Activators Regenerated By Electron Transfer Research Articles

Synthesis of Mechanically Robust Very High Molecular Weight Polyisoprene Particle Brushes by Atom Transfer Radical Polymerization.

Linear polyisoprene (PI) and SiO2-g-PI particle brushes were synthesized by both conventional and activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP). The morphology and solution state study on the particle brushes by transmission electron microscopy (TEM) and dynamic light scattering (DLS) confirmed the successful grafting of PI ligands on the silica surface. The presence of nanoparticle clusters suggests low grafting density (associated with the limited initiation efficiency of ARGET for PI). Nevertheless, particle brushes with very high molecular weights, Mn > 300,000, were prepared, which significantly improved the dispersion of silica nanoparticles and also contributed to excellent mechanical performance. The reinforcing effects of SiO2 nanofillers and very high molecular weight PI ligands were investigated by dynamic mechanical analysis (DMA) as well as computational simulation for the cured linear PI homopolymer/SiO2-g-PI particle brush bulk films.

Oscillatory and Relaxation Study of the Interfacial Rheology of Star Polymers with Low-Grafting-Density PEO Arms and Hydrophobic Poly(divinylbenzene) Cores.

Star polymers have been gaining interest due to their tunable properties. They have been used as effective stabilizers for Pickering emulsions. Herein, star polymers were synthesized via activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP). Poly(ethylene oxide) (PEO) with terminal α-bromoisobutyrate ATRP functionality was used as a macroinitiator and divinylbenzene as a crosslinker for the arm-first star synthesis. Stars with PEO arms with a molar mass of either 2 or 5 kDa had a relatively low density of grafted chains, i.e., ca. 0.25 chain/nm2. The properties of PEO stars adsorbed at oil-water interfaces were investigated using interfacial tension and interfacial rheology. The magnitude of interfacial tensions at oil-water interfaces depends on the nature of the oil phase, being lower at the m-xylene/water interface than at the n-dodecane/water interface. Small differences were observed for stars with different molecular weights of PEO arms. The overall behavior of PEO stars adsorbed at an interface can be considered as an intermediate between a particle and a linear/branched polymer. Obtained results offer an important insight into the interfacial rheology of PEO star polymers in the context of their application as stabilizers for Pickering emulsions.

Glycopolymers Mediate Suicide Gene Therapy in ASGPR-Expressing Hepatocellular Carcinoma Cells in Tandem with Docetaxel.

Cationic glycopolymers stand out as gene delivery nanosystems due to their inherent biocompatibility and high binding affinity to the asialoglycoprotein receptor (ASGPR), a target receptor overexpressed in hepatocellular carcinoma (HCC) cells. However, their synthesis procedure remains laborious and complex, with problems of solubilization and the need for protection/deprotection steps. Here, a mini-library of well-defined poly(2-aminoethyl methacrylate hydrochloride-co-poly(2-lactobionamidoethyl methacrylate) (PAMA-co-PLAMA) glycopolymers was synthesized by activators regenerated by electron transfer (ARGET) ATRP to develop an efficient gene delivery nanosystem. The glycoplexes generated had suitable physicochemical properties and showed high ASGPR specificity and high transfection efficiency. Moreover, the HSV-TK/GCV suicide gene therapy strategy, mediated by PAMA144-co-PLAMA19-based nanocarriers, resulted in high antitumor activity in 2D and 3D culture models of HCC, which was significantly enhanced by the combination with small amounts of docetaxel. Overall, our results demonstrated the potential of primary-amine polymethacrylate-containing-glycopolymers as HCC-targeted suicide gene delivery nanosystems and highlight the importance of combined strategies for HCC treatment.

Modification of cellulose nanocrystals via surface-initiated ARGET ATRP and their reinforcement of poly(lactic acid)-based biocomposites

