Cellulose-based graft copolymers prepared by simplified electrochemically mediated ATRP

Polymers for Advanced Techs

2017

The vitamin B8‐based macroinitiator with six 2‐bromoisobutyric initiating sites was prepared for the first time by the transesterification reaction of meso‐inositol with 2‐bromoisobutyryl bromide. A series of six‐armed (co)polymers, containing hydrophilic poly(di(ethylene glycol) methyl ether methacrylate) and amphiphilic poly(di(ethylene glycol) methyl ether methacrylate)‐block‐poly(methyl methacrylate) as the arms and meso‐inositol as the core, were obtained by low ppm atom transfer radical polymerization (ATRP) methods, utilizing 30 ppm of catalyst complex. Under Fe0‐mediated supplemental activators and reducing agents ATRP, Cu0‐mediated supplemental activators and reducing agents ATRP, Ag0‐mediated activators regenerated by electron transfer ATRP, and simplified electrochemically mediated ATRP conditions, polymerization proceeded on to high conversion while maintaining low dispersity (Đ = 1.05–1.16) giving well‐defined six‐armed star (co)polymers. 1H NMR spectral results confirm the formation of new star‐shaped block (co)polymers. The absence of intermolecular coupling reactions during synthesis was confirmed by gel permeation chromatography analyses of the side chains of received star (co)polymers. These vitamin B8‐based star (co)polymers may find biomedical applications as thermo‐sensitive drug delivery systems, biosensors, and tissue engineering solutions. Copyright © 2017 John Wiley & Sons, Ltd.

Section: Methodsmentioning

confidence: 99%

Synthesis of inositol‐based star polymers through low ppm ATRP methods

Polymers for Advanced Techs

2017

“…The counter electrode (CE) was Al wire ( l = 10 cm, d = 1 mm). Values for potentials adapted for electrolysis were ascertained from CV measurements at a 0.1 V/s scan rate using saturated calomel electrode (SCE; Gamry) reference electrode (RE) …”

Section: Methodsmentioning

confidence: 99%

“…These polymerization methods include ring‐opening polymerization, click reaction, cationic polymerization, anionic polymerization, radical (co)polymerization, reversible addition‐fragmentation chain transfer polymerization (RAFT), nitroxide‐mediated polymerization (NMP), and atom transfer radical polymerization (ATRP), as well as combinations of different methods . Considering these techniques, macromolecular brushes can be synthesized via three main approaches: “grafting through”, “grafting onto”, or “grafting from” . Undoubtedly, “grafting from” is one of the most useful technique which involves attachment of initiator molecules to the backbone and growing of polymer chains via polymerization; therefore, macromolecular brushes with high grafting density can be prepared by using these tactics …”

Section: Introductionmentioning

confidence: 99%

Synthesis of naringin‐based polymer brushes via seATRP

Polymers for Advanced Techs

2017

The flavonoid-based macromolecule initiator was prepared for the first time by the transesterification reaction of naringin with 2-bromoisobutyryl bromide. In accordance with the "grafting from" methodology, a naringin-based copolymer brush with a polar naringenine-7-rhamnosidoglucoside core and an amphiphilic poly(methyl methacrylate)-block-poly(Nisopropylacrylamide) (PMMA-b-PNIPAM) side chains was synthesized for the first time via a simplified electrochemically mediated ATRP (seATRP), utilizing only 40 ppm of catalytic complex. The rate of the polymerizations was controlled by applying optimal potential or current values during preparative electrolysis to prevent the possibility of intermolecular coupling of the growing polymer brushes. Naturally derived polymer brushes showed narrow molecular weight distributions (Đ = 1.06−1.08).1 H NMR spectral results confirm the formation of citrus-based polymer brushes. These new naringin-based polymer materials may find biomedical applications as thermo-sensitive drug delivery systems, membranes, and biologically active thin films in tissue engineering.

“…Recently, a simplified electrochemically mediated ATRP ( se ATRP) was developed, a procedure which does not require the separation of cathodic and anodic compartments in the e ATRP reactor . The use of an undivided cell allowed for a simpler reaction setup and lower cost of the process.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Well‐Defined Polymer Brushes from Silicon Wafers via Surface‐Initiated se ATRP

Krys

Wang

et al. 2017

Macromol. Chem. Phys.

Synthesis of densely grafted (co)polymer brushes, including poly(n‐butyl acrylate), poly(2‐dimethylaminoethyl methacrylate), poly(n‐butyl acrylate)‐block‐poly(tert‐butyl acrylate), and poly(2‐dimethylaminoethyl methacrylate)‐block‐poly(tert‐butyl acrylate) from silicon wafer surfaces via a simplified surface‐initiated electrochemically mediated atom transfer radical polymerization under constant potential/current conditions is reported. A sacrificial (nontethered) initiator is added to form free polymer chains in solution used to estimate the molecular weights and molecular weight distributions of chains attached to the surface. The polymers show narrow molecular weight distributions (Đ = 1.10–1.33). Water contact angle measurements and ellipsometry are used to characterize wettability and thicknesses of the modified surfaces. Grafting densities up to 0.93 nm−2 are obtained. The rate of the polymerization is controlled by applying more negative potential values, which results in an increase in the surface thickness (up to 116 nm). Finally, the poly(tert‐butyl acrylate) blocks are hydrolyzed to the poly(acrylic acid) blocks. These new, densely grafted brushes are promising candidates for applications in microelectronics, nanotechnology, tailoring of surface properties, nanopatterning, or antifouling coatings.