Search

Polymer and ionic liquid (IL) mixtures have attracted an increasing amount of attention due to their unique properties and potential applications. The interactions between poly(ethylene oxide) (PEO) and imidazolium ILs of different cation alkyl lengths and anion structures have been investigated by measuring melting points (Tm), contact angles, and rheological properties. Tm of crystalline PEO dramatically decreased when it was blended with ILs. Similarly, the contact angles of different ILs on a PEO surface proportionally decreased. The interaction energy, as calculated from melting point depression using the Flory equation, increased with the length of imidazolium alkyl cations and the size of anions. The different anionic structures had a more significant influence on the interaction energy than the alkyl chain lengths of cations. These trends accorded with the solubility obtained by high-energy X-ray diffraction and swelling ratio measurements of PEO in different ILs and the solubility of poly(methyl methacrylate) in different ILs. The rheological behavior of PEO in three different anionic ILs has also been studied to determine the effect of the anions on PEO conformations. The molecular weight dependence of the intrinsic viscosity of PEO in ILs revealed that the solvent quality of ILs (from poor solvents to good solvents) is highly influenced by anionic structures, which was consistent with the results of the melting point depression and contact angle. [ABSTRACT FROM AUTHOR]

A novel class of dumbbell-shaped dendritic molecules with a p-terphenylene core was synthesized, and their self-assembling properties were investigated. The incorporation of bulky dendritic wedges to the central stiff aromatic scaffolds could finely tune their solubility in many organic solvents. Unlike the self-assembly behavior of p-terphenylen-1,4′′-ylenebis(dodecanamide), the p-terphenylene cored different generation dendritic molecules could form gels in several kinds of organic solvents through a cooperative effect of the π−π stacking, hydrogen-bonding, and van der Waals forces. Interestingly, significant fluorescence enhancement was observed after gelation. Extensive investigations with atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), rheological measurements, UV−vis absorption spectroscopy, FT-IR spectroscopy, 1H NMR, and X-ray powder diffraction (XRD) revealed that these dendritic molecules self-assembled into elastically interpenetrating one-dimensional nanostructures in organogels. [ABSTRACT FROM AUTHOR]