Available online at www.sciencedirect.com ScienceDirect Materials Today: Proceedings 13 (2019) 53–58 www.materialstoday.com/proceedings 2214-7853© 2019 Elsevier Ltd. All rights reserved. Peer-review under responsibility of the scientific committee of The 6th International Conference on Advanced Materials Science and Technology 2018, 6th ICAMST. ICAMST 2018 Stearic Acid Coating Material Loading Effect to Quartz Crystal Microbalance Sensor Setyawan Purnomo Sakti a,b,* , Masruroha b , Daniel Dwipaskawijaya Kamasi a , Nike Fitayatul Khusnah a a Department of Physics, Brawijaya University, Jl Veteran, Malang, 65145, Indonesia b Colaborative Research Centre for Advanced System and Material Technology, Brawijaya University, Jl. Veteran, Malang 65145, Indonesia Abstract The coating layer was a crucial aspect for the selectivity of the Quartz Crystal Microbalance sensor. The coating layer can contribute to the loading effect of the sensor. The loading effect of the polystyrene film to the sensor is negligible, whilst the stearic acid coating layer contributes high damping. The calculated film thickness of the stearic acid using an assumption of the rigid was different from the measured film thickness using profilometer. The thickness difference between the measured film and Butterworth van Dyke model calculation indicated that the stearic acid film could be considered as a nonrigid film. © 2019 Elsevier Ltd. All rights reserved. Peer-review under responsibility of the scientific committee of The 6th International Conference on Advanced Materials Science and Technology 2018, 6th ICAMST. Keywords: QCM sensor; loading effect; stearic acid; thick coating; impedance spectrum 1. Introduction Coating the QCM surface with a specific layer seems to be an effective way to optimize the performance of QCM in contact with gas or liquid. Numerous researches have been conducted to boost its performance. With functional layers deposited on the QCM, it gains higher sensitivity or selectivity [1-2]. Nevertheless, the thickness and material * Corresponding author. Tel.: +62-341-575833; fax: +62-341-554403. E-mail address: sakti@ub.ac.id