Structural transformation of nanorods in artificial nanochannels: Influence of nanochannel size and mass fraction of homopolymer

In this work, various nanorods (NRs) with different structures by self-assembly of copolymer polystyrene -b-poly (4-vinylpyridine) (PS36 & sdot;5K-b-P4VP16K, SVP-16) and homopolystyrene (hPS3.35k) in cylindrical anodic aluminum oxide (AAO) templates were obtained. Structural transformation in NRs was investigated by varying the AAO nanochannel size and the mass fraction of hPS3.35k. As the mass fraction of hPS3.35k increases, a typical structure change of NRs can be observed, from a continuous concentric lamellar shape to intermittent irregular blocks and finally to dense spherical structures. The AAO channel size also significantly influences the internal structure of the NRs and the arrangement of the P4VP particles, and the ionic current changes remarkably after the self assembly of SVP-16/hPS3.35k with different weight fractions of hPS3.35k (phi hPS). Furthermore, mesoporous nanorods with controlled structures can be obtained by selective swelling of the micro-regional fraction of BCPs in organic solvents. This work provides valuable insights into the structural transformation of self-assembled polymers in artificial nanochannels, benefiting understanding the underlying mechanism of ion transport.