Potassium ion implantation into glassy carbon

Potassium ion implantation into glassy carbon (GC) was carried out to modify its surface to form a hydrophilic character. The ion implantation was performed using acceleration energies of 150 and 50 keV, with dosages between 1 x 1015 and 1 x 1017 ions/cm2. The wettability was evaluated from the contact angle of water on the substrates. For an acceleration energy of 150 keV, little change in the contact angle on the GC surface was observed. At an acceleration energy of 50 keV, the contact angle decreased with increasing K-ion dosage and decreased to zero at a dosage of 1 x 1017 ions/cm2. The distribution profiles of the K atoms were evaluated using Rutherford backscattering spectroscopy to investigate the properties of the hydrophilic surface. At an acceleration energy of 150 keV, the depth distribution of K atoms showed a Gaussian dependency. This profile is in a good agreement with a theoretical distribution calculated by the TRIM-98 code. At an acceleration energy of 50 keV, an additional peak appeared near the surface for an ion dosage of 5 x 1016 ions/cm2. The intensity of the two peaks increased and distribution widened at a dosage of 1 x 1017 ions/cm2. The decrease in contact angle can be explained by the distribution of the K atoms in the GC substrate