(P < 0.05). Contact angles of material surfaces are presented in Table 2. The same decreasing order of contact angles was demonstrated as was the case with roughness parameters (Table 1); silicon (118.85°), Teflon (104.07°), SUS No.4 (98.98°), PVC (78.50°), and glass (53.04°). Significant differences in contact angles were observed among the materials (P < 0.05).