Macromolecular Chemistry and Physics

Front Cover: The cover illustrates a sandwiched (PEI/PCGF)/SiO₂/(PEI/PCGF) membrane composed of a middle silica layer and upper and lower PEI/PCGF layers. The inorganic silica layer suppresses methanol permeation, while the two organic layers provide sufficient mechanical strength and flexibility. The sandwiched membrane is shown floating on (upper left) and cutting into (upper right) water, on a metal gasket (lower left), and after its incorporation into a finger cot (lower right). Further details can be found in the article by H. Li^*, M. Yi, and F. Jiang on page 863.

A new type of nanoporous hydroquinone/catechol formaldehyde resin is prepared by a one-pot synthesis. There are sufficient intrinsic hydroxyl groups in the resins to endow these materials with improved hydrophilicity. The high surface areas of the resins mean that almost every hydroxyl group can be readily accessible. These resins are suitable for application in recovery of precious-metal ions.

Due to depleting fossil resources and environmental concerns, the utilization of renewable feedstocks is one necessary step toward a sustainable development. Here, the direct use of high oleic sunflower oil, a commercially available plant oil, as a monomer (building block) for polymer synthesis is described. Applications possibilities are manifold and might include lubricants, reactive diluents, drug delivery systems, and many more.

A design strategy based on an organic/inorganic/organic sandwich structure for ultra-thin, flexible, free-standing, proton-conducting membranes has been proposed. In the tri-layer assembled, the middle surfactant-templated SiO₂ layer suppresses methanol permeation, while the lower and upper organic PEI/poly(o-cresyl glycidyl ether)-co-formaldehyde (PCGF) layers provide sufficient mechanical strength and flexibility.

Amphiphilic block copolymers are a special class of polymers. In the present paper new polymers of this type containing N-vinyl pyrrolidone units as water soluble sequences are characterized at molecular level. Beside expected polymer structures resulting from the RAFT synthesis unexpected end groups were found indicating a non-ideal mechanism of polymerization.

UV polymerisation of PEG-methacrylate oligomers for development of biocompatible microfluidic structures is studied. The PEG material has no inhibition effect in the DNA amplification reaction (lanes 5–7 refer to the PEG-methacrylate and lane 4 is a positive control), while there is a partial but significant inhibition with the glass substrate (lanes 1–3).

Molecular structure effect on the self-assembled structures and optical properties of three azobenzene-substituted polydiacetylenes was studied. Molecular structures and intermolecular interaction could modulate the stacking structure at both the molecular and the supramolecular levels, resulting in different polymerization behavior, tunable morphology, and thermal stability of the assembled films.

High molar mass norbornene based co- and terpolymers containing hydroxyl functionalities were obtained with excellent yields by the scandium catalyst [Sc(η⁵-C₅Me₄SiMe₃)(η¹-CH₂SiMe₃)₂(THF)]/[Ph₃C][B(C₆F₅)₄]. Good OH content and T_g values up to 100 °C were obtained. The requirements for the success were catalyst preactivation and use of isolated AlⁱBu₃-protected 5-norbornene-2-methanol.

Successful synthesis of less toxic and hydrolytically degradable polycations based on free radical chemistry is shown here. The formation and characterization of highly stable polycation/DNA polyplexes is also reported. The new materials show promise for a wide variety of applications.

For the first time, the Sonogashira coupling reaction has been applied to the synthesis of AB₂-type hyperbranched polymers in NLO area. Despite the relatively lower density of the effective chromophore moieties, P1 demonstrated enhanced second-harmonic coefficient (153.9 pm · V⁻¹) than its linear analog polymer (P2, 98.2 pm · V⁻¹), due to three-dimensional spatial isolation effect arising from the hyperbranched structure.

Starch microspheres with average diameter of 0.6 μm are synthesized for the first time without using any crosslinking reagent using the sonochemical method. Our simple technique enables also the production of starch microspheres containing insulin, if the drug added to the reaction vessel before ultrasonic irradiation. The obtained microspheres can be used for drug delivery applications.

Linear-hyperbranched hybrid block copolymers based on poly(ethylene oxide) and hyperbranched poly(glycerol) have been developed, which bear a single pyrene or tetradecyl moiety at the linear chain end (α-position) and multiple hydroxyl termini at the other. These polar polymer architectures can effectively solubilize multiwalled carbon nanotubes in water.

Cleavable polymers. Atom transfer radical polymerization (ATRP) initiators containing TFA-labile p-alkoxybenzyl ester Wang linkers and terminal functional groups (e.g., COOH, N₃, OH, C≡CH or NHFmoc) have been synthesized and characterized. These molecules allow the design of well-defined soluble polymer supports for organic synthesis, biochemistry, polymer chemistry or catalysis.

A series of polythiophene derivatives P1-P5 containing carbazole side chains were designed and synthesized by the Stille polymerization. All carbazole containing polymers showed broad absorption in the visible region. The power conversion efficiencies of solar cells using blends of polymers and PC₆₁BM were determined to be 0.29, 0.56, 0.86, 0.70, and 0.56% for P1, P2, P3, P4 and P5, respectively. The improvement of efficiency needs a balance of the broad absorption and ordered packing of polymer chains in solid state.

Reduction-sensitive self-aggregate delivery system of doxorubicin was obtained using amphiphilic mPEG-Cys-PCL copolymers. Intermolecular disulfide bonds via oxidation stabilized the polymeric aggregates even in the diluted condition similar to that in the bloodstream and addition of DTT destabilized the aggregates to burst encapsulated doxorubicin in the reductive condition.