Application of Alkyne‐TCNQ Addition Reaction to Polymerization

The polymerization using a high‐yielding addition reaction between electron‐rich alkynes and 7,7,8,8‐tetracyanoquinodimethane (TCNQ) derivatives is described. The bifunctional monomer containing two TCNQ moieties and the counter comonomer bearing two dialkylaniline (DAA)‐substituted alkynes are reacted in 1,2‐dichloroethane under mild heating conditions. At the high monomer concentrations, high molecular weight linear polymers are obtained, while the reaction at the low monomer concentrations produces a significant amount of the cyclic compounds. A clear relationship between the monomer concentration and the cyclic compound amount is demonstrated. The obtained polymers feature a sufficient thermal stability with the decomposition temperature exceeding 300 °C as well as strong charge‐transfer (CT) bands and redox activities ascribed to the produced donor–acceptor moieties. These features are also used to optimize the polymerization conditions and to estimate the chemical structures.

     

Copolymers of Intrinsic Microporosity Based on 2,2′,3,3′‐Tetrahydroxy‐1,1′‐dinaphthyl

A series of new copolymers with high molecular weight and low polydispersity, prepared from tetrahydroxydinaphthyl, tetrahydroxyspirobisindane, and tetrafluoroterephthalonitrile monomers, prevent efficient space packing of the stiff polymer chains and consequently show intrinsic microporosity. One copolymer, DNPIM‐33, has an excellent combination of properties with good film‐forming characteristics and gas transport performance, and exhibits higher selectivity than the corresponding spirobisindane‐based homopolymer PIM‐1 for gas pairs, such as O₂/N₂, with a corresponding small decrease in permeability. This work demonstrates that significant improvements in properties may be obtained through development of copolymers with intrinsic microporosity (CoPIMs) that extends the spectrum of high‐molecular‐weight ladder structures of poly(dibenzodioxane)s.

     

Heparin‐Controlled Growth of Polypyrrole Nanowires

Summary: Heparin, a potent anticoagulant, has been used for the first time for the synthesis of PPy nanowires serving not only as an anion dopant but also as an effective morphology‐directing agent. The obtained PPy nanowires exhibit long and fine structures with smooth surface and the average diameter of the nanowires is about 90–100 nm and lengths are several hundred nanometers to micrometers. The possible formation mechanism of PPy nanowires may be related to the chain structure of heparin with functional groups ( SO and  COO⁻) on the surface. The effect of concentrations of pyrrole monomers and heparin on the morphology and size of PPy nanowires has been investigated.

SEM image of PPy nanowires synthesized in the presence of heparin.     

Self‐Assembly of Cylinder‐Forming ABA Triblock Copolymers under Cylindrical Confinement

The self‐assembly of two types of linear ABA triblock copolymers confined in cylindrical nanopores is studied using simulated annealing. The effects of pore size and block copolymer chain architecture on morphology, chain conformations and bridging fraction are investigated. For the bulk cylinder‐forming copolymers, novel structures such as helices and stacked toroids form, which depend sensitively on the pore size. Several significant differences between the two types of copolymers are predicted and explained based on the differences in their chain conformations and chain architectures. A simple model is proposed to explain the mean square radius of gyration for the bridge and loop chains.

     

Single Polyelectrolyte Microcapsules Fabricated By Glutaraldehyde‐Mediated Covalent Layer‐By‐Layer Assembly

Summary: Single polyelectrolyte component microcapsules and multilayers, exemplified by poly(allylamine hydrochloride) (PAH), have been prepared using a method of glutaraldehyde (GA)‐mediated covalent layer‐by‐layer (LbL) assembly. The GA cross‐linking of the adsorbed PAH results in surfaces covered by reactive aldehyde groups, which can then react with PAH to result in another layer of covalently linked PAH. The repeated assembly of single polyelectrolyte in an LbL manner can be thus achieved. The PAH multilayers can grow linearly along with the layer number, and their thickness can be controlled at the nanometer scale, as verified by UV‐vis absorption spectrometry and ellipsometry. Single polyelectrolyte microcapsules are obtained after removal of the template cores at low pH. The morphology and integrity are confirmed by scanning force microscopy and confocal laser scanning microscopy.

