Enzymatic Synthesis of Muconic Acid-Based Polymers: Trans, Trans-Dimethyl Muconate and Trans, β-Dimethyl Hydromuconate.

The vast majority of commodity polymers are acquired from petrochemical feedstock, and these resources will plausibly be depleted within the next 100 years. Therefore, the utilization of carbon-neutral renewable resources for the production of polymers is crucial in modern green chemistry. Herein, we report an eco-friendly strategy that uses enzyme catalysis to design biobased unsaturated (co)polyesters from muconic acid derivatives.

Metal cation responsive anionic microgels: behaviour towards biologically relevant divalent and trivalent ions.

Anionic poly(vinylcaprolactam-co-itaconicacid-co-dimethylitaconate) microgels were synthesized via dispersion polymerization and their responsiveness towards cations, namely Mg, Sr, Cu and Fe, was investigated. The itaconic moieties chelate the metal ions which act as a crosslinker and decrease the electrostatic repulsion within the network, leading to a decrease in the gel size. The responsiveness towards the metal ion concentration has been studied via dynamic light scattering (DLS) and the number of ions bonded within the network has been quantified with ion chromatography.

Deepening the insight into poly(butylene oxide)--poly(glycidol) synthesis and self-assemblies: micelles, worms and vesicles.

Aqueous self-assembly of amphiphilic block copolymers is studied extensively for biomedical applications like drug delivery and nanoreactors. The commonly used hydrophilic block poly(ethylene oxide) (PEO), however, suffers from several drawbacks. As a potent alternative, poly(glycidol) (PG) has gained increasing interest, benefiting from its easy synthesis, high biocompatibility and flexibility as well as enhanced functionality compared to PEO.

Supramolecular Mimic for Bottlebrush Polymers in Bulk.

A series of poly(tetrahydrofuran)s with molecular weights above entanglement molecular weight were synthesized, and one of their end-groups was functionalized with a supramolecular entity so that the corresponding polymers form a brushlike structure suitable for comparison with conventional irreversible bottlebrush polymers. To compare their relaxation mechanisms, linear rheology was employed and showed that a hierarchical relaxation, which is usually observed in bottlebrush polymers, occurs in these materials, too. The polymer chain segments close to the supramolecular backbone are highly immobilized due to strong association in the center of polymer brush and cannot relax via reptation mechanism, which is mainly responsible for linear entangled polymer relaxations.

Effect of Divalent Cation on Swelling Behavior of Anionic Microgels: Quantification and Dynamics of Ion Uptake and Release.

Poly(-vinylcaprolactam--itaconate) (P(VCL--IADME) microgels were synthesized varying the molar ratio between VCL and IADME via free radical precipitation polymerization in the presence of quaternary ammonium surfactant. In order to determine the effect of the divalent metal ions on the structure and the swelling behavior of the microgel systems, both neutral and charged forms of the hydrogels after hydrolysis were investigated. The triggered gel collapse caused by the divalent metal ion together with the quantification of the metal ion uptake was studied in detail by titration and ion chromatography methods and revealed the minimum concentration around 0.

pH-Triggered Membrane in Pervaporation Process.

Dehydration of binary methyl acetate-water mixtures under neutral, acidic, and basic conditions was carried out by using PERVAP composite membranes based on polyvinyl alcohol and poly(1-vinylpyrrolidone--2-(dimethylamino)ethyl methacrylate) P(VP--DMAEMA). The effects of an acid (HCl) and a base (NaOH) on the separation performance of the membrane during the pervaporation process were investigated. The pH-responsive nature of membranes has been confirmed by swelling tests and analysis of the chemical structure of polymeric membranes.

Repurposing Biocatalysts to Control Radical Polymerizations.

Reversible-deactivation radical polymerizations (controlled radical polymerizations) have revolutionized and revitalized the field of polymer synthesis. While enzymes and other biologically derived catalysts have long been known to initiate free radical polymerizations, the ability of peroxidases, hemoglobin, laccases, enzyme-mimetics, chlorophylls, heme, red blood cells, bacteria, and other biocatalysts to control or initiate reversible-deactivation radical polymerizations has only been described recently. Here, the scope of biocatalytic atom transfer radical polymerizations (bioATRP), enzyme-initiated reversible addition-fragmentation chain transfer radical polymerizations (bioRAFT), biocatalytic organometallic-mediated radical polymerizations (bioOMRP), and biocatalytic reversible complexation mediated polymerizations (bioRCMP) is critically reviewed, and the potential of these reactions for the environmentally friendly synthesis of precision polymers, for the preparation of functional nanostructures, for the modification of surfaces, and for biosensing is discussed.

Linear Viscoelasticity of Weakly Hydrogen-Bonded Polymers near and below the Sol-Gel Transition.

Supramolecular polymers bearing weak hydrogen bonds (sticker) can express outstanding dynamic properties due to their labile association. Studying the linear viscoelasticity (LVE) of this type of polymer can provide us with sufficient knowledge to design polymeric materials for applications that need dynamic properties such as self-healing. Using different compositions of flexible weak stickers, LVE analysis showed scalings corresponding to a transition from a linear precursor to a cluster.

Crystal structure of di-aqua-tris-(1-ethyl-1H-imidazole-κN (3))(sulfato-κO)nickel(II).

In the title complex, [Ni(SO4)(C5H8N2)3(H2O)2], the Ni(II) ion is coordinated by three facial 1-ethyl-1H-imidazole ligands, one monodentate sulfate ligand and two water mol-ecules in a slightly distorted octa-hedral coordination environment. In the crystal, two pairs of O-H⋯O hydrogen bonds link complex mol-ecules, forming inversion dimers incorporating R 2 (4)(8), R 2 (2)(8) and R 2 (2)(12) rings. The dimeric unit also contains two symmetry-unique intra-molecular O-H⋯O hydrogen bonds.