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Anatase nanocrystals were successfully synthesized and deposited onto polyacrylonitrile fibers with photocatalytic self-cleaning activity using the sol-gel process at low temperature. The original and treated samples have been characterized by several techniques such as scanning electron microscopy, fourier transform infrared spectroscopy, x-ray diffraction, diffuse reflectance spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The TiO 2 nanoparticles, have been found to form a homogeneous thin film on the fiber surface. The photocatalytic activity, tested by measuring the degradation of adsorbed Eosin Yellowish dye. The photoactivity of the titanium dioxide coated fibres is much higher than that observed in case of untreated fibers. The photocatalytic selfcleaning properties of the treated fibers was fully maintained performing several cycles of photodegradation. This preparation technique can be also applied to new fabrics to create self-cleaning properties in them. The thermogravimetric study of PAN/TiO 2 composite showed a slight increase of weight loss in the second step, which implied that, the dehydrogenation and oxygen uptake reactions would be promoted by the TiO 2 to some extent.Keywords: Polyacrylonitrile; Titanium dioxide; Thermogravimetric analysis; Differential scanning calorimetry; Photodegradation; Eosin Yellowish e-mail: Shalkeh737@gmail.com INTRODUTIONPolyacrylonitrile (PAN) is one of the most widely used precursor polymers for making high performance carbon fibers [1][2][3][4][5]. Study of the degradation of polyacrylonitrile has been a subject of interest for decades owing to its commercial value for the production of carbon fibers [6][7][8][9][10]. Spectroscopy, including infrared, ultraviolet, solid-state nuclear magnetic resonance (NMR) and x-ray photoelectron spectroscopy (XPS), and thermal analysis, including differential scanning calorimetry (DSC), differential thermal analysis (DTA) and thermogravimetric analysis (TGA), are the common tools in the study of polyacrylonitrile degradation [11][12][13][14].Semiconductor photocatalysis has been gathering much attention recently due to its promising application in chemical conversion and storage of solar energy for solar cells, hydrogen production, refractory pollutants elimination and self-cleaning surface [15][16][17][18].Among various oxide semiconductor photocatalysts, titanium oxide (TiO 2 ) has been proven so far to be the most promising material used for both fundamental research and practical applications. Because of its highly efficient photoreactivity, biological and chemical inertness, cost effectiveness, non-toxicity, and long-term stability against photocorrosion and chemical corrosion, titanium dioxide has been frequently employed in the environmental treatment and purification purposes [18][19][20][21][22]. Anatase TiO 2 has been identified as the most effective and useful photocatalyst under near UV illumination [23].The pairs of free electrons and holes are formed in the conduction and va...

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Self-cleaning polymeric fibers have been successfully prepared by depositing ZnO nanoparticle onto wool and polyacrylonitrile (PAN) fibers with good compatibility and significant photocatalytic self-cleaning activity using the sol-gel process at ambient temperature. scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area analysis, and thermogravimetric analysis have been adopted as the characterization techniques. Transmission electron microscopy studies revealed presence of zinc oxide nanoparticles with 10-15 nm in size. Brunauer-Emmett-Teller measurement showed surface area of 48 m 2 /g for the ZnO nanoparticles. Photocatalytic activity of the self-cleaning materials were tested by measuring the photo-assisted degradation of methylene blue (MB) and eosin yellowish (EY) under ultraviolet-visible illumination.The results indicate that both of the ZnO-coated polyacrylonitrile and ZnO-coated wool fibers acquire photocatalytic activity toward dyes degradation. The photocatalytic activity of the treated fibers is maintained upon several numbers of photodegradation cycles. This facile and cheap preparation technique can be also applied to new polymeric fabrics to produce self-cleaning materials for industrial application.

The photocatalytic activity of TiO 2 and ZrO 2 -coated polyacrylonitrile (PAN) fibers was compared through the self-cleaning of methylene blue and eosin yellowish. TiO 2 and ZrO 2 nanocrystals were successfully synthesized and deposited onto PAN fibers with photocatalytic self-cleaning activity using the sol-gel process at low temperature. The pristine and treated samples have been characterized by several techniques, such as scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy, X-ray diffraction, and thermogravimetric analysis. The TiO 2 nanoparticles with 10-20 nm in size, and ZrO 2 with 20-40 nm have been synthesized to form dispersed particles on the fiber surface, which shows photocatalytic properties when exposed to UV-Vis light. The photocatalytic activity, tested by measuring the degradation of adsorbed methylene blue and Eosin Y. Photocatalytic activity of TiO 2 -coated fibers toward dyes degradation was higher than that of ZrO 2 -coated fibers. This preparation technique can be also applied to new fabrics to create self-cleaning and UV irradiation protection properties in them.