Surface modification of the Ti surface with SF or TiBP-SF.
Pure wrought Ti disks (ø7 mm × 1 mm) were purchased from Furuuchi Chemistry (Tokyo, Japan). The surface of each Ti disk was polished with a sequence of 320-, 600-, and 1200-grit silicon carbide papers (RIKEN, Saitama, Japan) under a stream of water. The polished Ti surface was used after being rinsed with ultrapure water (MilliQ®), ultrasonically cleaned with acetone, and then dried at room temperature. For coating, the disk was immersed in 5 ml 2 mass% SF or TiBP-SF aqueous solution at 20 °C for 24 h. After being air-dried at 20 °C for 1 h, the disk was rinsed with 70% ethanol and then air-dried again at 20 °C for 24 h.