Investigating the Mechanism of Copper(0)-Mediated Living Radical Polymerization in Aqueous Media

One Reaction: Two Types of Mechanism-SARA-ATRP and SET-LRP-for MMA Polymerization in the Presence of PVC

This study presents for the first time the polymerization of methyl methacrylate (MMA) in the presence of poly(vinyl chloride) (PVC) that takes place by both SARA-ATRP and SET-LRP mechanisms. The two types of polymerizations that occur in the system are PMMA grafting to the PVC backbone and the formation of a new PMMA polymer, both occurring in the presence of a Cu0wire. The polymerizations were controlled as confirmed by the molecular weight evolution, polymerization kinetics, and variations in the dispersity value. The MMA polymerization in the presence of PVC at 60 and 70 °C leads to the formation of two polymer species characterized by an increase in the molecular weight with the conversion and a narrowing of the dispersity value with the reaction progress. To increase the degree of control over the polymerization, the same reaction was performed at room temperature, which allowed us to highlight the presence of the SARA-ATRP and SET-LRP mechanisms via subsequent polymer chain extensions. The results demonstrated that PMMA grafting on PVC polymers follows a SARA-ATRP mechanism, while the formation of a PMMA homopolymer entails a SET-LRP process. The influence of solvent nature on the polymerization reaction was studied by performing the grafting of N-isopropylacrylamide (NIPAM) onto the surface of PVC particles in aqueous media in the presence and in the absence of CuCl2. The polymerization reactions and the obtained materials were studied by gel permeation chromatography (GPC), 1H NMR, DMA, scanning electron microscopy (SEM), and atomic force microscopy (AFM).

Cu(0)-RDRP of acrylates using an alkyl iodide initiator

In the vast majority of atom transfer radical polymerizations, alkyl bromides or alkyl chlorides are commonly employed as initiators. Herein, alkyl iodides are demonstrated as ATRP initiators.

Aqueous copper-mediated reversible deactivation radical polymerization (RDRP) utilizing polyetheramine derived initiators

Polyetheramines (Jeffamines™) are used in Copper-mediated reversible deactivation radical polymeriation (Cu-RDRP) in water for the synthesis of temperature-responsive block copolymers.

Synthetic approaches for multiblock copolymers

Multiblock copolymers (MBCs) are an emerging class of synthetic polymers that exhibit different macromolecular architectures and behaviours to those of homopolymers or di/triblock copolymers.

Accessible and sustainable Cu(0)-mediated radical polymerisation for the functionalisation of surfaces

Towards use of environmentally benign solvents and ambient conditions for surface functionalisation by controlled growth of thick cationic polymer brushes.

Boosting or moderating surface-initiated Cu(0)-mediated controlled radical polymerization with external additives

External additives regulate the copper disproportionation/comproportionation equilibrium to control polymer brush growth in surface-initiated Cu(0)-mediated controlled radical polymerization.

Self-assembly of giant bottlebrush block copolymer surfactants from luminescent organic electronic materials

Bottlebrush copolymers have shown promise as building blocks for self-assembled nanomaterials due to their reduced chain entanglement relative to linear polymers and their ability to self-assemble with remarkably low critical micelle concentrations (CMCs). Concurrently, the preparation of bottlebrush polymers from organic electronic materials has recently been described, allowing multiple optoelectronic functions to be incorporated along the length of single bottlebrush strands. Here we describe the self-assembly of bottlebrush surfactants containing soluble n-butyl acrylate blocks and carbazole-based organic semiconductors, which self-assemble in selective solvent to give spherical micelles with CMCs below 54 nM. These narrowly dispersed structures were stable in solution at high dilution over periods of months, and could further be functionalized with fluorescent dyes to give micelles with quantum yields of 100%. These results demonstrate that bottlebrush-based nanostructures can be formed from organic semiconductor building blocks, opening the door to the preparation of fluorescent or redox-active micelles from giant polymeric surfactants.

Cu(0)-RDRP as an efficient and low-cost synthetic route to blue-emissive polymers for OLEDs

Cu(0)-RDRP has been used to prepare deep-blue emissive polymers for OLEDs using a simple room-temperature procedure with copper wire catalyst.

Microscale synthesis of multiblock copolymers using ultrafast RAFT polymerisation

We demonstrate that ultrafast RAFT in the presence of air can be scaled down to 2 μL with good control using microvolume insert vials as the polymerisation vessel.

Fast track access to multi-block copolymers via thiol-bromo click reaction of telechelic dibromo polymers

Multi-block copolymers offer a plethora of exciting properties, easily tuned by modulating parameters such as monomer composition, block length, block number and dispersity.

Organic Arsenicals as Functional Motifs in Polymer and Biomaterials Science

Arsenic (As) exhibits diverse (bio)chemical reactivity and biological activity depending upon its oxidation state. However, this distinctive reactivity has been largely overlooked across many fields owing to concerns regarding the toxicity of arsenic. Recently, a clinical renaissance in the use of arsenicals, including organic arsenicals that are known to be less toxic than inorganic arsenicals, alludes to the possibility of broader acceptance and application in the field of polymer and biomaterials science. Here, current examples of polymeric/macromolecular arsenicals are reported to stimulate interest and highlight their potential as a novel platform for functional, responsive, and bioactive materials.

Controlled aqueous polymerization of acrylamides and acrylates and "in situ" depolymerization in the presence of dissolved CO2

Aqueous copper-mediated radical polymerization of acrylamides and acrylates in carbonated water resulted in high monomer conversions (t < 10 min) before undergoing depolymerization (60 min > t > 10 min). The regenerated monomer was characterized and repolymerized following deoxygenation of the resulting solutions to reyield polymers in high conversions that exhibit low dispersities.

