Fragmentation Chain Transfer Polymerization Research Articles

Polyoxometalate-Polymer Directed Macromolecular Architectonics of Silver Nanoparticles as Effective Antimicrobials.

A novel inorganic-organic-inorganic ternary bioactive material formulated on antimicrobial peptide-based polymer has been reported. Supramolecular approach has been employed to incorporate molecularly crowded tyrosine-based polymer stabilized silver nanoparticles into membrane bound vesicles exploiting polyoxometalate-triggered surface templating strategy. Utilizing the covalent reversible addition fragmentation chain transfer (RAFT) polymerization and exploiting templated supramolecular architectonics at biopolymer interface, the bioactive ternary polymeric nanohybrids have been designed against Shigellosis leveraging the antibacterial activities of silver nanoparticle, cationic amphiphilic tyrosine polymer and inorganic polyoxometalate. The detail investigation against Shigella flexneri 2a cell line demonstrates that the collaborative mechanism of the ternary hybrid composite enhances the bactericidal activity in comparison to only polyoxometalate and polymer stabilized silver nanoparticle with an altered mechanism of action which is established via detailed biological analysis.

Tyrosine-Phosphorylated Peptide Imprinted Particles Prepared by Reversible Addition–Fragmentation Chain Transfer Polymerization and “Epitope” Strategy: Selective Recognition of Phosphorylated Angiotensin II

Tyrosine-Phosphorylated Peptide Imprinted Particles Prepared by Reversible Addition–Fragmentation Chain Transfer Polymerization and “Epitope” Strategy: Selective Recognition of Phosphorylated Angiotensin II

Pyrazino[2,3-f][1,10]phenanthroline Derivatives as Robust Photocatalysts Enabling ppm-Level Organocatalyzed Photoinduced Electron/Energy Transfer Reversible Addition–Fragmentation Chain Transfer Polymerization

Pyrazino[2,3-<i>f</i>][1,10]phenanthroline Derivatives as Robust Photocatalysts Enabling ppm-Level Organocatalyzed Photoinduced Electron/Energy Transfer Reversible Addition–Fragmentation Chain Transfer Polymerization

Four-Component Statistical Copolymers by RAFT Polymerization.

This manuscript serves as the starting point for in-depth research of multicomponent, statistical, methacrylate-based copolymers that potentially mimic the behavior of proteins in aqueous solutions. These synthetic macromolecules are composed of specially chosen comonomers: methacrylic acid (MAA), oligoethylene glycol methyl ether methacrylate (OEGMA475), 2-(dimethylamino)ethyl methacrylate (DMAEMA) and benzyl methacrylate (BzMA). Monomer choice was based on factors such as the chemical nature of pendant functional groups, the polyelectrolyte/polyampholyte and amphiphilic character and the overall hydrophobic-hydrophilic balance (HLB) of the obtained quaterpolymers. Their synthesis was achieved via a one-pot reversible addition fragmentation chain transfer (RAFT) polymerization in two distinct compositions and molecular architectures, linear and hyperbranched, respectively, in order to explore the effects of macromolecular topology. The resulting statistical quaterpolymers were characterized via 1H-NMR and ATR-FTIR spectroscopies. Their behavior in aqueous solutions was studied by dynamic (DLS) and electrophoretic light scattering (ELS) and fluorescence spectroscopy (FS), producing vital information concerning their self-assembly and the structure of the formed aggregates. The physicochemical studies were extended by tuning parameters such as the solution pH and ionic strength. Finally, the quaterpolymer behavior in FBS/PBS solutions was investigated to test their colloid stability and biocompatibility in an in vivo-mimicking, biological fluid environment.

Unravelling Competitive Interactions between Polymer Side Chains and End Groups with β-Cyclodextrin.

