Magnetic Polymers

Abstract

Discovery of doped polyacetylenes and the following extensive investigations of π‐conjugated conducting polymers also evoked the attempt creating magnetic organic polymers. In the last two decades, theoretical and experimental studies on π‐conjugated organic molecules bearing plural unpaired electrons have elucidated a clear correlation between the molecular connectivity or substitution positions of the radical groups on the conjugated skeleton and spin multiplicity or spin quantum number (S) at a ground state. A stabilized high‐spin state (spin alignment, S > 2/2) among the plural unpaired electrons was achieved based on an intramolecular and strong through‐bond spin‐exchange interaction through pi‐conjugation. Here we start with molecular structure‐S correlation of diradical model molecules as an example, and then extend the criteria for designing high‐spin organic polymers. The highest spin alignment (S) value of the polymers has been improved year by year through two main molecular design approaches: (i) π‐conjugated polymers bearing pendant radical groups, and (ii) cross‐conjugated, radical‐integrated polymers. Advantages and limitations of these two approaches are described, and the two‐dimensionally extended organic polyradical molecules (hyperbranched and/or cross‐conjugated network) are highlighted in this chapter. The molecular‐based, tunable magneto‐responsible polymer dots can lead to the potential application for the magnetic information storage, and the opto‐magnetic and electro‐magnetic properties of the polyradicals are promising field. The high‐spin organic polyradical molecules with chemical stability, flexibility, plasticity, and moldability will open a new field of magnetic organic materials.

Synthesis and Charge–Discharge Studies of Poly(ethynylphenyl)galvinoxyles and Their Use in Organic Radical Batteries with Aqueous Electrolytes

“…Smaller and cheaper energy sources can be used for electronic applications like biochips, smart packages, and sensors. Because of their long cycle life, ORBs could be utilized in such systems for months or years without significant capacity loss …”

Melt‐Polymerization of TEMPO Methacrylates with Nano Carbons Enables Superior Battery Materials

“…Havingalow molar mass, as imple structure, and containing ah ighly stable nitroxide radicalg roup that shows reversible, fast redox processes, [11,12] PTMA has attracted much attention [13][14][15] since the originalp roposal by Nishidea nd NEC Corp. [16,17] The theoretical capacityf or the single-electron process (nitroxide-oxoammonium couple) is about1 10 mAh g À1 ,a nd the redox potential is as high 3.6 Vv ersus Li/Li + . Havingalow molar mass, as imple structure, and containing ah ighly stable nitroxide radicalg roup that shows reversible, fast redox processes, [11,12] PTMA has attracted much attention [13][14][15] since the originalp roposal by Nishidea nd NEC Corp. [16,17] The theoretical capacityf or the single-electron process (nitroxide-oxoammonium couple) is about1 10 mAh g À1 ,a nd the redox potential is as high 3.6 Vv ersus Li/Li + .…”

Polymeric materials for lithium‐ion cells

“…During the charging process, the p ‐type radical polymer in the cathode is oxidized to the oxoammonium form. During the discharging process, the nitroxide radical is regenerated by reduction of the oxoammonium …”