Development of a magnetic hybrid material capable of photoinduced phase separation of iron chloride by shape memory and photolithography

Abstract

Magnetic material ordering is indispensable for improvement of magnetic susceptibility in limited polymer matrix space. In this study, a polymer matrix is designed to orient FeCl₄⁻. As a result of this design, magnetic properties are observed in the hybrid material. However, partial control of magnetic susceptibility is important for practical applications of magnetic polymer materials. Here, FeCl₃ was partially ordered using a photodegradable Fe complex and a polymer having shape memory properties, in which uniaxial orientation of polymer segments causes a temporary shape. Although FeCl₃ was phase-separated from polymethyl methacrylate (PMMA), the complex composed of tetrabutylphosphonium cations and FeCl₄⁻ anions (TBP[FeCl₄]) was uniformly dispersed in the PMMA matrix and produced FeCl₃ by photodegradation. Interestingly, FeCl₃ produced by photoreaction was ordered during shape recovery, from a temporary shape, due to phase separation of Fe oxide from the polymer matrix. Furthermore, UV light was partially irradiated on the sample using a photomask, to partially order the iron oxide. Hybrid samples of ordered FeCl₃ exhibited a 1.6 μm-interval striped pattern. These samples exhibited three times the magnetic susceptibility of disordered FeCl₃. This study makes contributions to the development of hybrid materials, incorporating inorganic materials into polymer matrix structures, thereby enhancing their properties, and utility.