This study investigates unexpected competitive host-guest interactions of β-cyclodextrin (β-CD), which can occur with polymers in aqueous solution, using the examples of the two polymers poly(oligo(ethylene glycol) methyl ether methacrylate) and poly(glycerol mono methacrylate). Systematic structural modifications of the polymer provide insight into the host-guest interaction with β-CD and the competition between side chains and end groups such as hydrophobic end groups remaining from reversible addition fragmentation chain transfer polymerization or intentionally implemented molecular recognition units such as arylazopyrazole photoswitches.

Fluorine-modified polymers reduce the adsorption of immune-reactive proteins to PEGylated gold nanoparticles.

Aim: To investigate the influence of fluorine in reducing the adsorption of immune-reactive proteins onto PEGylated gold nanoparticles. Methods: Reversible addition fragmentation chain transfer polymerization, the Turkevich method and ligand exchange were used to prepare polymer-coated gold nanoparticles. Subsequent in vitro physicochemical and biological characterizations and proteomic analysis were performed. Results: Fluorine-modified polymers reduced the adsorption of complement and other immune-reactive proteins while potentially improving circulatory times and modulating liver toxicity by reducing apolipoprotein E adsorption. Fluorine actively discouraged phagocytosis while encouraging the adsorption of therapeutic targets, CD209 and signaling molecule calreticulin. Conclusion: This study suggests that the addition of fluorine in the surface coating of nanoparticles could lead to improved performance in nanomedicine designed for the intravenous delivery of cargos.

Defining New Benchmarks of Low CTAB‐Concentration‐Based Gold Nanorod Synthesis: The Underestimated Potential of Polymer‐Directed Anisotropic Growth

AbstractThis work presents new anisotropic growth‐directing copolymers suitable for the seed‐mediated growth of gold nanorods (GNRs). Copolymers with different architectures are studied. They all contain dimethylaminomethyl methacrylate (DMAEMA) functionalized with 1‐bromohexadecane (BHD) as the vital component. For the synthesis of the different copolymers, the photo‐iniferter reversible addition–fragmentation chain transfer (photoRAFT) polymerization is used, where DMAEMA is combined with a lower critical solution temperature (LCST) polymer block for better solubility after the functionalization. The results show that the presented copolymers can induce anisotropic growth of gold nanoparticles. Additionally, the influence of the LCST of the water‐soluble block and the temperature of the growth solution on the GNR synthesis are investigated. Furthermore, the plasmonic behavior of the resulting GNRs solution is investigated at temperatures around the LCST of the copolymer.

Synthesis via Reversible Addition–Fragmentation Chain Transfer Polymerization and Deep Control Property of Amphiphilic Self-assembled Poly(ethylene oxide)-block-polystyrene

Synthesis via Reversible Addition–Fragmentation Chain Transfer Polymerization and Deep Control Property of Amphiphilic Self-assembled Poly(ethylene oxide)-<i>block</i>-polystyrene

Diblock Copolymers of Methacryloyloxyethyl Phosphorylcholine and Dopamine Methacrylamide: Synthesis and Real-Time Adsorption Dynamics by SEIRAS and RAIRS.

Amphiphilic diblock copolymers containing a block of 2-methacryloyloxyethyl phosphorylcholine (MPC) with unique properties to prevent nonspecific protein adsorption and enhance lubrication in aqueous media and a block of dopamine methacrylamide (DOPMA) distinguished by excellent adhesion performance were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization for the first time. The DOPMA monomer with an acetonide-protected catechol group (acetonide-protected dopamine methacrylamide (ADOPMA)) was used, allowing the prevention of undesirable side reactions during polymerization and oxidation during storage. The adsorption behavior of the diblock copolymers with protected and unprotected catechol groups on gold surfaces was probed using attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectroscopy, surface-enhanced infrared absorption spectroscopy (SEIRAS), and reflection-absorption infrared spectroscopy (RAIRS). The copolymers pMPC-b-pADOPMA demonstrated physisorption with rapid adsorption and ultrasound-assisted desorption, while the copolymers pMPC-b-DOPMA exhibited chemical adsorption with slower dynamics but a stronger interaction with the gold surface. SEIRAS and RAIRS allowed proving the reorientation of the diblock copolymers during adsorption, demonstrating the exposure of the pMPC block toward the aqueous phase.

