The synthesis and electrochemical characterization of novel polymers bearing phenoxyl‐radicals as redox‐active side chains is described. The monomers are synthesized from the corresponding phenols and quinones, respectively. These compounds are subsequently polymerized via ring‐opening metathesis polymerization. The electrochemical properties of the phenoxyl‐radical polymers are characterized using cyclic voltammetry and the most promising polymer is investigated as active material in a lithium coin‐cell, creating the first phenoxyl‐lithium battery. These phenoxyl‐containing polymers represent interesting anode materials for organic radical and lithium batteries due to their suitable redox‐potentials and possibility to create batteries with higher potentials as well as straightforward synthesis procedures.
Synthesis of a cyclodextrin (CD) polyrotaxane is achieved for the first time by simultaneous free radical polymerization of isoprene, threading by CD, and stoppering by copolymerization of styrene. This reaction is performed in an eco‐friendly manner in an aqueous medium similar to classical emulsion polymerization. Threaded CD rings of the polyrotaxane are cross‐linked by hexamethylene diisocyanate, leading to highly elastic slide‐ring gels.
A template‐free method is described to fabricate continuous‐phase, porous polymer films by simultaneous phase separation during vapor deposition polymerization. The technique involves concurrent polymerization, crosslinking, and phase separation of condensed species and reaction products. Deposited films form open‐cell, macroporous structures consisting of crosslinked and glassy poly(glycidyl methacrylate). By limiting phase separation during vapor phase deposition, spatially dependent morphologies, such as layered morphologies, can be grown. Results show that combining vapor deposition polymerization with phase separation establishes morphological control, which may be applied to applications including cellular scaffolds, thin cushions and vibration dampers, and membranes for separations.
A new approach to stabilize carbon nanotubes (CNTs) in aqueous solution with a reduction‐responsive water‐soluble polymer is reported. The novel polymer synthesized by a controlled radical polymerization is functionalized with pendant pyrene groups capable of adhering to the surface of CNTs through π–π noncovalent interactions, and labeled with disulfide linkages to exhibit reduction‐responsive cleavage. Upon the cleavage of junction disulfide linkages in a reducing environment, water‐soluble polymers are shed, retaining clean CNT surfaces for electrochemical catalytic reactions.
Diselenide‐containing polymers are facilely synthesized from polymers prepared by atom transfer radical polymerization (ATRP). Benefiting from the ATRP technology, this protocol provides a flexible route for controlling the polymer structure, which allows for a great variety of architectures of selenium‐containing polymer materials for applications in various fields. The oxidative and reductive responsive behavior of the obtained diselenide‐containing polymers is also investigated.
PFpP macromolecules, synthesized via migration insertion polymerization of CpFe(CO)2(CH2)3PPh2 (FpP), exhibit reactive Fp end groups for further migration insertion reactions in the presence of phosphines. A number of alkyl diphenylphosphines with varied alkyl length, Ph2PCn (n = 6, 10, 18), have been prepared for the reaction, resulting in PFpP‐PPh2Cn (n = 6, 10, 18) amphiphiles. The phosphines with longer alkyl chains impose steric hindrance for the reaction and therefore require longer reaction times and excess phosphines relative to PFpP.
The synthesis of a series of dithienosilole–benzotriazole donor–acceptor statistical copolymers with various donor–acceptor ratios is reported, prepared by Kumada catalyst‐transfer polymerization. Statistical copolymer structure is verified by 1H NMR and optical absorption spectroscopy, and supported by density functional theory (DFT) calculations. The copolymers exhibit a single optical absorption band that lies between dithienosilole and benzotriazole homopolymers, which shifts with varying donor–acceptor content. A chain extension experiment using a partially consumed benzotriazole solution as a macroinitiator followed by addition of dithienosilole leads to the synthesis of a statistical dithienosilole–benzotriazole block copolymer from a pure benzotriazole block, demonstrating that both chain extension and simultaneous monomer incorporation are possible using this methodology.
This paper reports on the synthesis of well‐defined polyacrylamide‐based nanogels via reversible addition–fragmentation chain transfer (RAFT) dispersion polymerization, highlighting a templateless route for the efficient synthesis of nanogels based on water‐soluble polymers. RAFT dispersion polymerization of acrylamide in co‐nonsolvents of water–tert‐butanol mixtures by chain extension from poly(dimethylacrylamide) shows well‐controlled polymerization process, uniform nanogel size, and excellent colloidal stability. The versatility of this approach is further demonstrated by introducing a hydrophobic co‐monomer (butyl acrylate) without disturbing the dispersion polymerization process.
