Synthesis of New Pyridazine‐Based Monomers and Related Polymers for Photovoltaic Applications

New aromatic compounds with a pyridazine core have been synthesized. Four electron‐withdrawing monomers have been easily prepared from simple condensation reactions and ring closure procedures. Optimized HOMO, LUMO, and bandgap energy levels have been obtained. The resulting conjugated polymers have been tested in organic solar cells. First studies have revealed power conversion efficiencies up to 0.5% for an active area of 1.0 cm².

     

Ordered Honeycomb‐Structured Films from Dendronized PMA‐b‐PEO Rod‐Coil Block Copolymers

Summary: Fabrication of honeycomb‐patterned films from amphiphilic dendronized block copolymer (PEO₁₁₃‐b‐PDMA₈₂) by ‘on‐solid surface spreading’ and ‘on‐water spreading’ method is reported. Highly ordered honeycomb films with quasi‐horizontally paralleled double‐layered structure can be fabricated by the on‐solid surface spreading method. This work raises the possibility that such structures can be formed in amphiphilic dendronized block copolymers and extends the family of source materials.

     

In vitro Evaluation of Hexagonal Polymeric Micelles in Macrophage Phagocytosis

This paper develops a non‐spherical polymeric micelle using an amphiphilic block copolymer and a porphyrin crystalline structure. The nanoscale polymer micelles were characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM), revealing particle sizes of approximately 150 nm with a particular shape in the hexagonal lattice. The shape shows the selective uptake efficacy for the HeLa and macrophage cells, and inhibits phagocytosis against the macrophage.

     

Erratum: Resolving the sign ambiguity in the singular value decomposition

J. Chemometrics 22 (2): 135–140. DOI: 10.1002/cem.1122 It has come to our attention that an error arose during correction of this article. In Figure 3, Step 3 should as appear as follows:

     

1,1‐Diphenyl Ethylene‐Mediated Radical Polymerisation: A General Non‐Metal‐Based Technique For The Synthesis Of Precise Core Cross‐Linked Star Polymers

This communication details the successful synthesis of low polydispersity core cross‐linked star (CCS) polymers via DPE‐mediated polymerisation. We demonstrate the ability to produce poly(methyl methacrylate) and poly(acrylonitrile) CCS polymers that are currently inaccessible via the two most common non‐metal‐based controlled radical polymerisation techniques (NMP and RAFT polymerisations).

     

The Peculiar Response of DNA Hydrogel Fibers to a Salt and pH Stimulus

DNA hydrogels which are composed of an entangled network without a crosslinker are synthesized and examined in regards to their sensitivity to salt and pH changes. The DNA hydrogel fibers only exhibited a marked response – that is a fast and large change in length – under biological conditions ([Na⁺] = 0.15 M at pH = 7) and are therefore suitable materials for bio‐inspired devices.

     

Kinetic Analysis of A2 + AB2 Polymerization Approach

The kinetic model of the co‐polycondensation with A₂ and AB₂ type monomers is developed and the analytical expressions of the various molecular parameters of the products are derived rigorously. The monomer feed ratio (α) of A₂ to AB₂ significantly affects the molecular parameters and the critical condition of gelation. Gelation can be avoided if α is > . At the critical state, the degree of branching decreases firstly and reaches its minimum value at about α≈0.22. Then, it increases with increasing α‐value. In comparison with experimental results, non‐equal reactivity of the active groups should be considered.

     

Putting Electrospun Nanofibers to Work for Biomedical Research

Electrospinning has been exploited for almost one century to process polymers and related materials into nanofibers with controllable compositions, diameters, porosities, and porous structures for a variety of applications. Owing to its high porosity and large surface area, a non‐woven mat of electrospun nanofibers can serve as an ideal scaffold to mimic the extracellular matrix for cell attachment and nutrient transportation. The nanofiber itself can also be functionalized through encapsulation or attachment of bioactive species such as extracellular matrix proteins, enzymes, and growth factors. In addition, the nanofibers can be further assembled into a variety of arrays or architectures by manipulating their alignment, stacking, or folding. All these attributes make electrospinning a powerful tool for generating nanostructured materials for a range of biomedical applications that include controlled release, drug delivery, and tissue engineering.

     

A New Class of Blue‐Emitting Materials for LED Applications: Triarylamine N‐Functionalised 2,7‐Linked Carbazole Polymers

Attachment of triarylamino‐functional groups at the 9‐position of 2,7‐linked carbazole polymers results in blue‐emitting materials with two independent redox processes that were attributed to the triarylamino groups and the polymer backbone, respectively. This new class of blue‐emitting conjugated polymers was prepared via a Suzuki cross‐coupling reaction and showed low turn‐on voltages in electroluminescent devices as a result of their low ionisation potentials. The photophysical, electrochemical and electroluminescent properties of these materials are discussed.

     

Self‐Organizing Alignment of Carbon Nanotubes in Thermoplastic Polyurethane

Summary: A simple compounding technique for the fabrication of polymer nanocomposites with single‐walled carbon nanotubes having exceptional alignment and improved mechanical properties is described. The aligned‐nanotube composite was prepared by dissolving single‐walled carbon nanotubes in a solution of thermoplastic polyurethane and tetrahydrofuran. Solvent‐polymer interactions that induce the orientation of soft chain segments during the swelling and moisture curing stage are believed to serve as a driving force for the macroscopic alignment of the carbon nanotubes.

Alignment of single‐walled carbon nanotubes in thermoplastic polyurethane during polar solvent exposure.     

Engineering Polymer Informatics: Towards the Computer‐Aided Design of Polymers

The computer‐aided design of polymers is one of the holy grails of modern chemical informatics and of significant interest for a number of communities in polymer science. This paper outlines a vision for the in silico design of polymers and presents an information model based on modern semantic web technologies, thus laying the foundations for achieving the vision.

     

Modification of Polysaccharides Through Controlled/Living Radical Polymerization Grafting—Towards the Generation of High Performance Hybrids

This review covers the literature concerning the modification of polysaccharides through controlled radical polymerizations (NMP, ATRP and RAFT). The different routes to well‐defined polysaccharide‐based macromolecules (block and graft copolymers) and graft‐functionalized polysaccharide surfaces as well as the applications of these polysaccharide‐based hybrids are extensively discussed.

     

Phosphorylation of Cotton Cellulose with Baker's Yeast Hexokinase

Here we report for the first time on phosphorylation of cotton cellulose using baker's yeast hexokinase and phosphoryl donor adenosine‐5′‐triphosphate. An enzymatic assay was adopted for determination of the degree of phosphorylation of cellulose. This functional modification of cellulose resulted in improved colorability and flame resistance.

Phosphorylated glucopyranose unit of cellulose.     

Effects of Catalyst Isoquinoline in Polymerization Process on the Aggregation Structures of Polyimide in Solution

Summary: A thermoreversible gel or a dendritic crystal has been obtained in a novel polyimide solution at low temperature, depending on the approach taken to add the isoquinoline catalyst during the polymerization process. By adding the isoquinoline at the beginning of polymerization, two kinds of layer structures in the gel are developed. However, by adding the isoquinoline after the polymerization has been carried out for one hour, a perfect dendritic crystalline structure is gradually developed in the polymerization solution.

PLM photographs of the obtained polyimide crystals.