Oxygen-Tolerant Fabrication of Large-Area Hydrogel Films via Photoinduced Electron/Energy Transfer-Reversible Addition–Fragmentation Chain Transfer Polymerization

Oxygen-Tolerant Fabrication of Large-Area Hydrogel Films via Photoinduced Electron/Energy Transfer-Reversible Addition–Fragmentation Chain Transfer Polymerization

Influence of ionic liquid modified gold nanoparticles on conformational transition of poly(N-isopropylacrylamide)-b-poly(acryloylmorpholine) block copolymer

Utilizing stimuli-responsive polymers for surface modification of nanoparticle allows the adjustment of properties for individual system; however, limited research explores the impact of ionic liquid-modified gold nanoparticles (AuNPs) on the conformational phase transition of block copolymers. Herein, we synthesized poly(N-isopropylacrylamide)-b-poly(acryloylmorpholine) (PNIPAM-b-PACMO) copolymers by reversible addition − fragmentation chain-transfer polymerization and investigated the effect of ionic-liquid modified AuNPs (IL-AuNPs) on the aggregation behavior of the copolymer. Copolymerization of PNIPAM with PACMO shifted the lower critical solution temperature (LCST) towards higher temperature in comparison to LCST value of PNIPAM. Addition of IL-AuNPs further raises the transition temperature in concentration dependent manner. A more significant alteration in the transition temperature was observed in the presence of IL-AuNPs with a higher alkyl chain length. The variation in transition temperature of the copolymer by different IL-AuNPs yields benefits in the temperature responsive properties which can helpful for various applications.

The triumvirate of effective and rapid synthesis, analysis, and artificial intelligence to explore the structure-property relationship of copolymers

Understanding the structure-property relationship is of paramount importance for tailoring copolymers for specific applications. Poly(N-acryloylmorpholine)-block-poly(N-isopropylacrylamide) (PNAM-b-PNIPAM) diblock copolymers were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization with varying Mn and composition, providing the basis for deducing structure-property relationships. The chemical structure of the copolymers was analyzed by mass spectrometry (MS). A novel and efficient mass spectrum processing methodology was developed for the detailed analysis of polymers/copolymers that greatly expands the upper mass limit of the time-of-flight (TOF) analyzers in the linear mode up to 20,000 Da. Our method “makes visible” the mass peaks of the individual copolymer species and their isotopologues providing effective and fast automatized analysis. The self-assembly property of the thermoresponsive PNAM-b-PNIPAM diblocks in aqueous solutions was investigated by dynamic light scattering (DLS) experiments, and quantified by determining the incipient temperature of the phase transition. For rapid evaluation, an artificial neural network (ANN) was created to explore the hidden relationships between the structural information obtained by our novel mass analysis method and the properties as well as to predict the self-assembly behavior of the copolymers.

Sequence effects on the thermal cis–trans isomerization of side‐chain stearate‐containing azobenzene polymers

AbstractPhotochromic azobenzenes undergo light‐mediated trans–cis isomerization. The cis isomer reverts to the trans isomer thermally. To investigate the effect of different monomer sequences on the thermal stability of cis‐azobenzene, a series of copolymers, namely, block, and random structures containing stearic acid and azobenzene moieties as their side chains have been synthesized through reversible addition–fragmentation chain transfer (RAFT) polymerization. In this study, we investigate the photoisomerization of the trans and cis forms of the polymers and also the thermal reversal of the cis‐azobenzene photochromic systems. The isomerization data revealed significant differences in the isomerization timescales between the polymers and the corresponding monomer. It was observed that the local polarity around the azobenzene units within a polymer was significantly influenced by the chain segment depending on whether it was in the vicinity of the hydrophobic alkyl chains or other azobenzene units. This local environment of the azobenzene units regulates the stabilization of the transition states during the cis–trans thermal isomerization, consequently affecting the half‐life of the cis isomer.

