| Poly [2-methoxy-5-(2'-ethyl hexyloxy) -phenylene vinylene] (MEH-PPV), as a Light-emitting layer of anode material of OLED, has been closer to our life, its EL performance has also been the research focus in recent years. However, in practice, MEH - PPV film mechanics performance is also an important aspect which affects the stability and optical properties of thin film, but this part has been rarely reported.The mechanical properties of MEH-PPV thin films are determined by nanoindentation in this article. It summarizes the influence of the experimental parameters on the mechanical properties of thin films qualitatively, discusses the influence of the heat treatment for mechanical properties of rigid MEH-PPV and flexible PMMA films, compares the differences between the MEH-PPV and BEH-PPV thin films with different structures in the mechanical properties, and studies the mechanical properties of MEH-PPV thin films with different molecular weight.The results of nanoindentation experiment show that the elastic modulus and hardness increase along with the load increase, extending the holding time could reduce the elastic modulus and hardness of MEH - PPV film. In addition, increasing the loading rates would lead the elastic modulus and hardness values of MEH-PPV thin film decreased.From the heat treatment experiment, the elastic modulus and hardness of MEH-PPV thin film are the minimum when the temperature reaches the glass transition temperature (Tg). The elastic modulus of PMMA thin film increases with the heat treatment temperature increasing, but the hardness decreases with the heat treatment temperature increasing. The change of elastic modulus is much more than hardness for heat treatment.The elastic modulus of MEH-PPV thin film is larger than BEH-PPV, the structure influence is not obvious for hardness. The elastic modulus and hardness decrease with molecular weight increasing, and the changing of elastic modulus is much more than hardness.
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