Synthesis of Organic/Inorganic Hybrid Quatrefoil-Shaped Star-Cyclic Polymer Containing a Polyhedral Oligomeric Silsesquioxane Core

Ge, Zhishen; Wang, Di; Zhou, Yueming; Liu, Hewen; Liu, Shiyong

doi:10.1021/ma802585k

Cited by 122 publications

(82 citation statements)

References 62 publications

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“…43 The second one employs the intermolecular ring-closure reaction between an R,R-homobifunctional polymer precursor and a complementary bifunctional reactive reagent. 47,48 The third synthetic strategy is based on the coupling reaction between functionalized cyclic and linear polymer precursors. 45,49 Various intra-or intermolecular ring closure/coupling approaches such as electrostatic self-assembly and covalent fixation (ESA-CF), 50,51 amidation/esterification, 47,52,53 etherification reaction (hydroxyl 33 or thiol functionalities 54 ), and high-efficiency and quantitative click reactions 41,42,55 have been utilized.…”

Section: ' Introductionmentioning

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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Section: ' Introductionmentioning

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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“…Moreover, it has been previously predicated and experimentally proven that star polymers generally possess slightly higher T g value than their linear counterparts. [31] A comparison of DSC curve of star PS and linear PS after HF treatment, the linear PS were determined to 83.3 8C, which is lower than star PS (92.5 8C) since cleaving with HF results in the decrease of overall molecular weight and the increase of chain mobility by freeing of chain ends.…”

Section: The Synthesis Of Star (Ps) 8 -Poss Homopolymersmentioning

confidence: 97%

“…[29,30] Many of them have been prepared by using POSS initiators or monomers; however, few reports have utilized the living and controlled radical polymerization (LCRP) from an eight-functional POSS initiator. [31,32] Applying POSS monomers or initiators to LCRP is desirable to develop novel materials of varying composition, topology, and welldefined molecular weights. The synthesis of star homopolymers or block copolymers using the cubic POSS as a nanosized multifunctional initiator is particularly interesting.…”

Section: Introductionmentioning

confidence: 99%

Star Block Copolymers Through Nitroxide‐Mediated Radical Polymerization From Polyhedral Oligomeric Silsesquioxane (POSS) Core

Wang

Chang

et al. 2010

Macro Chemistry & Physics

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A series of star block copolymers were prepared through nitroxide‐mediated radical polymerization (NMRP) from polyhedral oligomeric silsesquioxanes (POSS) nanoparticle by core‐first polymerization. Eight N‐alkoxyamine groups were incorporated onto the eight corners of a POSS cube through quantitative hydrosilylation through addition of octakis(dimethylsiloxy)silsesquioxane (Q8M POSS) with 1‐(2‐(allyloxy)‐1‐phenylethoxy)‐2,2,6,6‐tetramethylpiperidine (allyl‐TEMPO) and Karstedt's agent (a platinum divinylsiloxane complex) was used as a catalyst. Octa‐N‐alkoxyamines POSS (OT‐POSS) were used as platform to synthesize star polystyrene‐POSS ((PS)8‐POSS) homopolymer and diblock copolymers of poly(styrene‐block‐4‐vinylpyridine)‐POSS ((PS‐b‐P4VP)8‐POSS) and poly(styrene‐block‐acetoxystyrene) ((PS‐b‐PAS)8‐POSS) through NMRP. In addition, subsequent selective hydrolysis of the acetyl protective group of (PS‐b‐PAS)8‐POSS, the poly(styrene‐block‐vinyl phenol) ((PS‐b‐PVPh)8‐POSS) with strong hydrogen bonding group was obtained. The detailed chemical structure and self‐assembled structures of these star block copolymers based on POSS were characterized by 1H NMR, FTIR, SEC, TEM, and SAXS analyses.magnified image

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“…1) and its reaction with a variety of alkynes. [25][26][27][28][29][30][31][32][33][34][35][36] The preparation of octa(3-azidopropyl)polyhedral oligomeric silsesquioxane POSS-(N 3 ) 8 requires a multi-step synthesis and suffers from a poor overall yield of 30-32%.…”

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Facile synthesis of novel hybrid POSS biomolecules via “Click” reactions

et al. 2017

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A novel alkyne-terminated cubic-octameric POSS was synthesised in high yield (82-90%). The X-ray crystal structure revealed intra-and intermolecular hydrogen bonding between the amide groups of the arms.Hybrid biomaterials were synthesised in nearly quantitative yields via a click reaction with (i) azido-NFmoc-norleucine and (ii) 3 0 -azido-3 0 -deoxythymidine.Among the most commonly studied scaffolds for developing hybrid biomaterials 1-4 is polyhedral oligomeric silsesquioxane (POSS). POSS units are symmetrical, three-dimensional cubic molecules, which are unique nanometer-sized hybrid inorganicorganic materials 5,6 with the formula ( 'click' chemistry, is a simple method for coupling organic molecules containing azide and alkyne functional groups in high yields and its use in the elds of peptide and protein biomedical and material sciences is accelerating.22,23 The click reaction has been used to synthesise POSS biomaterials such as hybrid POSS-PEG hydrogels 24 that support chondrocyte attachment and proliferation. Only one synthetic approach towards peptidyl silsesquioxanes using click chemistry has been reported to date.25-30 focussing on the synthesis of octa(3-azidopropyl)polyhedral oligomeric silsesquioxane POSS-(N 3 ) 8 (Fig. 1) and its reaction with a variety of alkynes.25-36 The preparation of octa(3-azidopropyl)polyhedral oligomeric silsesquioxane POSS-(N 3 ) 8 requires a multi-step synthesis and suffers from a poor overall yield of 30-32%. 32The synthesis and click reaction of mono alkyneheptaisobutyl POSS were rst reported by Müller et al. 37 and Wu et al. 38 Müller et al. 37 have used aminopropylheptaisobutyl polyhedral oligomeric silsesquioxane (POSS) to produce monoalkyne-POSS in three steps and the click coupling occurred between the azido-terminated polystyrenes and alkyne-POSS to afford mono-, di-, and pentafunctional POSS-containing hybrid polystyrenes as star-shaped telechelic POSS-containing hybrid polymers. Wu et al.38 have prepared alkyne-functionalized-POSS in three steps from allyl-heptaisobutyl substituted-POSS and the product was linked to an azido-functionalized elastomer of poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEB-CH 2 N 3 ) via a click coupling reaction to form a novel hybrid copolymer. These approaches focused mostly on the preparation of a hybrid copolymer based on mono-alkyne-heptaisobutyl and azido polystyrene. However, the preparation of octa-alkyne-terminated POSS and their click coupling reactions with azido-biomolecules to produce hybrid biomaterials has not been investigated yet. We believe that this approach will open a wide range of biomedical applications that were not accessible in the past.Herein we report a novel synthetic approach to hybrid biomaterials based on octa-alkyne-terminated POSS and their reaction with (i) azido-N-Fmoc-L-norleucine and (ii) 3 0 -azido-3 0 -deoxythymidine, using the CuAAC reaction. Our approach Fig. 1 Octa(3-azidopropyl)POSS.

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Synthesis of Organic/Inorganic Hybrid Quatrefoil-Shaped Star-Cyclic Polymer Containing a Polyhedral Oligomeric Silsesquioxane Core

Cited by 122 publications

References 62 publications

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

Star Block Copolymers Through Nitroxide‐Mediated Radical Polymerization From Polyhedral Oligomeric Silsesquioxane (POSS) Core

Facile synthesis of novel hybrid POSS biomolecules via “Click” reactions

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