Contact Angle Measurements over Macro, Micro and Nano Dimensioned Systems - Drops and Bubbles in Contact with Solid Surfaces - page 20

(A) (B)

(C)

Figure 13. (A) Oil/silanized silicon wafer. (B) Oil/mica. (C) Oil/metal sputtered wafer.

tems as like the microscopic origin of macroscopic wetting phenomena may be
collected in the huge production of the same Authors already cited in these pages
[211-214] among many others that focused their attention, for example, over the
friction problems of spreading phenomena of layered wetting structures. It may be
anyway useful to underline some points that affect almost each microscopic wetting
experience:
• the sample surface status,

• the deposition methodology,

• the contact angle value determination.

As an example Fig. 13(A, B, C) shows how do look, at metallographic micro-
scope analysis and the same magnifying factor, paraffin oil drops deposited by the
author with vaporizing and condensing technique over three different solid sur-
faces, respectively: silanized silicon wafer (Fig. 13A), muscovite mica (Fig. 13B)
and metal sputtered silicon wafer (Fig. 13C). By the simple visual evaluation of
these three very unlike solid surfaces it can be immediately perceived how the same
fluid, almost inert over all of the analyzed substrates, provides completely differ-
ent behaviors as a function of the solid surface energy features. Silanes (Fig. 13A),
when correctly deposited over a solid surface either by dip-coating either by vapor-