There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Hydrogels for biomedical applications.

A review on polymeric hydrogel membranes for wound dressing applications: PVA-based hydrogel dressings

Poly(ionic liquid)s: An update

This Perspective presents recent advances in macromolecular engineering enabled by ATRP. They include the fundamental mechanistic and synthetic features of ATRP with emphasis on various catalytic/initiation systems that use parts-per-million concentrations of Cu catalysts and can be run in environmentally friendly media, e.g., water. The roles of the major components of ATRP—monomers, initiators, catalysts, and various additives—are explained, and their reactivity and structure are correlated. The effects of media and external stimuli on polymerization rates and control are presented. Some examples of precisely controlled elements of macromolecular architecture, such as chain uniformity, composition, topology, and functionality, are discussed. Syntheses of polymers with complex architecture, various hybrids, and bioconjugates are illustrated. Examples of current and forthcoming applications of ATRP are covered. Future challenges and perspectives for macromolecular engineering by ATRP are discussed.

Macromolecular Engineering by Atom Transfer Radical Polymerization

Incorporating labile bonds inside polymer backbone and side chains yields interesting polymer materials that are responsive to change of environmental stimuli. Drugs can be conjugated to various polymers through different conjugation linkages and spacers. One of the key factors influencing the release profile of conjugated drugs is the hydrolytic stability of the conjugated linkage. Generally, the hydrolysis of acid-labile linkages, including acetal, imine, hydrazone, and to some extent β-thiopropionate, are relatively fast and the conjugated drug can be completely released in the range of several hours to a few days. The cleavage of ester linkages are usually slow, which is beneficial for continuous and prolonged release. Another key structural factor is the water solubility of polymer–drug conjugates. Generally, the release rate from highly water-soluble prodrugs is fast. In prodrugs with large hydrophobic segments, the hydrophobic drugs are usually located in the hydrophobic core of micelles and nanopa...

Designing Smart Polymer Conjugates for Controlled Release of Payloads

Natural Polymer-Based Antimicrobial Hydrogels without Synthetic Antibiotics as Wound Dressings

A functionalized poly(ionic liquid) coated magnetic nanoparticle (Fe3O4@PIL) catalyst was successfully synthesized by polymerization of functionalized vinylimidazolium in the presence of surface modified magnetic nanoparticles. The resulting heterogeneous catalyst is shown to be an efficient acidic catalyst for synthesis of 1,1-diacetyl from aldehydes under solvent free conditions and room temperature in high yields. Also, the catalyst shows good activity for the deprotection reaction of acylals. After completion of reaction, the catalyst was simply recovered by an external conventional magnet and recycled without significant loss in the catalytic activity. Because of the polymer layers coated surface of the magnetic nanoparticles, the catalyst has a good thermal stability and recyclability. The poly(ionic liquid) coated magnetic nanoparticles represents a novel class of heterogeneous catalyst which are particularly attractive in the practice of organic synthesis in an environmentally friendly manner.

Multi-Layer Functionalized Poly(Ionic Liquid) Coated Magnetic Nanoparticles: Highly Recoverable and Magnetically Separable Brønsted Acid Catalyst

Given the large amount of anthropogenic CO2 emissions, it is advantageous to use CO2 as feedstock for the fabrication of everyday products, such as fuels and materials. An attractive way to use CO2 in the synthesis of polymers is by the formation of five-membered cyclic organic carbonate monomers (5CCs). The sustainability of this synthetic approach is increased by using scaffolds prepared from renewable resources. Indeed, recent years have seen the rise of various types of carbonate syntheses and applications. 5CC monomers are often polymerized with diamines to yield polyhydroxyurethanes (PHU). Foams are developed from this type of polymers; moreover, the additional hydroxyl groups in PHU, absent in classical polyurethanes, lead to coatings with excellent adhesive properties. Furthermore, carbonate groups in polymers offer the possibility of post-functionalization, such as curing reactions under mild conditions. Finally, the polarity of carbonate groups is remarkably high, so polymers with carbonates side-chains can be used as polymer electrolytes in batteries or as conductive membranes. The target of this Review is to highlight the multiple opportunities offered by polymers prepared from and/or containing 5CCs. Firstly, the preparation of several classes of 5CCs is discussed with special focus on the sustainability of the synthetic routes. Thereafter, specific classes of polymers are discussed for which the use and/or presence of carbonate moieties is crucial to impart the targeted properties (foams, adhesives, polymers for energy applications, and other functional materials).

Polymers Based on Cyclic Carbonates as Trait d'Union Between Polymer Chemistry and Sustainable CO2 Utilization

The hemoprotein horseradish peroxidase (HRP) catalyzes the polymerization of N-isopropylacrylamide with an alkyl bromide initiator under conditions of activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) in the absence of any peroxide. This is a novel activity of HRP, which we propose to name ATRPase activity. Bromine-terminated polymers with polydispersity indices (PDIs) as low as 1.44 are obtained. The polymerization follows first order kinetics, but the evolution of molecular weight and the PDI upon increasing conversion deviate from the results expected for an ATRP mechanism. Conversion, M(n) and PDI depend on the pH and on the concentration of the reducing agent, sodium ascorbate. HRP is stable during the polymerization and does not unfold or form conjugates.

Farzad Seidi

Papers

Designing Smart Polymer Conjugates for Controlled Release of Payloads

Natural Polymer-Based Antimicrobial Hydrogels without Synthetic Antibiotics as Wound Dressings

Multi-Layer Functionalized Poly(Ionic Liquid) Coated Magnetic Nanoparticles: Highly Recoverable and Magnetically Separable Brønsted Acid Catalyst

Polymers Based on Cyclic Carbonates as Trait d'Union Between Polymer Chemistry and Sustainable CO2 Utilization

Horseradish peroxidase as a catalyst for atom transfer radical polymerization.