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.

Recent advances in high-performance flexible electronic devices have increased the demand for more diverse and complex nanofabrication methods; high-resolution, high-efficiency, and low-cost patterning strategies for next-generation devices are therefore required. In this study, we demonstrate the formation of dewetting-induced hierarchical patterns using two self-assembled materials: block copolymers (BCPs) and colloidal crystals. The combination of the two self-assembly methods successfully generates multiscale hierarchical patterns because the length scales of the periodic colloidal crystal structures are suitable for templating the BCP patterns. Various concentric ring patterns were observed on the templated BCP films, and a free energy model of the polymer chain was applied to explain the formation of these patterns relative to the template width. Frequently occurring spiral-defective features were also examined and found to be promoted by Y-junction defects.

Compatibility and physical properties of aliphatic polyketon (PK)/polyamide 6 (PA6) blend were investigated. The PK and PA6 showed high adhesion strength and thus impact strength of PK/PA6 blends was very high. It was observed that PK-PA6 copolymers are formed by a chemical reaction between the two polymers and the copolymers act as a reactive compatibilizer in the PK/PA6 blends. The presence of the PK-PA6 copolymer was confirmed by FTIR analysis. The adhesion strength between PK and PA6 was very high compared to a typical incompatible polymer pair. PA6 investigated herein has two end groups, NH2 and carboxylic acid. We also adopted end-capped PA6 that has two carboxylic acid end groups. The adhesion strength and impact strength of the PK/end-capped PA6 blends was much lower than that of PK/PA6 blends. More importantly, the PK-PA6 copolymer was not formed in the PK/end-capped PA6 blends. Thus, it was concluded that the chemical reaction occurs between the carbonyl of PK and the primary amine end group of PA6. Due to the high impact strength of PK/PA6 blends, possible applications could be automotive parts where higher impact strength is required.