Theoretische Physik I, Universität Bayreuth, 95440 Bayreuth, Germany.
J Chem Phys. 2013 Aug 7;139(5):054908. doi: 10.1063/1.4815919.
The dynamics of microphase separation and the orientation of lamellae in diblock copolymers are investigated in terms of a mean-field model. The formation of lamellar structures and their stable states are explored and it is shown that lamellae are stable not only for the period of the structure corresponding to the minimum of the free energy. The range of wavelengths of stable lamellae is determined by an efficient functional approach introduced with this work. The effects of the interaction of diblock copolymers with two confining substrates on the lamellae orientation are studied by an extensive analysis of the total free energy. By changing the wetting property at one boundary, a transition from a preferentially perpendicular to a parallel lamellar orientation with respect to the confining plates is found, which is rather independent of the distance between the boundaries. Simulations of the dynamics of microphase separation reveal that the time scale of the lamellar orientational order dynamics, which is quantitatively characterized in terms of an orientational order parameter and the structure factor, depends significantly on the properties of the confining boundaries as well as on the quench depth.
本文采用平均场模型研究了两嵌段共聚物的微相分离动力学和片晶的取向。本文探讨了片晶结构的形成及其稳定状态，结果表明片晶不仅在对应于自由能最小值的结构周期内稳定。本文引入了一种有效的功能方法来确定稳定片晶的波长范围。通过对总自由能的广泛分析，研究了两嵌段共聚物与两个限制衬底相互作用对片晶取向的影响。通过改变一个边界的润湿性，可以发现从优先垂直于限制板的片晶取向到平行取向的转变，这与边界之间的距离相当独立。微相分离动力学的模拟表明，片晶取向有序动力学的时间尺度，可通过取向有序参数和结构因子来定量描述，它显著依赖于限制边界的性质以及淬火深度。