Schematic illustration of the preparation of a single polyelectrolyte component microcapsule by GA‐mediated covalent LbL assembly.     

Vapor‐Based Synthesis of Poly[(4‐formyl‐p‐xylylene)‐co‐(p‐xylylene)] and Its Use for Biomimetic Surface Modifications

Summary: The vapor‐based synthesis and characterization of a reactive polymer, poly[(4‐formyl‐p‐xylylene)‐co‐(p‐xylylene)] ( 1 ), have been reported. The reactive polymer coating enables the immobilization of oligosaccharides via the chemoselective aldehyde‐hydrazide coupling reaction.

     

Synthesis of π‐Conjugated Polymer Consisting of Pyrrole and Fluorene Units by Ru‐Catalyzed Site‐Selective Direct Arylation Polycondensation

Polycondensation of 1‐(2‐pyrimidinyl)pyrrole with 2,7‐dibromo‐9,9‐dioctylfluorene via Ru‐catalyzed direct arylation gives the corresponding conjugated polymer with a molecular weight of 19 800 in 86% yield. The introduction of directing group, 2‐pyrimidinyl substituent, into the pyrrole monomer induces ortho‐metalation and provides the site‐selective direct arylation polycondensation at the α‐position of pyrrole unit without the protection of β‐position. The removal of 2‐pyrimidinyl substituent on the pyrrole unit proceeds efficiently and results in the enhancement of coplanarity along the main chain of the polymer.

     

Poly(ethylene glycol) Surface Coated Magnetic Particles

Summary: A methacrylate‐functionalized poly(ethylene glycol) macromonomer was copolymerized at the surface of methacrylate‐derivatized maghemite nanoparticles. After silylation of the magnetic core with methacryloxypropyltrimethoxysilane, two grafting procedures based on either a direct copolymerization reaction in water or an inverse emulsion polymerization were compared. A direct copolymerization led to low polymer surface amounts, whereas an inverse emulsion process allowed nanocomposite particles containing up to 90 wt.‐% polymer to be obtained.

TEM picture of maghemite‐PEG hybrid particles.     

Holes and Ledges Created by Multilayer Assembly on Polyelectrolyte Brushes: A Novel Route for the Three‐Dimensional Nanoscale Design of Surfaces

The layer‐by‐layer (LBL) assembly of poly(diallyldimethylammonium chloride) and poly(sodium styrene sulfonate) on poly(sulfo propyl methacrylate) brushes resulted in films with nanometer‐ and micrometer‐sized holes and ledges, observed by atomic force microscopy and scanning electron microscopy. Polyelectrolyte assembly was followed by the quartz microbalance technique. The formation of ledges and holes is explained by the interaction of the brush polymers with the incoming polyelectrolytes during the LBL assembly, inducing a spatially localized and self‐organized accumulation of the assembled polymers.

     

A Self‐Assembling Polythiophene Functionalised with a Cysteine Moiety

A new copolymer bearing a cysteine moiety, designed for molecular interaction, metal‐ion detection, and chiral recognition, was synthesised starting from the dibromo derivative of methyl N‐(tert‐butoxycarbonyl)‐S‐thien‐3‐ylcysteinate and distannylthiophene through a Stille coupling reaction. UV‐vis spectroscopy, circular dichroism, NMR spectroscopy, and gel permeation chromatography analyses evidenced that this polymer is able to form self‐assembling structures, through the formation of a hydrogen‐bond network, not only in the solid state but also in solution.

