ساخت و ارزيابي لايه هاي نازك نانوكامپوزيتي سراميكي با ويژگي هاي آب‌گريزي و روغن گريزي

Aluminum-doped zinc oxide , Sol–gel , Fumed silica nanoparticles , Carbon nanotubes , Hydro‎phobicity , Oleophobicity , Perfluorooctyltriethoxysilane

Fabrication an‎d Investigation of Ceramic Nanocomposite Thin Films with Hydro‎phobic an‎d Oleophobic Properties

نانو فناوري

In this study, aluminum-doped zinc oxide (AZO) thin films were synthesized on glass substrates using the sol–gel dip-coating technique. To investigate the effect of surface microstructure modification on the functional properties of the coatings, different concentrations of fumed silica nanoparticles an‎d carbon nanotubes (CNTs) were individually incorporated into the coating structure. Furthermore, to impart hydro‎phobic an‎d oleophobic characteristics, the coating surfaces were modified with a perfluorooctyltriethoxysilane (PFT) solution, which reduced the surface energy an‎d consequently enhanced the wettability properties. The X-ray diffraction (XRD) results confirmed the successful formation of the hexagonal wurtzite crystalline structure of aluminum-doped zinc oxide. Fourier-transform infrared spectroscopy (FTIR) further verified the successful formation of the oxide structure through the presence of characteristic Zn–O vibrational ban‎ds in both powder samples an‎d thin films. Surface morphology analysis using atomic force microscopy (AFM) revealed that increasing the concentration of fumed silica nanoparticles up to 0.5 wt.% significantly increased the surface roughness, with a maximum roughness value of 2148 nm. In addition, the highest surface roughness among the CNT-containing samples was observed for the coating consisting of five AZO layers an‎d 4 wt.% carbon nanotubes. Optical transmittance measurements showed that increasing the concentration of fumed silica nanoparticles, increasing the CNT content, an‎d increasing the number of AZO layers all led to a reduction in the transparency of the coatings. The enhanced surface roughness induced by the incorporation of fumed silica nanoparticles increased the water an‎d oil contact angles, thereby improving both hydro‎phobicity an‎d oleophobicity. The highest water contact angle of 137° an‎d the highest oil contact angle of 51° were achieved for the coating containing 0.5 wt.% fumed silica nanoparticles. In contrast, increasing the CNT concentration resulted in a decrease in both water an‎d oil contact angles, indicating that its contribution to improving hydro‎phobicity an‎d oleophobicity was less significant than that of fumed silica nanoparticles. Overall, the results demonstrate that modifying AZO coatings with fumed silica nanoparticles an‎d carbon nanotubes enables simultaneous control of surface roughness, optical transparency, an‎d wettability. Increasing the fumed silica content, together with surface modification using perfluorooctyltriethoxysilane, enhanced the surface roughness an‎d reduced the surface free energy, leading to a maximum water contact angle of 137° an‎d an oil contact angle of 51°. Conversely, although increasing the CNT content an‎d the number of AZO layers affected the surface microstructure, both factors reduced the optical transparency of the coatings. Therefore, the type an‎d concentration of nanofillers should be carefully selec‎ted according to the intended application of the coating while maintaining an appropriate balance between transparency, hydro‎phobicity, an‎d oleophobicity.

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