In order to improved the thermal stability and compatibility between cellulose nanocrystals (CNCs) and poly(lactic acid) (PLA), using activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP), customized functionalization of CNCs was achieved by surface grafting of poly(butyl acrylate) (PBA). PLA nanocomposites with different amounts of nanofillers (ranging from 1 to 5 wt%) was processed via hot-press approach. After the modification, the initial contact angle of nanocellulose increased from 50° to 120°, and the initial thermal degradation temperature increased from 150 °C to 270 °C. SEM revealed that modified CNCs were dispersed uniformly throughout the PLA matrix. The thermal characteristics of PLA composites reinforced with PBA-grafted CNCs were analyzed using DSC , demonstrating that the modified CNCs and PLA matrix had improved interactions. The compatibility of modified CNCs with the matrix was enhanced as a consequence of surface modified CNCs having better hydrophobicity and improved thermal stability. Tensile tests were used to evaluate the impact of CNCs on the mechanical characteristics, pointing an increase in the tensile strength, elongation and Young’s Modulus of roughly 350%, 100% and 120%, respectively, at 2 wt% CNC-PBA400 content. • Green composites from poly(lactic acid) and cellulose nanocrystals (CNCs). • Poly(butyl acrylate) grafting helped to disperse CNCs within PLA. • CNCs influenced the crystallization characterization and physico-mechanical properties of PLA.

Alternating Methyl Methacrylate/n-Butyl Acrylate Copolymer Prepared by Atom Transfer Radical Polymerization.

Poly(methyl methacrylate/n-butyl acrylate) [P(MMA/BA)] copolymer with an alternating structure was synthesized via an activator regenerated by electron transfer (ARGET) atom transfer radical (co)polymerization (ATRP) of 2-ethylfenchyl methacrylate (EFMA) and n-butyl acrylate (BA) with subsequent postpolymerization modifications (PPM). Due to the steric hindrance of the bulky pendant group of EFMA, as well as the low reactivity ratio of BA in copolymerization with methacrylates, copolymerization of EFMA and BA generated a copolymer with a high content of alternating dyads. A subsequent PPM procedure of the alternating EFMA/BA copolymer was comprised of the hydrolysis of a tertiary ester by trifluoroacetic acid and methylation by (trimethylsilyl)diazomethane. After the modifications, the architecture of the obtained alternating MMA/BA copolymers was compared with gradient and statistical copolymers with overall similar compositions, molecular weights, and dispersities. 13C NMR indicated the absence of either MMA/MMA/MMA or BA/BA/BA sequences, in contrast to an abundance of homotriads in either the statistical or especially in the gradient copolymer. All three copolymers had similar glass transition temperatures, as measured by differential scanning calorimetry (DSC), but the alternating copolymer had the narrowest range of glass transition.

SI-ATRP on the lab bench: A facile recipe for oxygen-tolerant PDMAEMA brushes synthesis using microliter volumes of reagents

Facile, low-cost, and environmentally friendly procedures for the synthesis of hybrid materials are highly desirable for industrial applications and large-scale synthesis. To meet these needs, this paper presents an ultra-simple, organic solvent-free and yet effective method for the synthesis of hybrid materials consisting of an inorganic core and an organic layer of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes. Bearing in mind the numerous works published in recent years on the synthesis of PDMAEMA via “normal” and low ppm ATRP using additional reductants or complicated and expensive apparatus, e.g. a photoreactor or potentiostat, this article is a step forward, reducing the costs of the process and increasing the safety of the experimenter. In order to develop the title “facile recipe” a series of reactions aimed at optimizing the synthesis conditions in which the monomer plays a dual role and participates simultaneously as a reducing agent according to the activators regenerated by electron transfer (ARGET) atom transfer radical polymerizations (ATRP) were carried out. As a result, an in-depth analysis of the synthesis conditions and the influence of the presence of oxygen allowed the development of a monomer-mediated ATRP procedure inspired by the principles of green chemistry. Finally, 30 ppm of Cu II Br 2 /TPMA (where TPMA: tris(2-pyridylmethyl)amine) and 20 μl/cm 2 of the reaction mixture were used to obtain a homogeneous polymeric brush layer with the thickness of 331 nm, which was revealed by atomic force microscopy (AFM) measurements. Additionally, the presence and composition of the obtained polymer brushes were confirmed by X-ray photoelectron spectroscopy (XPS) analyses and scanning electron microscope (SEM) with imaging of elemental composition on the decorated silicon surface. • Ultra-simple technique of ATRP was developed due to reducing properties of DMAEMA. • Oxygen-toletant SI-ATRP can be carried out directly on the lab bench. • 20 μL of reaction mixure as suffice to graft PDMAEMA brushes up to 330 nm. • Green procedure for PDMAEMA synthesis with application only 30 ppm Cu II Br 2 /TPMA.

