Analysis of individual block length of amphiphilic di- &amp; tri-block copolymers containing poly(ethylene oxide) and poly(methyl methacrylate)

Tufail, Muhammad Khurram; Abdul‐Karim, Rubina; Rahim, Sana; Musharraf, Syed Ghulam; Malik, Muhammad Imran

doi:10.1039/c7ra08804c

Cited by 15 publications

(10 citation statements)

References 65 publications

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“…Critical conditions corresponding to PEO has been documented in several articles. 26,28 In this study, critical conditions of MeO-PEO were established on a normal phase plain silica column using a binary mixture of THF and DMF as a mobile phase. THF promotes retention of MeO-PEO onto stationary phase while DMF strongly promotes elution.…”

Section: 14mentioning

confidence: 99%

Synthesis and characterization of 4-arm star-shaped amphiphilic block copolymers consisting of poly(ethylene oxide) and poly(ε-caprolactone)

et al. 2018

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Star-shaped polymers exhibit lower hydrodynamic volume, glass transition temperature, critical micelles concentration (CMC), and higher viscosity and drug-loading capacity compared to their linear counterparts. In the present study, amphiphilic biodegradable 4-arm star-shaped block copolymers, based on poly(ethylene oxide) (PEO) as a hydrophilic part and poly(3-caprolactone) (PCL) as a hydrophobic segment, are synthesized by ring-opening polymerization of 3-caprolactone employing pentaerythritol as an initiator and stannous octoate as a catalyst, followed by the coupling reaction with carboxyl-functionalized monomethoxy poly(ethylene oxide) (MeO-PEO-COOH). The structures of intermediates were deduced through 1 H-NMR and FT-IR spectroscopy. Average chemical composition of the star block copolymer is determined by proton NMR. Information related to molar mass distribution of targeted products and their precursors is obtained by size exclusion chromatography (SEC). However, due to its inherent poor resolution SEC could not reveal whether all the parent homopolymers are coupled to each other or remained unattached to the other segment. In order to comprehensively characterize the synthesized star-block copolymers, liquid chromatography at critical conditions of both blocks is employed. The study allowed for separation of homopolymer precursors from targeted star-block copolymers. The study exposed heterogeneity of star block copolymers that was not possible by conventional techniques.

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Section: 14mentioning

confidence: 99%

Synthesis and characterization of 4-arm star-shaped amphiphilic block copolymers consisting of poly(ethylene oxide) and poly(ε-caprolactone)

et al. 2018

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“…A NP column would be required to keep non‐polar PCL in exclusion regime. Critical conditions for PEO have been reported on NP columns of varying nature . As mentioned earlier, next point of concern would be solubility of all the components of analytes in the mobile phase.…”

Section: Resultsmentioning

confidence: 99%

“…At this compensation point, termed as critical elution point, corresponding polymer becomes "chromatographically invisible", consequently all chains with the same end-functionality elute at same elution time regardless of their molar mass. Hence, separation with regard to other blocks [24][25][26][27][28][29][30][31][32][33][34][35] or end-functionality [36][37][38][39] can be achieved. LCCC has been successfully applied for quantification of critical homopolymers and fair estimation of a non-critical block length in the block copolymer [20,24,40].…”

Section: Introductionmentioning

confidence: 99%

Chromatographic characterization of amphiphilic di‐ and tri‐block copolymers of poly(ethylene oxide) and poly(ε‐caprolactone)

Irfan

Bhayo

Musharraf

et al. 2018

J of Separation Science

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Amphiphilic di- and tri-block copolymers based on poly(ethylene oxide) as a hydrophilic segment and poly(ε-caprolactone) as a hydrophobic part are synthesized by the ring-opening polymerization of ε-caprolactone while using poly(ethylene glycol)s and methoxy poly(ethylene glycol)s of varying molar masses as macro-initiators. The synthesized block copolymers are characterized with respect to their total relative molar mass and its distribution by size exclusion chromatography. Liquid chromatography at critical conditions of both blocks is established for the analysis of individual block lengths and tracking presence of unwanted homopolymers of both types in the block copolymer samples. New critical conditions of polycaprolactone on reversed phase column are reported using organic mobile phase. The established critical conditions of polycaprolactone extended the applicable molar mass range significantly compared to already reported critical conditions of polycaprolactone in aqueous mobile phase. Block copolymers are also analyzed at critical conditions of poly(ethylene glycol). Complete analysis of the di- and tri-block copolymers at corresponding critical conditions provided a fair estimate of molar mass of non-critical block besides information regarding presence of homopolymers of both types in the samples.

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“…1−5 The APs are amphiphilic due to the presence of both hydrophilic and hydrophobic segments, resembling the structure of surfactant. 6,7 The hydrophobic and hydrophilic segments self-associate to form a core–shell structure consisting of a hydrophobic core and a hydrophilic corona. Triblock copolymer APs with BAB structure have attracted increasing attention due to their unique structure and associative properties, where A is the hydrophilic block and B is the hydrophobic block.…”

Section: Introductionmentioning

confidence: 99%

“…9,11−13 The size and morphology of the flower micelle can be tuned at the molecular level by manipulating the chemical composition, architecture, and molecular weight. 6…”

Section: Introductionmentioning

confidence: 99%

ARGET ATRP of Triblock Copolymers (PMMA-b-PEO-b-PMMA) and Their Microstructure in Aqueous Solution

et al. 2018

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Triblock copolymers poly(methyl methacrylate)- b -poly(ethylene oxide)- b -poly(methyl methacrylate) (PMMA- b -PEO- b -PMMA) with designed molecular weight of PMMA and PEO blocks were synthesized via the activator regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) of MMA. The Br-terminated Br–PEO–Br with the molecular weights of 20k and 100k were used as macroinitiators. ARGET ATRP was performed with ppm level amount CuBr 2 as the catalyst and ascorbic acid as the reducing agent to overcome the sensitivity to oxygen in a traditional ATRP. The molecular weight of the PMMA block was manipulated by changing the molar ratio of monomers to the Br–PEO–Br macroinitiators. The synthesis of PMMA- b -PEO- b -PMMA and its structure was confirmed by Fourier transform infrared and 1 H NMR, and the molecular weight of the PMMA block was determined by 1 H NMR. Aqueous solutions of PMMA- b -PEO- b -PMMA were prepared by solvent-exchange, and their microstructures were examined by tensiometry, static light scattering, and transmission electron microscopy. The effects of molecular weight of the PMMA and PEO blocks on the microstructure were elucidated.

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Analysis of individual block length of amphiphilic di- & tri-block copolymers containing poly(ethylene oxide) and poly(methyl methacrylate)

Abstract: Estimation of individual block lengths and extent of homopolymers.

Cited by 15 publications

References 65 publications

Synthesis and characterization of 4-arm star-shaped amphiphilic block copolymers consisting of poly(ethylene oxide) and poly(ε-caprolactone)

Synthesis and characterization of 4-arm star-shaped amphiphilic block copolymers consisting of poly(ethylene oxide) and poly(ε-caprolactone)

Chromatographic characterization of amphiphilic di‐ and tri‐block copolymers of poly(ethylene oxide) and poly(ε‐caprolactone)

ARGET ATRP of Triblock Copolymers (PMMA-b-PEO-b-PMMA) and Their Microstructure in Aqueous Solution

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