两种单晶硅基底表面接枝PSVBA聚合物刷后的摩擦学性能对比

Comparison of Tribological Properties of Two Monocrystalline Silicon Surfaces Grafted with PSVBA Brushes

为提高接枝表面的承载能力,延长其耐磨损寿命,采用原子转移自由基聚合反应(ATRP)在单晶硅表面上接枝了聚N-(4-乙烯基苄基)-N,N-二烷基氨基(PSVBA)刷,对比研究抛光(Ra=1.61 nm)和粗糙(Ra=0.32μm)的两种单晶硅表面有无接枝PSVBA聚合物刷的摩擦学性能。结果表明,与摩擦因数为1.4的未接枝表面相比,抛光面接枝聚合物刷后摩擦因数低至0.03,但因表面上的聚合物链易被磨断且不受保护,其耐磨寿命仅能维持2000个试验循环;粗糙面接枝聚合物刷后虽然摩擦因数上升至0.2,但该面上的摩擦试验可稳定运行约30 000个循环且未发生较大变化,其原因在于粗糙面上的微凹坑能够避免坑内的聚合物链与对摩副的直接接触,有效防止了该区域内聚合物刷的断裂,使其可以持续发挥润滑效果。因此,从延长服役寿命角度考虑,非光滑表面接枝聚合物刷具有较好的应用前景。

To improve the wear resistance and prolong the service life of the polymer brushes grafted surface, an atom transfer radical polymerization （ATRP） method was successfully used to graft PSVBA on silicon surface. A comparative study for the tribological properties between polymer brushes grafted on the polished （Ra=1.61 nm） and the unpolished （Ra=0.32 μm） surfaces was carried out. The results show that the friction coefficient is as low as 0.03 while the non-grafted surface is 1.4. The wear life of the surface can only maintain 2 000 test cycles because the polymer chains are easily broken. Although the friction coefficient of the grafted unpolished surface is rised to be 0.2, the friction test can be stably operated about 30 000 cycles without significant fluctuations. The micro pits on the rough surface can prevent the polymer brush from being worn out. Therefore, the polymer brush can be undisturbed and play a strong lubrication role. Considering from the perspective of long service life, grafting polymer brush on rough surfaces has a good prospect of application.