In situ monitoring of SI-ATRP throughout multiple reinitiations under flow by means of a quartz crystal microbalance

Toward Green Atom Transfer Radical Polymerization: Current Status and Future Challenges

Reversible-deactivation radical polymerizations (RDRPs) have revolutionized synthetic polymer chemistry. Nowadays, RDRPs facilitate design and preparation of materials with controlled architecture, composition, and functionality. Atom transfer radical polymerization (ATRP) has evolved beyond traditional polymer field, enabling synthesis of organic-inorganic hybrids, bioconjugates, advanced polymers for electronics, energy, and environmentally relevant polymeric materials for broad applications in various fields. This review focuses on the relation between ATRP technology and the 12 principles of green chemistry, which are paramount guidelines in sustainable research and implementation. The green features of ATRP are presented, discussing the environmental and/or health issues and the challenges that remain to be overcome. Key discoveries and recent developments in green ATRP are highlighted, while providing a perspective for future opportunities in this area.

Effect of Atom Transfer Radical Polymerization Reaction Time on PCB Binding Capacities of Styrene-CMA/QMA Core-Shell Iron Oxide Nanoparticles

Water pollution continues to be one of the greatest challenges humankind faces worldwide. Increasing population growth, fast industrialization and modernization risk the worsening of water accessibility and quality in the coming years. Nanoadsorbents have steadily gained attention as remediation technologies that can meet stringent water quality demands. In this work, core-shell magnetic nanoparticles (MNPs) comprised of an iron oxide magnetic core and a styrene based polymer shell were synthesized via surface initiated atom transfer radical polymerization (SI-ATRP), and characterized them for their binding of polychlorinated biphenyls (PCBs), as model organic contaminants. Acrylated plant derived polyphenols, curcumin multiacrylate (CMA) and quercetin multiacrylate (QMA), and divinylbenzene (DVB) were incorporated into the polymeric shell to create high affinity binding sites for PCBs. The affinity of these novel materials for PCB 126 was evaluated and fitted to the nonlinear Langmuir model to determine binding affinities (KD). The KD values obtained for all the MNP systems showed higher binding affinities for PCB 126 that carbonaceous materials, like activated carbon and graphene oxide, the most widely used adsorption materials for water remediation today. The effect of increasing ATRP reaction time on the binding affinity of MNPs demonstrated the ability to tune polymer shell thickness by modifying the reaction extent and initial crosslinker concentrations in order to maximize pollutant binding. The enhancement in binding affinity and capacity for PCB 126 was demonstrated by the use of hydrophobic, aromatic rich molecules like styrene, CMA, QMA and DVB, within the polymeric shell provides more sites for π-π interactions to occur between the MNP surface and the PCB molecules. Overall, the high affinities for PCBs, as model organic pollutants, and magnetic capabilities of the core-shell MNPs synthesized provide a strong rationale for their application as nanoadsorbents in the environmental remediation of specific harmful contaminants.

Visualization of Atom Transfer Radical Polymerization by Aggregation-Induced Emission Technology

Aggregation-induced emission (AIE) technology has been demonstrated to be a facile approach for in-situ monitoring atom transfer radical polymerization (ATRP). A series of tertraphenyl ethylene (TPE)-containing α-bromo compounds were synthesized and applied as ATRP initiators. The photoluminescent (PL) emission of the polymerization system is proved to be sensitive to the local viscosity owing to the AIE characteristics of TPE. Linear relationships between the resulting molecular weight M_n and PL intensity were observed in several polymerization systems with different monomers, indicating the variability of this technique. Compared to physical blending, the chemical bonding of the TPE group in the chain end has higher sensitivity and accuracy to the polymer segments and the surrounding environment. This work promoted the combination of the AIE technique and controlled living radical polymerization, and introduced such an optical research platform to the ATRP polymerization process.

Synthesis of acrylamide-based block-copolymer brushes under flow: monitoring real-time growth and surface restructuring upon drying

Block-copolymer brushes of water-soluble acrylamides have been synthesised by SI-ATRP under continuous flow and their growth monitored in situ by means of a quartz-crystal microbalance with dissipation (QCM-D).

Ultrasensitive Detection of DNA via SI-eRAFT and in Situ Metalization Dual-Signal Amplification

In this work, we report a new amplification strategy based on electrochemically mediated reversible addition-fragmentation chain transfer (eRAFT) and in situ metalization for electrochemical detection of DNA. First, peptide nucleic acid (PNA) probes were immobilized on the surface of the gold electrode, and when they hybridized with the target DNA, the chain transfer agent (CTA), 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPAD), of RAFT was connected to the PNA/DNA heteroduplex formed by the coordination bonding of Zr⁴⁺. Then glycosyloxyethyl methacrylates (GEMA) were assembled on the surface of the electrode by electrochemically mediated surface-initiated reversible addition-fragmentation chain transfer (SI-eRAFT) to form a polymer-containing sugar glucose. Next, the o-hydroxyl groups on the polysaccharide molecular skeleton were oxidized to aldehyde groups by sodium periodate (NaIO₄). The aldehyde groups generated then reduce silver ions to silver particles deposited on the electrode surface in situ, and this system was then subjected to differential pulse voltammetry (DPV). Under optimal conditions, the intensity of the stripping current and the logarithm of the target DNA (tDNA) concentration has a good linear relationship in the range of 10 aM to 1 pM (R² = 0.996), and the detection limit can go down to 5.4 aM (S/N = 3). Moreover, the method is suitable for single-nucleotide polymorphism (SNP) analysis and has strong anti-interference ability for the analysis of target ssDNA in serum samples.

Tuning and in situ monitoring of surface-initiated, atom-transfer radical polymerization of acrylamide derivatives in water-based solvents

SI-ATRP kinetics of acrylamide derivatives is studied in situ using a quartz crystal microbalance with dissipation (QCM-D). The effect of growth kinetics on polymer-brush dispersity have been examined using colloidal-probe atomic force microscopy.