Fluorene‐Based Co‐polymer with High Hole Mobility and Device Performance in Bulk Heterojunction Organic Solar Cells

A new donor–acceptor polymer based on 9,9‐dioctylfluorene is synthesized and tested in organic photovoltaic devices. Results show that the polymer exhibits good solubility in a range of organic solvents and has a high hole mobility. When blended with a PC₇₀BM acceptor and fabricated into a bulk heterojunction, photovoltaic devices having a maximum power conversion efficiency (PCE) of 6.2% and a peak external quantum efficiency of 74% are created. Such efficiencies are realized without any necessity for solvent additives or thermal annealing protocols.

     

A novel one‐pot oxidative deformylation of N‐formyldihydroquinolines employing ferric chloride hexahydrate. Synthesis of 4‐chloro‐2‐phenylquinolines and 4‐chloro‐2‐(1,3‐diphenyl‐1H‐pyrazol‐4‐yl)quinolines

A novel versatile one‐pot oxidative deformylation approach has been developed to synthesize 4‐chloro‐2‐phenylquinolines and 4‐chloro‐2‐(1,3‐diphenyl‐1H‐pyrazol‐4‐yl)quinolines from the corresponding N‐formyldihydroquinolines.     

A New Strategy for the Synthesis of Polyaniline Nanostructures: From Nanofibers to Nanowires

A new approach for the synthesis of polyaniline (PANI) nanostructures under UV light illumination has been developed, which is the first report of a templateless chemical process for preparing pure PANI nanowires. The acceleration effect of photo‐assistance on the polymerization can promote the homogeneous nucleation and elongation of the nanofibers and nanowires, leading to easy preparation of tunable diameters of the nanowires and nanofibers of PANI.

     

Regulation of Micellar Morphology of PCL‐b‐PEO Block Copolymers by Crystallization Temperature

The effect of crystallization temperature on the micellar morphology of PCL‐b‐PEO block copolymers in water has been studied. It is found that the micellar morphology of PCL_nPEO₄₄ and PCL_nPEO₁₁₃ changes with crystallization temperature in different ways because of two competitive factors: perfection of the PCL crystals in the core and deformation of the soluble PEO block. For PCL_nPEO₄₄, perfection of the PCL crystals dominates the micellar morphology and lamellar micelles are formed at a higher crystallization temperature. For PCL_nPEO₁₁₃ the micellar morphology is mainly determined by the tethering density and spherical micelles or cylindrical micelles with a larger length/diameter ratio are formed at a higher crystallization temperature because of the larger tethering density.

     

Ultrasound‐Assisted Synthesis of Hybrid Vanadium Oxide/Polyaniline Nanowires

A single‐step sonochemical procedure to synthesize hybrid vanadium oxide/polyaniline nanowires starting from crystalline V₂O₅ and aniline in aqueous medium is presented. The synthesis explores the effect of high power ultrasounds on heterogeneous solid–aqueous phases, which leads to 30 nm width wires of 5 to 10 µm in length. Monomer intercalation and oxidative polymerization within the inorganic matrix proceed simultaneously with morphological changes. The electronic conductivity of hybrid nanowires reaches 0.8 S · cm⁻¹ at room temperature.

     

Automated Parallel Temperature Optimization and Determination of Activation Energy for the Living Cationic Polymerization of 2‐Ethyl‐2‐oxazoline

Sixteen parallel polymerization reactions of 2‐ethyl‐2‐oxazoline have been performed at different temperatures in an automated synthesizer that allowed individual heating of each reactor. During the reactions samples were taken automatically, which were characterized by means of both online GPC and offline GC, in order to optimize the reaction temperature and to determine the activation energy of the polymerization.

     

On the Incorrectness of the Factor 2 in the Radical Termination Equation

The IUPAC recommended factor 2 preceding rate coefficients in the radical termination kinetic equations is claimed to be incorrect and confusing. This recommendation can lead to incorrect analysis of experimental data, especially while applying kinetic Monte Carlo simulations. The statement is based on the derivation of the corresponding relationships.

