ABSTRACT Plasma grafting of itaconic acid ontopolypropylene (PP) surface was carried out to investigate the nature of the graft‐initiating sites in the system. It has been observed that the grafting is initiated by three mechanisms: peroxy, alkoxy, and alkyl linkages. The relative contribution of the three routes shows that the alkoxy linkage plays a significant role in graft initiation. The investigations were carried out using different techniques, such as Energy‐ Dispersive X‐ray Spectroscopy (EDX) and X‐ray Photoelectron Spectroscopy (XPS), and the results support the findings., Although a small fraction of grafting was initiated by alkyl and peroxide linkages, the observations highlighted the prominence of the alkoxy route.. The study presents an interesting aspect of graft functionalization on polymeric materials to design the material surfaces for specific applications. Almost 68% of the grafts follow the hydroperoxide decomposition route, giving alkoxy linkage.

A novel approach for the surface-initiated atom transfer radical polymerization (SI-ATRP) of methoxyethyl methacrylate (MEMA) and 3-azidopropyl methacrylate (AZMA) on macroporous silicon substrates and their postfunctionalization by click chemistry with asymmetric catalysts is presented. Crystalline silicon was first used to monitor the multistep functionalization by quantitative IR-ATR spectroscopy. The attachment of an alkynyl FTIR marker on crystalline silicon demonstrated the effectiveness of the methodology, which was then applied onto macroporous silicon to anchor an enantiopure chromium-salen complex as a first step toward the development of new supported asymmetric organometallic catalysts on silicon-based materials. SEM and EDS measurements clearly show good homogeneity of the polymer growth through the porous layers with a uniform distribution of the catalysts (even deep inside the pores). The successful functionalization of macroporous silicon has confirmed the transferability of the technique to porous materials, highlighting its potential for application to even larger surface area substrates in future catalytic studies.

Essential oils (EOs) are potential bio-sourced candidates to be grafted on polymer surfaces to fight against bacterial infections by either restricting the growth of bacteria (bacteriostatic effect) or killing bacterial cells (bactericidal effect). This paper deals with the modification of terpenoid molecules intended to be later grafted on polymer-plasma-activated surfaces. Citronellol (CT) and geraniol (GR) were chosen for their antimicrobial activity and were successfully modified to obtain better reactive function towards polymer grafting. They were transformed into CT-oxide (CT-ox) and GR-oxide (GR-ox) through an accessible and green chemo enzymatic oxidation method. Microbiological tests were undertaken to estimate the antibacterial effects of CT and GR before and after modification. Three bacterial species have been used: Escherichia coli (E. coli, diderm Gram-negative), Staphylococcus aureus (S. aureus, monoderm Gram-positive), and Corynebacterium glutamicum (C. glutamicum, diderm Gram-positive). The results showed that antibacterial effects remained after epoxidation: tested molecules exhibited different impacts on the three bacterial strains. The tested molecules exhibited antibacterial activities by targeting bacterial cell envelopes, disrupting membrane integrity, and altering hydrophobicity. These actions led to the inhibition of bacterial growth or death of the bacteria, as evidenced by Zeta Potential (ZP) measurements, Scanning Electron Microscopy (SEM) imaging, and surface energy assessments. Our study conclusively confirmed the antibacterial effectiveness of CT-ox and GR-ox.

Designing heterogeneous catalysts that ensure efficient recycling and reuse of the catalyst in a wide range of transformations remains a real challenge. In this contribution, targeted copolymers are used as supports for the development of heterogeneous asymmetric catalysts. They are made up of two methacrylate monomers, 3‐azidopropylmethacrylate (AZMA), and 2‐methoxyethyl methacrylate (MEMA) used as a diluting agent. Polymerization was carried out using Cu(0)‐mediated reversible deactivation radical polymerization (RDRP), yielding two copolymers with controlled MEMA/AZMA compositions of 70/30 and 30/70 with moderate dispersity control (Ð = 1.32‐1.54), targeting polymers with a similar molar mass, which is important to achieve precise control of the catalyst loading to implement asymmetric catalysis. The copolymers were post‐functionalized using click chemistry with two salen complexes containing a chromium or a cobalt center, these species being recognized for their broad range of applications. The supported catalysts were evaluated in two reactions and recovered by precipitation and filtration techniques. The first reaction involved the asymmetric ring opening (ARO) of cyclohexene oxide with trimethylsilylazide, catalyzed by the chromium sites, the second reaction was the dynamic kinetic resolution (DKR) of epibromohydrin with water, promoted by the cobalt sites. The recycling was effective, demonstrating the robustness and viability of the procedure.

