| 초록 |
The thermotropic LC phase transition of regioregularity-controlled poly(3-dodecylthiophene) (RR-controlled P3DDTs) are investigated as a function of RR. This is great system because it can produce different strengths of LC interactions as well as the same molecular structure to exclude the additional factors. As the RR reduces, they exhibit decreased transition temperatures upon heating. Since the P3DDTs with lower RR consist of more regio-defects, they finally yield weaker interchain interactions and faster rod-to-coil conformations and disruption of ordered/oriented LC structures with heating. Furthermore, the formation of Form2 polymorph and the increasing ratio of Form2/Form1 polymorphs towards to lower RR are founded. Considering both the higher melting entropy of Form2 and faster breakdown of Form2 scattering peak upon heating, it is proposed that larger Form2/Form1 can promotes fatigues of LC structures, resulting in lower transition temperatures at lower RR. |
