Fluctuation effects in the theory of microphase separation of diblock copolymers in the presence of an electric field
Fluctuation effects in the theory of microphase separation of diblock copolymers in the presence of an electric field
复制标题
电场存在下二嵌段共聚物微相分离理论中的波动效应
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
S. Trimper
中科院分区：
文献类型：
--
作者：
I. Gunkel;S. Stepanow;T. Thurn‐Albrecht;S. Trimper
通过考虑时间无关的均匀电场对自一致Hartree近似内组分波动的影响，我们推广了对称双嵌段共聚物熔体微相分离的Fredrickson−Helfand理论。我们预测电场抑制成分波动，从而减弱一阶跃迁。在电场的作用下，有序-无序跃迁的临界温度向其平均场值偏移。无序相中的集体结构因子在电场作用下变得各向异性。序参量沿场方向的波动调制被最强地抑制。后者与有序状态下片的平行方向一致。
We generalize the Fredrickson−Helfand theory of the microphase separation in symmetric diblock copolymer melts by taking into account the influence of a time-independent homogeneous electric field on the composition fluctuations within the self-consistent Hartree approximation. We predict that electric fields suppress composition fluctuations, and consequently weaken the first-order transition. In the presence of an electric field the critical temperature of the order−disorder transition is shifted toward its mean-field value. The collective structure factor in the disordered phase becomes anisotropic in the presence of the electric field. Fluctuational modulations of the order parameter along the field direction are strongest suppressed. The latter is in accordance with the parallel orientation of the lamellae in the ordered state.