The self-assembly of a new series of amphiphilic polystyrene-b-poly(4-vinyldipicolinic acid) PS-b-PVDPA diblock copolymers in aqueous solution is reported in order to obtain core-shell nanoparticles composed of a PS core and a PVDPA shell. Diblock copolymers were synthesized by Supplemental Activation Reducing Agent-Atom Transfer Radical Polymerization (SARA-ATRP) with a degree of polymerization (DP) of the PS block in the range 112-260 and a DP of PVDPA block of 10, 30 or 50. Anionic latex nanoparticles of PS-b-PVDPA were prepared by solvent displacement methods. All the nanoparticle suspensions had a narrow size distribution (0.014 <= PDI <= 0.144) with zeta potential in the range -27 mV to -38 mV indicating electrostatic repulsions due to carboxylate anions and therefore high colloidal stability. DLS was used to determine nanoparticle size, with SEM and TEM used to determine and confirm both size and spherical shape. All three methods found the size for these nanoparticles to be in the range 75-120 nm. Using fluorimetry and DLS methods, Critical Aggregation Concentration (CAC) for each type of nanoparticle was determined to be within the range of 33-69 mg/L. Micelles were pH-responsive with stability in aqueous conditions for pH > 3.5. Micelles were stable at pH 5.5 for up to 40 days and at temperature up to 60 degrees C.

Poly(ethylene terephthalate) (PET) films were surface-modified according to microwave plasma activation allowing for dithiol functions grafting (1,6-hexanedithiol) in order to fabricate self-assembled photogenerated silver nanoparticles monolayers. The present study was carried out in constant discharge power conditions and the impact of the plasma treatment on PET wettability properties were reported. PET material modifications were characterized at various stages of the process: plasma activation, dithiol functionalization, and nanosilver grafting according to several experimental techniques: water contact angle measurements and X-ray photoelectron spectroscopy (XPS). The surface topography was studied by atomic force microscopy (AFM). Finally, antibacterial properties of PET material including silver nanoparticles were evaluated to determine the probability to reduce the surface bacterial adhesion of Staphylococcus aureus strain selected as pathogenic bacteria model. Surface grafted with silver nanoparticles was found to be particularly reactive and led to an inhibition of S. aureus adhesion around 96.2% in comparison with the unmodified PET material.

This paper reports a strategy for the elaboration of highly performing antibacterial PET surfaces according to an eco-friendly photoinduced process. Modified PET surfaces were elaborated through the grafting of a three dimensional (3D) biopolymer derived from vanillin with antibacterial activity. Biobased polymer grafting was performed through a grafting-from photopolymerization approach initiated from a photoinitiator compound preliminary functionalized onto PET surface. Antibacterial activity of the elaborated materials was tested against Gram-positive (Rhodococcus wratislaviensis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) strains. Antibacterial activity of the biopolymer covalently linked onto PET surface was observed for all tested bacterial strains. Antibacterial effect of vanillin derivative coated onto PET material was combined with a multi-scale roughness induced through the grafting process giving antifouling behaviour to the material. Besides, to improve antibacterial activity of the modified material, biobased network was used as binding sites for photoembedding of antimicrobial silver nanoparticles. The hybrid material showed excellent antibacterial properties against Gram-positive and Gram-negative tested cells. The enhancement of material antibacterial activity against this wide range of pathogens resulted of a combination of different effects: the antibacterial activity of coated vanillin derivative and nanosilver combined with a surface nanostructuration imparting antifouling properties. Grafting of biobased polymer network loaded with nanosilver onto PET material was characterized at various stages of the modification by UV-vis spectroscopy, water contact angle measurements, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The surface topography was studied by atomic force microscopy (AFM).

