Herein, a novel photoinitiated polymerization‐induced self‐assembly formulation via photoinitiated reversible addition–fragmentation chain transfer dispersion polymerization of glycidyl methacrylate (PGMA) in ethanol–water at room temperature is reported. It is demonstrated that conducting polymerization‐induced self‐assembly (PISA) at low temperatures is crucial for obtaining colloidal stable PGMA‐based diblock copolymer nano‐objects. Good control is maintained during the photo‐PISA process with a high rate of polymerization. The polymerization can be switched between “ON” and “OFF” in response to visible light. A phase diagram is constructed by varying monomer concentration and degree of polymerization. The PGMA‐based diblock copolymer nano‐objects can be further cross‐linked by using a bifunctional primary amine reagent. Finally, silver nanoparticles are loaded within cross‐linked vesicles via in situ reduction, exhibiting good catalytic properties.
Control over morphology and porosity of supramolecular complexed polylactide (PLA) microparticles can be achieved by manipulation of the supramolecular interactions between their constituent polymeric building blocks. It is expected that such modular systems are ideal candidates to serve as degradable delivery carriers. In view of this goal, this study reports about a modular fabrication of biodegradable microparticles from terpyridine (TPy) and bisterpyridine (bisTPy) end‐functionalized PLAs that can be transiently extended by chain association through differently strong complexation to three metal cations: Ni2+, Co2+, or Fe2+. Further influence on the morphology of the particles can be exerted by hydrogen‐bonding association of enantiomeric l ‐ and d ‐PLA chains in the form of stereocomplexes. Both effects cause different stabilization of phase‐separating TPy and bisTPy PLA micrograins in a process of droplet‐based microfluidic particle templating, resulting in different forms of microparticle porosity. If the resulting particles are tailored such to be highly porous, they exhibit a faster release of a model drug, (S)‐(+)‐4‐(3‐amino‐pyrrolidino)‐7‐nitrobenzo‐furazan, than if they have smooth surfaces. As a result, control over the synthetic parameters, and hence, the particle porosity, can be used to tune the release profiles of drugs from the PLA microspheres.
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 novel and robust route for the synthesis of a new amphiphilic brush copolymer, poly(glycidyl methacrylate)‐graft‐polyethylene glycol (PGMA‐g‐PEG), with high grafting densities of 97%–98% through a “grafting onto” method via carbon dioxide chemistry is reported. PGMA‐g‐PEG can self‐assemble and form stable spherical core–shell micelles in aqueous solution. Besides, the obtained PGMA‐g‐PEG polymer contains hydroxyurethane structures as the junction sites between the PGMA backbone and PEG side chain, which can be used for further modification.
A linear supramolecular polymer based on the self‐assembly of an easily available copillar[5]arene monomer is efficiently prepared, which is evidenced by the NMR spectroscopy, viscosity measurement, and DOSY experiment. The single‐crystal X‐ray analysis reveals that the polymerization of the AB‐type monomer is driven by the quadruple CH•••π interactions and one CH•••O interaction.
Using the third‐generation Grubbs catalyst, the living ring‐opening metathesis polymerization of ferrocene/cobalticenium copolymers is conducted with theoretical numbers of 25 monomer units for each block, and their redox and electrochemical properties allow using the Bard–Anson electrochemical method to determine the number of metallocenyl units in each block.
Copolymers of 2‐(methacrylamido)glucopyranose (MAG) and methacrylic acid (MAA) are synthesized by RAFT polymerization and then used as templates to prepare glycopolymer‐functionalized Ag nanoclusters (Gly‐Ag NCs) through microwave irradiation. Polymers and the resulting nanoclusters are characterized by NMR, GPC, UV‐Vis, SEM, TEM, AAS and fluorescence spectroscopy. The bio‐activity of the fluorescent Gly‐Ag NCs are further examined using GLUT‐1 over‐expressing cancer cells K562. Gly‐Ag NCs show efficient binding ability toward K562 cells and inhibit the cell viability in a dose dependent manner (IC50 = 0.65 μg mL–1), indicating their potential biological applications for both cancer imaging and targeted cancer therapy.
