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

Core/Shell Nanoparticles: Classes, Properties, Synthesis Mechanisms, Characterization, and Applications

There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

Hyperbranched polymers: from synthesis to applications

In the past few years, spiropyran has emerged as the molecule-of-choice for the construction of novel dynamic materials. This unique molecular switch undergoes structural isomerisation in response to a variety of orthogonal stimuli, e.g. light, temperature, metal ions, redox potential, and mechanical stress. Incorporation of this switch onto macromolecular supports or inorganic scaffolds allows for the creation of robust dynamic materials. This review discusses the synthesis, switching conditions, and use of dynamic materials in which spiropyran has been attached to the surfaces of polymers, biomacromolecules, inorganic nanoparticles, as well as solid surfaces. The resulting materials show fascinating properties whereby the state of the switch intimately affects a multitude of useful properties of the support. The utility of the spiropyran switch will undoubtedly endow these materials with far-reaching applications in the near future.

/pdf/spiropyran-based-dynamic-materials-4c1onvrhup.pdf

Spiropyran-based dynamic materials

Thermosensitive water-soluble copolymers with doubly responsive reversibly interacting entities

Cationic polymerization of glycidol ((hydroxymethyl)oxirane) may involve two competing propagation mechanisms: active chain end (ACE) mechanism (nucleophilic attack of the monomer on the tertiary oxonium ion active species) and activated monomer (AM) mechanism (an attack of the hydroxyl group of the polymer on the protonated monomer). The first mechanism should lead to polymers containing exclusively primary hydroxyl groups. Propagation by the AM mechanism leads on the other hand to polymers containing both primary and secondary (mostly) hydroxyl groups, depending on the detection of the opening of the protonated oxirane ring

Cationic polymerization of glycidol: coexistence of the activated monomer and active chain end mechanism

Loading of polymer nanocarriers: Factors, mechanisms and applications

Glycidol (2-epoxy-1-propanol) was polymerized under the action of Lewis acids (BF 3 OEt 2 , SnCl 4 ) and protonic acids (CF 3 COOH, CF 3 SO 3 H). Polymers with number-average molecular weights (Mn) varying from 2500 to 6000 g/mol were obtained. The structure of obtained polymers was characterized by 13 C and 29 Si NMR spectroscopy, and the amount of 1-3 units, 1-4 units and chain branches was determined. The structure of the polymers was related to the polymerization mechanism, especially to the contribution of activated monomer mechanism in chain growth

Cationic polymerization of glycidol. Polymer structure and polymerization mechanism

A series of star-shaped poly(2-ethyl-2-oxazoline)s was prepared by cationic polymerization. The polymerization was initiated by dipentaerythrityl hexakis(4-nitrobenzene sulfonate) and a tosylated hyperbranched polymer of glycidol. The polymerization proceeded in a controlled manner. The star structure of the products was determined by nuclear magnetic resonance. The molar mass distributions that were measured by gel permeation chromatography with multiangle laser light scattering were narrow, and the experimental values of the molar masses were close to those predicted. The very compact structure of the polymers obtained (compared with the linear counterparts) confirmed the star formation. The star poly(2-ethyl-2-oxazoline)s show a phase transition temperature in the range 62–75 °C. Comparison of this phase transition temperature with that of the linear poly(2-ethyl-2-oxazoline)s with the same molar masses indicates the influence of molar mass and topological structure of the macromolecule on temperature behavior. The prepared copolymers are spherical, which might be useful for the controlled transport and release of active compounds. Copyright © 2011 Society of Chemical Industry

Andrzej Dworak

Papers

Thermosensitive water-soluble copolymers with doubly responsive reversibly interacting entities

Cationic polymerization of glycidol: coexistence of the activated monomer and active chain end mechanism

Loading of polymer nanocarriers: Factors, mechanisms and applications

Cationic polymerization of glycidol. Polymer structure and polymerization mechanism

Star poly(2-ethyl-2-oxazoline)s—synthesis and thermosensitivity