The surface wettability of the silane-treated filter papers was
characterized by the water contact angle (WCA) measurements
and sto¨ ckigt size test. The WCA were measured using Surface
Electro Optics (Phoenix300) at an ambient temperature in the style of TAPPI standard method T458 [23], and the reported values are
averages of 5–8 measurements made on different areas of the
paper surface.