Polymers with Complex Architecture by Living Anionic Polymerization

Hadjichristidis, Nikos; Pitsikalis, Marinos; Pispas, Stergios; Iatrou, Hermis

doi:10.1021/cr9901337

Cited by 1,310 publications

(1,227 citation statements)

References 183 publications

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“…Figure 1(b) shows the 1 H NMR spectrum of 3, and all signals can be well-assigned according to its chemical structure. Besides the characteristic peaks of PEG main chain, newly appeared peaks g (2.7 ppm, NHCH 2 CH 2 N 3 ), f (3.0 ppm, triazole-CH 2 CH 2 NH), and e (4.5 ppm, triazoleACH 2 CH 2 NHA), as well as the presence of signals at 7.9 ppm characteristic of 1,2,3-triazole proton all supported the successful preparation of PEG-NHAN 3 (3).…”

Section: Synthesis Of Abc Miktoarm Star Terpolymermentioning

confidence: 65%

“…[1][2][3][4] The first few examples of the preparation of ABC miktoarm star terpolymers exclusively employed anionic polymerization, relying on the strict control of molar ratios between reactive species. [5][6][7][8][9][10][11][12][13] With the advent of controlled radical polymerizations, such as nitroxide-mediated radical polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer (RAFT) polymerization, the once challenging task of synthesizing ABC Correspondence to: S. Liu (E-mail: sliu@ustc.edu.cn) miktoarm star polymers has been rendered much easier.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of amphiphilic and thermoresponsive ABC miktoarm star terpolymer via a combination of consecutive click reactions and atom transfer radical polymerization

Liu

et al. 2009

J. Polym. Sci. A Polym. Chem.

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Well-defined amphiphilic and thermoresponsive ABC miktoarm star terpolymer consisting of poly(ethylene glycol), poly(tert-butyl methacrylate), and poly(N-isopropylacrylamide) arms, PEG(-b-PtBMA)-b-PNIPAM, was synthesized via a combination of consecutive click reactions and atom transfer radical polymerization (ATRP). Click reaction of monoalkynyl-terminated PEG with a trifunctional core molecule bis(2-azidoethyl)amine, (N 3 ) 2 ANH, afforded difunctional PEG possessing an azido and a secondary amine moiety at the chain end, PEG-NHAN 3 . Next, the amidation of PEG-NHAN 3 with 2-chloropropionyl chloride led to PEG-based ATRP macroinitiator, PEG(AN 3 )ACl. The subsequent ATRP of N-isopropylacrylamide (NIPAM) using PEG(AN 3 )ACl as the macroinitiator led to PEG(AN 3 )-b-PNIPAM bearing an azido moiety at the diblock junction point. Finally, well-defined ABC miktoarm star terpolymer, PEG(-b-PtBMA)-b-PNIPAM, was prepared via the click reaction of PEG(AN 3 )-b-PNIPAM with monoalkynyl-terminated PtBMA. In aqueous solution, the obtained ABC miktoarm star terpolymer self-assembles into micelles consisting of PtBMA cores and hybrid PEG/PNIPAM coronas, which are characterized by dynamic and static laser light scattering, and transmission electron microscopy. On heating above the phase transition temperature of PNIPAM in the hybrid corona, micelles initially formed at lower temperatures undergo further structural rearrangement and fuse into much larger aggregates solely stabilized by PEG coronas.

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Section: Synthesis Of Abc Miktoarm Star Terpolymermentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Synthesis of amphiphilic and thermoresponsive ABC miktoarm star terpolymer via a combination of consecutive click reactions and atom transfer radical polymerization

Liu

et al. 2009

J. Polym. Sci. A Polym. Chem.

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“…For comparison, linear diblock copolymer, (l-PNIPAM)-b-PCL (M n = 12,800, M w /M n = 1.12, Figure S1 of the Supporting Information), was also synthesized via ROP by using alkynyl-(OH)-PNIPAM 45 -Br as the initiator, following similar protocols employed for the synthesis of (l-PNIPAM)-b-PCL. 1 H NMR analysis revealed a DP of 63 for the PCL block, and thus the linear diblock copolymer was denoted as (l-PNIPAM 45 )-b-PCL 63 .…”

Section: Synthesis Of (C-pnipam)-b-pcl Via Ring-opening Polymerizatiomentioning

confidence: 99%

Synthesis of Amphiphilic Tadpole-Shaped Linear-Cyclic Diblock Copolymers via Ring-Opening Polymerization Directly Initiating from Cyclic Precursors and Their Application as Drug Nanocarriers

