Sugar-responsive block copolymers by direct RAFT polymerization of unprotected boronic acid monomers

Roy, Debashish; Cambre, Jennifer N.; Sumerlin, Brent S.

doi:10.1039/b802293c

Cited by 189 publications

(165 citation statements)

References 31 publications

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“…[14] We have synthesized a series of stimuli-responsive block copolymers, poly(ethylene glycol)-b-poly(styrene boronic acid) (PEG-b-PSBA, 2b-4b, Fig. 1A), by adopting the ATRP technique employing a PEG (M n ¼ 1,000 g mol À1 ) macroinitiator (synthetic details and characterization in Supporting Information (SI)).…”

mentioning

confidence: 99%

A Polymersome Nanoreactor with Controllable Permeability Induced by Stimuli‐Responsive Block Copolymers

et al. 2009

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A method to generate and control the permeability of polymersome membranes using mixtures of amphiphilic and stimuli‐responsive boronic acid‐containing block copolymers is reported. The latter block copolymers form phase‐separated domains in the polymersomes, which can be dissolved by increasing the pH of the medium or by introducing sugar molecules that covalently bind to the boronic acid moieties.

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confidence: 99%

A Polymersome Nanoreactor with Controllable Permeability Induced by Stimuli‐Responsive Block Copolymers

et al. 2009

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“…Well-defined boronic acid homo-and block copolymers were synthesized via ATRP [23][24][25] or RAFT [26] polymerization of styrenic boronic ester and subsequent post-polymerization deprotection of the boronic ester. Recently, Sumerlin and coworkers [3,27] reported the synthesis of well-defined PAAPBA-b-PNIPAM block copolymers via direct RAFT polymerization of unprotected AAPBA and NIPAM. Such copolymer is capable of forming micelles or reverse micelles depending on the temperature, pH, and glucose concentration.…”

Section: Introductionmentioning

confidence: 99%

“…RAFT agent S-1-dodecyl-S!-(#, #!-dimethyl-#$-acetic acid) trithiocarbonate (CTA) was synthesized as described in the literature [35]. AAPBA, PAAPBA and PAAPBA-b-PNIPAM were synthesized according to the literature methods [3,27]. The polydispersity indices (M w /M n ) of PAAPBA and PAAPBA-b-PNIPAM determined by Gel Permeation Chromatography (GPC) are 1.05 and 1.28, respectively.…”

Section: Introductionmentioning

confidence: 99%

The micellization and dissociation transitions of thermo-, pH- and sugar-sensitive block copolymer investigated by laser light scattering

Tang¹,

Wu²,

Duan³

2012

Express Polym. Lett.

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Abstract.A triple-stimuli responsive polymer, poly(3-acrylamidophenylboronic acid)-b-poly(N-isopropylacrylamide) (PAAPBA-b-PNIPAM), has been synthesized by reversible addition-fragmentation chain transfer polymerization. Temperature, pH, and fructose induced micellization and dissociation transition of block copolymer was investigated by a combination of static and dynamic laser light scattering. PAAPBA-b-PNIPAM copolymer self-assembles into micelles with PAAPBA block as core and PNIPAM as shell in lower pH aqueous solution at room temperature. Increasing the temperature causes the micelle to shrink due to the dehydration of PNIPAM segments at pH 6.2. After the elevation of solution pH from 6.2 to 10.0, the increase in the hydrophilicity of PAAPBA block leads to an expulsion of unimers from micelles. In addition, the fructose addition further enhances the dissociation of micelles. Our experiments demonstrate that the micelle to unimer transition process proceeds via the step-by-step sequential expulsion of individual chains.

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“…[36][37][38][39][40][41][42][43][44][45][46] As a consequence of the degenerative chain transfer mechanism, (co)polymers prepared by RAFT bear very specific end-groups, the chemical nature of which is dependent on the structure of the chain transfer agent (CTA) and, to a lesser extent, the CTA/initiator pair. Assuming no undesirable side reactions then the a terminus of a (co)polymer chain will be chemically identical to the R-group of the RAFT CTA while the x terminus bears a thiocarbonylthio functional group, the exact chemical structure of which will be dependent of the class of RAFT CTA used, that is, dithioester versus xanthate versus trithiocarbonate etc.…”

Section: Introductionmentioning

confidence: 99%

Sequential thiol‐ene/thiol‐ene and thiol‐ene/thiol‐yne reactions as a route to well‐defined mono and bis end‐functionalized poly(N‐isopropylacrylamide)

Chan

Hoyle

et al. 2009

J. Polym. Sci. A Polym. Chem.

208

191

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Sequential thiol-ene/thiol-ene and thiol-ene/thiol-yne reactions have been used as a facile and quantitative method for modifying end-groups on an N-isopropylacrylamide (NIPAm) homopolymer. A well-defined precursor of polyNIPAm (PNIPAm) was prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization in DMF at 70 C using the 1-cyano-1-methylethyl dithiobenzoate/2,2 0 -azobis(2-methylpropionitrile) chain transfer agent/initiator combination yielding a homopolymer with an absolute molecular weight of 5880 and polydispersity index of 1.18. The dithiobenzoate end-groups were modified in a one-pot process via primary amine cleavage followed by phosphine-mediated nucleophilic thiol-ene click reactions with either allyl methacrylate or propargyl acrylate yielding ene and yne terminal PNIPAm homopolymers quantitatively. The ene and yne groups were then modified, quantitatively as determined by 1 H NMR spectroscopy, via radical thiol-ene and radical thiol-yne reactions with three representative commercially available thiols yielding the mono and bis end functional NIPAm homopolymers. This is the first time such sequential thiol-ene/thiol-ene and thiol-ene/thiol-yne reactions have been used in polymer synthesis/end-group modification. The lower critical solution temperatures (LCST) were then determined for all PNIPAm homopolymers using a combination of optical measurements and dynamic light scattering. It is shown that the LCST varies depending on the chemical nature of the end-groups with measured values lying in the range 26-35 C.

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Sugar-responsive block copolymers by direct RAFT polymerization of unprotected boronic acid monomers

Abstract: Novel sugar-responsive block copolymers were prepared by RAFT block copolymerization of unprotected boronic acid monomers, providing a direct route to supramolecular assemblies that dissociate upon the addition of glucose.

Cited by 189 publications

References 31 publications

A Polymersome Nanoreactor with Controllable Permeability Induced by Stimuli‐Responsive Block Copolymers

A Polymersome Nanoreactor with Controllable Permeability Induced by Stimuli‐Responsive Block Copolymers

The micellization and dissociation transitions of thermo-, pH- and sugar-sensitive block copolymer investigated by laser light scattering

Sequential thiol‐ene/thiol‐ene and thiol‐ene/thiol‐yne reactions as a route to well‐defined mono and bis end‐functionalized poly(N‐isopropylacrylamide)

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