Fig. 2From: Tuning Surface Chemistry of Polyetheretherketone by Gold Coating and Plasma TreatmentZeta potential of plasma-treated PEEK (60 and 240 s) and Au-sputtered (30, 150, and 300 s; current 40 mA) PEEK samples in 1 mM KCl solution (green columns—fresh samples; brown columns—aged samples) and in PBS solution (gray columns)Back to article page