Contents lists available at ScienceDirect Progress in Organic Coatings journal homepage: www.elsevier.com/locate/porgcoat Transparent hard self-cleaning nano-hybrid coating on polymeric substrate Akbar Eshaghi Faculty of Materials Engineering, Malek Ashtar University of Technology, Shahin Shahr, Esfahan, Iran ARTICLEINFO Keywords: Nano-hybrid Coating Hydrophobic Self-cleaning Transparent Polycarbonate ABSTRACT In this research, GPTMS-silica nano-hybrid coatings were immobilized on polycarbonate (PC) substrates by a sol- gel method. Perfuorooctyl-trichlorosilane (PFTS) was utilized to modify the prepared nano-hybrid coating surface. The modifed nano-hybrid coatings were characterized by Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersive X-ray Spectrometry (EDS), atomic force microscopy (AFM), attenuated total re- fectance Fourier transform infrared spectroscopy (ATR-FTIR), UV–vis-NIR spectrophotometer, and water con- tact angle analyzer methods. In addition, the self-cleaning properties of the nano-hybrid coatings were in- vestigated. The results indicated that the formation of the nano-hybrid flm improved the hardness and transmittance of the PC substrate. FE-SEM image indicated the formation of the crack free coating on the PC substrate. In addition, the modifed nano-hybrid coating displays hydrophobicity (CA, 110°) and is very efcient at removing dust through water droplets. 1. Introduction Transparent polymer materials (such as polycarbonate, PC) have been become a popular topic in material science due to their unique properties such as lightweight, optical transparency, electrical and mechanical properties, and ease in their mass production. Such mate- rials are appropriate to replace inorganic glass in a wide range of ap- plications, including display panels of electronic devices, compact disks, lightweight eyewear lenses and safety windows. However, these materials have poor scratch resistance, abrasion resistance, and en- vironmental degradation that would limit their applications [1,2]. One approach to overcome these limitations is to apply transparent hard coatings. In addition to protective purpose, hard coatings may be functionalized to impart specifc properties like hydrophobicity [3]. Superhydrophobic surface defnes a surface with static water contact angle more than 150°. Superhydrophobic property has much attention due to its wide applications such as self-cleaning efect, anti-fog, anti- icing, oil-water separation, drag reduction, corrosion resistance, anti- bacterial and etc [4–6]. In the superhydrophobic surface water droplets cannot stay on a surface and roll of easily. Thus, the pollutants on the surface can also be easily picked up by the rolling water droplets and created a clean surface (self-cleaning efect). Therefore, fabrication of self-cleaning surface is considered in many industries such as the auto industry, satellite dishes and external architectural glass, windshields, solar cells, and optical devices because application of self-cleaning surface can decrease cleanup costs and improve device efciency [7–10]. Many researchers fabricated a transparent hybrid coating on polymeric substrates with self-cleaning and anti-scratch properties. Chang et al. [11] based on the modifed nano-silica/polymer have de- veloped a transparent hybrid hydrophobic hard coating on PMMA substrate. Their results indicated that water contact angle on the hybrid coating surface was 106° and pencil hardness reached to 6H. Ren et al. [12] have made transparent superhydrophobic thin flms on polymeric substrates. They created superhydrophobic thin flms in multiple stages: frst dip coating silica nanoparticles, then spray coating hollow of silica nanoparticles, followed by spray coating of mesoporous silica na- nosheets & poly (vinyl alcohol)(PVA). Finally, the thin flms were sur- face treated by a chemical vapor deposition of 1H,1H,2H,2H –per- furooctyltriethoxy silane (POTS). Their results indicated the optimized thin flm had a water contact angle of 164° and maximum transmittance of 96.0% (in the 300–2500 nm). The thin flm also showed good me- chanical durability than water droplet impact test and sand impact abrasion test. In the present study, a hard and transparent nano- composite coating based on the SiO 2 -GPTMS/ PFTS was deposited on the PC substrates by using a sol–gel process. Then, the hydrophobic, self-cleaning, optical and mechanical properties of the nanocomposite coatings were investigated. 2. Experimental 2.1. Materials 3-Glycidoxypropyl-trimethoxysilane (GPTMS) (%99 ≤ ), Ethylenediamine (EDA, 99.5%), Ethanol (%99) and hydrochloric acid https://doi.org/10.1016/j.porgcoat.2018.12.021 Received 14 November 2018; Received in revised form 3 December 2018; Accepted 16 December 2018 E-mail addresses: Eshaghi@mut_es.ac.ir, eshaghi.akbar@gmail.com. Progress in Organic Coatings 128 (2019) 120–126 0300-9440/ © 2018 Elsevier B.V. All rights reserved. T