     

Synthesis and Characterization of a Novel Calix[4]arene‐Based Periodic Mesoporous Organosilica

Summary: A new calix[4]arene‐based periodic mesoporous organosilica has been synthesized using tetraethoxysilane (TEOS) and a calix[4]arene‐based silane monomer as the precursors and cetyltrimethylammonium bromide (CTAB) surfactant as the structure‐directing template, and is shown to be capable of visual detection and entrapment of NO₂.

Synthesis of the novel mesoporous organosilica material containing covalently bound tetra‐O‐alkylated calix[4]arene hosts.     

Chain Transfer and Efficiency of End‐Group Introduction in Free Radical Polymerization of Methyl Methacrylate in the Presence of Poly(methyl methacrylate) Macromonomer

Summary: Experimental and modeling studies of addition–fragmentation chain transfer (AFCT) during radical polymerization of methyl methacrylate in the presence of poly(methyl methacrylate) macromonomer with 2‐carbomethoxy‐2‐propenyl ω‐ends (PMMA‐CO₂Me) at 60 °C are reported. The results revealed that AFCT involving PMMA‐CO₂Me formed in situ during methyl methacrylate polymerization has a negligible effect on the molecular weight distribution.

     

Prediction of Polymer Properties from their Structure by Recursive Neural Networks

Summary: We propose a new approach for predicting polymer properties from structured molecular representations based on recursive neural networks. To this aim, a structured representation is designed for the modeling of polymer structures. This representation can also account for average macromolecule characteristics. Preliminarily, this model is applied to the calculation of the T_g of (meth)acrylic polymers with different stereoregularity.

Representation of poly(methyl methacrylate) as a chemical tree and unfolding of the encoding process through its structure.     

Reduced Graphene Oxide/Poly(3‐hexylthiophene) Supramolecular Composites

Poly(3‐hexylthiophene) (P3HT) supramolecular structures are fabricated on P3HT‐dispersed reduced graphene oxide (RGO) monolayers and surfactant‐free RGO monolayers. P3HT is able to disperse RGO in hot anisole/N,N‐dimethylformamide solvents, and forms nanowires on RGO surfaces through a RGO induced crystallization process. The TEM and AFM investigation of the resultant P3HT/RGO composites shows that P3HT nanowires grow from RGO, and connect individual RGO monolayers. Raman spectroscopy confirms the interaction between P3HT and RGO, which allows the manipulation of the RGO electrical properties. Such a bottom‐up approach provides interesting graphene‐based composites for nanometer‐scale electronics.

     

Two‐Photon Pattern Bleaching for Characterizing Structural Changes in Polymer Films

Using two‐photon absorption, an array of spots in a dye‐doped polymer film can be bleached, creating a three‐dimensional structure that can be imaged with two‐photon or confocal microscopy. Microscopic deformations resulting from various treatments to the film can be characterized, for example, swelling or shrinking. This technique is demonstrated on dye‐doped poly(vinyl alcohol), in which the effect of swelling with the addition of water to the film is shown.

     

Urease‐Catalyzed Carbonate Precipitation inside the Restricted Volume of Polyelectrolyte Capsules

A new biomimetic approach for performing CaCO₃ synthesis exclusively inside micron‐sized polyelectrolyte capsules, based on the fermentative formation of a precipitative agent (CO₃²⁻ anion) by urease‐catalyzed urea hydrolysis, was developed. Precipitated CaCO₃ completely fills the interior capsule volume and has a metastable vaterite phase.

