The synthesis and properties of a new class of photoresponsive coumarin polyesters are described. Incorporation of the coumarin chromophore in the polymer chain provides interesting properties such as polymer chain crosslinking upon irradiation at 350 nm and chain un-cross-linking when irradiated at 254 nm. In addition, irradiation at 254 nm also results in polymer chain scission. The cross-linking, uncross-linking, and chain scission properties were studied by ssNMR, ATR-IR, and GPC measurements. These properties enable the fabrication of 2D surfaces having complementary micropatterned features. Also, initial biocompatibility profiles of the polymers and their irradiation products were demonstrated using MTT assays.

Porous micro- and nanostructured materials with desired morphologies and tunable pore sizes are of great interests because of their potential applications in environmental remediation. In this study, novel rattle-type carbon-alumina core-shell spheres were prepared by using glucose and metal salt as precursors via a simple one-pot hydrothermal synthesis followed by calcination. The microstructure, morphology, and chemical composition of the resulting materials were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N(2) adsorption-desorption techniques. These rattle-type spheres are composed of a porous Al(2)O(3) shell (thickness ≈ 80 nm) and a solid carbon core (diameter ≈ 200 nm) with variable space between the core and shell. Furthermore, adsorption experiments indicate that the resulting carbon-alumina particles are powerful adsorbents for the removal of Orange-II dye from water with maximum adsorption capacity of ~210 mg/g. It is envisioned that these rattle-type composite particles with high surface area and large cavities are of particular interest for adsorption of pollutants, separation, and water purification.

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A novel kind of amphiphilic hyperbranched polymer (AHP), poly(2-(dimethylamino)ethyl methacrylate)-co-polystyrene (HPTAM-co-PS), was synthesized via the combination of reversible addition–fragmentation chain-transfer polymerization and self-condensing vinyl polymerization (RAFT-SCVP). HPTAM-co-PS was functionalized via the highly efficient Menschutkin click reaction, resulting in hyperbranched poly(propargyl quaternary ammonium methacrylate)-co-polystyrene (HPPrAM-co-PS) with a hydrophilic quaternary ammonium salt core and hydrophobic PS shell. The average numbers of dye molecules trapped by each molecule of HPPrAM-co-PS (24.2 kDa) were 24.1 for methyl orange (MO), 22.0 for fluorescein sodium (FS), 24.2 for rose bengal (RB), and 238.4 for Congo red (CR). The polymer–dye complexes show excellent colouring effects for both PS and poly(styrene-b-butadiene-b-styrene) (SBS) membranes; the colour of the membrane containing AHP is very stable and uniform. Our work opens an avenue for the design of efficient dye-colouring additives and for the application of hyperbranched polymers in the field of polymer colouring.

The chemical modification of the pendant hydroxyl functional groups on cyclodextrins (CDs) significantly suppresses the hydrogen-bonding interactions between the cyclodextrin molecules and leads to the unique viscoelastic properties of hydroxypropylated polyrotaxane (HyPR) [Inomata et al. Macromolecules 2010, 43, 4660–4666]. HyPR consists of poly(ethylene glycol) (PEG) and α-CDs that are partially modified with a hydroxypropyl (Hy) group, setting them apart from other polyrotaxanes (PRs). The molecular dynamics of PR and HyPR with 25% (HyPR25) and 78% (HyPR78) modification ratios were investigated using various solid-state NMR techniques. Two-dimensional 1H–13C wide-line separation (WISE) NMR spectra of three samples demonstrated that the PEG chains provide two components of the restricted and the near-isotropic components in a fast motion limit at 329 K. The fraction of restricted dynamics of the threaded PEG chains was found to depend on the chemical modification ratio. In addition, WISE experiments proved that the CD side chains exhibit enhanced mobility when the modification fraction is increased. Centerband-only detection of exchange (CODEX) NMR was used to characterize the slow dynamics of both CD and PEG molecules with frequencies directly comparable to those used in viscoelastic measurements. The CD molecules undergo slow main-chain dynamics in HyPR78 in the mechanical-relaxation temperature range, whereas the other two systems do not. The temperature dependence of the correlation time ⟨τc⟩ determined by CODEX revealed Arrhenius behavior with a high activation energy (163 ± 16 kJ/mol), which is consistent with the previous viscoelastic result. The high activation energy for the dynamics of the CDs was interpreted in terms of cooperative motions with the threading PEG chains. The dependence of the evolution time of the CODEX data and simulation results indicated that the CD dynamics match random-jump and uniaxial rotation diffusion models. These results indicate that chemical modifications of the side groups can dramatically affect not only the molecular dynamics of both the CD main and side chains but also the threading of PEG chains across wide time scales.