力调制技术在区分聚合物薄膜晶畴、非晶畴中的应用

Application of force modulation to the separation of crystalline domains and amorphous domains in polymers

聚合物材料多为半晶态 ,晶畴和非晶畴共存。采用扫描探针显微术的力调制技术 ,成功区分出聚合物薄膜P(VDF TrFE)中存在的弹性性质相差悬殊的两类畴 :高弹性畴和低弹性畴 ,并推测高弹性畴对应于P(VDF TrFE)的晶畴。由此可见 。

Polymers are usually semi-crystalline materials in which crystalline and amorphous domains coexist. To have an understanding of the mechanisms of many functional polymers, it is necessary to experimentally distinguish the crystalline domains from the amorphous domains. Many research papers regarded the regular structures appearing in the morphology as the crystalline domains, but our research indicated that this conclusion is unreliable. Since the difference of the Young's elastic moduli between the crystalline and the amorphous domains may be great, it is possible to visualize the crystalline and the amorphous domains by the measurements of the local elasticity. But, till now, this method has not been reported yet. In our study, by means of the force modulation technique of scanning probe microscope, two kinds of domains with very different elasticity have been clearly distinguished in P(VDF-TrFE) films. It is assigned that the high elastic domains to be the crystalline and the low to be the amorphous. These two kinds of domains can hardly be distinguished only by morphology measurement. To approximately estimate the ratio of the Young's elastic moduli between the crystalline and the amorphous domains, Sneddon mechanics was introduced and many approximations were adopted. The result showed that the ratio was about 4.