Macromolecular Chemistry and Physics

Front Cover: Only stereocomplex crystallites accompanied with high spherulite growth rates were formed from low-molecular-weight poly(L-lactide)/poly(D-lactide) blends by crystallization above 120°C from the melt, regardless of poly(D-lactide) content (XD). The crystallization mechanism of the blends was independent of XD. Further details can be found in the article by L. Bouapao and H. Tsuji^*on page 993.

We examine via the inspection of examples from the recent literature whether there is evidence that a paradigm shift in polymer material design has occurred caused by the introduction of the click chemistry philosophy.

The stereocomplex spherulites of blends from low molecular weight Poly(L-lactide) (PLLA) and Poly(D-lactide) (PDLA) at around a PDLA content of 50% had a much higher maximum spherulite growth rate compared to those of pure PLLA and PDLA. On the basis of regime analysis, the stereocomplex crystallization mechanism in the blends remained unchanged, irrespective of PDLA content, in the crystallization temperature range above 130 °C.

Cell dynamics system simulations show that nanoparticles in diblock copolymer templates can assemble into various oriented structures, e.g., lamellae, cylinder, and alternating lamellae, on the macroscopic scale by selecting appropriate parameters under an electric field. These results aim to stimulate future work on large scale oriented block copolymer-templated nanoparticle assemblies for functional nanostructured systems.

Efficient grafting of hyperbranched polyglycerol (HPG) from the surface of hydroxyl-functionalized multiwalled carbon nanotubes (MWNTs) by in situ anionic ring-opening polymerization is reported. By mediating the feed ratio of glycidol to macroinitiator of hydroxyl-functionalized MWNTs (MWNT-OH), the content of HPG grafted from MWNTs in a wide range up to 90.8 wt.-% can be readily adjusted. The grafted HPG with numerous reactive hydroxyls not only improve the solubility of MWNTs greatly, but also can serve as a versatile platform for further chemical modification and bioconjugation, giving rise to multifunctional nanohybrids such as highly fluorescent nanotubes.

Renewable polyamides of the type PA X,20 were prepared via metathesis and catalytic amidation revealing good polymer properties. Optimization of the synthetic protocol could reduce the required amount of precious ruthenium metathesis catalyst by a factor of at least 100.

Sonication of amphiphilic block copolymer aqueous solutions results in the breakup of initially formed loose aggregates and the reorganization of diblock copolymer chains into monodisperse micelles.

The simultaneous copolymerization of ε-caprolactone (CLo) and ε-caprolactam (CLa) initiated by an ω-NH₂ macroinitiator was shown to formed a diblock copolymer containing a statistical polyesteramide block, as evidenced by ¹³C NMR. The lengths of the polyester and polyamide sequences within the polyesteramide block, and so the thermal and mechanical properties of the resulting materials, can be tuned depending on the initial co-monomer-to-amine molar ratio.

Two novel TTF-fused oligo-(aryleneethynylene)s with coplanarity of main chain and TTF side chains that reveal good electroactivity have been prepared. The continuous stacking and reversible electroactive properties indicate that this kind of TTF-fused oligomers may become a promising active material for organic electronic applications.

The in vitro biodegradability of novel biodegradable galactose polycation/hemoglobin multilayers with potential hepatic targetability via proteases was evaluated in detail on both planar substrates and CaCO₃ particles. This multilayered system has successfully been applied in sustained drug release in the presence of enzymes.

Back Cover: Cell dynamics system simulations show that the block copolymer-templated assembly of nanoparticles can be directed using electric fields. Depending on the particle types and their preference for one phase lamellae, alternating lamellae and cylinders are found. Further details can be found in the article by L.-T. Yan, H. G. Schoberth, and A. Böker on page 1003.