One-pot synthesis of responsive sulfobetaine nanoparticles by RAFT polymerisation: the effect of branching on the UCST cloud point

Willcock, Helen; Lu, Annhelen; Hansell, Claire; Chapman, Emma; Collins, I.R.; O’Reilly, Rachel K.

doi:10.1039/c3py00998j

Cited by 92 publications

(120 citation statements)

References 43 publications

(77 reference statements)

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“…Similar to the revolutionary changes brought to polyelectrolyte synthesis [106], polyzwitterions have equally profited from this development. RDRP techniques offer direct access to polymers bearing zwitterionic groups with previously unthinkable features, such as predefined molar masses and narrow molar mass distributions [163,[182][183][184][185][186][187][188][189] as well as well-defined functional end groups [61,166,182,[190][191][192][193][194][195][196][197][198][199][200][201][202][203][204][205][206][207][208]. Moreover, complex architectures, such as block copolymers [14,[46][47][48]166,167,169,173,187,, graft copolymers [164,213,237,[241][242]…”

Section: Synthesis By Chain Growth Polymerizationsmentioning

confidence: 99%

Structures and Synthesis of Zwitterionic Polymers

2014

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Abstract:The structures and synthesis of polyzwitterions ("polybetaines") are reviewed, emphasizing the literature of the past decade. Particular attention is given to the general challenges faced, and to successful strategies to obtain polymers with a true balance of permanent cationic and anionic groups, thus resulting in an overall zero charge. Also, the progress due to applying new methodologies from general polymer synthesis, such as controlled polymerization methods or the use of "click" chemical reactions is presented. Furthermore, the emerging topic of responsive ("smart") polyzwitterions is addressed. The considerations and critical discussions are illustrated by typical examples.

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Section: Synthesis By Chain Growth Polymerizationsmentioning

confidence: 99%

Structures and Synthesis of Zwitterionic Polymers

2014

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“…for producing biocompatible or low-fouling materials). Only recently has interest in the UCST behaviour of polysulfobetaines gained more impetus, mostly in order to † Electronic supplementary information (ESI) available: Synthesis of tertiary amine bearing methacrylates; a enlarge the scope of the "traditional" thermo-responsive polymers with LCST behaviour 15,[24][25][26][27][28][29][30] or to obtain stimuli-responsive materials of increasing complexity. [31][32][33][34][35][36][37][38][39][40] Chemically well-defined polysulfobetaines are most conveniently prepared via free radical polymerisation of the underlying monomers.…”

Section: Introductionmentioning

confidence: 99%

Effect of the zwitterion structure on the thermo-responsive behaviour of poly(sulfobetaine methacrylates)

Hildebrand

Laschewsky

Päch³

et al. 2017

Polym. Chem.

135

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A series of new sulfobetaine methacrylates, including nitrogen-containing saturated heterocycles, was synthesised by systematically varying the substituents of the zwitterionic group. Radical polymerisation via the RAFT (reversible addition-fragmentation chain transfer) method in trifluoroethanol proceeded smoothly and was well controlled, yielding polymers with predictable molar masses. Molar mass analysis and control of the end-group fidelity were facilitated by end-group labeling with a fluorescent dye. The polymers showed distinct thermo-responsive behaviour of the UCST (upper critical solution temperature) type in an aqueous solution, which could not be simply correlated to their molecular structure via an incremental analysis of the hydrophilic and hydrophobic elements incorporated within them. Increasing the spacer length separating the ammonium and the sulfonate groups of the zwitterion moiety from three to four carbons increased the phase transition temperatures markedly, whereas increasing the length of the spacer separating the ammonium group and the carboxylate ester group on the backbone from two to three carbons provoked the opposite effect. Moreover, the phase transition temperatures of the analogous polyzwitterions decreased in the order dimethylammonio > morpholinio > piperidinio alkanesulfonates. In addition to the basic effect of the polymers' precise molecular structure, the concentration and the molar mass dependence of the phase transition temperatures were studied. Furthermore, we investigated the influence of added low molar mass salts on the aqueous-phase behaviour for sodium chloride and sodium bromide as well as sodium and ammonium sulfate. The strong effects evolved in a complex way with the salt concentration. The strength of these effects depended on the nature of the anion added, increasing in the order sulfate < chloride < bromide, thus following the empirical Hofmeister series. In contrast, no significant differences were observed when changing the cation, i.e. when adding sodium or ammonium sulfate.