A facile and versatile approach to constructing colorless surface coatings based on green tea polyphenols is reported, which can further act as a photoinitiating layer to initiate radical polymerization. These colorless green tea polyphenol coatings are capable of successfully photografting polymer brushes, and the resulting polymer brush patterns show spatial shape adjustability by masked UV irradiation. Both surface modifications and photografted polymer brushes do not alter the original color of the substrates. This method could be promising for the development of surface modifications.
In this study, the group transfer polymerization (GTP) of the functional monomer 3‐(trimethoxysilyl)propyl methacrylate (TMSPMA) is reported to produce polymers of different architectures and topologies. TMSPMA is successfully polymerized and copolymerized with GTP to produce well‐defined (co)polymers that can be used to fabricate functional hybrid materials like hydrogels and films.
In this work, the synthesis of various halogenated thiophenol derivatives is presented. These thiophenols are used as monomers in light‐initiated SRN1‐type radical polymerization reactions. The method provides easy access to industrially relevant poly(paraphenylene sulfide) and poly(metaphenylene sulfide). The influence of the halide leaving group and of other substituents in the thiophenol monomer on the polymerization process is investigated.
Cyclic multiblock polymers with high‐order blocks are synthesized via the combination of single‐electron transfer living radical polymerization (SET‐LRP) and copper‐catalyzed azide‐alkyne cycloaddition (CuAAC). The linear α,ω‐telechelic multiblock copolymer is prepared via SET‐LRP by sequential addition of different monomers. The SET‐LRP approach allows well control of the block length and sequence as A‐B‐C‐D‐E, etc. The CuAAC is then performed to intramolecularly couple the azide and alkyne end groups of the linear copolymer and produce the corresponding cyclic copolymer. The block sequence and the cyclic topology of the resultant cyclic copolymer are confirmed by the characterization of 1H nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared spectroscopy, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry.
Stratified polymer brushes are fabricated using microcontact printing (μCP) of initiator integrated polydopamine (PDOPBr) on polymer brush surfaces and the following surface initiated atom transfer radical polymerization (SI‐ATRP). It is found that the surface energy, chemically active groups, and the antifouling ability of the polymer brushes affect transfer efficiency and adhesive stability of the polydopamine film. The stickiness of the PDOPBr pattern on polymer brush surfaces is stable enough to perform continuous μCP and SI‐ATRP to prepare stratified polymer brushes with a 3D topography, which have broad applications in cell and protein patterning, biosensors, and hybrid surfaces.
A robust and straightforward approach is introduced to synthesize inorganic nanoparticles chemically grafted with a zwitterionic poly(2‐methacryroyloxyethylphosphorylcholine) (PMPC) thin layers. The synthesis method is based on the surface‐mediated seeded polymerization. In order to observe how the polymer chain architectures affect colloidal interactions, the zinc oxide nanoparticles are grafted with linear brushes and with a thin hydrogel layer, respectively. The thickness of PMPC shell layers spans a few nanometers. The studies on suspension rheology for the nanoparticles show that the nanoparticles with PMPC brushes show the stronger repulsive force than those with the PMPC gel shell due to the entropic stabilization. When the shear force is applied to the Pickering emulsion produced by assembly of the nanoparticles, it is noticeable that the presence of PMPC brushes on the particles rather enhances the drop‐to‐drop attraction, which presumably stems from the entanglement of polymer chains between the contacted interfacial planes of the emulsion droplets during shearing.
Poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA)‐based brush poly(phosphoamidate)s are successfully synthesized by a combination of ring‐opening metathesis polymerization (ROMP) and atom transfer radical polymerization (ATRP) following either a commutative two‐step procedure or a straightforward one‐pot process using Grubbs ruthenium‐based catalysts for tandem catalysis. Compared with the traditional polymerization method, combining ROMP and ATRP in a one‐pot process allows the preparation of brush copolymers characterized by a relatively moderate molecular weight distribution and quantitative conversion of monomer. Moreover, the surface morphologies and aggregation behaviors of these polymers are studied by AFM and TEM measurements.