Cyclic polymers with alternating monomer sequence are synthesized for the first time based on the ring‐closure strategy. Well‐defined telechelic alternating polymers are synthesized by reversible addition–fragmentation chain transfer polymerization by copolymerizing the electron acceptor monomer of N‐benzylmaleimide and donor monomer of styrene with a feed ratio of 1 between them. The corresponding cyclic alternating polymers are then produced by the UV‐induced Diels–Alder click reaction to ring‐close the linear alternating polymer precursors under highly diluted reaction solution.
An acceleration effect and selective monomer addition during RAFT copolymerization of the oppositely‐charged ionic monomers in dilute aqueous solution at 25 °C are reported. The reaction is conducted using a non‐ionic water‐soluble polymer as a macromolecular chain transfer agent under visible light irradiation. A fast iterative polymerization can be induced, even in dilute solution, by the favorable ionic interactions and in situ self‐assembly of zwitterionic growing chains. Selelctive monomer addition is achieved in the statistical copolymerization due to the ion‐pairing of the oppositely‐charged monomers, such as precisely the same reaction rates at a 1:1 of monomer ratio, otherwise a faster reaction of the minor monomer component over the major one. These behaviors open up an avenue towards the rapid synthesis of sequence‐controlled zwitterionic polyelectrolytes that can satisfy the demands of emerging biological applications.
A highly living polymer with over 100 kg mol−1 molecular weight is very difficult to achieve by controlled radical polymerization since the unavoidable side reactions of irreversible radical termination and radical chain transfer to monomer reaction become significant. It is reported that over 500 kg mol−1 polystyrene with high livingness and low dispersity could be synthesized by a facile two‐stage reversible addition–fragmentation transfer emulsion polymerization. The monomer conversion reaches 90% within 10 h. High livingness of the product is ascribed to the extremely low initiator concentration and the chain transfer constant for monomer unexpectedly much lower than the well‐accepted values in the conventional radical polymerization. The two‐stage monomer feeding policy much decreases the dispersity of the product.
Optically active nano‐ and microparticles have constituted a significant category of advanced functional materials. However, constructing optically active particles derived from synthetic helical polymers still remains as a big challenge. In the present study, it is attempted to induce a racemic helical polymer (containing right‐ and left‐handed helices in equal amount) to prefer one predominant helicity in aqueous media by using emulsifier in the presence of chiral additive (emulsification process). Excitingly, the emulsification process promotes the racemic helical polymer to unify the helicity and directly provides optically active nanoparticles constructed by chirally helical polymer. A possible mechanism is proposed to explain the emulsification‐induced homohelicity effect. The present study establishes a novel strategy for preparing chirally helical polymer‐derived optically active nanoparticles based on racemic helical polymers.
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.
Hierarchical self‐assembly of transient composite hydrogels is demonstrated through a two‐step, orthogonal strategy using nanoparticle tectons interconnected through metal–ligand coordination complexes. The resulting materials are highly tunable with moduli and viscosities spanning many orders of magnitude, and show promising self‐healing properties, while maintaining complete optical transparency.
Glycopolymers attached to a surface possess the ability to bind to certain carbohydrate binding proteins in a highly specific manner, and because of this, the fabrication of glycopolymer‐modified surfaces has evolved as an effective route toward bioresponsive systems. Poly(N‐3,4‐dihydroxybenzenethyl methacrylamide‐co‐2‐(methacrylamido) glucopyranose) copolymers, containing sugar and catechol functionalities, are for the first time successfully prepared in a well‐controlled manner via room temperature single‐electron transfer initiation and propagation through radical addition fragmentation chain transfer technique. The polymerization behavior is investigated and it presents controlled features with first‐order kinetics and linear relationships between molecular weights and monomer conversions. Moreover, the copolymers are used to modify different types of surfaces (silicon, steel, and plastic), the properties of the surfaces and the specific lectin‐binding abilities are investigated by a combination of water contact angle, Fourier transform infrared spectroscopy (FT‐IR), X‐ray photoelectron spectra, scanning electron microscopy with energy dispersive X‐ray (SEM/EDX), atomic force microscopy, and confocal microscope measurements.
