Centrifugal Force-Induced Alignment in the Self-Assembly of Block Copolymers

In this study, a facile method is introduced for fabricating unidirectional block copolymer (BCP) self-assembly patterns induced by centrifugal force. Centrifugal force can be easily applied and manipulated but has never been used to control the orientation of soft matter, including BCP. During centrifugal force-induced self-assembly, the centrifugal force acts as a shear force in the BCP film to effectively align the BCP domains without a guide template. The structural analysis shows the notable improvement in the degree of orientation as the shear stress increased. Moreover, the shear stress applied by the centrifuge is calculated and systematically controlled by adjusting the rotation speed, film thickness, and radial distance within the centrifuge. This approach offers an effective route to fabricating well-aligned nanopatterns from BCPs without a guiding template or complicated facilities.