The synthesis, characterization, and testing of a range of novel bio‐inspired L‐DOPA‐derived poly(ester amide)s is presented, using a widely applicable, straightforward chemistry. A model system is used to study and establish the monomer and polymer synthetic protocols, and to provide a set of optimum reaction conditions. It is further shown that fully biobased L‐DOPA‐containing adhesive tapes can be fabricated, which are positively evaluated in terms of their adhesive properties. The newly developed synthetic protocol constitutes a versatile platform for accessing and tailoring a plethora of relevant structures, including a variety of potentially biocompatible poly(ethylene glycol)‐based materials.
The synthesis of an ambipolar π‐conjugated copolymer consisting of alternating diketopyrrolopyrrole and tetrafluorobenzene via direct arylation polymerization (DAP) is reported. Two different combinations of monomers are investigated under various catalytic conditions for DAP. The target polymer obtained under an optimized catalytic condition shows minimal structural defects, a number‐average molecular weight of 33.2 kDa, and balanced electron and hole mobility of 1 × 10−2 cm2 V−1 S−1 in the organic field‐effect transistors fabricated and tested under ambient conditions.
Cross‐linked azobenzene liquid‐crystalline polymer films with a poly(oxyethylene) backbone are synthesized by photoinitiated cationic copolymerization. Azobenzene moieties in the film surface toward the light source are simultaneously photoaligned during photopolymerization with unpolarized 436 nm light and thus form a splayed alignment in the whole film. The prepared films show reversible photoinduced bending behavior with opposite bending directions when different surfaces of one film face to ultraviolet light irradiation.
Botryoid‐shaped reactive terpolymer nanoparticles, whose aldehyde‐functional living domains are miniaturized into small‐sized discrete “grapes” and attached onto the outwardly‐branched scaffolds of fluorinated segments, are reported. These nanostructures can be fabricated by spontaneous structural reorganization of core–shell terpolymer micelles simply by manipulating drying conditions. The miniaturized discrete living domains are stabilized by outwardly‐branched scaffolds and exhibit excellent accessibility to solution media, thus can effectively respond to solution media, which is desired in sensor‐related applications.
This article summarizes recent progress in the post‐functionalization of conjugated polymers by electrochemical methods. These electrochemical polymer reactions typically proceed via electrochemical doping of a conjugated polymer film, followed by chemical transformation. Examples include the quantitative oxidative fluorination of polyfluorenes and oxidative halogenation of polythiophenes, as well as the reductive hydrogenation of polyfluorenones. The degree of functionalization, otherwise known as the reaction ratio, can be controlled by varying the charge passed through the polymer, allowing the optoelectronic properties of the conjugated polymers to be tailored. Wireless bipolar electrodes with an in‐plane potential distribution are also useful with regard to the electrochemical doping and reaction of conjugated polymers and allow the synthesis of films exhibiting composition gradients. Such bipolar electrochemistry can induce multiple reaction sites during electrochemical polymer reactions.
In this Communication, novel water‐soluble hyperbranched polysiloxanes (WHPSs) simultaneously containing hydroxyl and primary amine groups are developed. The polymers are constructed via melt polycondensation, that is, transesterification reaction between ethoxyl groups of (3‐aminopropyl)triethoxysilane and hydroxyl groups of dihydric alcohols, using a one‐step process under catalyst‐free conditions. Surprisingly, the resultant WHPSs can emit bright blue fluorescence in the 100% solid state under the irradiation of UV light, and their photoluminescence intensities in aqueous solutions continuously go up along with increasing concentrations. Interestingly, their hydrolyzates display more intense luminescence compared to the unhydrolyzed. The efficient and easily controllable preparation strategy provides a remarkable and versatile platform for the fabrication of neoteric fluorescent materials for various potential applications.
A pH‐responsive core cross‐linked star (CCS) polymer containing poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) arms was used as an interfacial stabilizer for emulsions containing toluene (80 v%) and water (20 v%). In the pH range of 12.1‐9.3, ordinary water‐in‐oil emulsions were formed. Intermediate multiple emulsions of oil‐in‐water‐in‐oil and water‐in‐oil‐in‐water were formed at pH 8.6 and 7.5, respectively. Further lowering the pH resulted in the formation of gelled high internal phase emulsions of oil‐in‐water type in the pH range of 6.4‐0.6. The emulsion behavior was correlated with interfacial tension, conductivity and configuration of the CCS polymer at different pH.
