Ayaki Kazariya and Shuichi Matsumura
Article: Enzymatic Synthesis and Crosslinking of Novel High Molecular Weight Polyepoxyricinoleate
Polymers 2012, 4(1), 486-500; doi:10.3390/polym4010486 - published online 10 February 2012
Show/Hide AbstractAbstract: Methyl epoxyricinoleate was prepared in high yield by the lipase-catalyzed epoxidation of methyl ricinoleate with H₂O₂. A high molecular weight polyepoxyricinoleate (PER) with a maximum weight average molecular weight (M_w) of 272,000 was enzymatically prepared by the polycondensation of methyl epoxyricinoleate using immobilized lipase from Burkholderia cepacia (lipase PS-IM) in bulk at 80 °C for 5 d. PER showed good low temperature fluidability. PER was readily cured by maleic anhydride (MA) at 80 °C to produce a chloroform-insoluble PER-MA film. Both the glass transition temperature and Young’s modulus increased with increasing MA content and PER M_w. In contrast, the elongation at break decreased with increasing MA content and PER M_w. Methyl epoxyricinoleate, PER and PER-MA showed biodegradability by activated sludge, and that of the PER-MA film decreased with increasing MA content.

Seung Ha Kim and Monica H. Lamm
Review: Multiscale Modeling for Host-Guest Chemistry of Dendrimers in Solution
Polymers 2012, 4(1), 463-485; doi:10.3390/polym4010463 - published online 10 February 2012
Show/Hide AbstractAbstract: Dendrimers have been widely used as nanostructured carriers for guest species in a variety of applications in medicine, catalysis, and environmental remediation. Theory and simulation methods are an important complement to experimental approaches that are designed to develop a fundamental understanding about how dendrimers interact with guest molecules. This review focuses on computational studies aimed at providing a better understanding of the relevant physicochemical parameters at play in the binding and release mechanisms between polyamidoamine (PAMAM) dendrimers and guest species. We highlight recent contributions that model supramolecular dendrimer-guest complexes over the temporal and spatial scales spanned by simulation methods ranging from all-atom molecular dynamics to statistical field theory. The role of solvent effects on dendrimer-guest interactions and the importance of relating model parameters across multiple scales is discussed.

Ophelie Riou , Lacramiora Zadoina , Barbara Lonetti , Katerina Soulantica , Anne-Françoise Mingotaud , Marc Respaud , Bruno Chaudret and Monique Mauzac
Article: In Situ and Ex Situ Syntheses of Magnetic Liquid Crystalline Materials: A Comparison
Polymers 2012, 4(1), 448-462; doi:10.3390/polym4010448 - published online 10 February 2012
Show/Hide AbstractAbstract: Magnetic hybrid liquid crystalline composites have been obtained either by thermal decomposition of a cobalt precursor in a solution containing a liquid crystal polymer or by dispersing preformed cobalt nanorods in a liquid crystal polymer matrix. The final materials are all mesomorphous and ferromagnetic. Their magnetic characteristics are compared as a function of the synthesis method.

Clemens Krempner
Review: Polysilane Dendrimers
Polymers 2012, 4(1), 408-447; doi:10.3390/polym4010408 - published online 9 February 2012
Show/Hide AbstractAbstract: The synthesis, structure and electronic properties of polysilane dendrimers, a relatively new class of highly branched and silicon-rich molecular architectures is reviewed. After a detailed discussion of main synthetic strategies to well-defined single-core and double-core polysilane dendrimers, important structural and conformational features determined by single crystal X-ray crystallography and ²⁹Si-NMR spectroscopy are presented. The last part highlights the most interesting photochemical properties of polysilane dendrimers such as UV absorption and emission behavior, which are compared with those of linear and branched polysilanes.

Victor T. Wyatt and Gary D. Strahan
Article: Degree of Branching in Hyperbranched Poly(glycerol-co-diacid)s Synthesized in Toluene
Polymers 2012, 4(1), 396-407; doi:10.3390/polym4010396 - published online 6 February 2012
Show/Hide AbstractAbstract: ¹H NMR and ¹³C NMR spectrometry (1-dimensional and 2-dimensional) have been used to assign chemical resonances and determine the degrees of branching for polyesters synthesized by the Lewis acid (dibutyltin(IV)oxide)-catalyzed polycondensation of glycerol with either succinic acid (n (aliphatic chain length) = 2), glutaric acid (n = 3) or azelaic acid (n = 7) in quasi-melt solutions with toluene. When 1:1 and 2:1 (diacid:glycerol) molar ratios were used, it was found that the glutaric acid-derived polymers gave the highest degree of polymer branching (31.2%, 85.6%, respectively) after the 24 h reaction period followed by the succinic acid-derived polymers (39.4%, 41.9%, respectively) and the azelaic acid-derived polymers (9.9%, 13.9%, respectively). Reactions performed at reflux for 24 h resulted in a 70.8% and 56.7% decrease in degree of branching for succinic acid and glutaric acid-derived polyesters, respectively. There is no indication that degree of branching is significantly affected by the presence or absence of solvent according to the results obtained in this research.

Julieta I. Paez , Marisa Martinelli , Verónica Brunetti and Miriam C. Strumia
Review: Dendronization: A Useful Synthetic Strategy to Prepare Multifunctional Materials
Polymers 2012, 4(1), 355-395; doi:10.3390/polym4010355 - published online 2 February 2012
Show/Hide AbstractAbstract: Dendronization is a synthetic methodology that offers important advantages. The resulting products, which are called dendronized materials, present new and specific properties. This review shows numerous examples in which individual dendrons are used as building blocks to prepare more complex arrays via covalent or non-covalent interactions. In particular, it points out how the structural information programmed into the dendritic architecture can be used in the dendronization process to generate nanostructures with specific tailored properties. We emphasize the use of different dendrons, with diverse chemical structure and size, to functionalize diverse substrates like linear polymers, and plane and curved inorganic surfaces. Apart from this, the review also demonstrates that self-assembly represents an ideal approach to create well-defined hyperbranched surfaces and it includes some discussion about the ability of both organic and inorganic building blocks to direct this process.