Self-propelled nanoswimmers are designed in a disk shape, consisting of tri-metallic segments: gold (Au), nickel (Ni), and platinum (Pt). A bubble propulsion mechanism originated from momentum change of a Au-Ni-Pt nanoswimmer-oxygen (O-2) bubble integral system is proposed. This innovative type of Au-Ni-Pt segmented nanoswimmers is fabricated using a layer-by-layer deposition method based on nano-electro-mechanical systems (NEMS) technology, whereby Pt functions as the chemical catalyst for the decomposition of hydrogen peroxide (H2O2) to produce O-2 bubbles detaching from its surface and water (H2O), which in turn generates a recoil force to thrust the nanoswimmers propelling forward. Two different sized nanoswimmers' motion is characterized by changing the temperature of H2O2 solution, revealing that O-2 bubbles are generated and detached from the surface of Pt, and the nanoswimmers can autonomously propel forward in either a linear or a circular way. Results show the big nanoswimmer propels forward faster than the small one at temperature below 27 degrees C, while the small nanoswimmer moves forward faster at temperature above 27 degrees C. In general, the speed of nanoswimmers is increased with the increment of the temperature of H2O2 solution, thus the propulsion of the nanoswimmers is temperature-dependent. (C) 2016 Elsevier B.V. All rights reserved.
