Thus, static
contact angle is slightly under influence of deposited layer. Thus,
better thermal performance despite the fouling formation can be
seen for surfaces with micro-structures rather than plain ones.
In terms of operating time, contact angle of water liquid drop on
the surface was constantly measured at different time intervals.
Results demonstrated that over the extended time, with increasing
the operating time, static contact angle slightly decreases, which is
due to the slight deposition rate of nano-particles on the surface.