     

One‐Pot Synthesis of Well‐Defined Amphiphilic and Adaptative Block Copolymers via Versatile Combination of “Click” Chemistry and ATRP

Well‐defined amphiphilic PCL‐b‐PDMAEMA block copolymers were successfully synthesized by a combination of ATRP and “click” chemistry following either a commutative two‐step procedure or a straightforward one‐pot process using CuBr · 3Bpy as the sole catalyst. Compared to the traditional coupling method, combining ATRP and click chemistry even in a “one‐pot” process allows the preparation of PCL‐b‐PDMAEMA diblock copolymers characterized by a narrow molecular weight distribution and quantitative conversion of azides and alkynes into triazole functions. Moreover, the amphiphilic character of these copolymers was demonstrated by surface tension measurements and critical micellization concentration was calculated.

     

Solvent Vapor‐Induced Nanowire Formation in Poly(3‐hexylthiophene) Thin Films

Summary: Nanowire lengths and length‐to‐width aspect ratios in regioregular poly(3‐hexylthiophene) (P3HT) were simply controlled through changes in the solvent vapor pressure during solidification. It is demonstrated that the nanowires grew by rod‐to‐rod association, in which the molecular long axis of the P3HT chains appeared to be well‐oriented parallel to the silicon substrate (Si/SiO_x). The formation of the nanowires took place by one dimensional self‐assembly, governed by π‐π stacking of the P3HT units.

TEM high contrast images showing P3HT nanowires fabricated by spin‐coating under a solvent vapor pressure.     

Crosslinkable Vesicles Self‐Assembled by Amphiphilic Hyperbranched Polyester

Summary: Amphiphilic hyperbranched polyester (H20‐AM) with methacrylate end groups was synthesized based on hyperbranched aliphatic polyester (Boltorn™ H20). Narrow‐dispersed crosslinkable vesicles were obtained by dissolving H20‐AM in water, and characterized by laser light scattering and TEM. The hollow structural vesicle is composed of around 350 H20‐AM molecules, having a radius of around 40 nm and of 1.9 × 10⁶ g · mL⁻¹. The vesicles were fixed by crosslinking of methacrylate groups to form shape‐persistent structures.

TEM images of the crosslinked vesicles at lower magnification.     

Binding and Sulfonation of Poly(acrylic acid) on Iron Oxide Nanoparticles: a Novel,Magnetic, Strong Acid Cation Nano‐Adsorbent

Summary: A novel, magnetic, strong acid cation nano‐adsorbent has been developed by the covalent binding of poly(acrylic acid) on the surface of Fe₃O₄ nanoparticles followed by sulfonation using sulfanilic acid via carbodiimide activation. The nano‐absorbent can be easily recovered or manipulated with an external magnetic field and shows a good capacity for the rapid and efficient adsorption of multivalent metal cations from aqueous solutions.

An illustration for the binding and sulfonation of PAA on Fe₃O₄ nanoparticles to produce a magnetic, strong acid cation nano‐adsorbent.     

Ethylene and Ethylene/Propylene Polymerization Behavior of Bis(phenoxy‐imine) Zr and Hf Complexes with Perfluorophenyl Substituents

The catalytic properties of bis(phenoxy‐imine) Zr and Hf complexes incorporating perfluorophenyl groups with methylaluminoxane were investigated. The fluorinated complexes produced far higher‐molecular‐weight polyethylenes and ethylene/propylene copolymers with increased activities compared with the non‐fluorinated congeners. Moreover, the fluorinated complexes displayed a higher incorporation ability for propylene.

Structures of complexes 1 – 4 .     

Synthesis of Polyaniline Nanobelts

Summary: Polyaniline nanobelts have been synthesized by a self‐assembly process using the chemical oxidative polymerization of aniline in a surfactant gel. The morphologies of polyaniline nanostructures were characterized by field‐emission scanning electron microscopy and transmission electron microscopy. The effects of the concentrations of cetyltrimethylammonium bromide on the morphologies of polyaniline nanostructures have also been investigated.

A scanning electron microscopy image of polyaniline nanobelts synthesized with 0.12 M cetyltrimethylammonium bromide at −7 °C.