANSITION OF ZnO HIERARCHICAL FILMS BY FLUOROALKYLSILANE MODIFICATION

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1867-1872 ◽  
Author(s):  
CHANGSONG LIU ◽  
QIANG ZHANG ◽  
TAO LI ◽  
ZHIWEN LI
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Hydrofluoric Acid ◽  
Hierarchical Structures ◽  
Zinc Nitrate ◽  
Zno Films ◽  
Water Droplets ◽  
Water Contact ◽  
Wetting Properties ◽  
Strong Adhesion

ZnO films with hierarchical structures were prepared in an aqueous solution of zinc nitrate, hexamethylenetetramine and hydrofluoric acid. They demonstrated superhydrophobicity and two superhydrophobic states conversion from sticky to slippy after they were modified by fluoroalkylsilane (FAS) self-assemble layers. Before FAS modification, ZnO hierarchical structures, having sphere-like microstructures with nano-petals, showed water contact angle of 151° and a sticky behavior: water droplets rest on such surface did not slide when the surface was tilted to any angle or even upside down, indicating a strong adhesion between water and the surface. However, after FAS modification, ZnO films showed an increase of water contact angle up to 164° and a large difference in dynamic wetting properties: water droplets moved spontaneously and hardly came to rest even on a horizontal surface. The transition from sticky ("Wenzel's state") to slippy ("Cassie's state") resulted from surface free energy change from high to low. The results also confirm that the low enough surface energy, cooperating with surface roughness, is crucial in making Cassie's state superhydrophobicity. The realization of conversion from sticky to slippy is of importance for further understanding wetting properties and applications of ZnO micronanostructures.

Long-Term Stable Metal Organic Framework (MOF) Based Mixed Matrix Membranes for Ultrafiltration

2020 ◽  
Author(s):  
Muayad Al-shaeli ◽  
Stefan J. D. Smith ◽  
Shanxue Jiang ◽  
Huanting Wang ◽  
Kaisong Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Mixed Matrix Membranes ◽  
Recovery Ratio ◽  
Mixed Matrix ◽  
Water Contact ◽  
Membrane Performance ◽  
Metal Organic ◽  
Matrix Membranes

<p>In this study, novel <a>mixed matrix polyethersulfone (PES) membranes</a> were synthesized by using two different kinds of metal organic frameworks (MOFs), namely UiO-66 and UiO-66-NH<sub>2</sub>. The composite membranes were characterised by SEM, EDX, FTIR, PXRD, water contact angle, porosity, pore size, etc. Membrane performance was investigated by water permeation flux, flux recovery ratio, fouling resistance and anti-fouling performance. The stability test was also conducted for the prepared mixed matrix membranes. A higher reduction in the water contact angle was observed after adding both MOFs to the PES and sulfonated PES membranes compared to pristine PES membranes. An enhancement in membrane performance was observed by embedding the MOF into PES membrane matrix, which may be attributed to the super-hydrophilic porous structure of UiO-66-NH<sub>2</sub> nanoparticles and hydrophilic structure of UiO-66 nanoparticles that could accelerate the exchange rate between solvent and non-solvent during the phase inversion process. By adding the MOFs into PES matrix, the flux recovery ratio was increased greatly (more than 99% for most mixed matrix membranes). The mixed matrix membranes showed higher resistance to protein adsorption compared to pristine PES membranes. After immersing the membranes in water for 3 months, 6 months and 12 months, both MOFs were stable and retained their structure. This study indicates that UiO-66 and UiO-66-NH<sub>2</sub> are great candidates for designing long-term stable mixed matrix membranes with higher anti-fouling performance.</p>

scholarly journals Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrzej Sikora ◽  
Dariusz Czylkowski ◽  
Bartosz Hrycak ◽  
Magdalena Moczała-Dusanowska ◽  
Marcin Łapiński ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Chemical Composition ◽  
Water Contact Angle ◽  
Plasma Sheet ◽  
Atmospheric Pressure ◽  
Argon Plasma ◽  
Fullerene Derivative ◽  
Water Contact ◽  
Pmma Polymer

AbstractThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number of plasma scans (up to 3) and, the kind of treated material. In order to assess the plasma effect, the possible changes in the wettability, roughness, chemical composition, and mechanical properties of the plasma-treated samples’ surfaces were evaluated by water contact angle goniometry (WCA), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The best result concerning the water contact angle reduction was from 83° to 29.7° for the PMMA material. The ageing studies of the PMMA plasma-modified surface showed long term (100 h) improved wettability. As a result of plasma treating, changes in the samples surface roughness parameters were observed, however their dependence on the number of plasma scans is irregular. The ATR-FTIR spectra of the PMMA plasma-treated surfaces showed only slight changes in comparison with the spectra of an untreated sample. The more significant differences were demonstrated by XPS measurements indicating the surface chemical composition changes after plasma treatment and revealing the oxygen to carbon ratio increase from 0.1 to 0.4.

scholarly journals Physicochemical Properties and Biocompatibility of Electrospun Polycaprolactone/Gelatin Nanofibers

2021 ◽  
Vol 18 (9) ◽  
pp. 4764
Author(s):  
Wei Lee Lim ◽  
Shiplu Roy Chowdhury ◽  
Min Hwei Ng ◽  
Jia Xian Law
Keyword(s):  
Contact Angle ◽  
Physicochemical Properties ◽  
Water Contact Angle ◽  
Ligament Injury ◽  
Great Promise ◽  
Composition Analysis ◽  
Water Contact ◽  
Tenogenic Differentiation ◽  
Good Biocompatibility ◽  
Tissue Grafts

Tissue-engineered substitutes have shown great promise as a potential replacement for current tissue grafts to treat tendon/ligament injury. Herein, we have fabricated aligned polycaprolactone (PCL) and gelatin (GT) nanofibers and further evaluated their physicochemical properties and biocompatibility. PCL and GT were mixed at a ratio of 100:0, 70:30, 50:50, 30:70, 0:100, and electrospun to generate aligned nanofibers. The PCL/GT nanofibers were assessed to determine the diameter, alignment, water contact angle, degradation, and surface chemical analysis. The effects on cells were evaluated through Wharton’s jelly-derived mesenchymal stem cell (WJ-MSC) viability, alignment and tenogenic differentiation. The PCL/GT nanofibers were aligned and had a mean fiber diameter within 200–800 nm. Increasing the GT concentration reduced the water contact angle of the nanofibers. GT nanofibers alone degraded fastest, observed only within 2 days. Chemical composition analysis confirmed the presence of PCL and GT in the nanofibers. The WJ-MSCs were aligned and remained viable after 7 days with the PCL/GT nanofibers. Additionally, the PCL/GT nanofibers supported tenogenic differentiation of WJ-MSCs. The fabricated PCL/GT nanofibers have a diameter that closely resembles the native tissue’s collagen fibrils and have good biocompatibility. Thus, our study demonstrated the suitability of PCL/GT nanofibers for tendon/ligament tissue engineering applications.

Osteoconductivity of Superhydrophilic Ti- and Zr-Alloy for Biomedical Application

2016 ◽  
Vol 879 ◽  
pp. 2524-2527
Author(s):  
Masazumi Okido ◽  
Kensuke Kuroda
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Strong Influence ◽  
Biomedical Application ◽  
Hydrophobic Surface ◽  
Hydrophilic Surface ◽  
Water Contact ◽  
Zr Alloy ◽  
Zr Alloys

Surface hydrophilicity is considered to have a strong influence on the biological reactions of bone-substituting materials. However, the influence of a hydrophilic or hydrophobic surface on the osteoconductivity is not completely clear. In this study, we produced super-hydrophilic and hydrophobic surface on Ti-and Zr-alloys. Hydrothermal treatment at 180 oC for 180 min. in the distilled water and immersion in x5 PBS(-) brought the super-hydrophilic surface (water contact angle < 10 (deg.)) and heat treatment of as-hydrothermaled the hydrophobic surface. The osteoconductivity of the surface treated samples with several water contact angle was evaluated by in vivo testing. The surface properties, especially water contact angle, strongly affected the osteoconductivity and protein adsorbability, and not the surface substance.

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

Polymers ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document