A switch from carbanions to aza‐anions is performed by the addition of N‐tosylaziridine (TAz) to living poly(styryl) (PS) chains. This is the first example of carbanionic aziridine ring‐opening which was previously activated by amidation with a tosyl group to enable nucleophilic ring‐opening by the living chain end. Poly(styrene)‐tosylaziridines (PS‐TAz) with narrow molecular weight distributions and variable molecular weights are synthesized. The removal of the tosyl group and subsequent functionalization is shown, evidencing quantitative transfer to azaanionic species. All polymers are characterized in detail by 1H NMR spectroscopy, DOSY 1H NMR spectroscopy, and size exclusion chromatography (SEC). This strategy allows the introduction of amine groups via anionic polymerization in analogy to the well‐established epoxide termination.
The successful chain‐growth copper(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) polymerization employing Cu(0)/pentamethyldiethylenetriamine (PMDETA) and alkyl halide as catalyst is first investigated by a combination of nuclear magnetic resonance, gel‐permeation chromatography, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. In addition, the electron transfer mediated “click‐radical” concurrent polymerization utilizing Cu(0)/PMDETA as catalyst is successfully employed to generate well‐defined copolymers, where controlled CuAAC polymerization of clickable ester monomer is progressed in the main chain acting as the polymer backbone, the controlled radical polymerization (CRP) of acrylic monomer is carried out in the side chain. Furthermore, it is found that there is strong collaborative effect and compatibility between CRP and CuAAC polymerization to improve the controllability.
Stimuli responsive surfaces that show reversible fluorescence switching behavior in response to temperature changes were fabricated. Oligo(ethylene glycol) methacrylate thermoresponsive polymers with amine end‐groups were prepared by atom transfer radical polymerization (ATRP). The polymers were patterned on silicon surfaces by electron beam (e‐beam) lithography, followed by conjugation of self‐quenching fluorophores. Fluorophore conjugated hydrogel thin films were bright when the gels were swollen; upon temperature‐induced collapse of the gels, self‐quenching of the fluorophores led to significant attenuation of fluorescence. Importantly, the fluorescence was regained when the temperature was cooled. The fluorescence switching behavior of the hydrogels for up to ten cycles was investigated and the swelling‐collapse was verified by atomic force microscopy. Morphing surfaces that change shape several times upon increase in temperature were obtained by patterning multiple stimuli responsive polymers.
Graphene oxide (GO) is effective in catalyzing a wide variety of organic reactions and a few types of polymerization reactions. No radical chain polymerizations catalyzed by GO have been reported. In this article, we probe the catalytic role and acceleration effect of GO for self‐initiated radical chain polymerizations of acrylic acid (AA) in the presence of GO and a pre‐existing polymer, poly(N‐vinylpyrrolidone) (PVP), from a calorimetric perspective. Gelation experiments and DSC studies show that GO can function as a catalyst to accelerate the radical chain polymerization of AA. Isothermal polymerization kinetic data shows that the addition of GO diminishes the induction periods and increases the polymerization rates, as indicated by the much enhanced overall kinetic rate constants and lowered activation energies. The catalytic effect of GO for the polymerization of AA is attributed to the acidity of GO and the hydrogen bonding interactions between GO and monomer molecules and/or polymers.
This work describes the synthesis of π‐conjugated polymers possessing arylene and 1,3‐butadiene alternating units in the main chain by the reaction of α,β‐unsaturated ester/nitrile containing γ‐H with aromatic/heteroaromatic aldehyde compound. By using 4‐(4‐formylphenyl)‐2‐butylene acid ethyl ester as a model monomer, the different polymerization conditions, including catalyst, catalyst amount, and solvent, are optimized. The polymerization of 4‐(4‐formylphenyl)‐2‐butylene acid ethyl ester is carried out by refluxing in ethanol for 72 h with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as a catalyst to give a 1,3‐butadiene‐containing π‐conjugated polymer, poly(phenylene‐1,3‐butadiene), in 84.3% yield with and / (PDI) estimated as 6172 and 1.65, respectively. Based on this new methodology, a series of π‐conjugated polymers containing 1,3‐butadiene units with different substituents are obtained in high yields. A possible mechanism is proposed for the polymerization through a six‐membered ring transition state and then a 1,5‐H shift intermediate.
