Int J Advanced Design and Manufacturing Technology, Vol. 13/ No. 4/ December – 2020 21 Research paper © 2020 IAU, Majlesi Branch Study on the Wettability and Optical Properties of Polydimethylsiloxane-SiO 2 Nano-composite Surfaces Reza Abedinzadeh 1, *, Hamid Shirian 2 Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr, Isfahan, Iran E-mail: abedinzadeh@iaukhsh.ac.ir*, reza_abd2001@yahoo.com *Corresponding author Janan Parhizkar 3 Nanotechnology Laboratory, Department of Chemistry, University of Isfahan, Isfahan, Iran E-mail: jananparhizkar@gmail.com Received: 4 March 2020, Revised: 18 June 2020, Accepted: 22 July 2020 Abstract: In this paper, the effects of different weight percentages of silica nano- particles on the wettability and optical properties of polymer based surfaces were investigated. The Polydimethylsiloxane (PDMS)-SiO2 nano-composites containing 0.5, 1, 2, 3 and 4 wt% silica were prepared and coated on the fabric surfaces by immersion technique at the ambient conditions. Then, the characterization of nano- composite coated samples was carried out by water contact angle technique, scanning electron and atomic force microscopes and diffuse reflectance spectroscopy. It was found that increasing the silica content caused to increase the water contact angle of sample to 158° which results in an improvement in the water repellency property. This can be due to the aggregation of silica nano-particles which led to higher surface roughness of sample. The AFM and SEM images validated the results of surface roughness. However, Silica-PDMS composite coated sample exhibited a lower transmittance value (57%) in comparison to the uncoated sample (90%). This can be ascribed to the light scattering by silica nano-particles. Keywords: Polydimethylsiloxane, SiO2 Nano-Particles, Super-Hydrophobic, Transmittance, Water Contact Angle Reference: Reza Abedinzadeh, Hamid Shirian, and Janan Parhizkar, “Study on the Wettability and Optical Properties of Polydimethylsiloxane-SiO2 Nano-composite Surfacesˮ, Int J of Advanced Design and Manufacturing Technology, Vol. 13/No. 4, 2020, pp. 21–29. DOI: Biographical notes: Reza Abedinzadeh received his PhD in Mechanical Engineering from Isfahan University of Technology 2015. He is currently Assistant Professor at the Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Isfahan, Iran. His current research interest includes Advanced Manufacturing Technology and Nanomaterials. Hamid Shirian received his MSc in Mechanical Engineering from Khomeinishahr Branch, Islamic Azad University. His current research interest includes nanomaterials. Janan Parhizkar received her MSc in Nanochemistry from University of Isfahan and a BSc in Pure Chemistry from Isfahan University of Technology. Her current research focuses on nanotechnology and nanomaterials.