Owing to the relatively high conductivity and unique redox behavior, polyaniline (PANI) has been one of the most technologically promising conducting polymers. Although various methodologies have been developed, fabrication of PANI microfibers has been a challenging task owing to the poor solubility in most organic solvents. By taking advantage of a microfluidic technology and organic soluble acid labile t‐Boc‐protected PANI (t‐Boc‐PANI) as the conducting polymer precursor, fabrication of PANI microfibers in a size‐controlled manner is possible. Introduction of a THF solution containing t‐Boc‐PANI, and dodecylbenzenesulfonic acid (DBSA) as a core flow, and water as a sheath flow into a microfluidic channel with a 3D hydrodynamic focusing effect results in crystallization of the polymer fiber. By changing the flow rate, linear PANI microfibers that range from 16.2 to 39.4 μm in diameter are readily obtained.
A novel bifunctional monomer, namely maleimide glycidyl ether (MalGE), prepared in a four‐step reaction sequence is introduced. This monomer allows for selective (co)polymerization of the epoxide group via cationic ring‐opening polymerization, preserving the maleimide functionality. On the other hand, the maleimide functionality can be copolymerized via radical techniques, preserving the epoxide moiety. Cationic ring‐opening multibranching copolymerization of MalGE with glycidol was performed, and a MalGE content of up to 24 mol% could be incorporated into the hyperbranched polymer backbone (Mn = 1000–3000 g mol−1). Preservation of the maleimide functionality during cationic copolymerization was verified via NMR spectroscopy. Subsequently, the maleimide moiety was radically crosslinked to generate hydrogels and additionally employed to perform Diels‐Alder (DA) “click” reactions with (functional) dienes after the polymerization process. Radical copolymerization of MalGE with styrene (Mn = 5000–9000 g mol−1) enabled the synthesis of a styrene copolymer with epoxide functionalities that are useful for versatile crosslinking and grafting reactions.
Thermoresponsive linear polymers and their corresponding aggregates or nanogels typically show similar thermoresponsive profiles. In this study, the authors demonstrate reversible chemical switching between linear polymers and their cross‐linked nanogels. The linear polymers exhibit sharp thermal transitions typical of common thermoresponsive polymers but the cross‐linked nanogels exhibit “linear” thermal transitions over a relatively broad temperature range. The reversible switching between these two different polymer architectures with distinct thermoresponses represents a unique example of how the responsive properties of smart polymers can be significantly manipulated via polymer architecture engineering.
Anion recognition between the triurea receptor and phosphate anion is demonstrated as the cross‐linkage to build supramolecular polymer gels for the first time. A novel multi‐block copolymer ( 3) is designed to have functional triurea groups as cross‐linking units along the polymer main chain. By virtue of anion coordination between the triurea receptor and phosphate anion with a binding mode of 2:1, supramolecular polymer gels are then prepared based on anion recognition using 3 as the building block.
This communication reports the first example of precision polyolefin nanoalloys where an exotic immiscible polymer is nanometrically dispersed with stability in a polyolefin matrix in a highly controlled mode. Following the preparation of polypropylene/multiwalled carbon nanotubes nanocomposites (PP/MWCNTs) by in situ Ziegler‐Natta polymerization, the hydroxyl groups on the surfaces of individual MWCNTs are used to initiate ring‐opening polymerization of ε‐caprolactone, resulting in PP/poly(ε‐caprolactone) (PCL) alloy with PCL grafted on MWCNTs. Upon phase formation, the PP/MWCNTs‐g‐PCL alloys exhibit a unique PCL dispersion morphology, which is stable and solely governed by PCL molecular weight.
Today's olefin metathesis catalysts show high reactivity, selectivity, and functional group tolerance and allow the design of new syntheses of precisely functionalized polymers. Here the synthesis of a new end‐capping reagent is investigated allowing the introduction of a highly reactive activated ester end‐group at the polymer chain end as well as its prefunctionalization to directly introduce functional moieties. The versatility of this new end‐capping reagent is demonstrated by utilizing it to synthesize a so‐called termimer (a monomer with termination capabilities). Copolymerization of a norbornene derivative with the termimer leads to hyperbranched ring‐opening metathesis polymerization polymers as proven by gel permeation chromatography and MALDI‐ToF‐(matrix‐assisted laser desorption/ionization time of flight) mass spectrometry.
A straightforward synthetic procedure for the double modification and polymer–polymer conjugation of telechelic polymers is performed through amine‐thiol‐ene conjugation. Thiolactone end‐functionalized polymers are prepared via two different methods, through controlled radical polymerization of a thiolactone‐containing initiator, or by modification of available end‐functionalized polymers. Next, these different linear polymers are treated with a variety of amine/acrylate‐combinations in a one‐pot procedure, creating a library of tailored end‐functionalized polymers. End group conversions are monitored via SEC, NMR, and MALDI‐TOF analysis, confirming the quantitative modification after each step. Finally, this strategy is applied for the synthesis of block copolymers via polymer–polymer conjugation and the successful outcome is analyzed via LCxSEC measurements.
