Macromolecular Rapid Communications

Front Cover: A novel pH sensitive shape-memory polymer (SMP) is prepared by cross-linking the β-cyclodextrin modified alginate (β-CD-Alg) and diethylenetriamine modified alginate (DETAAlg). The pH reversible β-CD-DETA inclusion complexes serve as a reversible phase, and the cross-linked alginate chains serve as a fixing phase. The material can be processed into temporary shape as we required at pH 11.5 and recover to its initial shape at pH 7. The polymer has great potential in medical applications as it is biocompatible and biodegradable and the shape transition pH value is close to that of body fluids. Further details can be found in the article by Xiao-Juan Han, Zhen-Qiang Dong, Min-Min Fan, Yan Liu, Jian-Hu li, Yi-Fu Wang, Qi-Juan Yuan, Bang-Jing Li,* and Sheng Zhang* on page 1055.

Back Cover: Nearly monodisperse thermosensitive dumbbell-shaped core-shell microgels are fabricated, and are found to be a uniform model system. The microgels undergo a phase transition into an ordered, crystal-like state, which is indicated by Bragg-reflections in the visible range and supported by rheological measurements. Further details can be found in the article by F. Chu, M. Siebenbürger, F. Polzer, C. Stolze, J. Kaiser, M. Hoffmann, N. Heptner, J. Dzubiella, M. Drechsler, Y. Lu, and M. Ballauff* on page 1042.

This Feature Article deals with the self assembly and physical chemistry of polyelectrolytes: multilayers and brushes. Pictured is an atomic force microscopy image of patterned poly(sulfo propyl methacrylate) brushes on top of which a multilayer of poly(styrene sodium sulfonate) and poly(dimethyl diallyl ammonium chloride) is assembled and then partially removed by a surfactant, resulting in the formation of polymer walls at the edges of the patterned brushes.

Red iridium triplet emitters are shielded by polyphenylene dendrons to prevent self quenching, and not needing a diluting matrix. They are decorated on the outside with triphenylamines for improving hole transport and charge recombination.

Nearly monodisperse thermosensitive dumbbell-shaped core-shell microgels are fabricated, which turn out to be a uniform model system. Bragg reflection of the microgel suspensions indicates the formation of crystals, which has been further supported by rheological measurements where the shear-melting of the crystal phase is clearly detected.

The synthesis of porous PEG microgels by hard templating with CaCO₃ microparticles is described. A new approach for the straightforward formation of nonaggregated, well-defined PEG microgels is presented. The obtained PEG microgels are inverse replicates of their templates in terms of shape, size, and porosity and represent attractive materials for encapsulation and applications such as catalysis and drug delivery.

This paper describes a biocompatible and biodegradable SMP, which can be processed into different temporary shapes at pH 11.5 and recover to its permanent shape at pH 7. The shape memory effect was obtained using the pH sensitive inclusion behavior between CD molecules and guest molecules. The recovery ratio and the fixity ratio were 95.7 ± 0.9% and 94.8 ± 1.1%, respectively.

Enantiomeric mPEG–PH–PLA triblock copolymers self-assemble into nanoparticles by sterocomplexation. The morphology, stability, and biocompatibility of the stereocomplex nanoparticles are investigated. The mean diameter of the stereocomplex nanoparticles is stabilized around 100 nm when the pH values are changed from 7.9 to 5.0. The stereocomplexation could decrease the cytotoxicity of the PDLA blocks.

A novel strategy for the iron-mediated AGET ATRP of PEGMA was developed successfully in water using FeCl₃.6H₂O as the catalyst, water-soluble tri(3,6-dioxaheptyl) amine (TDA-1) as the ligand and ascorbic acid as the reducing agent. This strategy may help develop a “green” way of synthesizing biomaterials.

A fully substituted 3-silolene bearing four dimethylsilyl groups is first synthesized, whose hydrosilylation with diethynylsilole in the presence of Karstedt's catalyst generates a stereoregular silole-containing hyperbranched poly(silylenevinylene) in high yield, with excellent thermal stability, strong fluorescence, and sensitive response to explosives.