Investigation on nano-frictional performance of glucose-assisted ZnO sol–gel film on quartz substrate

In the work, the ZnO films were fabricated using the glucose-assisted sol–gel method under different precursor concentrations. The ZnO films were composed of many ZnO nanoparticles with polycrystalline hexagonal wurtzite structure. Its frictional, adhesive properties and interface contact types between the atomic force microscope tip and the samples were investigated based on Amontonʹs laws and the general Carpickʹs transition equation, respectively. The results showed that the tip–sample contacts corresponded to the Johnson–Kendall–Robert/Derjaguin–Muller–Toporov (DMT) transistion model for ZnO films. Frictional forces for the four samples were linearly dependent on external loads and adhesive forces at higher loads and lower loads, respectively. Frictional tests showed that sample “b” exhibited the highest nano-frictional coefficient due to the highest capillary force formed on the ZnO surface. The ZnO sol–gel film might be promising for applications in the lubrication of nano/micro electromechanical systems.