Copolymers are valuable supports for obtaining heterogeneous catalysts that allow their recycling and therefore substantial savings, particularly in the field of asymmetric catalysis. This contribution reports the use of two comonomers: Azido-3-propylmethacrylate (AZMA) bearing a reactive azide function was associated with 2-methoxyethyl methacrylate (MEMA), used as a spacer, for the ATRP synthesis of copolymers, and then post-functionalized with a propargyl chromium salen complex. The controlled homopolymerization of MEMA by ATRP was firstly described and proved to be more controlled in molar mass than that of AZMA for conversions up to 63%. The ATRP copolymerization of both monomers made it possible to control the molar masses and the composition, with nevertheless a slight increase in the dispersity (from 1.05 to 1.3) when the incorporation ratio of AZMA increased from 10 to 50 mol%. These copolymers were post-functionalized with chromium salen units by click chemistry and their activity was evaluated in the asymmetric ring opening of cyclohexene oxide with trimethylsilyl azide. At an equal catalytic ratio, a significant increase in enantioselectivity was obtained by using the copolymer containing the largest part of salen units, probably allowing, in this case, the more favorable bimetallic activation of both the engaged nucleophile and electrophile. Moreover, the catalytic polymer was recovered by simple filtration and re-engaged in subsequent catalytic runs, up to seven times, without loss of activity or selectivity.

With respect to the increasing need for fully characterizing surface-tethered polymer brushes, the capacity of quantitative IR-Fourier transform infrared (FTIR) spectroscopy using a multiple-internal-reflection Si prism as the attenuated total reflection (ATR) element is investigated to directly characterize the surface chemical modifications occurring during a surface-initiated controlled polymerization. A simple two-step strategy is used involving first the covalent grafting of atom transfer radical polymerization (ATRP) initiators on a hydrogenated silicon surface and the subsequent polymerization of styrene. Three prefunction-alized surfaces designated Si-Br1, Si-Br2, and Si-Br3 are obtained by different procedures. The initiator grafting densities obtained by quantitative IR are 1.7 ?? 0.3 nm???2 for Si-Br1, 1.5 ?? 0.3 nm???2 for Si-Br2, and 0.9 ?? 0.2 nm???2 for Si-Br3. After the polymerization of styrene under the same experimental conditions (grafting from without sacrificial initiators) and a careful Soxhlet rinse to remove physisorbed polymers formed in solution, almost no polymerization is observed using Si-Br1 with a value of the density in polymerized styrene units of 12 ?? 2 nm???2, which is probably due to the chelating effect of the amino linkers used for grafting the initiators in Si-Br1. In contrast, the densities in styrene units are 54 ?? 11 nm???2 using Si-Br2 and 141 ?? 28 nm???2 using Si-Br3. The degree of polymerization (DP) has been evaluated by measuring the polymer thickness (by ellipsometry and atomic force microscopy, AFM) and using a scaling law relating the latter to DP for dry polymer brushes. High DP values of 200 and 1000 are found in the case of Si-Br2 and Si-Br3, respectively. The fraction of active polymerization initiators is found to be 15???18%, independent of the initiator surface density. In contrast, polymerization kinetics appear affected by steric hindrance and conformational disorder among grafted initiators. This approach for determining surface densities of grafted initiators and grafted polymer chains and DPs is fully generalizable to any other polymer system.

The present work addresses for the first time the controlled synthesis of poly(pentafluorophenyl methacrylate) (PPFPMA) using Cu(0)-mediated reversible deactivation radical polymerization (Cu(0)-mediated RDRP). The influences of several components like ligand, initiator, and solvent are examined and discussed in details to deduce the best-found condition to synthesize PPFPMA with low dispersity (1.05-1.33) in a wide range of molecular weight (6000 g mol-1 to 129 000 g mol- 1). The polymerization under the best-found condition shows controlled polymerization features with no induction period, linear first-order kinetics, and linear correlation in monomer conversion. In addition, the chain-end fidelity of polymer obtained by found-optimized conditions is also investigated by various techniques including 1H NMR, MALDI-ToF, and chain extension experiments.

