Fabrication of durable porous and non-porous superhydrophobic LLDPE/ SiO 2 nanoparticles coatings with excellent self-cleaning property M. Satapathy a , P. Varshney a , D. Nanda a , S.S. Mohapatra a , A. Behera b , A. Kumar a, ⁎ a Advanced Materials Laboratory, Department of Chemical Engineering, National Institute of Technology (NIT) Rourkela, Odisha 769008, India b Department of Metallurgical and Materials Engineering, National Institute of Technology (NIT) Rourkela, Odisha 769008, India abstract article info Article history: Received 9 January 2017 Revised 26 June 2017 Accepted in revised form 10 July 2017 Available online xxxx In this current work, SiO 2 nanoparticles embedded linear low density polyethylene (LLDPE) superhydrophobic coatings on glass substrates were fabricated using dip-coating technique. Porosity of SiO 2 nanoparticles coupled LLDPE superhydrophobic coatings was also varied using non-solvent (ethanol) by employing phase separation method. Surface morphology, water contact angle, self-cleaning and water-repellency of coatings were charac- terized. Furthermore, the stability of these coatings was also evaluated by conducting thermal, chemical and me- chanical stability tests at perturbation conditions. Along with, comparative studies of porous and non-porous LLDPE/SiO 2 coatings on their performances were presented in the current work. By creating porosity and/or em- bedding SiO 2 nanoparticles in to LLDPE matrix, superhydrophobicity is achieved with water contact angle of 170° and sliding angle of 3.8°. Coatings exhibit the excellent self-cleaning property. Their superhydrophobic property is also maintained after annealing in temperature range from 40 to 120 °C. Water jet impact test reveals the ex- cellent water repellent nature of coatings. Non-porous coatings exhibit more stability in pH range from 2 to 9 than porous coatings. By abrasion test with micro-fiber cloth and tape peeling tests, it is observed that porous coatings are more durable than non-porous coatings. The aforesaid coatings have great industrial applications. © 2017 Elsevier B.V. All rights reserved. Keywords: Water-repellency Superhydrophobic Self-cleaning Porous polymer 1. Introduction Nature has bestowed human beings with a lot of examples on superhydrophobic or non-wettable surfaces. Few examples of non-wet- table surfaces are lotus leaf [1,2], gecko's feet [2,3], wings of butterflies [2] and legs of water strider [4]. Superhydrophobic surfaces are the sur- faces with water contact angle N 150° and readily repel water. These nat- urally occurring non-wettable surfaces has inspired scientists to mimic their water repellent [2–4,6] and self-cleaning [2–6] behavior in prepa- ration of artificial superhydrophobic surfaces. Different fabrication tech- niques to achieve artificial superhydrophobicity are lithography [7,8], etching [9–11], dip-coating [12–17], spin-coating [18], spray-coating [19–21], sol-gel [22–24], anodisation [25,26], chemical vapour deposi- tion [27], electrochemical deposition [28], self-assembly [29,30], casting [31] and nano-imprinting [32]. In general, preparation of artificial superhydrophobic surfaces involves two approaches. First approach is to create rough structure on hydrophobic surface and the second ap- proach is to modify the rough surface with materials of low surface energy. In order to fabricate superhydrophobic surfaces; polymers, low sur- face energy organic materials have grabbed the attention of many scientists due to the presence of non-polar hydrophobic (–CH 2 -) groups in main chain, low cost and easy availability. Certain properties of linear low density polyethylene (LLDPE) such as high tensile strength, impact resistance, flexibility, durability and resistance to chemicals make it an ideal base material for polymer matrix [33,34]. Because of these proper- ties, LLDPE has tremendous applications in packaging (plastic bags and sheets), cable covering, toys, lids, containers and pipes [34]. In recent decade, efforts have been made to develop superhydrophobic and durable LLDPE surfaces which have a great po- tential to solve industry related complex problems such as cleaning the accumulated unwanted liquid/contaminants. Few studies have been reported on synthesis of superhydrophobic LLDPE and other types of polyethylene (PE). For instances, Shixiang Lu et al. [35] reported the formation of a non-corrosive stable superhydrophobic surface pre- pared on zinc substrates using ethanol-xylene solution of high density polyethylene (HDPE) and graphene oxide with a water contact angle of 154°. Mao Peng et al. [36] obtained a conductive superhydrophobic surface made from multi-wall carbon nanotube (MWCNT) embedded polyethylene surface having a contact angle of 165 ± 3°. Zheng Jianyong et al. [37] developed a bionic superhydrophobic LLDPE polymer film having contact angle 152.7 ± 0.8° where calcium carbonate (CaCO 3 ) was used as a template through replica-molding technique. Jerome Fresnais et al. [38] reported the formation of transparent superhydrophobic polyethylene surfaces by one-step (CF 4 plasma Surface & Coatings Technology xxx (2017) xxx–xxx ⁎ Corresponding author. E-mail address: kumaraditya@nitrkl.ac.in (A. Kumar). SCT-22509; No of Pages 9 http://dx.doi.org/10.1016/j.surfcoat.2017.07.025 0257-8972/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Surface & Coatings Technology journal homepage: www.elsevier.com/locate/surfcoat Please cite this article as: M. Satapathy, et al., Surf. Coat. Technol. (2017), http://dx.doi.org/10.1016/j.surfcoat.2017.07.025