Synthesis of cationic ruthenium complex-loaded reverse polymer micelles and application for two-color pressure and temperature sensing

• Published in: Polymer (Guilford) 2024-02, Vol.294, p.126732, Article 126732
• Main Authors: Obata, Makoto, Tanaka, Hinano, Iijima, Yoshimi, Nakakita, Kazuyuki
• Format: Article
• Language: English
• Subjects: Block copolymer; RAFT polymerization; Reverse polymer micelle
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2024.126732

The microphase separation of block copolymers was employed for dye compartmentalization in pressure-sensitive paint (PSP) and temperature-sensitive paint (TSP) technologies. Block copolymers comprising an anionic segment, poly(methacrylic acid) (PMAA), and poly(methyl methacrylate) (PMMA) or poly(isobutyl methacrylate) (PIBM) were synthesized via successive reversible addition–fragmentation chain transfer polymerization, followed by selective acid hydrolysis. The resulting copolymers were dissolved in a mixture of CH2Cl2 and toluene. CH2Cl2 was removed by slow evaporation to afford a transparent toluene solution of reverse polymer micelles, in which the anionic segments aggregated to form a polar core. Tris(1,10-phenanthroline)ruthenium(II) (Ru(phen)32+), a typical TSP dye, was encapsulated in the micelles during micellization. Five or ten carboxy groups were required to hold one Ru(phen)32+ species. The Ru(phen)32+ localization in the micelles did not affect their optical properties. The luminescence of Ru(phen)32+, which is temperature-sensitive, disappeared in a conventional PSP binder, such as PIBM. Contrarily, the TSP prepared using Ru(phen)32+-loaded reverse polymer micelles exhibited luminescence with excellent temperature sensitivity. Two-color PSP/TSP was successfully fabricated using 5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato platinum(II) as a PSP dye and Ru(phen)32+-loaded reverse polymer micelles as a TSP dye with a binder. [Display omitted] •The reverse polymer micelle was successfully prepared via slow solvent quality change.•Cationic Ru complexes were encapsulated in a reverse polymer micelle.•Ru complex-loaded reverse micelle exerted a temperature-dependent luminescence.•Two-color PSP/TSP was successfully prepared for pressure and temperature dual sensing.