Archive for the ‘Paper of the Week’ Category

Paper of the week: Renewable, fluorescent, and thermoresponsive cellulose copolymers

Hufendiek et al. report the preparation of renewable, fluorescent, and thermoresponsive cellulose copolymers via light-induced ligation in solution copolymers.


Hufendiek et al. introduce a mild photochemically driven strategy for the synthesis of fluorescent cellulose copolymers using filter paper as the starting material. Thermoresponsive behaviour in water is imparted to the brush-like structures by grafting of poly(N-isopropylacrylamide) side chains. All reactions take place in homogenous solutions, allowing the design of novel advanced materials from renewable resources.

Renewable, fluorescent, and thermoresponsive: cellulose copolymers via light-induced ligation in solution by Andrea Hufendiek, Christopher Barner-Kowollik and Michael A. R. Meier, Polym. Chem., 2015, 6, 2188-2191

Remzi Becer is a web-writer and Advisory Board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Paper of the week: Nanoscale detection of metal-labeled copolymers in patchy polymersomes

Ruiz-Pérez et al. report the nanoscale detection of metal-labelled copolymers in patchy polymersomes.

The synthesis of polymersome-forming block copolymers using two different synthetic routes based on Atom Transfer Radical Polymerisation (ATRP) and Reversible Addition Fragmentation chain Transfer (RAFT) polymerisation is reported. Functionalisation with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) allowed the block copolymer chains to be labelled with electron-dense metal ions (e.g. indium). The resulting metal-conjugated copolymers can be visualised by transmission electron microscopy with single chain resolution, hence enabling the study of polymer/polymer immiscibility and phase separation on the nano-scale.

Nanoscale detection of metal-labeled copolymers in patchy polymersomes by Lorena Ruiz-Pérez, Jeppe Madsen, Efrosyni Themistou, Jens Gaitzsch, Léa Messager, Steven P. Armes and Giuseppe Battaglia, Polym. Chem., 2015, 6, 2065-2068.

Remzi Becer is a web-writer and Advisory Board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Paper of the week: Titin-mimicking polycyclic polymers with shape regeneration and healing properties

Schuetz et al. describe polycyclic polymers with shape regeneration and healing properties.

Polycyclic polymers based on cyclic (ABC)n-multiblock-copolymers are formed via stepwise polymerization of three individual blocks and exploiting the ring merging reaction of these ring polymers. The so-obtained precursor ring-polymers were interconnected via click reaction. Small blocks within the rings with the ability to form self-complementary hydrogen bonds lead to intra- and intermolecular links between polycyclic polymers. The obtained materials, which mimic nature’s paragon Titin, have some extraordinary material properties concerning elasticity and energy dissipation.

Titin-mimicking polycyclic polymers with shape regeneration and healing properties by Jan-Hendrik Schuetz, Peng Wentao and Philipp Vana, Polym. Chem., 2015,6, 1714-1726.

Remzi Becer is a web-writer and Advisory Board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Paper of the week: A fast track strategy toward highly functionalized dendrimers with different structural layers

Sharma et al. describe a fast track strategy toward highly functionalized dendrimers with different structural layers: an “onion peel approach”

An accelerated strategy depending on different chemical building blocks between each layer, coined “onion peel”, was used to construct a library of third generation dendrimers with 108, 180 and 252 hydroxyl surface groups using a combination of microwave assisted highly efficient CuAAC and thiol–ene reactions. These dendrimers were conveniently acquired with high purity and good yields in a divergent manner using a variety of orthogonal and dense AB3, AB5, and AB7building blocks. The resulting polyhydroxylated dendrimers tested in several human cell types did not impair mitochondrial metabolic function or cell viability suggesting that they are good candidates for applications in biological investigations.

A fast track strategy toward highly functionalized dendrimers with different structural layers: an “onion peel approach” by Rishi Sharma, Issan Zhang, Leïla Abbassi, Rabindra Rej, Dusica Maysinger and René Roy, Polym. Chem., 2015, 6, 1436-1444.

Remzi Becer is a web-writer and Advisory Board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Paper of the week: Dynamic intracellular delivery of antibiotics via pH-responsive polymersomes

Lane et al. report the intracellular delivery of antibiotics via pH-responsive polymersomes.

