‘One-pot’ sequential deprotection/functionalisation of linear-dendritic hybrid polymers using a xanthate mediated thiol/Michael addition

Abstract

Xanthate functional dendritic ATRP macroinitiators, synthesised via a new orthogonal strategy, have been used to form a library of linear-dendritic hybrids via one-pot, post polymerisation, deprotection/acrylate Michael addition.

Synthesis, nanoprecipitation and pH sensitivity of amphiphilic linear–dendritic hybrid polymers and hyperbranched-polydendrons containing tertiary amine functional dendrons

“…S28); however, hyp-polydendron synthesis using the G 1 -Br and G 2 -Br initiators propagated noticeably slower than their analogous linear-dendritic polymer reactions. S28); M w values up to 1.02 Â 10 6 g mol À1 were observed, suggesting significant contributions to the physical mass of each sample from complex branched structures containing on average 480 primary chains (18), 465 primary chains (19), 445 primary chains (20) and 417 primary chains (21). Linear semilog plots were observed within the branched polymerisations using each of the initiators, confirming first order kinetics (ESI, † Fig.…”

“…1B). When using the G 0 -Br, G 1 -Br and G 2 -Br initiators 11-13, gel formation was seen within the HPMA/EGDMA copolymerisations at this ratio but soluble hyp-polydendrons (19,20,21) were achieved at lower brancher : initiator ratios (0.90 : 1) again suggesting a lower initiator efficiency, as poor initiation will lead to fewer propagating polymer chains and a higher effective brancher : chain ratio within each reaction. When using the G 0 -Br, G 1 -Br and G 2 -Br initiators 11-13, gel formation was seen within the HPMA/EGDMA copolymerisations at this ratio but soluble hyp-polydendrons (19,20,21) were achieved at lower brancher : initiator ratios (0.90 : 1) again suggesting a lower initiator efficiency, as poor initiation will lead to fewer propagating polymer chains and a higher effective brancher : chain ratio within each reaction.…”

“…Molecular weight analyses were enabled by determining average dn/dc values (ESI, † Table S2). Each primary chain of the hyp-polydendrons 19, 20 and 21 contains a dendron initiator end group, therefore the weight average branched architectures contain approximately 65 tertiary amines (19), 90 tertiary amines (20) or 68 tertiary amine (21) chain-end functional groups. S28); M w values up to 1.02 Â 10 6 g mol À1 were observed, suggesting significant contributions to the physical mass of each sample from complex branched structures containing on average 480 primary chains (18), 465 primary chains (19), 445 primary chains (20) and 417 primary chains (21).…”

“…[10][11][12][13] In contrast, divergent growth leads to large increases in both the molecular weight of the material and its physical sample mass but an exponentially increasing number of reactions are required at the periphery of growing macromolecule, leading to difficulty in accurate attainment of each generation; 14,15a recent application of ''click'' chemistries have been shown to present options to overcome many of these synthetic issues. These include the introduction of dendrons as pendant side chains, 16,17 to produce dendronised polymers, and the placement of dendrons at linear polymer chain-ends, [18][19][20] to form linear-dendritic polymer hybrids. These include the introduction of dendrons as pendant side chains, 16,17 to produce dendronised polymers, and the placement of dendrons at linear polymer chain-ends, [18][19][20] to form linear-dendritic polymer hybrids.…”

Thiol-Michael addition miniemulsion polymerizations: functional nanoparticles and reactive latex films

“…The thiol-Michael addition reaction achieves quantitative yield in the reaction between thiols and electron deficient double bonds under benign conditions 5,6 . As such, it is considered as one of the "click" chemistries and has been shown to be a powerful tool for a wide 20 range of applications in polymer chemistry, including the formation of polymer networks 7 , polymer conjugation 8 and modification 9,10 . Recent advances in thiol-Michael addition polymerization include initiation with spatiotemporal control [11][12][13][14][15][16][17] , synthesis of dendrimers 18,19 and hydrogels 20 , sequence controlled 25 polymers 21,22 and various implementations in heterogeneous systems 23,24 .…”