A novel route for the synthesis of poly(ethylene glycol)‐b‐polystyrene copolymer, starting from commercially available poly(ethylene glycol) methyl ether and azido terminated polystyrene prepared by atom transfer radical polymerization and subsequent nucleophilic substitution, is applied with simplicity and high efficiency. The combination of photoinduced copper (I)‐catalyzed alkyne‐azide cycloaddition (CuAAC) and ketene chemistry reactions proceeds either simultaneously or sequentially in a one‐pot procedure under near‐visible light irradiation. In both cases, excellent block copolymer formations are achieved, with an average molecular weight of around 7000 g mo1−1 and a polydispersity index of 1.20.
A fused ladder indacenodithiophene (IDT)‐based donor–acceptor (D–A)‐type alternating conjugated polymer, PIDTHT‐BT, presenting n‐hexylthiophene conjugated side chains is prepared. By extending the degree of intramolecular repulsion through the conjugated side chain moieties, an energy level for the highest occupied molecular orbital (HOMO) of –5.46 eV – a value approximately 0.27 eV lower than that of its counterpart PIDTDT‐BT – is obtained, subsequently providing a fabricated solar cell with a high open‐circuit voltage of approximately 0.947 V. The hole mobility (determined using the space charge‐limited current model) in a blend film containing 20 wt% PIDTHT‐BT) and 80 wt% [6,6]‐phenyl‐C71 butyric acid methyl ester (PC71BM) is 2.2 × 10–9 m2 V–1 s–1, which is within the range of reasonable values for applications in organic photovoltaics. The power conversion efficiency is 4.5% under simulated solar illumination (AM 1.5G, 100 mW cm–2).
The use of zinc glutarate (ZnGA) as a heterogeneous catalyst for the copolymerization of epichlorohydrin, an epoxide with an electron‐withdrawing substituent, and CO2 is reported. This catalyst shows the highest selectivity (98%) for polycarbonate over the cyclic carbonate in epichlorohydrin/CO2 copolymerization under mild conditions. The (epichlorohydrin‐co‐CO2) polymer exhibits a high glass transition temperature (Tg), 44 °C, which is the maximum Tg value obtained for the (epichlorohydrin‐co‐CO2) polymer to date.
Polyethers—polymers with the structural element (R'‐O‐R)n in their backbone—are an old class of polymers which were already used at the time of the ancient Egyptians. However, still today these materials are highly important with applications in all areas of our life, reaching from the automotive and paper industry to cosmetics and biomedical applications. In this Review, different aliphatic polyethers like poly(epoxide)s, poly(oxetane)s, and poly(tetrahydrofuran) are discussed. Special emphasis is placed on the history, the polymerization techniques (industrially and in academia), the properties, the applications as well as recent developments of these materials.
Phenylalaninol enantiomers are one of the most important chiral compounds due to its presence in biologically active molecules and pharmaceutical products. In this paper, a novel chiral fluorescence polymer sensor incorporating (S)‐BINOL and oligomeric aniline via a nucleophilic addition–elimination reaction is designed and synthesized. Polymer sensor exhibits “turn‐off” fluorescence quenching response upon the addition of Hg2+, and “turn‐on” moderate fluorescence enhancement behavior towards phenylalaninol enantiomers. Meanwhile, this kind of (S)‐BINOL‐based polymer sensor can exhibit highly selective enantioselective recognition response towards (L)‐phenylalaninol upon the addition of Hg2+ and the value of ef can reach as high as 5.4, which can be attributed to the formation of in situ generated radical cation arisen from oligomeric aniline moiety by Hg2+ induction.
An alkyne‐functionalized ruthenium(II) bis‐terpyridine complex is directly copolymerized with phenylacetylene by alkyne polymerization. The polymer is characterized by size‐exclusion chromatography (SEC), 1H NMR spectroscopy, cyclic voltammetry (CV) measurements, and thermal analysis. The photophysical properties of the polymer are studied by UV–vis absorption spectroscopy. In addition, spectro‐electrochemical measurements are carried out. Time‐resolved luminescence lifetime decay curves show an enhanced lifetime of the metal complex attached to the conjugated polymer backbone compared with the Ru(tpy)22+ model complex.
Polymer beads have attracted considerable interest for use in catalysis, drug delivery, and photonics due to their particular shape and surface morphology. Electrospinning, typically used for producing nanofibers, can also be used to fabricate polymer beads if the solution has a sufficiently low concentration. In this work, a novel approach for producing more uniform, intact beads is presented by electrospinning self‐assembled block copolymer (BCP) solutions. This approach allows a relatively high polymer concentration to be used, yet with a low degree of entanglement between polymer chains due to microphase separation of the BCP in a selective solvent system. Herein, to demonstrate the technology, a well‐studied polystyrene‐poly(ethylene butylene)–polystyrene triblock copolymer is dissolved in a co‐solvent system. The effect of solvent composition on the characteristics of the fibers and beads is intensively studied, and the mechanism of this fiber‐to‐bead is found to be dependent on microphase separation of the BCP.
