A ferrocene-viologen linked "bipolar" type redox-active ionic liquid ([FcCVC][TFSI]) was synthesized as an electrochromic (EC) material that functions without any other additives: solvents, supporting electrolytes and sacrificial agents. The efficiency of a prototype symmetrical EC cell was 70 cm C at 1.0 V. The EC process was stable even after over 10 000 potential cycles.
Three polyurethanes (PRX1500Me-PU, PRX4000Me-PU, and PRX6000Me-PU) crosslinked by polyrotaxanes (PRXs), which consist of half-methylated α-cyclodextrins (CyDs) and poly(oxyethylene)glycols with different chain lengths (PEG1500, PEG4000, and PEG6000), were synthesized. The filling ratios of CyD in PRX1500, PRX4000and PRX6000 are 75, 63 and 37 %, respectively. A polyurethane crosslinked by half-methylated CyD (CDMe-PU) was also prepared for comparison of their structure and properties. ATR-FT-IR spectra of the PUs showed that the formation ratio of hydrogen bond between the PU chains around PRXs increased with increase in the filling ratio. DSC and dynamic viscoelastic measurements and tensile tests for the PUs revealed that (i) reorganized-crystallization of the soft segment chains of PRX1500Me-PU easily occurred because of formation of a pure phase for them; (ii) the thermal and physical behaviors of PRX6000Me-PU are similar to those of CDMe-PU because CyDs as the crosslink points disperse in a similar fashion in the PUs; (iii) the PRX4000 with the moderate filling ratio of CyD in PRX4000Me-PU makes slow reorganized-crystallization of the soft segment chains in the PU as well as improves the tensile performance among the PUs.
Four polyurethanes (PUs) crosslinked by polyrotaxanes (PRXs) of two filling ratios of CyD (63% for PRX4000 and 37% for PRX6000) and with modification ratios of 1 and 2 for a PU chain. The PUs were abbreviated as PU6000(1), PU6000(2), PU4000(1), and PU4000(2), in which 4000 and 6000 are the molecular weights of PEGs as an axle molecule of the PRX and the numbers in parentheses are the modification ratios of the PU chain. ATR-FT-IR, DSC, viscoelastic measurements and tensile test were carried out to investigate their thermal and physical properties. The formation of hydrogen bonds between the PU chains increased with increase in the modification ratio of the PU chain. PU4000(2) possessing the half filling ratio of CyD and higher modification ratio of the PU chain made the recrystallization of the soft segment slow. PU4000(1) with the half filling ratio of CyD and lower modification ratio of the PU chain showed the highest tensile strength among the PUs. In contrast, PU6000(2) with the lower filling ratio of CyD and higher modification ratio of the PU chain showed the highest elongation among the PUs, implying that the sliding effect based on the rotaxane structure occurred.
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