In the previous work, the poly(4-vinyl dimethyl dipicolinate) (PVDPM) polymer grafted on poly(vinyl chloride) (PVC) and poly(ethylene terephthalate) (PET) film or industrial fibers proved its efficiency for trapping uranium and many lanthanides in a liquid environment. In this work, we propose to graft our active polymer on fibers obtained by electrospinning to increase the specific surface of our final material. To address this challenge, surface grafting of electrospun chlorinated poly(vinyl chloride) (PVC-co-CPVC) fibers using supplemental activation reducing agent atom transfer radical polymerization (SARA-ATRP) of poly(4-vinyldipicolinic acid) (PVDPA, acid form of PVDPM) were successfully prepared. The (PVC-co-CPVC)-g-PVDPA fibers show a fast increase in the degree of grafting that goes from 54% after 4 h to 369% after 72 h. Further insights demonstrate successful complexation between the new functional electrospun (PVC-co-CPVC)-g-PVDPA fibers and europium, which proves that it could be a potential candidate for scavenging lanthanides or any agent able to interact with ligands (PVDPA), which opens up innovative application perspectives in the field of polymeric materials.

Copolymers with two distinguished reactive repeating units are of great interest, as such copolymers might open the possibility of obtaining selective and/or consequent copolymers with different chemical structures and properties. In the present work, copolymers based on two active esters (pentafluorophenyl methacrylate and p-nitrophenyl methacrylate) with varied compositions were synthesized by Cu(0)-mediated reversible deactivation radical polymerization. This polymerization technique allows the preparation of copolymers with high to quantitative conversion of both comonomers, with moderate control over dispersity (Đ = 1.3–1.7). Additionally, by in-depth study on the composition of each copolymer by various techniques including elemental analysis, NMR, FT-IR, and XPS, it was possible to confirm the coherence between expected and obtained composition. Thermal analyses by DSC and TGA were implemented to investigate the relation between copolymers’ composition and their thermal properties. Finally, an evaluation of the difference in reactivity of the two monomer moieties was confirmed by post-modification of copolymers with a primary amine and a primary alcohol as the model.

Oceans uranium reserve of 4.5 billion tons can be the answer for the next-generation sustainable nuclear energy. However, extracting the extremely diluted uranium (3.3 ppb) is a difficult task and adsorption materials with high selectivity and uptake capacity are still to be found. Here, we propose the use of poly(4-vinyldipicolinic acid) (PVDPA) as a new highly promising polymer for uranium harvesting from seawater. PVDPA showed a uranium uptake capacity of 597 mg/g in simulated seawater conditions, even at high ionic strength and in the presence of the challenging vanadium species, that tend to limit the performance of other existing materials. PVDPA is also built from a solid PVC-based substrate using an easy and oxygen tolerant strategy. The used PVDPA-modified fibers showed a uranium uptake capacity of 392 mg/g and reached the adsorption equilibrium in less than 3 h, the fastest and highest reported, to the best of our knowledge. The cheap, easy and fast preparation, combined with fast and high uranium recovery, make PVDPA highly promising, not only for uranium harvesting from seawater, but also for treating waters contaminated with uranium. (C) 2019 Elsevier Ltd. All rights reserved.