Self‐Aligned Polymer Film Patterning on Microstructured Silicon Surfaces

AbstractBased on a recently developed selective etching process for silicon samples with buried implants, this work presents a method for utilizing the generated material contrast between silicon and silicon oxide to selectively deposit polymers on the patterned surface. Besides depositing polystyrene selectively on the etched parts via drop‐casting and dewetting, polymer chains are selectively grafted to the oxidic surface parts. To this end, the oxide surfaces are selectively modified via functional alkoxysilanes, whereas etched silicon surfaces are unreactive. Using either a two‐step or a straight‐forward one‐step process employing commercially available chemicals, atom transfer radical polymerization (ATRP) initiator functions are attached selectively to the non‐etched surface areas, and subsequently used to polymerize either methyl methacrylate (MMA) or N‐isopropyl acrylamide (NIPAM) in a controlled surface‐initiated activator regenerated by electron transfer (ARGET)‐ATRP process. This procedure allows for the further self‐aligned functionalization of the micropatterned samples, enabling the production of highly functional, patterned surfaces, potentially suitable for applications in areas such as cell adsorption, microfluidics, or functional microsystems, e.g., MEMS.

ARGET ATRP of Methyl Acrylate and Methyl Methacrylate with Diazocine-Derived Initiators

Diazocine-functionalized initiators for atom transfer radical polymerization (ATRP) were synthesized and tested for their efficiency in controlled radical polymerizations of methyl acrylate and methacrylate under reaction conditions for activators regenerated by electron transfer (ARGET). The α-bromoisobutyl condensates of anilide and benzyloxycarbonate required high amounts of reducing agents and catalysts for the initiation. On the other hand, violet light irradiation during ATRP caused severe retardation or termination during initiation of the anilide compound, in contrast to the previously reported photoinduced initiation under otherwise very similar conditions. The final linear elastomers obtained from optimized polymerization kinetics responded to light irradiation of 405 and 525 nm wavelengths by Z/E photoisomerization of diazocine in both solution and in the solid state. The E → Z thermal relaxation rate was highly influenced by electronic effects on the diazocine ring, the solvent, and the polymer matrix in the solid state. Our polymers find potential use as photonic materials in ultraviolet light sensors and optical waveguides.

Selective Protein Conjugation of Poly(glycerol monomethacrylate) and Poly(polyethylene glycol methacrylate) with Tunable Topology via Reductive Amination with Multifunctional ATRP Initiators for Activity Preservation

In this study, we compare poly(glycerol monomethacrylate) (PGMA) of different chain lengths and architectures (linear and two-arm) with poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA) as an alternative polymer platform for the synthesis of a new generation of protein–polymer conjugates. Mono- and two-arm functional atom-transfer radical polymerization (ATRP) initiators were designed and selectively attached to lysozyme at the N-terminus via reductive amination. Site-specific, grafting from activator regenerated by electron transfer (ARGET) ATRP was carried out in phosphate buffer, and the reaction parameters were optimized to obtain polymer conjugates with predetermined molar mass and topology. The activity preservation under proteolytic and high-temperature conditions showed a clear dependence on the structure of the repeating unit and on the macromolecular architecture. These results highlighted the potential of PGMA as a poly(ethylene glycol) (PEG) alternative for the half-life extension of biotherapeutics. Moreover, this synthetic approach may inspire the design of a new class of protein–polymer conjugates through an optimal combination of macromolecular composition and topology.

Esterification process of incorporation CS2 activation and its effect on the properties of hydrophobic modified cotton filter fabric via ARGET-ATRP

Hydrophobic modification of cellulose via activation synergistic activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) method has been proved to effectively improve the long-term hydrophobic stability of cotton filter fabric. However, the extra activation process will inevitably increase the complexity of the reaction process. In this work, carbon disulfide (CS2) was incorporated into the ARGET-ATRP reaction system to avoid adding redundant reaction links. Specifically, the activation and acyl bromination processes were combined, and then the graft modification reaction between the acyl bromide cotton filter fabric and 1-octadecene (1-Oct) was realized by the ARGET-ATRP. The effect of the combined process on the hydrophobic modification reaction and performance of cotton filter fabric was investigated. The results showed that, under the optimum dosages of activator CS2, acyl bromide reagent BiB and monomer 1-Oct, the activator CS2 was directly incorporated into the acyl bromination process. And after ARGET-ATRP Hydrophobic modification, the initial water contact angle (CA) of the obtained hydrophobically modified cotton filter fabric reached 145.0°, the residual contact angle (RCA) after the water droplet retention time of 210 min could still arrive at 125.4°, showing a corresponding attenuation rate (Dr) of 13.5%, which suggested excellent hydrophobicity and durability. Notably, the hydrophobically modified cotton filter fabric also exhibited excellent resistance to chemical corrosion, abrasion resistance and ultrasonic stripping resistance. Furthermore, this hydrophobically modified filter fabric can efficiently separate different types of oil–water mixtures. Even after 12 cycles of oil–water separation process, the separation efficiency still exceeded 95%, and the CA of the modified filter fabric before and after separation was basically unchanged.

