Available online at www.sciencedirect.com ScienceDirect Materials Today: Proceedings 5 (2018) 11144–11152 www.materialstoday.com/proceedings 2214-7853 © 2017 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of The 5th Thailand International Nanotechnology Conference (NanoThailand2016). NanoThailand2016 Electrowetting on dielectric (EWOD) of sessile microdroplets containing gold nanoparticles Crismar Patacsil a,c *, Erwin Enriquez b , Raphael A. Guerrero a a Department of Physics, Ateneo de Manila University, Loyola Heights, Quezon City 1108, Philippines b Department of Chemistry, Ateneo de Manila University, Loyola Heights, Quezon City 1108, Philippines c Department of Physical Sciences, College of Science, University of the Philippines Baguio, Baguio City 2600, Philippines Abstract Our electrowetting set-up consists of a bottom copper electrode coated with a thin insulating layer of dielectric (uncured polydimethylsiloxane) and a platinum wire upper electrode in contact with the sessile gold nanofluid droplet sitting on the dielectric layer. EWOD experiments are conducted with the following concentrations of gold nanofluid (in µM): 0.5, 0.33, 0.25, 0.05, 0.01, 0.005 and control fluid. Results show enhanced electrowetting response for microdroplets containing higher concentrations of gold nanoparticles. The specific capacitance is calculated for each concentration and is found to increase with increasing concentration, in agreement with an electromechanical model for the electrowetting phenomena. © 2017 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of The 5th Thailand International Nanotechnology Conference (NanoThailand2016). Keywords: Nanotechnology; gold nanoparticles; nanofluid; Electrowetting on dielectric (EWOD); contact angle. 1. Introduction The wetting property of solid materials continues to be studied due to important applications in many natural and industrial processes. Applying an external voltage affects the contact angle and offers a way to manipulate wettability without changing the chemical composition of the contacting phases. Electrowetting is the decrease in contact angle, thereby enhancing the wettability of a solid material with respect to a given liquid, achieved by * Corresponding author. Tel.: +639088860426. E-mail address: cppatacsil@gmail.com