Sequence-controlled multi-block copolymerization of acrylamides via aqueous SET-LRP at 0 °C

Abstract

Aqueous single electron transfer living radical polymerization (SET-LRP) has been employed to synthesize multi-block homopolymers and copolymers of a range of acrylamide monomers including N-isopropylacrylamide (NIPAM), 2-hydroxyethyl acrylamide (HEAA), N,N-dimethyl acrylamide (DMA) and N,N-diethylacrylamide (DEA).

Universal Conditions for the Controlled Polymerization of Acrylates, Methacrylates, and Styrene via Cu(0)-RDRP

“…31,32 The latter two approaches have demonstrated high end group fidelity even at near-quantitative conversions as exemplified by the in situ synthesis of multiblock copolymers. [33][34][35][36][37][38][39] Moreover, to the best of our knowledge, in situ chain extensions with copper mediated polymerization approaches have only been reported for relatively high kp monomers such as acrylates, as methacrylates are more susceptible to termination, chain transfer and side reactions. Importantly, all these techniques are capable of polymerizing specific families of monomers, however choosing the appropriate method depending on the targeted polymer can also be challenging.…”

Aqueous SET-LRP catalyzed with “in situ” generated Cu(0) demonstrates surface mediated activation and bimolecular termination

“…63,64 Almost all initiators employed in other metal catalyzed LRP such as alkyl halides, 65,66 sulfonyl halides, 33,48,65,[67][68][69] N-halides 2,70 can be used as such or modified to become soluble for SET-LRP in various media including H 2 O. Only very few systematic investigations on SET-LRP with Cu(0) generated by disproportionation of Cu(I)X "in situ" in water 26,37,38,42 and in mixtures of water with other solvents are available. 1,2,26,37,38,47 It is important to mention that from many LRP methods that provide polymers with narrow molecular weight distribution, only SET-LRP generates polymers with both narrow molecular weight distribution and quantitative or near quantitative chain-end functionality.…”

“…Only very few systematic investigations on SET-LRP with Cu(0) generated by disproportionation of Cu(I)X "in situ" in water 26,37,38,42 and in mixtures of water with other solvents are available. 1,2,26,37,38,47 It is important to mention that from many LRP methods that provide polymers with narrow molecular weight distribution, only SET-LRP generates polymers with both narrow molecular weight distribution and quantitative or near quantitative chain-end functionality. 6,7,[48][49][50][51]57,[71][72][73][74][75][76][77] Narrow molecular weight distribution is an important feature of the polymers prepared by LRP but the most significant structural parameter of these polymers is the quantitative or near quantitative chain-end functionality combined with narrow molecular weight distribution.…”

“…3 Subsequently, SET-LRP was expanded to acrylates, [4][5][6][7][8][9][10][11][12][13][14][15][16][17] methacrylates, 8,[18][19][20][21][22][23][24][25] acrylamides, [26][27][28][29][30][31] methacrylamide, 32 acrylonitrile, 33,34 and monomers containing more complex water soluble side groups, such as sugars, 35,36 N-(2-hydroxypropyl) methacrylamide, 32 dimethylacrylamide, 26 N-isopropylacrylamide, 26,[37][38][39] oligo(ethylene oxide) methyl ether acrylate, 40 oligo(ethylene oxide) methyl ether methacrylate, 41 hydroxyethyl acrylate, 10 hydroxyethyl methacrylate 23 and acryloyl morpholine. 42 At the same time as these developments, the list of solvents used in SET-LRP was expanded to other solvents that in combination with aliphatic N-donor ligands, such as tris[(2-dimethylaminoethyl)...…”

Sequence-controlled polymers via reversible-deactivation radical polymerization

“…Although there is a problem with the accuracy regarding the number of inserted monomers due to the limitation by Poisson distribution, 18 an icosablock copolymer can be synthesized by repeating the addition of three equivalent monomers of various pendant groups 20 times. Similar multiblock copolymers of acrylates have been synthesized via aqueous single-electron transfer living radical polymerization 19 or Cu-mediated photopolymerization. [20][21][22] GRADIENT COPOLYMERS VIA TANDEM MONOMER TRANSFORMATION When two kinds of the same monomer derivatives (i.e., alkyl methacrylates) are copolymerized, the sequence of the resultant copolymer is totally random regardless of whether the polymerization is performed with RDRP or not, as the radical species from the two comonomers show no preference for the next monomer.…”