Guo Dan, Li Jingnan, Xie Guoxin, Wang Yuanyuan, Luo Jianbin
State Key Laboratory of Tribology, Tsinghua University , Beijing 10084, China.
Langmuir. 2014 Jun 24;30(24):7206-12. doi: 10.1021/la501485e. Epub 2014 Jun 12.
The mechanical properties of polystyrene (PS) nanospheres of ca. 50-1000 nm in diameter were evaluated by using an atomic force microscope (AFM). The compressive elastic moduli of individual nanospheres were obtained by analyzing the AFM force-displacement curves on the basis of the Hertz and JKR contact theories. The results showed that the elastic moduli of PS nanospheres of different sizes were in the range of 2-8 GPa. The elastic modulus of PS nanospheres increased with the decrease of the sphere diameter, especially when the diameter was less than 200 nm. The measurement errors due to tip wear and the deformation at the bottom of the sphere were analyzed. Mechanisms for the size dependence on the elastic modulus of PS nanospheres were also discussed.
使用原子力显微镜（AFM）评估了直径约50 - 1000 nm的聚苯乙烯（PS）纳米球的力学性能。通过基于赫兹和JKR接触理论分析AFM力 - 位移曲线，获得了单个纳米球的压缩弹性模量。结果表明，不同尺寸的PS纳米球的弹性模量在2 - 8 GPa范围内。PS纳米球的弹性模量随球直径的减小而增加，特别是当直径小于200 nm时。分析了由于针尖磨损和球底部变形引起的测量误差。还讨论了PS纳米球弹性模量尺寸依赖性的机制。
