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

As the most important skeletal component in plants, the polysaccharide cellulose is an almost inexhaustible polymeric raw material with fascinating structure and properties. Formed by the repeated connection of D-glucose building blocks, the highly functionalized, linear stiff-chain homopolymer is characterized by its hydrophilicity, chirality, biodegradability, broad chemical modifying capacity, and its formation of versatile semicrystalline fiber morphologies. In view of the considerable increase in interdisciplinary cellulose research and product development over the past decade worldwide, this paper assembles the current knowledge in the structure and chemistry of cellulose, and in the development of innovative cellulose esters and ethers for coatings, films, membranes, building materials, drilling techniques, pharmaceuticals, and foodstuffs. New frontiers, including environmentally friendly cellulose fiber technologies, bacterial cellulose biomaterials, and in-vitro syntheses of cellulose are highlighted together with future aims, strategies, and perspectives of cellulose research and its applications.

Cellulose: Fascinating Biopolymer and Sustainable Raw Material

The Huisgen 1,3-dipolar cycloaddition reaction of organic azides and alkynes has gained considerable attention in recent years due to the introduction in 2001 of Cu(1) catalysis by Tornoe and Meldal, leading to a major improvement in both rate and regioselectivity of the reaction, as realized independently by the Meldal and the Sharpless laboratories. The great success of the Cu(1) catalyzed reaction is rooted in the fact that it is a virtually quantitative, very robust, insensitive, general, and orthogonal ligation reaction, suitable for even biomolecular ligation and in vivo tagging or as a polymerization reaction for synthesis of long linear polymers. The triazole formed is essentially chemically inert to reactive conditions, e.g. oxidation, reduction, and hydrolysis, and has an intermediate polarity with a dipolar moment of ∼5 D. The basis for the unique properties and rate enhancement for triazole formation under Cu(1) catalysis should be found in the high ∆G of the reaction in combination with the low character of polarity of the dipole of the noncatalyzed thermal reaction, which leads to a considerable activation barrier. In order to understand the reaction in detail, it therefore seems important to spend a moment to consider the structural and mechanistic aspects of the catalysis. The reaction is quite insensitive to reaction conditions as long as Cu(1) is present and may be performed in an aqueous or organic environment both in solution and on solid support.

Cu-catalyzed azide-alkyne cycloaddition.

Following Sharpless' visionary characterization of several idealized reactions as click reactions, the materials science and synthetic chemistry communities have pursued numerous routes toward the identification and implementation of these click reactions. Herein, we review the radical-mediated thiol-ene reaction as one such click reaction. This reaction has all the desirable features of a click reaction, being highly efficient, simple to execute with no side products and proceeding rapidly to high yield. Further, the thiol-ene reaction is most frequently photoinitiated, particularly for photopolymerizations resulting in highly uniform polymer networks, promoting unique capabilities related to spatial and temporal control of the click reaction. The reaction mechanism and its implementation in various synthetic methodologies, biofunctionalization, surface and polymer modification, and polymerization are all reviewed.

Thiol–Ene Click Chemistry

5.1. Nanoalloys of Group 11 (Cu, Ag, Au) 865 5.1.1. Cu−Ag 866 5.1.2. Cu−Au 867 5.1.3. Ag−Au 870 5.1.4. Cu−Ag−Au 872 5.2. Nanoalloys of Group 10 (Ni, Pd, Pt) 872 5.2.1. Ni−Pd 872 * To whom correspondence should be addressed. Phone: +39010 3536214. Fax:+39010 311066. E-mail: ferrando@fisica.unige.it. † Universita di Genova. ‡ Argonne National Laboratory. § University of Birmingham. | As of October 1, 2007, Chemical Sciences and Engineering Division. Volume 108, Number 3

Nanoalloys: From Theory to Applications of Alloy Clusters and Nanoparticles

The modification of polymers after the successful achievement of a polymerization process represents an important task in macromolecular science. Cycloaddition reactions, among them the metal catalyzed azide/alkyne ‘click’ reaction (a variation of the Huisgen 1,3-dipolar cycloaddition reaction between terminal acetylenes and azides) represents an important contribution towards this endeavor. They combine high efficiency (usually above 95%) with a high tolerance of functional groups and solvents, as well as moderate reaction temperatures (25–70 °C). The present review assembles recent literature for applications of this reaction in the field of polymer science (linear polymers, dendrimers, gels) as well as the use of this and related reactions for surface modification on carbon nanotubes, fullerenes, and on solid substrates, and includes the authors own publications in this field. A number of references (>100) are included.

http://www.c2p2-cpe.com/imgBase/download/Click%20Review.pdf

‘Click’ Chemistry in Polymer and Materials Science

The metal catalyzed azide/alkyne ‘click’ reaction (a variation of the Huisgen 1,3-dipolar cycloaddition reaction between terminal acetylenes and azides) has vastly increased in broadness and application in the field of polymer science. Thus, this reaction represents one of the few universal, highly efficient functionalization reactions, which combines both high efficiency with an enormously high tolerance of functional groups and solvents under highly moderate reaction temperatures (25–70 °C). The present review assembles an update of this reaction in the field of polymer science (linear polymers, surfaces) with a focus on the synthesis of functionalized polymeric architectures and surfaces.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/marc.200800089

'Click' Chemistry in Polymer and Material Science: An Update

‘Click’ Chemistry in Polymer and Material Science: An Update: ‘Click’ Chemistry in Polymer and Material Science: An Update

As polymers and polymeric materials are “the” smart invention and technological driving force of the 20th century, the quest for self-healing or self-repairing polymers is strong. The concept of supramolecular self-healing materials relies on the use of noncovalent, transient bonds to generate networks, which are able to heal the damaged site, putting aspects of reversibility and dynamics of a network as crucial factors for the understanding and design of such self-healing materials. This Review describes recent examples and concepts of supramolecular polymers based on hydrogen bonding, π–π interactions, ionomers, and coordinative bonds, thus convincingly discussing the advantages and versatility of these supramolecular forces for the design and realization of self-healing polymers.

Self‐Healing Polymers via Supramolecular Forces

This Review describes recent results on the precise spatial distribution control of metal and semiconductor nanoparticles into domains of microphase-separated block copolymers. Specific focus is directed towards selective incorporation into a specific microphase of a block copolymer. Details on theoretical aspects concerning nanoparticle incorporation as well as practical examples are given. Furthermore, examples on applications and technological aspects of the resulting nanoparticle/polymer nanocomposites are provided.

Wolfgang H. Binder

Papers

‘Click’ Chemistry in Polymer and Materials Science

'Click' Chemistry in Polymer and Material Science: An Update

‘Click’ Chemistry in Polymer and Material Science: An Update: ‘Click’ Chemistry in Polymer and Material Science: An Update

Self‐Healing Polymers via Supramolecular Forces

Controlled Arrangement of Nanoparticle Arrays in Block-Copolymer Domains