Copper-catalyzed ARGET ATRP of styrene from ethyl α-haloisobutyrate in EtOAc/EtOH, using ascorbic acid/Na2CO3 as reducing system

Atom transfer radical polymerization (ATRP) is one of the most powerful techniques to synthesize precisely tailored polymers and macrostructures. Activators regenerated by electron transfer (ARGET) ATRP was developed as a “green” strategy to decrease the load of the metal catalyst. However, ARGET ATRP usually uses not-so-green reducing agents (e.g. Sn2+) or expensive and industrially impractical procedures. For these reasons, we report an ARGET ATRP of styrene with various carbonates as reducing agents, both alone and paired with ascorbic acid (AA), using monofunctional initiators and Cl or Br as exchanging atoms. The solvent mixture is composed of the green combination of EtOAc and EtOH, even in the presence of modest amounts of H2O. Cyclic voltammetry was used to evaluate the effect of H2O on the catalyst, as well as the absence of AA. The system returned high yields and low dispersities with low amounts of catalyst (~60 ppm) and moderate reaction times. Excellent results were obtained only with the Cl-ATRP system. NMR spectroscopy and kinetic analyses proved the livingness of the final polymer chains.

Regulating Gelation Time and Kinetics Analysis Based on the ARGET ATRP Mechanism

ABSTRACTA novel activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) initiation system composing of an initiator sodium chloroacetate, a catalyst ferric chloride, and a reducing agent ascorbic acid was developed to improve the gelation time of the in situ crosslinked polymer system. The kinetics of polymerization of acrylamide showed features of a living/controlled process in which the concentrations of the growing radicals [P·] are kept constant throughout the polymerization process. Compared with conventional potassium persulfate initiators, the gelation time of the in situ crosslinked polymer system can be improved to 40 h or even longer using the ARGET ATRP initiation system at 80 °C due to the low radical concentration and slow polymerization reaction. Core flooding test showed that the ARGET ATRP initiating system developed could initiate the polymerization reaction of the in situ crosslinked polymer system in the core. However, the gelation time was extended in comparison to that of the result obtained in the bottle, resulting from the dilution and adsorption of ARGET ATRP components during the injection process. The research expands the application field of the ARGET ATRP principle and has a promising prospect on controlling the gelation time of the in situ crosslinked polymer system. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 519–527

Surface-Initiated ARGET ATRP of Antifouling Zwitterionic Brushes Using Versatile and Uniform Initiator Film.

In this study, we developed a uniform initiator layer that can be formed on various surfaces, and formed site-selectively, for the subsequent antifouling polymer brush formation. Initially, metal-organic films composed of tannic acid (TA) and FeIII ions (TA-FeIII) were formed on various surfaces, followed by functionalization with an aryl azide-based initiator (ABI) under photoreaction. In particular, combination with a photolithographic technique enabled the presentation of initiators only on the intended region within a single-surface platform. A resultant initiator film (TF-ABI) was formed under mild reaction conditions and meets the uniformity and transparency requirements concurrently. Subsequently, we showed that TF-ABI can be further utilized to form a polymer brush by proceeding with surface-initiated polymerization using a zwitterionic monomer, namely, sulfobetaine acrylamide (SBAA). Instead of applying a classical, yet air-sensitive atom transfer radical polymerization (ATRP) technique, we utilized an activator regenerated by electron transfer (ARGET) ATRP under air conditions without a cumbersome deoxygenation step. Overall, our initiator layer allowed the antifouling poly(SBAA) brush to be used on various surfaces, and enabled their pattern generation.

