The composite lubricating materials research group from the Lanzhou Institute of Chemical Physics of the CAS has successfully prepared polytetrafluoroethylene (PTFE) nano-microspheres with uniform particle size via a facile method. They have received a Chinese invention patent for the preparation technique. The patent is No. ZL: 200710188579.9 received on April 27.

Researchers first prepared fluorination carbon nano-tubes from hydroxylation carbon nano-tubes and perfluoroheptanecarboxylic acid. Then they mixed the fluorination carbon nano-tubes with tetrafluoroethylene powder and put them into the dispersant. After ultrasonic dispersion, removal of solvent and drying, PTFE particles with average particle size between 90 and 120 nanometers are obtained. The addition of fluorination carbon nano-tubes can strengthen the dispersion of tetrafluoroethylene in the dispersant so as to control the shape and particle size of nanospheres. Compared with existing approaches, the method is simple and uniform particle size of nanospheres can be achieved.

PTFE is a kind of excellent solid lubricating materials. Its linear structure and ultra-low molecular cohesion make it easy for molecules to slide against each other, which endows PTFE with ultra-low friction coefficient. Under high temperature or high pressure, PTFE nano-particles can easily form fluoride film on the friction surfaces and also fill the wear surfaces, which reduces the surface wear of materials. In addition, since the hardness, toughness and modulus of elasticity of PTFE nano -particles are increased compared with other conventional particles, PTFE nano-particles can serve as bearings between the sliding surfaces and further reduce the wear and friction.