Polymerization of acrylates based on n-type organic semiconductors using Cu(0)-RDRP

Three acrylic monomers have been prepared based on organic semiconductor motifs commonly used as n-type materials in organic light-emitting diodes (OLEDs) and organic thin-film transistors (OTFTs) and polymerized by Cu(0)-RDRP.

Optimisation of grafting of low fouling polymers from three-dimensional scaffolds via surface-initiated Cu(0) mediated polymerisation

Well-controlled low fouling polymers brushes were grafted from the surface of biodegradable electrospun fibres for advanced tissue engineering applications.

Cu(0)-RDRP of acrylates based on p-type organic semiconductors

A series of four acrylic monomers were synthesized based on p-type organic semiconductor motifs found commonly in organic light-emitting diodes (OLEDs), organic thin-film transistors (OTFTs) and organic photovoltaics (OPVs).

Synthesis of star-glycopolymers by Cu(0)-mediated radical polymerisation in the absence and presence of oxygen

Star glycopolymers were synthesized in the absence and presence of oxygen, and show strong binding to specific lectins.

Grafting PNIPAAm from β-barrel shaped transmembrane nanopores

The research on protein-polymer conjugates by grafting from the surface of proteins has gained significant interest in the last decade. While there are many studies with globular proteins, membrane proteins have remained untouched to the best of our knowledge. In this study, we established the conjugate formation with a class of transmembrane proteins and grow polymer chains from the ferric hydroxamate uptake protein component A (FhuA; a β-barrel transmembrane protein of Escherichia coli). As the lysine residues of naturally occurring FhuA are distributed over the whole protein, FhuA was reengineered to have up to 11 lysines, distributed symmetrically in a rim on the membrane exposed side (outside) of the protein channel and exclusively above the hydrophobic region. Reengineering of FhuA ensures a polymer growth only on the outside of the β-barrel and prevents blockage of the channel as a result of the polymerization. A water-soluble initiator for controlled radical polymerization (CRP) was consecutively linked to the lysine residues of FhuA and N-isopropylacrylamide (NIPAAm) polymerized under copper-mediated CRP conditions. The conjugate formation was analyzed by using MALDI-ToF mass spectrometry, SDS-PAGE, circular dichroism spectroscopy, analytical ultracentrifugation, dynamic light scattering, transmission electron microscopy and size exclusion chromatography. Such conjugates combine the specific functions of the transmembrane proteins, like maintaining membrane potential gradients or translocation of substrates with the unique properties of synthetic polymers such as temperature and pH stimuli handles. FhuA-PNIPAAm conjugates will serve as functional nanosized building blocks for applications in targeted drug delivery, self-assembly systems, functional membranes and transmembrane protein gated nanoreactors.

Light-Controlled Radical Polymerization: Mechanisms, Methods, and Applications

The use of light to mediate controlled radical polymerization has emerged as a powerful strategy for rational polymer synthesis and advanced materials fabrication. This review provides a comprehensive survey of photocontrolled, living radical polymerizations (photo-CRPs). From the perspective of mechanism, all known photo-CRPs are divided into either (1) intramolecular photochemical processes or (2) photoredox processes. Within these mechanistic regimes, a large number of methods are summarized and further classified into subcategories based on the specific reagents, catalysts, etc., involved. To provide a clear understanding of each subcategory, reaction mechanisms are discussed. In addition, applications of photo-CRP reported so far, which include surface fabrication, particle preparation, photoresponsive gel design, and continuous flow technology, are summarized. We hope this review will not only provide informative knowledge to researchers in this field but also stimulate new ideas and applications to further advance photocontrolled reactions.

Polymerisation of 2-acrylamido-2-methylpropane sulfonic acid sodium salt (NaAMPS) and acryloyl phosphatidylcholine (APC) via aqueous Cu(0)-mediated radical polymerisation

The scope of aqueous Cu(0)-mediated living radical polymerisation has been expanded with the preparation of poly(2-acrylamido-2-methylpropane sulfonic acid)sodium salt (P(NaAMPS)) and poly(acryloyl phosphatidycholine) (PAPC).

SET-LRP of acrylates catalyzed by a 1 penny copper coin

Controlled polymerization of acrylates can be catalyzed by one of the cheapest catalysts, a 1 pence coin.

Surface-initiated SET-LRP mediated by mussel-inspired polydopamine chemistry for controlled building of novel core–shell magnetic nanoparticles for highly-efficient uranium enrichment

Surface-initiated SET-LRP integrated with polydopamine chemistry to prepare core–shell magnetic nanoparticles for uranium enrichment.

Cu(0)-mediated living radical polymerization: recent highlights and applications; a perspective

Cu(0)-mediated living radical polymerization or single electron transfer living radical polymerization (Cu(0)-mediated LRP or SET-LRP) is a versatile polymerization technique that has attracted considerable interest during the past few years for the facile preparation of advanced materials.

SET-LRP of NIPAM in water via in situ reduction of Cu(ii) to Cu(0) with NaBH4

The direct and quantitative reduction of the air-stable Cu(ii)Br₂/Me₆TREN to Cu(0) by NaBH₄ represents a new method for the aqueous single electron transfer-living radical polymerization (SET-LRP) of water soluble polymers.

Design of a hydrophilic ruthenium catalyst for metal-catalyzed living radical polymerization: highly active catalysis in water

A novel hydrophilic phosphine ligand for a ruthenium catalyst was synthesized towards useful living radical polymerization in water.

Synthesis of well-defined catechol polymers for surface functionalization of magnetic nanoparticles

Well-defined fluorescent functional polymers with terminal catechol groups were synthesized by SET-LRP under aqueous conditions for “grafting to” modification of iron oxide nanoparticles.