Hydroxypropyl cellulose/Poly(aniline-co-pyridine-oxyl) as a liquid crystal polymer/polyradical blend with helical magnetic structure

A helical magnetic polymer was synthesized by blending a polyradical and hydroxypropyl cellulose (HPC), which is a helical liquid crystal. First, achiral m-linked poly(aniline-co-pyridine) was synthesized via Buchwald-Hartwig coupling, and poly(aniline-co-pyridine-oxyl) as a linear polyradical was then prepared by Tokumaru method. Helicity was induced in the linear polyradical simply by blending with HPC as a helical cholesteric liquid crystal. The magnetic properties of the polyradical and the HPC/polyradical blend composite were evaluated by performing electron spin resonance, superconducting quantum interference device, and vibrating sample magnetometer measurements, which revealed that the linear polyradical shows diamagnetism up to 5 K and the polymer bend exhibits weak diamagnetism at high temperature and paramagnetism at low temperature.