Wettability study of sensing electrodes based on MoS2 nanosheets

Molybdenum disulfide (MoS
2
) has been widely used in the field of electrochemical sensing. The characteristics of sensing electrodes affect sensing performance so that it is of great importance to study the surface characteristics of the electrodes. Herein, the surface roughness and wettability of MoS
2
nanosheets-based electrodes were studied by an atomic force microscopy and a contact angle-measuring system respectively. The electrodes modified by MoS
2
nanosheets exhibit significant changes in surface roughness varying from 2.19 nm to 0.22 µm and in the water contact angle varying from
$59.9\pm 4.2^{\circ}$
to
$72.8\pm 4.0^{\circ}$
. Analysis of surface energy reals that the variation in polar component and dispersion component changes the wettability. In addition, the coating thickness-dependent wettability of the electrodes was further investigated. The measured data suggests that the higher the thickness, the lower the contact angle. The result reveals the interaction between the electrode surface based on MoS
2
nanosheets and water, which paves a new way to improve sensing performance of the electrodes.