Photoinduced Sequence-Controlled Copper-Mediated Polymerization: Synthesis of Decablock Copolymers

Photoinitiated copper-mediated radical polymerization offers an one-pot and time efficient method of preparing a decablock copolymer PMA-PtBA-PMA-PDEGA-PMA-PtBA-PMA-PDEGA-PnBA-PDEGA with an overall molecular weight of 8500 g·mol^-1. The molecular weight is in close agreement with theoretical expectations and significantly narrow dispersities (Đ = 1.1-1.17) are achieved for the various block extensions. The tert-butyl group of the decadeblock was deprotected to form PMA-PAA-PMA-PDEGA-PMA-PAA-PMA-PDEGA-PnBA-PDEGA. The deprotection is confirmed by the disappearance of tert-butyl signal and the loss of molecular weight investigated by ¹H NMR and SEC, respectively. The carboxylic group of PAA is protonated in acidic solution (water insoluble) and deprotonated in basic solution (water-soluble). This enables a conformational change of PMA-PAA-PMA-PDEGA-PMA-PAA-PMA-PDEGA-PnBA-PDEGA in water/ethanol mixture (80/20%v/v), as is demonstrated by a turbid solution at pH 2 and transparent solutions at pH 10.

In the (Very) Long Run We Are All Dead: Activation and Termination in SET-LRP/SARA-ATRP

The rate constants of activation and termination were determined for SET-LRP/SARA-ATRP polymerizations of methyl acrylate. Measurement of the rate of generation of CuBr₂ throughout the reaction (using data from Levere et al., Macromolecules 2012, 45, 8267-8274) allowed evaluation of the chain length dependence of the two rate constants, which were found to be 1.25(9) × 10^-4DP_n^-0.51(3) cm·s^-1 (activation) and 3.1(1) × 10⁹DP_n^-0.49(2) L·mol^-1·s^-1 (termination). Addition of the CuBr₂ deactivator at the beginning of the reaction is found to result in a higher proportion of dead chains due to rapid termination of short chains.

Synergistic Effect of 1-Butyl-3-methylimidazolium Hexafluorophosphate and DMSO in the SARA ATRP at Room Temperature Affording Very Fast Reactions and Polymers with Very Low Dispersity

An unusual synergistic effect between 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) and dimethyl sulfoxide (DMSO) mixtures is reported for the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of methyl acrylate (MA) using a catalytic system composed by sodium dithionate (Na2S2O4) and CuBr2/Me6TREN (Me6TREN: tris[2-(dimethylamino)ethyl]amine) at room temperature. To the best of our knowledge, the use of ionic liquids (IL) has never been reported for the SARA ATRP. The kinetic data obtained for a broad range of target molecular weights revealed very fast polymerization rates, low dispersity values (Đ < 1.05) and well-defined chain-end functionalities.

Synthesis of cationic poly((3-acrylamidopropyl)trimethylammonium chloride) by SARA ATRP in ecofriendly solvent mixtures

Successful supplemental activator and reducing agent atom transfer radical polymerization of (3-acrylamidopropyl)trimethylammonium chloride under ecofriendly conditions.

Improvement of the control over SARA ATRP of 2-(diisopropylamino)ethyl methacrylate by slow and continuous addition of sodium dithionite

The kinetics and detailed mechanism of SARA ATRP of 2-(diisopropylamino)ethyl methacrylate (DPA) were investigated.

Synthesis of well-defined functionalized poly(2-(diisopropylamino)ethyl methacrylate) using ATRP with sodium dithionite as a SARA agent

2-(Diisopropylamino)ethyl methacrylate was polymerized by Atom Transfer Radical Polymerization using sodium dithionite as a reducing agent and supplemental activator with a Cu(ii)Br₂/Me₆TREN catalytic system.