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The ring-opening polymerization behavior of five-membered lactones fused to a cyclohexane ring, T6L and C6L, was investigated under various conditions. The t-BuOK-initiated anionic polymerization of T6L produces polymers having Mn values of 5000. In remarkable contrast, C6L did not polymerize at all, implying the increase in ring strain of the lactone ring by trans-fused cyclohexane. The anionic polymerization of T6L was reversible, and the thermodynamic parameters characterizing the polymerization of T6L were estimated to be ΔHp°=−18 kJ·mol−1 and ΔSp°=–65 J·K−1mol−1.
π-Conjugated polymers attract attention from showing not only an interesting electric and optical property but also workability. The random co-oligomers with N-cyclohexylmaleimide and N-substituted carbazole in the main chain were carried out by Yamamoto coupling reaction. The co-oligomers showed the fluorescence color of red from blue. Especially, when 2,7-dibromo-N-hexylcarbazole was used as the monomer, the fluorescence color of the resulting co-oligomer changed from magenta to blue by the difference of polarity of solvent.
The solvent evaporation rate in the production of three types of poly(vinylidene fluoride) (PVDF) crystalline structures by using the solvent casting method was quantified. The PVDF crystalline structures were predominantly determined by solvent evaporation rate. PVDF (form I) was obtained when the solvent evaporation rate was <0.0001 g min−1, PVDF (form II) was obtained when the solvent evaporation rate >0.2 g min−1 and PVDF (form III) was obtained when the solvent evaporation rate was from 0.03 to 0.00058 g min−1.
In this paper, we have studied the effects of increasing poly(methyl methacrylate) (PMMA) concentration on the triboluminescent properties of europium dibenzoylmethide triethylammonium (EuD4TEA). The research shows that the amount of PMMA could be increased such that the EuD4TEA PMMA polymer could be sensitive to selective minimum energies. Thus, a functional triboluminescent polymer was successfully obtained for the first time.
Both looped and linear polydimethylsiloxane (PDMS) polymer brushes were fabricated onto a Si substrate using the ‘grafting to’ method. As water is a poor solvent for PDMS, linear polymer brushes tended to be dewetted in water, forming aggregates. Therefore, a linear polymer brush showed a rough surface in water. In contrast, a looped polymer brush surface was smooth even in water. Aggregation was suppressed because both ends were tethered to the surface.
Monolithic polydimethylsiloxane (PDMS) thin film layers were prepared by adhering two partly cured films together at different curing times. For dielectric electroactive polymer (DEAP) uses the lamination performed slightly above the gelation threshold, namely at the time where the monolayer films had gained 30% of the final mechanical strength, was extremely favorable. The lamination process for DEAP bilayers can actually be used as a process to improve the overall performance of the DEAP, and hence enable the large-scale production of DEAP transducers.
The aim of this study is to establish the factors that affect the formation of polyion complex (PIC) vesicles. The effects of anionic segment length of PEG-PAspy, and chemical structure of the side chains of Homo-P(Asp-Cn)x on the properties of PICs were carefully examined. It was found that PEG weight fraction (fPEG) has a significant role in determining the PIC morphologies as PICs with fPEG <10% formed submicron/nanosized polyion complex vesicles (Nano-PICsomes), whereas micelles were selectively fabricated at fPEG >10%. In addition, Homo-P(Asp-Cn)x containing five and six carbon atoms on the aliphatic spacers in their side chains facilitated the formation of Nano-PICsomes (compared with the shorter ones). These findings shed new light on how to control the structure and properties of PIC assemblies for diverse material applications.
The combined effect of cytotoxic T-lymphocyte antigen-4-Ig (CTLA4Ig) and interleukin-1 receptor antagonist (IL1ra) on the survival of subcutaneous mouse islet grafts with temperature-sensitive hydrogel, pNIPAAm-chitosan-hyaluronic acid (CPNHA), and gelatin microspheres in an allogeneic mouse model is examined. The survival of the allogeneic islets was prolonged when the grafts were transplanted into a subcutaneous matrix composed of CPN-CTLA4Ig-HA (CPNCHA) and gelatin microspheres containing IL1ra relative to those implanted in CPNHA containing gelatin microspheres without an immunomodulator.