Reversible addition-fragmentation chain transfer (RAFT) polymerisation was employed to prepare a series of copolymers consisting of 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) methyl ether methacrylate (FWavg [similar] 950 Da) (O950) with variable comonomer compositions and molecular weights for use as polymeric scaffolds. Reactivity ratios for the monomer pair were determined to be 1.37 and 0.290 respectively. To these scaffolds, trithiocarbonate-based RAFT chain transfer agents (CTAs) were grafted using carbodiimide chemistry. The resultant graft chain transfer agents (gCTA) were subsequently employed to polymerise dimethylaminoethyl methacrylate (DMAEMA) and N-(2-hydroxypropyl)methacrylamide (HPMA) between degrees of polymerisation (DP) of 25 and 200. Kinetic analysis for the polymerisation of DMAEMA targeting a DP of 100 from a 34 arm graft gCTA show linear Mn conversion and pseudo first order rate plots with narrow molecular weight distributions that move toward lower elution volumes with monomer conversion. Đ values for these polymerisations remain low at around 1.20 at monomer conversions as high as 70%. pH-responsive endosomalytic brushes capable of spontaneously self-assembling into polymersomes were synthesised and a combination of dynamic light scattering (DLS), cryoTEM, and red blood cell haemolysis were employed to evaluate the aqueous solution properties of the polymeric brush as a function of pH. Successful encapsulation of ceftazidime and pH-dependent drug release properties were confirmed by HPLC. Intracellular antibiotic activity of the drug-loaded polymersomes was confirmed in a macrophage coculture model of infection with Burkholderia thailandensis and RAW 264.7 cells.

Dynamic intracellular delivery of antibiotics via pH-responsive polymersomes by D. D. Lane, F. Y. Su, D. Y. Chiu, S. Srinivasan, J. T. Wilson, D. M. Ratner, P. S. Stayton and A. J. Convertine, Polym. Chem., 2015,6, 1255-1266.

Remzi Becer is a web-writer and Advisory Board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Paper of the week: Efficient microencapsulation of a liquid isocyanate with in situ shell functionalization

Nguyen et al. outline the efficient microencapsulation of a liquid isocyanate with in situ shell functionalization.

Nguyen et al. report on a one-pot, facile approach for the encapsulation of the liquid hexamethylene diisocyanate isocyanurate trimer in polyurea microcapsules formed via the oil-in-water interfacial reaction of an uretonimine-modified diphenyl methane diisocyanate trimer with triaminopyrimidine; with in situ shell functionalization/modification using different types of hydrophobic agents. Remarkably, the use of hexamethylenedisilazane resulted in microcapsules of about 70 μm in diameter, with a smooth outer surface and a high isocyanate core content up to 85 wt% as determined by quantitative online FT-IR analysis of the extracted core. On the other hand, the use of an alkylamine, fluorinated aromatic amine and/or perfluoride amine provided microcapsules of approximately 100 to 150 μm in diameter containing around 65–75 wt% of the isocyanate core content, with the outer shell surface bearing pendant hydrophobic groups as confirmed by SEM-EDX. The effects of the functionalizing compound on the microcapsule properties such as shell morphology, size distribution and stability were assessed. After one day immersion in water, the initial isocyanate content of the microcapsules with a non-functionalized shell dropped rapidly from 49 to 15 wt%, whereas the ones with the modified shell structure maintained their core content, suggesting a significantly enhanced microcapsule stability.

Efficient microencapsulation of a liquid isocyanate with in situ shell functionalization by Le-Thu T. Nguyen, Xander K. D. Hillewaere, Roberto F. A. Teixeira, Otto van den Berg and Filip E. Du Prez, Polym. Chem., 2015, 6, 1159-1170.

Remzi Becer is a web-writer and Advisory Board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Paper of the week: Highly regioselective Pd/C-catalyzed direct arylation toward thiophene-based π-conjugated polymers

Hayashi et al. have successfully developed a highly regioselective Pd/C-catalysed direct arylation toward thiophene-based π-conjugated polymers.