This article reports a rational strategy for preparing smart oligo(ethylene glycol)‐based hybrid microgels loaded with high content of homogeneously distributed preformed magnetic nanoparticles (NPs) (up to 33 wt%). The strategy is based on the synthesis of biocompatible multiresponsive microgels by precipitation copolymerization of di(ethylene glycol) methyl ether methacrylate, oligo(ethylene glycol) methyl ether methacrylate, methacrylic acid, and oligo(ethylene glycol)diacrylate. An aqueous dispersion of preformed magnetic NPs is straightforwardly loaded into the microgels. Robust monodisperse thermoresponsive magnetic microgels are produced, exhibiting a constant value of the volume phase transition temperature whatever the NPs content. The homogeneous microstructure of the initial stimuli‐responsive biocompatible microgels plays a crucial role for the design of unique well‐defined ethylene glycol‐based thermoresponsive hybrid microgels.
The synthesis of a novel photoreactive poly(ethylene glycol) (PEG)‐based polymer with caged carbonyl groups is reported. We further demonstrate its use for the on‐demand fabrication of hydrogels. For rapid gelation, a hydrazide‐functionalized PEG is used as the second component for the hydrogel preparation. The photoreactive PEG‐based polymer is designed for controlled cleavage of the protecting groups upon exposure to UV light releases free aldehyde moieties, which readily react with hydrazide groups in situ. This hydrogel system may find applications in controlled release drug delivery applications, when combined with in situ gelation. Furthermore, the possibility of forming gels specifically upon UV irradiation gives an opportunity for 3D fabrication of degradable scaffolds.
In this article, a versatile 2‐D conjugated polymer, PNDTP‐DPP, containing alkylphenyl substituted naphthodithiophene is synthesized and characterized. PNDTP‐DPP exhibits good solubility and crystallinity with a π−π stacking distance of ≈3.7 Å. Investigation of polymer solar cells (PSCs) and organic field‐effect transistors (OFET) demonstrates a promising power conversion efficiency (PCE) of 4.11% and a high hole mobility of up to 0.86 cm2 V–1 s–1, so this is one of the few examples of versatile polymers that show both good field‐effect mobility and PCE.
In this paper, a novel synthesis of polyethylene glycol (PEG)‐modified polypyrrole (PPy) nanomaterials is demonstrated by combining reversible addition‐fragmentation chain transfer polymerization and oxidative polymerization. Dye molecules with a heat‐labile linker are used as a model drug and covalently anchored onto the PEGlated PPy nanomaterials via “click chemistry.” The strong absorption of such PPy nanomaterials in the near‐infrared region endows the system excellent photothermal effect, which can be used not only as efficient photothermal agents for photothermal therapy but also good controllers of a drug‐release system by retro D–A reaction.
An ultraviolet (UV)‐cleavable bottlebrush polymer is synthesized using the “grafting‐onto” strategy by combining living radical polymerization and copper‐catalyzed azide‐alkyne cycloaddition (CuAAC). In this approach, reversible addition‐fragmentation chain transfer polymerization is used to prepare a poly(methylacrylate) backbone with azide side groups, while atom transfer radical polymerization is employed to prepare polystyrene (PS) side chains end‐functionalized with o‐nitrobenzyl (UV‐cleavable) propargyl groups. CuAAC is then used to graft PS side chains onto the polymer backbone, producing the corresponding bottlebrush polymers with UV‐cleavable PS side chains. The formation of the bottlebrush polymer is characterized by 1H nuclear magnetic resonance spectroscopy, gel permeation chromatography (GPC), and Fourier transform infrared spectroscopy. The cleavage behavior of the bottlebrush polymer is monitored in tetrahydrofuran solution under UV irradiation by GPC and viscosity measurements.
Copper‐free azide‐alkyne click chemistry is utilized to covalently modify polyvinyl chloride (PVC). Phthalate plasticizer mimics di(2‐ethylhexyl)‐1H‐triazole‐4,5 dicarboxylate (DEHT), di(n‐butyl)‐1H‐1,2,3‐triazole‐4,5‐dicarboxylate (DBT), and dimethyl‐1H‐triazole‐4,5‐dicarboxylate (DMT) are covalently attached to PVC. DEHT, DBT, and DMT have similar chemical structures to traditional plasticizers di(2‐ethylhexyl) phthalate (DEHP), di(n‐butyl) phthalate (DBP), and dimethyl phthalate (DMP), but pose no danger of leaching from the polymer matrix and forming small endocrine disrupting chemicals. The synthesis of these covalent plasticizers is expected to be scalable, providing a viable alternative to the use of phthalates, thus mitigating dangers to human health and the environment.
Temperature‐triggered phase separation of recombinant proteins has offered substantial opportunities in the design of nanoparticles for a variety of applications. Herein, the temperature‐triggered phase separation behavior of a recombinant hydrophilic resilin‐like polypeptide (RLP) is described. The transition temperature and sizes of RLP‐based nanoparticles can be modulated based on variations in polypeptide concentration, salt identity, ionic strength, pH, and denaturing agents, as indicated via UV–Vis spectroscopy and dynamic light scattering (DLS). The irreversible particle formation is coupled with secondary conformational changes from a random coil conformation to a more ordered β‐sheet structure. These RLP‐based nanoparticles could find potential use as mechanically‐responsive components in drug delivery, nanospring, nanotransducer, and biosensor applications.