Photoiniferter-RAFT polymerization mediated by bis(trithiocarbonate) disulfides

Photoiniferter reversible addition fragmentation chain transfer (PI-RAFT) polymerization has gained significant attention; however, scalable methodologies are still lacking.

Dual-templating synthesis of superhydrophobic Fe3O4/PSt porous composites for highly efficient oil-water separation

Fe3O4/PSt porous composites with low density, interconnected network structure and superhydrophobic were prepared successfully by a dual-templating method, including High Internal Phase Emulsion (HIPEs) template method and the introduction of organic template species. It was worth mentioning that a novel amphiphilic di-block copolymers P(DMAEMA-b-St) were prepared as emulsifier by reversible addition fragmentation chain transfer (RAFT) polymerization method. At the same time, the effects of PS block length, emulsifier content, Fe3O4 content, DVB content and dispersed phase proportion on HIPEs droplet size and the corresponding polyHIPEs oil absorption were researched. The results showed that the oil adsorption capacity of 9.43 g/g toward toluene under optimal conditions. Subsequently, adsorption isotherm and adsorption kinetics were investigated. The results were shown that the adsorption of oil on adsorbent followed Freundlich model and pseudo-second-order (PSO) model. In addition, the adsorption experiments on a variety of oils demonstrated the wide applicability of Fe3O4/PSt porous composites. The cycling experiments proved that the Fe3O4/PSt porous composites had excellent cycling ability, were easy to recover and could be reused for multiple times. Finally, the adsorption column experiments showed that Fe3O4/PSt porous composites had powerful potential for industrial applications.

Elucidating the Role of Optical Activity of Polymers in Protein-Polymer Interactions.

Proteins are biomolecules with potential applications in agriculture, food sciences, pharmaceutics, biotechnology, and drug delivery. Interactions of hydrophilic and biocompatible polymers with proteins may impart proteolytic stability, improving the therapeutic effects of biomolecules and also acting as excipients for the prolonged storage of proteins under harsh conditions. The interactions of hydrophilic and stealth polymers such as poly(ethylene glycol), poly(trehalose), and zwitterionic polymers with various proteins are well studied. This study evaluates the molecular interactions of hydrophilic and optically active poly(vitamin B5 analogous methacrylamide) (poly(B5AMA)) with model proteins by fluorescence spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and circular dichroism (CD) spectroscopy analysis. The optically active hydrophilic polymers prepared using chiral monomers of R-(+)- and S-(-)-B5AMA by the photo-iniferter reversible addition fragmentation chain transfer (RAFT) polymerization showed concentration-dependent weak interactions of the polymers with bovine serum albumin and lysozyme proteins. Poly(B5AMA) also exhibited a concentration-dependent protein stabilizing effect at elevated temperatures, and no effect of the stereoisomers of polymers on protein thermal stability was observed. NMR analysis, however, showed poly(B5AMA) stereoisomer-dependent changes in the secondary structure of proteins.

Preparation of two zwitterionic polymer functionalized stationary phases and comparative evaluation under mixed-mode of reversed phase/ hydrophilic interaction/ion exchange chromatography

