Self-Assembly of Block Copolymers in Constrained Systems

3 Self-Assembly of Block Copolymers in Constrained Systems 

The microphase separation of block copolymers in a constrained situation has attracted interest both from experiments and theories. There are several important characters to make this system favorable in fabricating nanoscale features. Firstly, the constrained situation helps confine the dimension of microphase separation into microscale or nanoscale, so the materials formed in such a system spontaneously possess microstructures. Secondly, the constrained situation can suppress the fluctuation of phase separation and help create an ordered pattern at large scale. Thirdly, the surface of the constrained situation can be deliberately modified to direct the microphase separation of block copolymers with attention to make nonbulk structures. 

Geometrically, the constrained situation can be a one-dimensional, two-dimensional, or three-dimensional. Most previous simulation studies concentrated on the 

DYNAMICS SIMULATIONS OF MICROPHASE SEPARATION IN BLOCK COPOLYMERS 

Recently, researchers paid more attention to the guided self-assembly of block copolymer thin films on a patterned surface. The patterned surface means the surface of a constrained situation is chemically or physically modified to form a pattern with specific property and size. A series of exquisite structures are found in the microphase separation of block copolymer under the patterned surface. In the theoretic work of Wu and Dzenis [43], they designed two kinds of patterned surface to direct the block copolymer self-assembly (Fig. 15.7). The self-assembled structures are found strongly influenced by the commensurability of polymer bulk period and pattern period. With mismatched patterns on two surfaces, both MC simulation [44] and SCFT researching [45] predicted the titled lamellae and perforated lamellae structures for symmetric diblock copolymers. Petrus et al. carried out a detailed investigation on the microphase separation of symmetric and asymmetric diblock copolymers confined between two planar surfaces using DPD simulation [46,47]. It is found that various nonbulk nanostructures can be fabricated by the nanopatterns on the surfaces. 

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