High retreatability and dimensional stability of polymer grafted waterlogged archaeological wood achieved by ARGET ATRP

To explore new methods to maintain the dimensional stability of waterlogged archaeological wood after drying and keep the natural cell lumens unaltered for future retreatments, activator regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) is employed to consolidate archaeological wood. To prepare the ATRP process, the waterlogged archaeological wood samples (Pinus massoniana with maximum moisture content of around 529%) were first modified by 2-bromoisobutyryl bromide in CH2Cl2 to acquire C-Br bonds as initiators. Then, butyl methacrylate or styrene was polymerized to the remaining cell walls with catalyst (CuBr2), reductant (ascorbic acid) and ligand (PMDETA) in ethanol. After the treatment, the samples were washed and naturally dried. The results characterized by microscopy showed that the polymerization only took place within the remaining cell walls, showing no sign of collapse or distortion after air drying, and all natural cell lumens could be retained for future retreatments. Also, anti-shrinkage efficiencies as high as 87.8% for the wood sample grafted with polystyrene and 98.5% for the wood sample grafted with polybutylmethacrylate were obtained from the treatment described in this paper, indicating modification of grafting polymer through ARGET ATRP can help maintain the dimensional stability of water archaeological wood effectively.

Star-shaped poly(2-aminoethyl methacrylate)s as non-viral gene carriers: Exploring structure-function relationship

Gene therapy shows much promise in treating many inheritable and acquired diseases, but challenges remain in the design of gene vectors with low cytotoxicity and high transfection efficiency. Elucidating the structure-function relationship of non-viral polymer-based gene carriers is crucial for improving the design and performance of safe and effective gene therapy approaches. The cationic poly(2-aminoethyl methacrylate) (PAEM) containing primary amino side groups is an attractive carrier for gene delivery. This study focuses on four PAEM-based polycations with well-defined molecular weight and chain architecture. The polymers include three cyclodextrin (CD)-cored star-shaped PAEM polycations (s-PAEM), synthesized by atom transfer radical polymerization (ATRP), and a linear PAEM polycation (l-PAEM), synthesized via activators regenerated by electron transfer (ARGET) ATRP. All four polycations could condense plasmid DNA (pDNA) into spherical polyplexes with small sizes (<200 nm). The polyplexes showed excellent stability during storage and were able to resist electrostatic destabilization. The cytotoxicity of these polycations was depended on dose and target cell type and was influenced by molecular weight and chain architecture, yet the polyplexes showed little cytotoxicity regardless of the type of polymer used. The transfection efficiency of PAEM polycations was highly dependent upon molecular weight, molecular architecture (star versus linear) and target cell type. In most cases, polyplexes formed by high-molecular-weight s-PAEM performed the best. Moreover, at a specific N/P ratio, the transfection efficiency mediated by s-PAEM was higher in MCF-7 breast cancer cells than in COS-7 fibroblast-like cells, but such cell-type dependence was not obvious for l-PAEM. These findings indicate that the star-shaped PAEM polycations could be promising gene carriers for gene therapy applications.

Antifouling Surface Coating Using Droplet-Based SI-ARGET ATRP of Carboxybetaine under Open-Air Conditions.

The formation of a dense zwitterionic brush through surface-initiated atom transfer radical polymerization (SI-ATRP) is a typical graft-from approach used to achieve antifouling surfaces with high fidelity; however, their air-tightness may cause inconvenience to users. In this context, activator regenerated by electron transfer (ARGET) ATRP is emerging as an alternative surface-coating tool because limited amount of air is allowed to form a dense polymer brush. However, the degree of air tolerance that can ensure a thick polymer brush has not been clearly defined, limiting its practical usage under ambient-air conditions. In this study, we investigated the SI-ARGET ATRP of carboxybetaine (CB) by changing the air conditions, along with the air-related parameters, such as the concentration of the reducing agent, the volume of the polymerization solution (PS), or the solvent composition, and correlated their effects with the poly(CB) thickness. Based on the optimized reaction conditions, a poly(CB) brush with reliable thickness was feasibly formed even under open-air conditions without a degassing step. In addition, a microliter droplet (∼100 μL) of PS was sufficient to proceed with the SI-ARGET ATRP for the covering of a poly(CB) brush on the surface area of interest. By applying an optimized SI-ARGET ATRP of CB, antifouling was feasibly achieved in the surface region of interest using an array to form a large surface area under fully exposed air conditions. In other words, optimized SI-ARGET ATRP enabled the formation of a thick poly(CB) brush on the surfaces of various dimensions under open-air conditions.

