Polycarbonate/Titania Hybrid Films with Localized Photo-Induced Magnetic-Phase Transition

Abstract

Materials that exhibit the photo-induced magnetic-phase transition of titania are receiving significant attention because they can be easily switched between diamagnetism and paramagnetism by UV irradiation. However, it is difficult to store photo-induced titanium (Ti3+) in air because of its easy oxidation upon oxygen exposure. In this study, titania/polycarbonate hybrid films were prepared using linear 1,6-hexanediol (PHMCD), cyclic 1,4-cyclohexanedimethanol (PCHCD), or their copolymerized carbonate oligomers using the sol–gel method. The oxygen permeability of the hybrid film decreased as the ratio of the ring structure increased by a factor of approximately 32 from PHMCD with only the chain structure to PCHCD with only the ring structure. These hybrid films can generate Ti3+ under a UV irradiation of 250 W for 2 h, and the difference in oxygen permeability significantly affected the lifetime of the Ti3+ by a factor of up to 120. In addition, the tensile tests and IR measurements demonstrated that UV irradiation had little effect on the mechanical intensity and matrix chemical structure. Moreover, the magnetic susceptibility of Ti3+ present in PCHCD was confirmed to be 6.2 (10−3 emu/g(titania)) under an external magnetic field of 5 T induced using a superconducting quantum interference device.

Skillful Control of Dispersion and 3D Network Structures: Advances in Functional Organic–Inorganic Nano-Hybrid Materials Prepared Using the Sol-Gel Method

“…Despite its excellent magnetic properties, Ti(III) is easily oxidized in the presence of oxygen and cannot withstand long-term use, which is a new problem. Hara et al [84] exploited the packing effect of the cyclohexane skeleton to control the oxygen permeability. The lifetime of Ti(III) in polycarbonate (PC), which does not have a cyclohexane skeleton, was ~2 h, but by nanodispersing titania in PC with a cyclohexane skeleton, they succeeded in extending the lifetime to ~10 d, which is 120 times longer than previously obtained.…”

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

“…Partially tuning the magnetic susceptibility, rather than changing the magnetic susceptibility of the entire material, could enhance utility in magnetic storage media. [33][34][35][36][37] The order of nanoparticles and polymer crystals in a polymer matrix is controlled by shape memory polymers (SMPs). [38][39][40][41] SMPs are an emerging class of intelligent materials that deform temporarily and change shape, but recover their original shape under environmental stimuli, such as heat, 42,43 light, 44,45 and an electric field.…”

“…Partially tuning the magnetic susceptibility, rather than changing the magnetic susceptibility of the entire material, could enhance utility in magnetic storage media. 33–37…”

Macroscopic Property Evaluation of Titania Nanocomposite Polymer Capable of Drawing Double-Network Macrostructure Using Photolithography

“…To introduce double-network polymers into a normal molding process, it is beneficial to generate cross-linking points after the molding process. The modular patterning of films using photoreactions can add cross-linking points after deposition. − For example, Clet et al demonstrated a precise microscale patterning to modify the modulus of silicone elastomers . Furthermore, Sugimoto et al reported that by designing heat-cross-linking and photo-cross-linking parts, an increase in the Young’s modulus by more than 2 orders of magnitude was achieved by performing a photo-cross-linking process after a normal elastomer manufacturing heat process .…”