Mimicking the Nature to Achieve Superhydrophobic Surfaces by Vapor Phase Deposition

2007 ◽  
Vol 1008 ◽  
Author(s):  
Sushant Gupta ◽  
Arul Arjunan Chakkaravarthi ◽  
Rajiv Singh ◽  
Nate Stevens ◽  
Jeff Opalko ◽  
...  

AbstractA novel technique was developed to create superhydrophobic polytetrafluoroethylene (PTFE) surface using nanosecond pulse electron deposition (PED) technique. The PTFE or Teflon thin films deposited on silicon substrate showed superhydrophobicity evidenced by the contact angle of 166±2 degrees. The SEM micrographs reveal the clustered growth of the deposited film and two level sub-micron asperities which is corroborated by the AFM. FTIR and contact angle studies were conducted to study the chemical nature and the wetting properties of the films.

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 958
Author(s):  
Yeong-Maw Hwang ◽  
Cheng-Tang Pan ◽  
Bo-Syun Chen ◽  
Phuoc Huu Le ◽  
Ngo Ngoc Uyen ◽  
...  

In the present study, the structural, morphological, compositional, nanomechanical, and surface wetting properties of Bi2Se3 thin films prepared using a stoichiometric Bi2Se3 target and a Se-rich Bi2Se5 target are investigated. The Bi2Se3 films were grown on InP(111) substrates by using pulsed laser deposition. X-ray diffraction results revealed that all the as-grown thin films exhibited were highly c-axis-oriented Bi2Se3 phase with slight shift in diffraction angles, presumably due to slight stoichiometry changes. The energy dispersive X-ray spectroscopy analyses indicated that the Se-rich target gives rise to a nearly stoichiometric Bi2Se3 films, while the stoichiometric target only resulted in Se-deficient and Bi-rich films. Atomic force microscopy images showed that the films’ surfaces mainly consist of triangular pyramids with step-and-terrace structures with average roughness, Ra, being ~2.41 nm and ~1.65 nm for films grown with Bi2Se3 and Bi2Se5 targets, respectively. The hardness (Young’s modulus) of the Bi2Se3 thin films grown from the Bi2Se3 and Bi2Se5 targets were 5.4 GPa (110.2 GPa) and 10.3 GPa (186.5 GPa), respectively. The contact angle measurements of water droplets gave the results that the contact angle (surface energy) of the Bi2Se3 films obtained from the Bi2Se3 and Bi2Se5 targets were 80° (21.4 mJ/m2) and 110° (11.9 mJ/m2), respectively.


2017 ◽  
Vol 866 ◽  
pp. 313-317
Author(s):  
Buppachat Toboonsung

An electrical sheet resistance and water contact angle of titanium dioxide nanoparticle thin films were prepared by sparking process. The experiments were carried out by the titanium wires as electrodes of sparking process and varied the sparking time of 1-4 h and the annealing temperature of 200-400 OC for 2 h. The as-deposited and as-annealed of thin films on glass substrate were measured a water contact angle and a sheet resistance whereas a surface was analyzed by a scanning electron microscopy. The results found that the optimum as-deposited TiO2 NP thin films was shown the homogeneity surface, the minimum sheet resistance and the duplicate water contact at the sparking time of 3 h. The optimum as-deposited TiO2 NP thin films was annealed which the water contact angle and the sheet resistance of the as-annealed TiO2 NP thin films decreased with increasing the annealing temperature. However, the hydrophilic property was shown optimum at the annealing temperature of 400 OC.


2011 ◽  
Vol 409 ◽  
pp. 814-819 ◽  
Author(s):  
J. J. Victor ◽  
D. Facchini ◽  
G. Palumbo ◽  
Uwe Erb

In this study, the surface structure of a self-cleaning, superhydrophobic leaf was examined using electron microscopy and optical methods, and its wetting properties were measured using a contact angle goniometer. Using the micro/nanostructural surface features of this leaf as a blueprint, an inexpensive surface structuring technique was developed by modifying the surface of nanocrystalline nickel to create a template. These templates were then pressed into softened polyethylene at elevated temperatures and pressures, thereby transferring the structured surface to the polymer samples. All templates and pressed polymers were characterized in the same manner as the leaves. This method increased the wetting angle for polyethylene from 96° to 151° and reduced the tilt angle from 38° to <5°.