Core-shell nanoparticles (NPs) are attracting increasing interest in nanomedicine as they exhibit unique properties arising from the combined assets of core and shell materials. Porous nanoscale metal-organic frameworks (nanoMOFs) are able to incorporate with high payloads a large variety of drugs. Like other types of NPs, nanoMOFs need to be functionalized with engineered coatings to ensure colloidal stability, control in vivo fate and drug release. To do so, a novel biodegradable cyclodextrin (CD)-based shell was designed in this study. Water soluble γ-CD-citrate oligomers grafted or not with fluorophores were successfully synthesized using citric acid as crosslinker and efficiently anchored onto the surface of porous nanoMOFs. As compared to monomeric CDs, the oligomeric CD coatings could offer higher interaction possibilities with the cores and better possibilities to graft functional moieties such as fluorescent molecules. The amounts of γ-CD-citrate oligomers onto the nanoMOFs were as high as 53 ± 8 wt%. The yield reached up to 86% in the optimized system. These core-shell nanocomposites were stable upon storage, in contrast to the naked nanoMOFs. In addition, the presence of the coating prevented the doxorubicin (DOX)-loaded nanoMOFs from aggregation. Moreover, due to the presence of fluorophores conjugated to the shell, fluorescence-lifetime microscopy enabled deciphering the coating mechanism. DOX loadings reached 48 ± 10 wt% after 24 h incubation with the drug solution. After coating for additional 24 h, DOX loadings reached 65 ± 8 wt%.

Grafting polymers bearing active esters, especially pentafluorophenyl methacrylate (PFPMA), onto or from surface is a promising approach towards the preparation of highly functional materials due to the ease in post-polymerisation modification of their corresponding polymers. Herein, a handy and efficient chemical modification process is proposed to modify extreme surface of poly(ethylene terephthalate) (PET) films towards the final purpose of grafting PFPMA polymer from PET surface via surface-initiated Cu(0)-mediated radical polymerisation. The characteristics of modified surface were evaluated after each step using various techniques including water contact angle, attenuated total reflectance Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron spectroscopy. Due to its robust conditions, the proposed approach allows grafting at ease PFPMA polymer from PET supporting surface, which not only enhances the reactivity of this inert material but also improves significantly the hydrophobicity of the surface.

New antibacterial PET surfaces were developed from vanillin-derived biobased monomer. An easy one-step and high yielding synthesis of N-(4-hydroxy-3-methoxybenzyl)-acrylamide monomer was successfully achieved. PET was modified by a two-step procedure: Type II photoinitiator was first grafted through a PET aminolysis with N,N-diethylethylenediamine, then the photopolymerization of the biobased acrylamide monomer was performed according to a "grafting from" technique. PET surface modifications were characterized by XPS and LW-visible spectroscopies, as well as water contact angle measurements. Finally, antiadhesion biotests were conducted to evaluate the potential antibacterial performances of the modified surfaces against gram-positive (Rhodococcus wratislaviensis and Staphylococcus aureus) and gram-negative (Escherichia colt and Pseudomonas aeruginosa) strains.

Novel photochromic polymers highlight through their solid-state optical properties the key role of grafting onto the coloration and fading kinetics.

Poly(ethylene terephthalate) (PET) substrates were modified by means of surface-initiated supplemental activator and reducing agent atom transfer radical polymerization (SI-SARA-ATRP) of 4-vinylpyridine (4VP). Substrates were pretreated in order to graft chloromethylbenzene (CMB) units capable of initiating the radical polymerization reaction of 4VP units. Surface characterization techniques, including Water Contact Angle (WCA), Attenuated Total Reflection (ATR), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) showed a successful grafting of a stable, smooth and homogenous layer of p4VP. This process offers the advantages of a rapid, simplified and low cost strategy to chemically modify polymer substrates with covalently bonded layer of the pH responsive p4VP for different applications. Moreover, by using TOF-SIMS profiling, we were able to track a density gradient along the z-axis generated by the interpenetrating phases of the different layers of the final modified surface. Fact that we correlated to the various positions of initiation sites within the polyethylenimine (PEI) used for PET aminolysis prior to CMB grafting. Our strategy will be used in future work to graft other polymers for different applications where industrial scale viable options are needed.

PMB-NPTFA 1a is a new month bench stable and powerful reagent for the formation of PMB ethers. Several alcohols were protected in high yields and short reaction times, using low reagent loading and small catalytic amounts of Bi(OTf)3. The mild conditions of the reaction confer a good orthogonality to acid- and base-sensitive protecting groups.