Molecular level ordering in poly(4-vinylpyridine) by non-covalent cross-linking with a magnetic cross-linker

Abstract

The crystal structures of polymers have received considerable interest and attention in the field of organic electronic device. Molecular level ordering is an important and challenging objective because it can improve the efficiency of systems and generate new types of systems. Various approaches have been used for molecular level ordering of polymers for their various applications. However, the control of the precise molecular level ordering of polymers is difficult due to their chain entaglements. It requires the design of systems with molecular level precision. To deal with these challenges, we have attention to new fabrication strategy for molecular level ordering in polymer by using simple chemical cross-linking with functional cross-linker. Herein, we demonstrate the magnetic order for one-dimensional monatomic chains of Fe atoms generated by non-covalent cross-linking using hydrogen bonding between poly (4-vinylpyridine) (P4VP) and 1,1-ferrocene dicarboxylic acid (FDA). Molecular-level self-assembly during the hydrogen bonding of P4VP with FDA results in the sub-nanometer level ordering of pyridine moieties and FDA. A high voltage electron microscope and X-ray diffraction were used to confirm the ordered morphologies. Furthermore, the magnetic order of monoatomic Fe chains are investigated by large localized orbital moments and correspondingly large magnetic anisotropy energies compared to bulk FDA.