     

A Novel Route for Fabricating Metal‐Polymer Composite Nanoparticles with Phase‐Separated Structures

Au nanoparticles (NPs) and polymer composite particles with phase‐separation structures were prepared based on phase separation structures. Au NPs were successfully synthesized in amphiphilic block‐copolymer micelles, and then composite particles were formed by a simple solvent evaporation process from Au NPs and polymer solution. The phase separated structures (Janus and Core‐shell) were controlled by changing the combination of polymers having differing hydrophobicity.

     

Directed Crystallisation of Synthetic Polymers by Low‐Molar‐Mass Self‐Assembled Templates

A novel and powerful method of microstructure control in polyolefins is presented. By dispersing tiny amounts of sorbitol derivatives in the polymer, the subsequent crystal growth can be controlled with modest prior flow‐fields; in particular high levels of preferred orientation are generated in the resultant crystals. Under shear flow, the additive forms highly extended crystals which lie parallel to the flow‐field and which serve to direct the crystallisation of the polymer leading to a massive amplification of the anisotropy present in the melt.

TEM image of a carbon replica taken from an etched surface of a PE sample containing 1% of DBS.     

Novel Top‐Surface Imaging Process by Selective Chemisorption of Poly(dimethyl siloxane) on Diazoketo‐Functionalized Single Component Photoresist

A novel top‐surface imaging process was successfully established using selective chemisorption of amine‐functionalized poly(dimethyl siloxane) onto the carboxylic groups formed on the surface of diazoketo‐functionalized polymer film by UV light irradiation. The chemisorbed poly(dimethyl siloxane) worked as an efficient etch mask for the subsequent oxygen plasma etching process for pattern generation. High‐resolution patterns were resolved with the new imaging process.

     

Single‐Line EPR Spectra from Radicals Encapsulated in Aggregates of Amphiphilic Block Copolymers with Hydrophobic Dendritic Pendants in Water

Summary: A water‐insoluble organic 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical is solubilized in aqueous solutions of aggregates of amphiphilic block copolymers with hydrophobic dendritic pendants. The number (100–200) of DPPH molecules solubilized in an aggregate, which is evaluated from UV‐visible absorption spectra, is in agreement with that of the DPPH radicals determined from electron paramagnetic resonance (EPR) spectroscopy. The DPPH radicals are stably solubilized without decomposition in the polymer aggregates. The radicals exhibit a single‐line EPR absorption, which is narrowed by the interspin interaction, and indicates the assembly formation of DPPH radicals in polymer aggregates. These results suggest the effective utilization of the DPPH radical as a spin‐probe indicator in aqueous solutions.

When DPPH is solubilized in aqueous solutions of NaAMPS‐b‐G2(n3), the polymer solutions become purple colored, which is characteristic of the DPPH radical.     

Self‐Complementary Nucleoside‐Thiophene Hybrid Systems: Synthesis and Supramolecular Organization

Versatile synthetic methods towards a variety of thiophene‐nucleobase hybrid systems are reported. Adenine‐ and thymine‐based modified nucleosides characterized by a bithiophene unit linked to the C5′ or C8 position through an ethylenamino or an ethylensulfanyl bridge were synthesized and successfully polymerized in the presence of FeCl₃. The self‐organization properties of the pure polymers as well as their mixtures ‐ with complementary nucleobases ‐ were investigated by means of optical microscopy and AFM in cast film showing complex supramolecular structures resulting from the interplay of multiple intermolecular interactions.

     

Synthesis and Surface Morphology of Tetraaniline‐block‐Poly(L‐lactate) Diblock Oligomers

Summary: Tetraaniline‐block‐poly(L ‐lactide) diblock oligomers are synthesized via ring‐opening polymerization. The diblock oligomers cast from an L ‐lactide selective solvent (chloroform) show spherical aggregates for the leucoemeraldine state, and ring‐like structures that are composed of much smaller spherical aggregates for the emeraldine state. The formation mechanisms of the two different surface morphologies are discussed in detail.

Surface morphology changes induced by oxidation of the aniline segment of tetraaniline‐block‐poly(L ‐lactate) and drying effects.