This experimental work deals with the measurement of the contact angle of the nanocomposites made of phase change material (PCM) OM 08 and multi-wall carbon nanotubes (MWCNTs) with different volume concentrations namely, 0.05%, 0.1%, 0.3%, 0.5%. Two different types of copper substrate, namely copper plate with and without shot blasting, were used in this study. It was identified that the droplet contact angles of the nanocomposites were increased with the increase in volume concentration. Also, an increase in the droplet contact angle was more predominant at the higher volume concentration of MWCNTs. The nanocomposite with 0.5 vol.-% of MWCNT has a maximum droplet contact angle of 42.1° and 40.01° respectively on the normal and SBS copper substrate. The use of the highly roughed SBS effectively reduced the contact angle of the nanocomposite by 2° and 2.3° during the first and second passes respectively. © 2021 Institute of Materials, Minerals and Mining Published by Taylor & Francis on behalf of the Institute.