2011

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We report on the facile synthesis of well-defined amphiphilic and thermoresponsive tadpole-shaped linear-cyclic diblock copolymers via ring-opening polymerization (ROP) directly initiating from cyclic precursors, their self-assembling behavior in aqueous solution, and the application of micellar assemblies as controlled release drug nanocarriers. Starting from a trifunctional core molecule containing alkynyl, hydroxyl, and bromine moieties, alkynyl-(OH)-Br, macrocyclic poly(N-isopropylacrylamide) (c-PNIPAM) bearing a single hydroxyl functionality was prepared by atom transfer radical polymerization (ATRP), the subsequent end group transformation into azide functionality, and finally the intramacromolecular ring closure reaction via click chemistry. The target amphiphilic tadpoleshaped linear-cyclic diblock copolymer, (c-PNIPAM)-b-PCL, was then synthesized via the ROP of ε-caprolactone (CL) by directly initiating from the cyclic precursor. In aqueous solution at 20°C, (c-PNIPAM)-b-PCL self-assembles into spherical micelles consisting of hydrophobic PCL cores and well-solvated coronas of cyclic PNIPAM segments. For comparison, linear diblock copolymer with comparable molecular weight and composition, (l-PNIPAM)-b-PCL, was also synthesized. It was found that the thermoresponsive coronas of micelles self-assembled from (c-PNIPAM)-b-PCL exhibit thermoinduced collapse and aggregation at a lower critical thermal phase transition temperature (T c ) compared with those of (l-PNIPAM)-b-PCL. Temperature-dependent drug release profiles from the two types of micelles of (c-PNIPAM)-b-PCL and (l-PNIPAM)-b-PCL loaded with doxorubicin (Dox) were measured, and the underlying mechanism for the observed difference in releasing properties was proposed. Moreover, MTT assays revealed that micelles of (c-PNIPAM)-b-PCL are almost noncytotoxic up to a concentration of 1.0 g/L, whereas at the same polymer concentration, micelles loaded with Dox lead to ∼60% cell death. Overall, chain topologies of thermoresponsive block copolymers, that is, (c-PNIPAM)-b-PCL versus (l-PNIPAM)-b-PCL, play considerable effects on the self-assembling and thermal phase transition properties and their functions as controlled release drug nanocarriers. ' INTRODUCTIONIn the past decades, enduring attention has been paid to explore the intrinsic correlation between the chain topology of block copolymers and their physical properties, self-assembling behavior in selective solvents or in bulk states, and the associated functional applications. 1-3 It has been well-established that the topological structures and chemical composition of nonlinearshaped block copolymers can exhibit dramatic effects on the solution properties and self-assembling morphologies as compared with their linear counterpart. [4][5][6][7][8][9] It is worthy of noting that the developments of a variety of controlled radical polymerization techniques 10 such as atom transfer radical polymerization (ATRP), 11-13 reversible addition-fragmentation chain transfer (RAFT) polymerization, [14][...

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“…DCC (4.69 g, 22.6 mmol) dissolved in 5 ml of CH 2 Cl 2 was immediately added and the mixture was stirred at room temperature for 24 h. The precipitated dicyclohexylurea was filtered off, the solvent was evaporated, and the remaining product was purified by column chromatography (silica gel) eluting with hexane gradually changing to 4:1 hexane/ethyl acetate to give final product anthracen-9-ylmethyl 2,2,5-trimethyl-1,3-dioxane-5-carboxylate, 7, as a yellow solid (yield = 3.8 g, 72%). 1 …”

Section: Synthesis Of Furan-protected Maleimide End-functionalized Ptmentioning

confidence: 99%

“…Star polymers are branched polymers consisting of several linear chains linked to a central core [1]. Star polymers show different crystalline, mechanical and viscoelastic properties compared to their linear counterparts.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of an ABCD 4-Miktoarm Star Quaterpolymer Through a Diels–Alder Click Reaction

Altintas

Hızal

Tunca

2009

Designed Monomers and Polymers

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An ABCD 4-miktoarm star quaterpolymer with A = poly(ε-caprolactone) (PCL), B = poly(tert-butyl acrylate) (PtBA), C = polystyrene (PS) and D = poly(methyl methacrylate) (PMMA) arms was prepared using the Diels-Alder reaction strategy. Firstly, PCL with anthracene (PCL-Anth) and PtBA with furan-protected maleimide (PtBA-MI) end-functionalities were synthesized separately via ring-opening polymerization of ε-CL and atom transfer radical polymerization of tBA, respectively. These homo-polymers were linked via the Diels-Alder click reaction in toluene at 100 • C in order to give PCL-b-PtBA co-polymer. Next, this block co-polymer is utilized successively as macroinitiator in nitroxide-mediated radical polymerization of styrene and in free radical photo-polymerization of MMA in order to achieve the PCL-PtBA-PS-PMMA 4-miktoarm star quaterpolymer.

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Polymers with Complex Architecture by Living Anionic Polymerization

Cited by 1,310 publications

References 183 publications

Synthesis of amphiphilic and thermoresponsive ABC miktoarm star terpolymer via a combination of consecutive click reactions and atom transfer radical polymerization

Synthesis of amphiphilic and thermoresponsive ABC miktoarm star terpolymer via a combination of consecutive click reactions and atom transfer radical polymerization

Synthesis of Amphiphilic Tadpole-Shaped Linear-Cyclic Diblock Copolymers via Ring-Opening Polymerization Directly Initiating from Cyclic Precursors and Their Application as Drug Nanocarriers

Synthesis of an ABCD 4-Miktoarm Star Quaterpolymer Through a Diels–Alder Click Reaction

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