Q150t turbo pumped es sputter coater carbon coater

For the Au–Ni–TiO₂ magnetic Janus micromotors, the TiO₂ particle monolayers were prepared according to the above method. The particles were then sputter-coated with a thin nickel layer over 60 s using a Q150T Turbo-pumped ES sputter coater/carbon coater (Quorum). The nickel layer thickness is 10 nm, as measured by a Dektak 150 Surface Profiler (Veeco). The particles were subsequently sputter-coated with a layer of gold (40 nm) over 3 cycles of 60 s.

TiO₂ microspheres were prepared using a previously reported solvent extraction/evaporation method [43 (link)]. Firstly, titanium butoxide (1.0 mL, Sigma #244112) was dissolved in ethanol (40 mL), and the resulting solution stirred for 3 min. After this time, the solution was incubated at room temperature for 3 h. The resulting TiO₂ microspheres were then collected by centrifugation at 8000 rpm for 5 min and washed three times with ethanol (Guangzhou Chemical Reagent Co.) and ultrapure water (18.2 MΩ cm), prior to drying in air at room temperature. The TiO₂ microspheres were then annealed at 400 °C for 2 h to obtain anatase TiO₂ microspheres (1.0 μm mean diameter), which were then employed as base particles for the TiO₂–Au light-driven Janus micromotors. After dispersion of the TiO₂ particles (1.0 mg) in ethanol (2.0 mL), the resulting suspension was dropped onto glass slides and dried uniformly at ambient temperature to give particle monolayers. These particles were then partially covered with a thin gold layer by 3 cycles of 60 s ion sputtering (Q150T Turbo-pumped ES sputter coater/carbon coater, Quorum). The resulting metal layer thickness is 40 nm, as measured by a Dektak 150 Surface Profiler (Veeco). Finally, the desired TiO₂–Au Janus micromotors were obtained following sonication of the glass slide in deionized water for 5 s.