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Yhaya F, Binauld S, Callari M, Stenzel MH. One-Pot Endgroup-Modification of Hydrophobic RAFT Polymers with Cyclodextrin by Thiol-ene Chemistry and the Subsequent Formation of Dynamic Core–Shell Nanoparticles Using Supramolecular Host–Guest Chemistry. Aust J Chem 2012. [DOI: 10.1071/ch12158] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Poly(methyl methacrylate) PMMA, synthesized using reversible addition fragmentation chain transfer (RAFT) polymerization, was heated in a solvent at 100°C for 24 h leading to the loss of the RAFT endfunctionality and the complete conversion into a vinyl group. Mono(6-deoxy-6-mercapto)-β-cyclodextrin (β-CD-SH) was subsequently clicked onto the polymer by a thiol-ene reaction leading to PMMA with one β-CD as a terminal group (PMMA70–β-CD). Meanwhile, a RAFT agent with an adamantyl group has been prepared for the polymerization of 2-hydroxyethyl acrylate (HEA) leading to PHEA95–Ada. Two processes were employed to generate core–shell nanoparticles from these two polymers: a one-step approach that employs a solution of both polymers at stoichiometric amounts in DMF, followed by the addition of water, and a two step process that uses PMMA solid particles with surface enriched with β-CD in water, which have a strong tendency to aggregate, followed by the addition of PHEA95–Ada in water. Both pathways led to stable core–shell nanoparticles of ~150 nm in size. Addition of free β-CD competed with the polymer bound β-CD releasing the PHEA hairs from the particle surface. As a result, the PMMA particles started agglomerating resulting in a cloudy solution. A similar effect was observed when heating the solution. Since the equilibrium constant between β-CD and adamantane decreases with increasing temperature, the stabilizing PHEA chains cleaved from the surface and the solution turned cloudy due to the aggregation of the naked PMMA spheres. This process was reversible and with decreasing temperature the core–shell nanoparticles formed again leading to a clear solution.
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Schmidt BVKJ, Rudolph T, Hetzer M, Ritter H, Schacher FH, Barner-Kowollik C. Supramolecular three-armed star polymers via cyclodextrin host–guest self-assembly. Polym Chem 2012. [DOI: 10.1039/c2py20293j] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Schmidt BVKJ, Hetzer M, Ritter H, Barner-Kowollik C. Miktoarm star polymers via cyclodextrin-driven supramolecular self-assembly. Polym Chem 2012. [DOI: 10.1039/c2py20214j] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Zhang Q, Li GZ, Becer CR, Haddleton DM. Cyclodextrin-centred star polymers synthesized via a combination of thiol-ene click and ring opening polymerization. Chem Commun (Camb) 2012; 48:8063-5. [DOI: 10.1039/c2cc33742h] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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