A ferrocene–viologen linked “bipolar” type redox-active ionic liquid ([FcC11VC1][TFSI]2) 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 cm2 C−1 at 1.0 V. The EC process was stable even after over 10 000 potential cycles.

•Polyurethanes crosslinked by polyrotaxanes (PRXs) were designed and synthesized.•Tightly packed CyDs enhances the reorganized-crystallization of the soft segment chains.•Loosely packed CyDs act as individually dispersed crosslink points.•Moderately packed CyDs makes slow reorganized-crystallization of the soft segment chains.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, PRX4000 and 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.

•Novel polyurethanes containing [2] and [3]rotaxanes have been synthesized.•PCL can be used as the soft segment and to keep the rotaxane formation.•The rotaxanes disturb the recrystallization of the PCL component.•Introduction of the [3]rotaxane causes enhancement of the tensile property of the PU.We have successfully synthesized novel polyurethanes where PU1 contains a [3]rotaxane that consists of N-3,5-di-tert-butylbenzyl-N-3-hydroxypropylammonium hexafluorophosphate (AOH1) and N,N′-Dimethyl-N,N′-bis(dibenzo-24-crown-8)-terephthalamide (BisC) as well as PU2 contains a [2]rotaxane that consists of AOH1 and dibenzo-24-crown-8 ether. Diphenylmethanediisocyanate (MDI), 1,4-butanediol (BD) and poly(ε-caprolactone)diol (PCL) were used as an isocyanate, chain expander, and soft segment, respectively. A polyurethane without any rotaxane structures (PU0) were also prepared as a reference polymer. The existence of the rotaxanes in the polyurethanes was confirmed by 1H NMR spectroscopy and TGA measurement. ATR-FT-IR spectral measurement revealed that the rotaxanes disturb the formation of hydrogen bonding between the polyurethane chains. From the DSC result, the rotaxanes retard the recrystallization of the PCL unit whereas no influence on the glass transition temperatures of the polyurethanes was observed. The retarding effect appeared remarkably with PU1. These thermal behaviors of the polyurethanes were also supported by viscoelastic measurement. In tensile test, the tensile strength and break of strain of PU1 were larger than those of PU2.

An acrylic pressure-sensitive adhesive (PSA), bearing octadecyl acrylate, methyl acrylate and acrylic acid groups, and crosslinked by aluminum acetylacetonate (AlACA), displayed behavior unique among acrylic PSAs in that its adhesion, which decreases with an increase in temperature, began to increase again from around 150 °C. In order to understand this behavior, the structure and thermal properties of the PSA were investigated in detail, along with another PSA crosslinked by a covalent crosslinking agent (Az). From thermal mechanical analysis, the PSA with ionic crosslinks (AlACA) showed three softening points at 20, 60, and 160 °C. In comparison, the PSA covalently crosslinked by Az only exhibited two softening points (at 20 and 60 °C). The softening point at 160 °C is clearly related to ionic chelate crosslinking. DSC measurements indicated that the softening point at 20 °C resulted from melting of the ordered octadecyl group, and the softening point at 60 °C was due to an increase in the mobility of the main chain. The temperature dependence of viscoelastic measurements revealed that the viscosity of the PSA crosslinked by AlACA increased at around 160 °C. From these results, we considered that the distinctive adhesion of the PSA crosslinked by AlACA could be due to ligand exchange at the aluminum crosslinking points, which are chelated by carboxy groups built in the main chain.

A ferrocene–viologen linked “bipolar” type redox-active ionic liquid ([FcC11VC1][TFSI]2) 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 cm2 C−1 at 1.0 V. The EC process was stable even after over 10 000 potential cycles.