Author(s):  
Ying Song ◽  
Min Zou

This paper reports a study on fabricating superhydrophobic surfaces with micro- and nanohierarchical topography by dynamic nanomasking (DNM) and deep reactive ion etching (DRIE). In this study, thin layers of gold (Au) were sputtered on silicon (Si) wafers followed by annealing the samples in a conventional furnace to break the thin films into Au nanoparticles attached to the Si surfaces. These randomly distributed nanoparticles served as dynamic nanomasks during DRIE processes, in which sulphur hexafluoride (SF6) and octofluorocyclobutane (C4F8) were used as etching and polymerization gases, respectively. Surface topography and wetting properties of the samples were characterized by scanning electron microscopy (SEM) and a video-based optical contact angle meter (VOCAM). SEM images show that this technique created micro-sized craters with Au nanoparticles residing on the ridges of the microstructures. The largest water contact angle (WCA) obtained by this method is about 163°. The surface superhydrophobicity is attributed to the combination of micro- and nano-hierarchical topography and surface polymerization.


2015 ◽  
Vol 9 (3) ◽  
pp. 2461-2469
Author(s):  
S. R. Gosavi ◽  
K. B. Chaudhari

CdS thin films were deposited on glass substrates by using successive ionic layer adsorption and reaction (SILAR) method at room temperature. The effect of SILAR growth cycles on structural, morphological, optical and electrical properties of the films has been studied.  The thickness of the deposited film is measured by employing weight difference method. The X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) studies showed that all the films exhibit polycrystalline nature and are covered well with glass substrates. The values of average crystallite size were found to be 53 nm, 58 nm, 63 nm and 71 nm corresponding to the thin films deposited with 30, 40, 50 and 60 SILAR growth cycles respectively. From the UV–VIS spectra of the deposited thin films, it was seen that both the absorption properties and energy bandgap of the films changes with increasing number of SILAR growth cycles. A decrease of electrical resistivity has been observed with increasing SILAR growth cycle. 


2018 ◽  
Author(s):  
Nicholas Marshall

A set of experiments in surface-initiated ring-opening metathesis polymerization, including end-functionalization of growing brushes and contact angle/cyclic voltammetry measurements. We report preparation and CV of two different conjugated polymer films, and several endgroup and sidechain functionalization experiments using cross-metathesis and active ester substitution.<br>


2011 ◽  
Vol 306-307 ◽  
pp. 25-30 ◽  
Author(s):  
Ping Luo ◽  
Zhan Yun Huang ◽  
Di Hu Chen

In this work, titanium oxide nanorod arrays were fabricated by using the hydrothermal method on fluorine-doped tin oxide (FTO) coated glass. The diameter of the nanorods could be controlled from 150 nm to 30 nm by changing the growth parameters. The surface morphology and the structure of the samples were characterized by SEM and XRD. The wetting properties were identified by contact angle measurement. Platelet attachment was investigated to evaluate the blood compatibility of the samples with different nanoscale topographies. Results show that the nanotopographical surfaces perform outstanding blood compatibility, and the adhering platelet decreased with the increasing diameter of the nanorods.


2007 ◽  
Vol 330-332 ◽  
pp. 877-880 ◽  
Author(s):  
E.S. Thian ◽  
J. Huang ◽  
Serena Best ◽  
Zoe H. Barber ◽  
William Bonfield

Crystalline hydroxyapatite (HA) and 0.8 wt.% silicon-substituted HA (SiHA) thin films were produced using magnetron co-sputtering. These films were subjected to contact angle measurements and in vitro cell culture study using human osteoblast-like (HOB) cells. A wettability study showed that SiHA has a lower contact angle, and thus is more hydrophilic in nature, as compared to HA. Consequently, enhanced cell growth was observed on SiHA at all time-points. Furthermore, distinct and well-developed actin filaments could be seen within HOB cells on SiHA. Thus, this work demonstrated that the surface properties of the coating may be modified by the substitution of Si into the HA structure.


2013 ◽  
Vol 829 ◽  
pp. 917-921
Author(s):  
Saber Ghannadi ◽  
Hossein Abdizadeh ◽  
Mohammad Reza Golobostanfard

Titania thin films were prepared by electrophoretic deposition at various deposition times (1, 5 and 10 min) in constant applied potential (5 V). For this purpose, modified titania sol was prepared as a colloidal suspension. The influence of deposition time on the thickness and optical properties of titania films was investigated. Scanning electron microscope images illustrate compact and homogeneous titania films deposited on FTO substrates. The results show that the film thickness increases with increasing the deposition time. It could be inferred from UV-Vis spectroscopy that increasing the thickness of deposited film causes higher absorbance at UV region. Also, increasing the deposition time from 1 to 5 min leads to increase in optical band gap of the deposited films.


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