A convenient synthesis of sustainable polyamides, which contain side groups and stereocenters, starting from the biobased small terpene β‐pinene is reported. The polyamides, which are obtained via the pinene‐based lactam via ring‐opening polymerization, show excellent thermal properties, rendering this approach very interesting for the utilization of novel biobased and structurally significant high‐performance polymers and materials. Polymer masses and yields are shown to be dependent on different parameters, and the stereoinformation of the lactam monomer can thus be transferred into the polymer chain. In addition, another lactam side product can also be transformed to polyamides.
Thin, phenylboronic acid‐containing polymer coatings are potentially attractive sensory layers for a range of glucose monitoring systems. This contribution presents the synthesis and properties of glucose‐sensitive polymer brushes obtained via surface RAFT polymerization of 3‐methacrylamido phenylboronic acid (MAPBA). This synthetic strategy is attractive since it allows the controlled growth of PMAPBA brushes with film thicknesses of up to 20 nm via direct polymerization of MAPBA without the need for additional post‐polymerization modification or deprotection steps. QCM‐D sensor chips modified with a PMAPBA layer respond with a linear change in the shift of the fundamental resonance frequency over a range of physiologically relevant glucose concentrations and are insensitive toward the presence of fructose, thus validating the potential of these polymer brush films as glucose sensory thin coatings.
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.
This paper describes a method for fabricating protein‐based capsules with semipermeable and enzyme‐degradable surface barriers. It involves the use of a simple fluidic device to generate water‐in‐oil emulsion droplets, followed by cross‐linking of proteins at the water–oil interface to generate a semipermeable surface barrier. The capsules can be readily fabricated with uniform and controllable sizes and, more importantly, show selective permeability toward molecules with different molecular weights: small molecules like fluorescein sodium salt can freely diffuse through the surface barrier while macromolecules such as proteins can not. The proteins, however, can be released by digesting the surface barrier with an enzyme such as pepsin. Taken together, the capsules hold great potential for applications in controlled release, in particular, for the delivery of protein drugs.
Polyurethane (PU) monomer mixtures containing commercially available o‐nitrobenzyl‐based photocleavable monomers have been formulated and tested as low‐cost positive tone photoresists. The photolysis reaction is studied by UV spectroscopy. Well‐defined micropatterns on 2 μm thick photodegradable PU films are obtained using 365 nm light exposure. This strategy is also extended to improved formulations based on synthesized o‐nitrobiphenylpropyl derivatives with enhanced photochemical properties for single photon excitation and high two‐photon absorption cross‐sections. Improved pattern resolution in 2D and the capability of 3D resolution using a scanning laser at 780 nm is demonstrated. This work demonstrates the potential of PUs as readily available, versatile, and easy‐to‐use photoresist materials for low‐cost lithography applications.
Hydrozirconation on vinyl‐terminated substrates (silicon wafer and nanosilica sphere) is employed as an efficient way for immobilization of zirconocene catalyst through Zr C bonds, which is applied in surface coordination ethylene polymerization producing surface‐tethered polyethylene (PE). The formation of Zr C σ bond induced by hydrozirconation provides an initiator precursor for growing a layer of PE covalently linked onto substrates. The results from SEM, AFM, and TEM show that the surface polymerization is controlled by hydrozirconation. Surface pattern or core–shell structure with crystalline PE coating can be formed, when silicon wafer is selectively functionalized with vinyl‐groups or vinyl‐modified nanosilica is applied. It is believed that hydrozirconation for the synthesis of zirconocene initiator can be a versatile route to prepare polyolefin hybrid materials.
