Wetting characteristics of ZnO smooth film and nanowire structure with and without OTS coating

Lin, Li Yu; Kim, Hyun Joon; Kim, Dae Eun

doi:10.1016/j.apsusc.2008.05.337

Cited by 28 publications

(21 citation statements)

References 26 publications

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“…Two theoretical models (Wenzel model and Cassie-Baxter model) form the basic guidelines for the study of the hydrophobic surface. 84,85 For a liquid drop on a solid surface, the contact angle, Q, is determined by the surface free energies involved: (16) where g sv , g sl and g lv are the (solid/vapor), (solid/liquid), and (liquid/vapor) tensions, respectively. The main feature of the ZnO-based nanostructures is its gradual transition between different hierarchical morphologies, which allows us to investigate the geometrical effects on the wetting behavior of the samples.…”

Section: Contact Angle Measurementsmentioning

confidence: 99%

Nanostructured ZnO thin films for self-cleaning applications

2017

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Controlling the properties of nanostructured zinc oxide (ZnO) is an interesting way to broaden its multifunctionality. ZnO nanostructured films were grown on glass substrates under different conditions by a simple two-step wet chemical method. A low-cost successive ionic layer adsorption and reaction (SILAR) method was used to grow ZnO seed layers at 80 C. Then, different hierarchical based ZnO nanostructured thin films were deposited onto the ZnO seed layers by chemical bath deposition (CBD).The influence of deposition time (t D ) and pH on the surface morphology, wettability behavior, structural and optical properties of the ZnO nanostructured films were systematically investigated. The structural, morphological, optical and wetting properties were studied by X-ray diffraction (XRD), field emission scanning microscopy (FE-SEM), UV-Vis spectrophotometer, and water contact angle (WCA) measurement, respectively. The surface morphology revealed a complex and orientated hierarchical based ZnO nanostructured films with diverse shapes from hexagonal nanorods to hexagonal nanoplates and even much more complex plates/rods and flower-like shapes by changing deposition time and pH of the precursor. XRD results confirm the synthesis of nanostructured ZnO of the hexagonal structure with a preferential orientation along the (002) lattice plane. The average crystallite size, D, is altered between 41.41 to 68.43 nm dependent on the morphology of the ZnO film and pH of the precursor. At pH 6.5, the films are hydrophilic for 10 h # t D # 6 h and hydrophobic for 6 h < t D < 10 h. The wetting properties of the films were enhanced by increasing or decreasing pH around 6.5. Morphology and thickness of the ZnO nanostructure could efficiently control the transmittance, absorbance, optical band gap, and the extinction coefficient of the films. The optical band gap is blue shifted from 2.45 to 3.62 eV@pH 6.5 as the deposition time increased from 2 to 8 h and blue shifted from 2.72 to 3.62 eV@8 h as the pH value increased from 5.5 to 6.5. The existence of stable hydrophobic zinc oxide nanostructured films at room temperature at a large-scale and with band gaps around 3.62 eV supports their use in selfcleaning and gas sensing applications.

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Section: Contact Angle Measurementsmentioning

confidence: 99%

Nanostructured ZnO thin films for self-cleaning applications

2017

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“…The static contact angles, measured in the absence of UV light irradiation, in both cases are similar, around 32 , much lower than the values characteristic for pure ZnO thin films of $110 (Ref. 9) and $90 , 37 or ZnO nanowire structures of $100 . 37 Moreover, a linear decrease in contact angle values can be observed with the increase in the irradiation time.…”

Section: Resultsmentioning

confidence: 54%

“…9) and $90 , 37 or ZnO nanowire structures of $100 . 37 Moreover, a linear decrease in contact angle values can be observed with the increase in the irradiation time. However, the slopes of the two graphs are different.…”

Section: Resultsmentioning

confidence: 98%

Effect of nitrogen doping on wetting and photoactive properties of laser processed zinc oxide-graphene oxide nanocomposite layers

György

Pino

Logofatu

et al. 2014

Journal of Applied Physics

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Zinc oxide-graphene oxide nanocomposite layers were submitted to laser irradiation in air or controlled nitrogen atmosphere using a frequency quadrupled Nd:YAG (λ = 266 nm, τFWHM ≅ 3 ns, ν = 10 Hz) laser source. The experiments were performed in air at atmospheric pressure or in nitrogen at a pressure of 2 × 104 Pa. The effect of the irradiation conditions, incident laser fluence value, and number of subsequent laser pulses on the surface morphology of the composite material was systematically investigated. The obtained results reveal that nitrogen incorporation improves significantly the wetting and photoactive properties of the laser processed layers. The kinetics of water contact angle variation when the samples are submitted to laser irradiation in nitrogen are faster than that of the samples irradiated in air, the surfaces becoming super-hydrophilic under UV light irradiation.

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“…Other uses of ZnO by many techniques to alter surface hydrophobicity are well documented. These include microcontact printing [27], cathodic electrodeposition [28], solution-dipping template methods [29], natural zinc metal oxidation [30], metal-organic chemical vapor deposition (MOCVD) [31], chemical bath deposition [32], vapor-liquid-solid growth (VLS) [33][34][35], DC plasma processing [36] and hydrothermal growth processes [37,38]. In most cases, these efforts involve unitary (single roughness) surface morphologies followed by chemical modification to generate low energy superhydrophobic surfaces.…”

Section: Introductionmentioning

confidence: 99%