Pd/C heterogeneous catalysts were used in the direct arylation polycondensation of thiophenes. The efficient and highly regioselective polycondensation of thiophene monomers was achieved under phosphine-free conditions to give linear π-conjugated alternating copolymers with high molecular weight in high yield.

Highly regioselective Pd/C-catalyzed direct arylation toward thiophene-based π-conjugated polymers by Shotaro Hayashi, Yoshihisa Kojima and Toshio Koizumi Polym. Chem., 2015,6, 881-885.

Remzi Becer is a web-writer and Advisory Board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Paper of the week: Novel polymer synthesis methodologies using combinations of thermally- and photochemically-induced nitroxide mediated polymerization

Guillaneuf and Gigmes and co-workers discuss novel polymer synthesis methodologies using combinations of thermally- and photochemically-induced nitroxide mediated polymerization

The combination of thermally- and photochemically-induced polymerization using light-sensitive alkoxyamines was investigated. The thermally driven polymerizations were performed via the cleavage of the alkoxyamine functionality, whereas the photochemically-induced polymerizations were carried out either by nitroxide mediated photo-polymerization (NMP2) or by a classical type II mechanism, depending on the structure of the light-sensitive alkoxyamine employed. Once the potential of the various structures as initiators of thermally- and photo-induced polymerizations was established, their use in combination for block copolymer syntheses was investigated. With each alkoxyamine investigated, block copolymers were successfully obtained and the system was applied to the post-modification of polymer coatings for application in patterning and photografting.

Novel polymer synthesis methodologies using combinations of thermally- and photochemically-induced nitroxide mediated polymerization by Jason Morris, Sofia Telitel, Kathryn E. Fairfull-Smith, Steven E. Bottle, Jacques Lalevée, Jean-Louis Clément, Yohann Guillaneuf and Didier Gigmes Polym. Chem., 2015,6, 754-763

Remzi Becer is a web-writer and Advisory Board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Paper of the week: The power of one-pot: a hexa-component system containing π–π stacking, Ugi reaction and RAFT polymerization for simple polymer conjugation on carbon nanotubes

Yang et al. have developed a one pot approach to prepare polymer-carbon nanotube conjugates.

A hexa-component system has been successfully developed for simple polymer conjugation on carbon nanotubes. The well-known Ugi reaction has been recognized as a multicomponent click (MCC) reaction to efficiently collaborate with π–π stacking and RAFT polymerization to construct this delicate one-pot system. The CNT–(co)polymer composites inherit the properties of the conjugated polymers and can be well dispersed in both organic and aqueous solvents. As a simple and efficient method, this one-pot system might have the potential to become a general approach to prepare carbon-based composites.

The power of one-pot: a hexa-component system containing π–π stacking, Ugi reaction and RAFT polymerization for simple polymer conjugation on carbon nanotubes by Bin Yang, Yuan Zhao, Xu Ren, Xiaoyong Zhang, Changkui Fu, Yaling Zhang, Yen Wei and Lei Tao, Polym. Chem., 2015,6, 509-513.

Remzi Becer is a web-writer and Advisory Board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Paper of the week: Precise one-pot synthesis of fully conjugated end-functionalized star polymers containing poly(fluorene-2,7-vinylene) (PFV) arms

Nomura et al. present the one-pot synthesis of star shaped conjugated polymers.

A facile, precise one-pot synthesis of end-functionalized star (triarm) polymers consisting of poly(9,9-di-n-octylfluorene-2,7-vinylene)s (PFVs), the triblock copolymers [by incorporation of tri(2,5-dialkoxy-1,4-phenylene vinylene) or terthiophene units as the middle segment], has been achieved by olefin metathesis followed by Wittig-type coupling. Effects of the PFV conjugation length, the middle segment and the end groups on the emission properties have been studied.

Precise one-pot synthesis of fully conjugated end-functionalized star polymers containing poly(fluorene-2,7-vinylene) (PFV) arms by Kotohiro Nomura, Tahmina Haque, Tomohiro Miwata, Akiko Inagaki and Kenji Takamizu Polym. Chem., 2015,6, 380-388

Remzi Becer is a web-writer and advisory board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)