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“…In fact, small contaminations by inorganic salts might be the reason for at least some of the apparently conflicting data on the phase transition temperatures of certain poly(sulfobetaine)s such as polySPE in the literature. 15,16,45,46 A striking feature of the salt effects observed for the solutions of polySHPP is however, that the effectiveness of the anions correlates inversely with the empirical Hofmeister series, [47][48][49] namely, salting-in effectiveness increases in the order Br − < Cl − < SO 4 2− . This behaviour is opposite to all previous findings for poly(sulfobetaine)s, such as polySPP 14 and polySPE, 15,24,39,50 or their analogues.…”

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confidence: 99%

Modulating the solubility of zwitterionic poly((3-methacrylamidopropyl)ammonioalkane sulfonate)s in water and aqueous salt solutions via the spacer group separating the cationic and the anionic moieties

2016

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Modulating the solubility of zwitterionic poly((3-methacrylamidopropyl) ammonioalkane sulfonate)s in water and aqueous salt solutions via the spacer group separating the cationic and the anionic moieties Postprint Complementary to the well-established zwitterionic monomer 3-((3-methacrylamidopropyl)dimethylammonio)propane-1-sulfonate (SPP), the closely related monomers 2-hydroxy-3-((3-methacrylamidopropyl)dimethylammonio)propane-1-sulfonate (SHPP) and 4-((3-methacrylamidopropyl)dimethylammonio)-butane-1-sulfonate (SBP) were synthesised and polymerised by reversible addition-fragmentation chain transfer (RAFT) polymerisation, using a fluorophore labeled RAFT agent. The polyzwitterions of systematically varied molar masses were characterised with respect to their solubility in water and aqueous salt solutions. Both poly(sulfobetaine)s show thermoresponsive behaviour in water, exhibiting phase separation at low temperatures and upper critical solution temperatures (UCST). For both polySHPP and polySBP, cloud points depend notably on the molar mass, and are much higher in D 2 O than in H 2 O. Also, the cloud points are effectively modulated by the addition of salts. The individual effects can be in parts correlated to the Hofmeister series for the anions studied. Still, they depend in a complex way on the concentration and the nature of the added electrolytes, on the one hand, and on the detailed nature of the spacer group separating the anionic and the cationic charges of the betaine moiety, on the other hand. As anticipated, the cloud points of polySBP are much higher than the ones of the analogous polySPP of identical molar mass.Surprisingly, the cloud points of polySHPP are also somewhat higher than the ones of their polySPP analogues, despite the additional hydrophilic hydroxyl group present in the spacer separating the ammonium and the sulfonate moieties. These findings point to a complicated interplay of the various hydrophilic components in polyzwitterions with respect to their overall hydrophilicity. Thus, the spacer group in the betaine moiety proves to be an effective additional molecular design parameter, apparently small variations of which strongly influence the phase behaviour of the polyzwitterions in specific aqueous environments.

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One-pot synthesis of responsive sulfobetaine nanoparticles by RAFT polymerisation: the effect of branching on the UCST cloud point

Cited by 92 publications

References 43 publications

Structures and Synthesis of Zwitterionic Polymers

Structures and Synthesis of Zwitterionic Polymers

Effect of the zwitterion structure on the thermo-responsive behaviour of poly(sulfobetaine methacrylates)

Modulating the solubility of zwitterionic poly((3-methacrylamidopropyl)ammonioalkane sulfonate)s in water and aqueous salt solutions via the spacer group separating the cationic and the anionic moieties

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