Zwitterions are a promising choice to prepare separation materials because of their hydrophilicity and biocompatibility. We described the preparation of two zwitterionic polymer functionalized stationary phases and evaluation under mixed-mode chromatography. A zwitterionic monomer, S-(4-vinylbenzyl) cysteine (SVC), was synthesized and bonded to silica via reversible addition fragmentation chain transfer (RAFT) polymerization to afford a zwitterionic stationary phase, Sil-SVC. A hydrophobic monomer, N-(4-phenylbutan-2-yl) acrylamide (NPA), was copolymerized with SVC onto the stationary phase (Sil-SVCNPA) for comparison. The stationary phases were characterized with FT-IR, TGA, EA, and zeta-potential measurements. Mobile phase composition (ACN content, pH and salt concentration) was varied to study the retention property. Linear solvation energy relationship and Van't Hoff plot were used to investigate the retention mechanism and how chromatographic conditions influenced it. Both stationary phases showed a mixed-mode of RPLC/HILIC/IEC and satisfactory performance in separating hydrophobic analytes (alkylbenzenes and polycyclic aromatic hydrocarbons), hydrophilic nucleotide and bases, and anions, high column efficiency of 60,000 plates·m−1 was achieved. In summary, zwitterionic polymers are attractive options to prepare stationary phases and the retention property can be easily regulated by copolymer.

Photo-RDRP for everyone: Smartphone light-induced oxygen-tolerant reversible deactivation radical polymerization

Oxygen-tolerant reversible deactivation radical polymerization (RDRP) was carried out utilizing a smartphone flashlight. Well-controlled poly(oligo(ethylene oxide) monomethyl ether methacrylate) (POEOMA500) with relatively low dispersity (Đ = 1.16–1.35) was obtained employing dual catalysis atom transfer radical polymerization (ATRP) with CuBr2/tris(2-pyridylmethyl)amine (TPMA) and three different organic photocatalytic dyes (i.e. eosin Y (EY), fluorescein (FL), and riboflavin (RF)). The smartphone flashlight was also used for carrying out oxygen-tolerant photoinduced electron/energy transfer (PET) reversible addition–fragmentation chain transfer (RAFT) polymerization with EY and dithioesters RAFT agents , and photoiniferter (PI) RAFT polymerization with trithiocarbonate RAFT agent. The formation of crosslinked gels and facile measurement of gel points via recording the gelation process by in-built smartphone camera was also demonstrated.

Synthetic copolymers with natural product side‐chain pendents

AbstractDehydroabietic acid is a natural product in the class of rosins. Here we report the design, synthesis and characterization of copolymers containing dehydroabietate side‐chain pendents, derived from homologated dehydroabietic ethyl methacrylate and tert‐butoxy carbonyl (Boc) l‐alanine methacryloyloxyethyl ester with varying comonomer proportions by reversible addition fragmentation chain transfer polymerization. The cleavage of Boc groups from the copolymers resulted in water‐soluble copolymers with cationic surface charge. Since proper hydrophobic−hydrophilic balance in a single polymer chain is maintained, the copolymers self‐assembled in aqueous media with a critical aggregation concentration of 2.8–3.0 mg L−1, confirmed by fluorescence spectroscopy. 1H NMR spectroscopy, dynamic light scattering, SEM and AFM were used to further investigate the aqueous solution self‐assembly of random copolymers. The collective findings from 1H NMR, dynamic light scattering, SEM and AFM clearly revealed the existence of micellar particles in water with alanine units on the surface of the nanoaggregates and homologated dehydroabietate pendents along with the hydrophobic main‐chain backbone in the core. In addition, to get a clear insight into the nanoaggregates' potential for drug encapsulation in aqueous medium, Nile Red was incorporated as a model hydrophobic dye. © 2023 Society of Industrial Chemistry.

Controlled synthesis and solution properties of copolymers of methacrylic esters and ammonium-containing methacrylamide

Copolymers based on oligo(ethylene glycol) methacrylate, dodecyl methacrylate, and the cationic monomer N-methacryloylaminopropyl-N,N-dimethyl-N-propylammonium bromide have been obtained by reversible addition−fragmentation chain-transfer polymerization in high yields and in a controlled mode. The influence of the composition of the obtained polymers on the solubility in water and organic solvents, distribution in the water-octanol system, and interfacial tension at the water-oil interface is shown. The presence of thermoresponsive properties for polymers in water was found, and their aggregation in aqueous media was also studied.