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A multi-reactive polysaccharide-based inisurf (acting both as initiator and stabilizer) has been designed for the first time from dextran with the aim of preparing dextran-covered nanoparticles with covalent linkage between core and coverage. This inisurf was used for polymerizing butyl acrylate in miniemulsion by AGET-ATRP. Both hydrophobic phenoxy groups and initiator groups (bromoisobutyryl ester) were introduced within hydrophilic dextran chain, conferring it amphiphilic and macroinitiator characters. Amphiphilic properties of dextran inisurfs have been evidenced as well as their ability to stabilize the direct miniemulsion of n-butyl acrylate. After optimization of polymerization conditions with model studies, assays were successfully realized with dextran-based inisurfs. Because of their amphiphilic character, inisurfs migrated at oil/water interface and initiated polymerization from bromoisobutyryl ester groups. Therefore graft copolymers were produced at oil/water interface, due to the multifunctional character of these inisurfs and constituted the particle inner core with covalent links to the dextran coverage., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Atom Transfer Radical Polymerization (ATRP) and Ring-Opening Polymerization (ROP) were combined to synthesize diblock environmental friendly poly(ϵ-caprolactone)-block-poly(methyl ether diethylene glycol methacrylate) (PCL- b -PMEO 2 MA) through a sequential two-step strategy. These PCL- b -PMEO 2 MA copolymers were produced using 2-hydroxyethyl-2-bromoisobutyrate as bifunctional initiator. In the first step, ϵ-caprolactone was initiated by the hydroxyl group of this particular initiator. Tin octoate, zinc triflate and bismuth triflate were tested as non-toxic catalysts to obtain α-bromide–ω-hydroxy bifunctional PCL macroinitiator. Secondly, the controlled ATRP of MEO 2 MA was tuned from the same bifunctional initiator. Finally, PCL- b -PMEO 2 MA were produced by carrying out ATRP of MEO 2 MA from PCL macroinitiator. Preliminary data on self-assembly of such thermo-sensitive PCL- b -PMEO 2 MA in aqueous phase are given. [ABSTRACT FROM AUTHOR]

ABSTRACT Polymers containing o-nitrobenzyl esters are promising for preparation of light sensitive materials. o-Nitrobenzyl methacrylate has already been polymerized by controlled ATRP or RAFT. Unfortunately, the radical polymerization of o-nitrobenzyl acrylate (NBA) was not controlled until now due to inhibition and retardation effects coming from the nitro-aromatic groups. Recent developments in the Single Electron Transfer-Living Radical Polymerization (SET-LRP) provide us an access to control this NBA polymerization and living character of this NBA SET-LRP is demonstrated. Effects of CuBr2 and ligand concentrations, as well as Cu(0) wire length on SET-LRP kinetics are shown presently. A first-order kinetics with respect to the NBA concentration is observed after one induction period. SET-LRP proceeds with a linear evolution of molecular weight and a narrow distribution. High initiation efficiency close to 1 and high chain-end functionality (∼93%) are reached. Chain extension of poly( o-nitrobenzyl acrylate) is realized with methyl acrylate (MA) to obtain well defined poly( o-nitrobenzyl acrylate)-b-poly(methyl acrylate) (PNBA- b-PMA). Finally, light-sensitive properties of PNBA are checked upon UV irradiation. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2192-2201 [ABSTRACT FROM AUTHOR]

ABSTRACT A cholesterol-based liquid crystal monomer, diethylene glycol cholesteryl ether acrylate (DEGCholA), has been successfully polymerized by atom transfer radical polymerization (ATRP) for the first time. Appropriate experimental conditions to control the polymerization of DEGCholA have been investigated using a model initiator (ethyl 2-bromoisobutyrate) in tetrahydrofuran (THF) or toluene at 60 °C. Well-controlled ATRP of DEGCholA was obtained using N, N, N′, N′, N″-pentamethyldiethylenetriamine as ligand in THF at 60 °C. These conditions were then applied to initiate the ATRP of DEGCholA from multifunctional macroinitiators based on dextran. Using a protection/deprotection synthetic scheme, novel graft glycopolymers (Dex- g-PDEGCholA) have been synthesized. The mesomorphic properties of DEGCholA, PDEGCholA, and Dex- g-PDEGCholA have been studied by thermal polarizing optical microscopy, differential scanning calorimetry, and X-ray scattering. PDEGCholA and Dex- g-PDEGCholA show an interdigitated smectic A phase (SmAd) between Tg (∼30 °C) and around 170 °C. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3829-3839 [ABSTRACT FROM AUTHOR]

