Ultrathin films composed of diazoresin（DR）and polyacrylic acid（PAA）were fabricated.The surface morphology of the films in water was measured using an atomic force microscopy（AFM）.The self-assembly technique make...Ultrathin films composed of diazoresin（DR）and polyacrylic acid（PAA）were fabricated.The surface morphology of the films in water was measured using an atomic force microscopy（AFM）.The self-assembly technique makes the surface rather flat and uniform.The friction force and its dependence on the velocity differ from the surface charge of the thin films.The friction force of repulsive DR/PAA film increases linearly with velocity and has lower values than that of attractive DR film over the full range of velocity.As the velocity increases,the attractive friction of DR film first decreases to a minimum at a velocity of 2 line/s and then increases all the way.When the surface is repulsive to the friction substrate,the friction of thin films that is determined by hydrated lubrication of polymer chains that is ultralubricated;when it is adhesive to the friction substrate,the friction is mainly contributed from the elastic deformation of adsorbed polymer chains in the low velocity region and from viscous sliding in the presence of hydrated-layer lubrication of the polymer chains in the higher velocity region.展开更多
An apparatus was specifically developed for micro-friction and adhesion measurements. The force measurement range is 10-2000 μN with a horizontal speed of 10-400 μm/s. The apparatus was tested using a 0.7-mm diamete...An apparatus was specifically developed for micro-friction and adhesion measurements. The force measurement range is 10-2000 μN with a horizontal speed of 10-400 μm/s. The apparatus was tested using a 0.7-mm diameter steel ball as the upper specimen to measure the micro friction and adhesion behaviour of a Si （100） wafer and a TiB2 film. The effects of rest time, speed, and load were studied. The results show that the maximum static and sliding friction forces of both the Si （100） wafer and the TiB2 film increase with the load. At low speeds, the influence of speed on the friction force is significant. The adhesion forces of the Si （100） wafer and the TiB2 film increase with rest time, reaching stable values after about 3000 s. The TiB2 film has significantly less adhesion and micro friction forces than the Si （100） wafer.展开更多
基金Supported by the National Natural Science Foundation of China(51273059)Young Teachers International Communication Program of Hubei Province Education Administration of China(2012-1)Foundation of Hubei Provincial Key Laboratory of Green Materials for Light Industry
文摘Ultrathin films composed of diazoresin（DR）and polyacrylic acid（PAA）were fabricated.The surface morphology of the films in water was measured using an atomic force microscopy（AFM）.The self-assembly technique makes the surface rather flat and uniform.The friction force and its dependence on the velocity differ from the surface charge of the thin films.The friction force of repulsive DR/PAA film increases linearly with velocity and has lower values than that of attractive DR film over the full range of velocity.As the velocity increases,the attractive friction of DR film first decreases to a minimum at a velocity of 2 line/s and then increases all the way.When the surface is repulsive to the friction substrate,the friction of thin films that is determined by hydrated lubrication of polymer chains that is ultralubricated;when it is adhesive to the friction substrate,the friction is mainly contributed from the elastic deformation of adsorbed polymer chains in the low velocity region and from viscous sliding in the presence of hydrated-layer lubrication of the polymer chains in the higher velocity region.
基金the National Natural Science Foundation of China (No. 50475012)the National Key Basic Research and Devel-opment (973) Program (No. 2003CB716201)
文摘An apparatus was specifically developed for micro-friction and adhesion measurements. The force measurement range is 10-2000 μN with a horizontal speed of 10-400 μm/s. The apparatus was tested using a 0.7-mm diameter steel ball as the upper specimen to measure the micro friction and adhesion behaviour of a Si （100） wafer and a TiB2 film. The effects of rest time, speed, and load were studied. The results show that the maximum static and sliding friction forces of both the Si （100） wafer and the TiB2 film increase with the load. At low speeds, the influence of speed on the friction force is significant. The adhesion forces of the Si （100） wafer and the TiB2 film increase with rest time, reaching stable values after about 3000 s. The TiB2 film has significantly less adhesion and micro friction forces than the Si （100） wafer.