Here, a conjugated polymer VTTPD based on thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) and dithiophene with vinyl as linker is synthesized and characterized. Electrochemical and optical studies indicate the LUMO and HOMO energies of the polymer are −3.70 and −5.39 eV. Theoretical calculation with density functional theory suggests that H‐bonds are formed between the TPD carbonyl (O) and its neighboring vinyl (H) which benefit the planarity and π‐conjugation of the polymer backbone. Bottom contact bottom gate organic field effect transistor devices based on VTTPD are fabricated and examined in air. After annealing at 160 °C, the devices exhibit excellent performance of μh = 0.4 cm2 V−1 s−1, Ion/off = 106, Vth within −10 V to −5 V. Thin film morphologies before and after the annealing process are also investigated with XRD and AFM.
Radial symmetry is essential for the conventional view of the polymer spherulite microstructure. Typically it is assumed that, in the course of the spherulite morphogenesis, the lamellar crystals grow radially. Using submicron X‐ray diffraction, it is shown that in banded spherulites of poly(propylene adipate) the crystals have the shape of a helix with flat‐on crystals winding around a virtual cylinder of about 6 µm in diameter. The helix angle of 30° implies that the crystal growth direction is tilted away from the spherulite radius by this angle. The implications of the helical crystal shape contradict the paradigm of the spherulitic microstructure. The radial growth rate of such spherulites does not correspond to the crystal growth rate, but to the propagation rate of the virtual cylinder the ribbons wind around.
Recent studies have shown that polymersomes templated by microfluidic double‐emulsion possess several advantages such as high monodispersity and encapsulation efficiency compared with those generated based on thin‐film rehydration and electroformation. Stabilizers, including bovine serum albumin (BSA) and polyvinyl alcohol (PVA), have been used to enhance the formation and stability of double emulsions that are used as templates for the generation of polymersomes. In this work, the effect of stabilizers on the mechanical response of double‐emulsion‐templated polymersomes using micropipette aspiration is investigated. It is demonstrated that the existence of stabilizers results in the inelastic response in polymersomes in the early stage of solvent removal. However, aged polymersomes that have little residual solvent show elastic behavior. Polymersomes prepared from PVA‐stabilized double emulsions have noticeably lower area expansion moduli than polymersomes prepared from stabilizer‐free and BSA‐stabilized double emulsions, suggesting that PVA is incorporated in the bilayer membrane of polymersomes.
Furfuryl glycidyl ether (FGE) represents a highly versatile monomer for the preparation of reversibly cross‐linkable nanostructured materials via Diels–Alder reactions. Here, the use of FGE for the mid‐chain functionalization of a P2VP‐b‐PEO diblock copolymer is reported. The material features one furan moiety at the block junction, P2VP68‐FGE‐b‐PEO390, which can be subsequently addressed in Diels–Alder reactions using maleimide‐functionalized counterparts. The presence of the FGE moiety enables the introduction of dyes as model labels or the formation of hetero‐grafted brushes as shell on hybrid Au@Polymer nanoparticles. This renders P2VP68‐FGE‐b‐PEO390, a powerful tool for selective functionalization reactions, including the modification of surfaces.
To obtain materials useful for the biomedical field, toxic catalysts should be removed from the synthetic route of polymerization reactions and of their precursors. Lipase‐catalyzed ring‐opening polymerization and the synthesis of cyclic precursors can be performed with the same catalyst under different conditions. Here, we highlight the use of lipases as catalysts and optimization of their performance for both ring‐closing and ring‐opening polymerization, via varying parameters such as ring size, concentration, substrate molar ratio, temperature, and solvent. While the conditions for ring‐closing reactions and ring‐opening polymerizations of small molecules, such as ε‐caprolactone, have been extensively explored using Candida antarctica lipase B (CALB), the optimization of macrocyclization, especially for more bulky substrates is surveyed here. Finally, recent methods and polymer architectures are summarized with an emphasis on new procedures for more sustainable chemistry, such as the use of ionic liquids as solvents and recycling of polyesters by enzymatic pathways.
Type II photoinitiated self‐condensing vinyl polymerization for the preparation of hyperbranched polymers is explored using 2‐hydroxyethyl methacrylate (HEMA) or 2‐(dimethylamino)ethyl methacrylate (DMAEMA), and methyl methacrylate as hydrogen donating inimers and comonomer, respectively, in the presence of benzophenone and camphorquinone under UV and visible light. Upon irradiation at the corresponding wavelength, the excited photoinitiator abstracts hydrogen from HEMA or DMAEMA leading to the formation of initiating radicals. Depending on the concentration of inimers, type of the photoinitiator, and irradiation time, hyperbranched polymers with different branching densities and cross‐linked polymers are formed.