To easily perform atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in homogeneous medium from unprotected polysaccharidic macroinitiators, the ATRP of MMA carried out in dimethylsulfoxide has been firstly reinvestigated using Cu(I)Br as metal catalyst and ethyl 2-bromoisobutyrate as initiator. Two ligands, 2,2′-bipyridyne (Bpy) and N-( n-propyl)-2-pyridylmethanimine ( n-Pr-PMI), have been compared, as well as the addition of Cu(II)Br (10 molar % relative to Cu(I)Br) or the adjustment of experimental temperature (from 30 to 60 °C). Appropriate conditions were founded for both ligands to achieve a controlled ATRP. Bpy giving far much faster polymerization compared to n-Pr-PMI, n-Pr-MI was preferred as ligand for accurate tuning of the conversion. Experimental procedure was then applied to unprotected macroinitiators based on dextran to obtain amphiphilic poly(methyl methacrylate) grafted dextran. While homopolymerization was controlled in these conditions, parameters have to be adjusted for the hydrophilic unprotected macroinitiators to prevent gel formation and control ATRP. [ABSTRACT FROM AUTHOR]

Among all photosensitive monomers reported in the literature, o -nitrobenzyl acrylate (NBA) was selected in this present study. Two strategies were compared to produce azido-terminated poly( o -nitrobenzyl acrylate) (PNBA) using controlled Single Electron Transfer-Living Radical Polymerization (SET-LRP). In a parallel way, dextran (Dex) was modified by the introduction of several alkynyl-terminated hydrophobic chains. Finally, an Huisgen-type Copper (I)-catalyzed Azide–Alkyne Cycloaddition (CuAAC) click-chemistry was carried out to produce amphiphilic Dex- g -PNBA glycopolymers with different number and length of PNBA grafts. 2D DOSY 1 H NMR was used to prove the formation of such glycopolymers. Preliminary study on Dex- g -PNBA self-assembly was done by measuring the critical water content (CWC) above which Dex- g -PNBA started to auto-organize themselves to produce nano-objects. Finally, under UV irradiation, PNBA grafts turn into poly(acrylic acid) ones giving light-sensitive properties to such amphiphilic Dex- g -PNBA. Such properties were evaluated and compared with those of PNBA. [ABSTRACT FROM AUTHOR]

Aiming to prepare oily core pH-sensitive nanocapsules (NCs) for anticancer drugs delivery, the use of a dextran-based transurf (DexN 3- τ CTA γ) as both stabilizer and macromolecular chain transfer agent in methyl methacrylate/2-(diethylamino)ethyl methacrylate (MMA/DEAEMA) miniemulsion copolymerization was investigated. NCs of about 195 nm with an oily-core of Miglyol 810 (M810) and a dextran coverage covalently linked to the poly(MMA- co -DEAEMA) intern shell have been obtained. Compared to the non-sensitive PMMA-based NCs (prepared in a similar way), these novel objects were shown to swell in acidic media and to trigger Coumarin 1 release in physiological relevant pH range. As a starting point of NCs biological effects, cytotoxicity and NCs-proteins interactions studies were performed with both PMMA and poly(MMA- co -DEAEMA)-based NCs. Finally, free azide functions from dextran-based coverage were successfully exploited to attach fluorescent model dyes to NCs surface. The overall results suggest that this novel NCs platform could be potentially used as drug nanocarriers for intravenous injection. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Multi-reactive dextran-based inisurfs are used for a minemulsion polymerization. • Inisurfs act as macroinitiators and stabilizers of miniemulsion AGET-ATRP of MMA. • Inisurfs confine the ATRP at oil/water interface which improves its control. • Potentially biocompatible dextran-covered oily-core nanocapsules are produced. • Nanocapsules morphology is achieved only for the largest oil content. Abstract A convenient one-step method is developed to prepare potentially biocompatible nanocapsules (NCs) with a biocompatible oily core (Miglyol 810, M810), a poly(methyl methacrylate) (PMMA) shell and a dextran coverage. For that, a multi-reactive dextran derivative containing both hydrophobic phenoxy and ATRP initiator groups is used as inisurf (macroinitiator and stabilizer) in an Activator Generated by Electron Transfer-Atom Transfer Radical Polymerization (AGET-ATRP) miniemulsion process. Such dextran inisurfs are shown to efficiently stabilize the direct miniemulsion of MMA with M810 as co-stabilizer, and to confine the polymerization at the oil/water interface via their multiple initiator sites. Grafted copolymers are produced from the inisurf, whose grafts constitute the inner polymeric shell of NCs and are linked to the dextran coverage. The confinement of such polymerization at interface is found to reduce initiator group efficiency, but also to improve both polymerization kinetics and control in comparison with one molecular model initiator. Increasing M810 content promotes the oily core/PMMA shell phase separation during polymerization and the formation of slightly larger NCs, without affecting polymerization kinetics. [ABSTRACT FROM AUTHOR]