In the last decades, metallopolymers have received great attention due to their various applications in the fields of materials and chemistry. In this article, a neutral 18‐electron exo‐substituted η4‐cyclopentadiene CpCo(I) unit‐containing polymer is prepared in a controlled/“living” fashion by combining facile click chemistry and ring‐opening metathesis polymerization (ROMP). This Co(I)‐containing polymer is further used as a heterogeneous macromolecular catalyst for atom transfer radical polymerization (ATRP) of methyl methacrylate and styrene.
Polymeric nanosheets organized by molecular building blocks bearing specifically oriented reactive groups provide abundant and versatile strategies for tailoring structure and chemical functionality periodically over extended length scales that complement graphene. Here we report the bulk synthesis of free‐standing polymeric nanosheets via spatially confined polymerization from an elaborate 2D supramolecular system composed of two liquid‐crystalline lamellar bilayer membranes of a self‐assembled nonionic surfactant—dodecylglyceryl itaconate (DGI)—sandwiched by a water layer. By employing a covalent polymerization on the lamellar bilayer membranes, single‐bilayer‐thick (4.2 nm), and large area (greater than 100 μm2) polymeric nanosheets of bilayer membranes are achieved. The polymeric nanosheets could serve as a well‐defined 2D platform for post‐functionalization for producing advanced hybrid materials by introducing the reactions on the hydroxyl groups at the head of DGI on the outer surfaces.
Four novel conjugated polymers ( P1‐4 ) with 9,10‐disubstituted phenanthrene (PhA) as the donor unit and 5,6‐bis(octyloxy)benzothiadiazole as the acceptor unit are synthesized and characterized. These polymers are of medium bandgaps (2.0 eV), low‐lying HOMO energy levels (below −5.3 eV), and high hole mobilities (in the range of 3.6 × 10−3 to 0.02 cm2 V−1 s−1). Bulk heterojunction (BHJ) polymer solar cells (PSCs) with P1‐4 :PC71BM blends as the active layer and an alcohol‐soluble fullerene derivative (FN‐C60) as the interfacial layer between the active layer and cathode give the best power conversion efficiency (PCE) of 4.24%, indicating that 9,10‐disubstituted PhA are potential donor materials for high‐efficiency BHJ PSCs.
This review describes different synthetic strategies towards sequence‐defined, monodisperse macromolecules, which are built up by iterative approaches and lead to linear non‐natural polymer structures. The review is divided in three parts: solution phase‐, solid phase‐, and fluorous‐ and polymer‐tethered approaches. Moreover, synthesis procedures leading to conjugated and non‐conjugated macromolecules are considered and discussed in the respective sections. A major focus in the evaluation is the applicability of the different approaches in polymer chemistry. In this context, simple procedures for monomer and oligomer synthesis, overall yields, scalability, purity of the oligomers, and the achievable level of control (side‐chains, backbone, stereochemistry) are important benchmarks.
Metallocenes are organometallic compounds with reversible redox profiles and tunable oxidation and reduction potentials, depending on the metal and substituents at the cyclopentadienyl rings. Metallocenes have been introduced in macromolecules to combine the redox‐activity with polymer properties. There are many examples of such hydrophobic polymer materials, but much fewer water‐soluble examples are found scattered across the polymer literature. However, in terms of drug delivery and other biological applications, water solubility is essential. For this very reason, all the synthetic routes to water‐soluble metallocene containing polymers are collected and discussed here. The focus is on neutral ferrocene‐ and ruthenocene‐containing and charged cobaltocenium‐containing macromolecules (i.e., symmetrical sandwich complexes). The synthetic protocols, self‐assembly behavior, and other benefits of the obtained materials are discussed.
A simplistic convenient “arm‐first” catalytic synthesis method is demonstrated to render soft unimolecular star polyethylene nanoparticles. Low‐dispersity polyethylene arms of controllable length and topology are first synthesized via Pd‐catalyzed “living” ethylene polymerization. The subsequent addition of norbornadiene as a unique cross‐linker renders the block polymer containing a short polynorbornadiene (PNBD) sequence. Efficient and rapid catalytic cross‐linking of the PNBD sequences occurs in the polymer precipitation and drying steps to give rise to star polyethylene nanoparticles. The star polymers are featured with tunable arm length and topology, high molecular weight (as high as 1770 kg mol−1), high arm numbers (as high as 88), and desirable average nanoparticle size (29−72 nm).
