AlSunaidi A, den Otter W K, Clarke J H R
Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
J Chem Phys. 2009 Mar 28;130(12):124910. doi: 10.1063/1.3089701.
Microphase separation and liquid-crystalline ordering in diblock and triblock rod-coil copolymers (with rod-to-coil fraction f=0.5) were investigated using the dissipative particle dynamics method. When the isotropic disordered phases of these systems were cooled down below their order-disorder transition temperatures T(ODT), lamellar structures were observed. For rod-coil diblock copolymers, the lamellar layers were obtained below T=2.0. This temperature was found to be higher than the T(ODT) for normal coil-coil diblock copolymers. Significant ordering of the rods was observed only below T=0.9 which is the isotropic-nematic transition temperature for rodlike fluids. For the triblock rod-coil copolymers, both microphase separation and rod ordering occurred at T=0.9. Normal coil-coil triblock copolymers were found to undergo microphase separation at T=0.8, which is about half the T(ODT) of the normal diblock copolymers. Investigations of the mean square displacement and the parallel and the perpendicular components of the spatial distribution function revealed that at low temperatures, the rod-coil diblock copolymers exhibit smectic-A and crystalline phases, while the triblock copolymers show smectic-C and crystalline phases. No nematic phases were observed at the density and interaction parameters used in this study.
使用耗散粒子动力学方法研究了二嵌段和三嵌段棒-线团共聚物（棒与线团的比例f = 0.5）中的微相分离和液晶有序性。当这些体系的各向同性无序相冷却至其有序-无序转变温度T(ODT)以下时，观察到层状结构。对于棒-线团二嵌段共聚物，在T = 2.0以下获得层状层。发现该温度高于普通线团-线团二嵌段共聚物的T(ODT)。仅在T = 0.9以下观察到棒的显著有序化，T = 0.9是棒状流体的各向同性-向列相转变温度。对于三嵌段棒-线团共聚物，微相分离和棒的有序化均在T = 0.9时发生。发现普通线团-线团三嵌段共聚物在T = 0.8时发生微相分离，这大约是普通二嵌段共聚物T(ODT)的一半。对均方位移以及空间分布函数的平行和垂直分量的研究表明，在低温下，棒-线团二嵌段共聚物呈现近晶-A相和晶相，而三嵌段共聚物呈现近晶-C相和晶相。在本研究使用的密度和相互作用参数下未观察到向列相。