Thiourea Dioxide As a Green and Affordable Reducing Agent for the ARGET ATRP of Acrylates, Methacrylates, Styrene, Acrylonitrile, and Vinyl Chloride.

Thiourea dioxide, a green and inexpensive compound used at industrial scale, was employed as reducing agent for the controlled polymerization of a wide range of monomer families, namely, acrylates (methyl acrylate, 2-hydroxyethyl acrylate, butyl acrylate, methacrylates (2-(dimethylamino)ethyl methacrylate, 2-aminoethyl methacrylate hydrochloride, and methyl methacrylate), styrene, acrylonitrile, and vinyl chloride (nonactivated monomer) by ATRP. Mechanistic studies confirmed that the polymerizations are ruled by the activators regenerated by electron transfer (ARGET) mechanism. It is worth noting that vinyl chloride has never been polymerized by ARGET ATRP. The system proved to be very versatile and robust, working in organic solvents, organic/water mixtures, and aqueous medium at near room temperature with low metal catalyst concentration. Chain extension experiments confirmed the high chain-end functionality of the polymers, allowing the preparation of several well-defined block copolymers.

Tin(II) 2-ethylhexanoate and ascorbic acid as reducing agents in solution ARGET ATRP: A kinetic study approach by mathematical modeling and simulation

The mechanism of activators regenerated by electron transfer (ARGET) associated with atom transfer radical polymerization (ATRP) has attracted attention because of the transition metal catalyst reduction in the conventional ATRP process. In this paper, a comprehensive mathematical model for solution ARGET ATRP technique is presented, following a distinct approach, in which reaction kinetics for the reducing agent is detailed. Tin(II) 2-ethylhexanoate and ascorbic acid were studied as reducing agents with copper(II) halide complex as a catalyst, and the ARGET mechanism for both of them was proposed and validated with experimental data available in the literature. The kinetic rate constants for such reducing agents (kr) were obtained by an optimization algorithm, and the molecular weights and dispersity were predicted using the method of moments. The higher the initial concentrations of copper (II) halide complex and reducing agent, the higher the number-average molecular weight and the lower the dispersity. Simulation results also confirm that the initial concentration of copper(II) halide complex is a critical parameter with higher sensitivity than the reducing agent in solution ARGET ATRP process.

Preparation of hydrophobically modified cotton filter fabric with high hydrophobic stability using ARGET-ATRP mechanism.

This paper reports on the hydrophobic modification of cotton fabric grafted with 1-octadecene via an activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) mechanism. Particularly, the activation treatment of raw cotton fabric, its influence on the graft-copolymerization by the ARGET-ATRP method, along with the super-hydrophobicity and hydrophobic stability of the modified cotton fabric are discussed. Furthermore, the microstructure and elemental variation were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and the energy dispersion spectrum (EDS) technique. The results show that chemical activation of the raw cotton fabric can significantly improve the follow-up hydrophobic modification process. Specifically, the contact angle of the hydrophobically modified cotton fabric increased to 145° after activation, and thus, this fabric presents more stable hydrophobicity (corresponding to a 5.5% contact angle attenuation) than a non-activated fabric. The hydrophobic modification reaction was carried out using a chemically optimum stoichiometric ratio of m(CuBr2) : m(C9H23N3) : m(C2H5OH) : m(C18H36) : m(C6H8O6) = 0.015 : 0.052 : 17.9 : 2.4 : 0.05, at a temperature of 30–55 °C over 8 h. Furthermore, the SEM and AFM images revealed that more copolymer micro/nano-level particles were present on the surface of the fibers of the hydrophobically modified cotton fabric, indicating that the hydrophobic property and stability of the cotton fabric increase with the grafting density on the cotton fabric.

Biocatalytic ATRP in solution and on surfaces.

The promiscuity of enzymes allows for their implementation as catalysts for non-native chemical transformations. Utilizing the redox activity of metalloenzymes under activator regenerated by electron transfer (ARGET) ATRP conditions, well-controlled and defined polymers can be generated. In this chapter, we review bioATRP in solution and on surfaces and provide experimental protocols for hemoglobin-catalyzed ATRP and for surface-initiated biocatalytic ATRP. This chapter highlights the polymerization of acrylate and acrylamide monomers and provides detailed experimental protocols for the characterization of the polymers and of the polymer brushes.