Archive for May, 2017

Polymer Chemistry Lectureship Award Julien Nicolas at APME 2017

Dr Julien Nicolas (Université Paris Sud, France) was presented the 2017 Polymer Chemistry Lectureship award at APME 17 – Advanced Polymers via Macromolecular Engineering in Ghent. The prize was awarded by Polymer Chemistry Associate Editor Prof. Dr. Christopher Barner-Kowollik from Queensland University of Technology and Karlsruhe Institute of Technology.

 
APME 2017 (Advanced Polymers via Macromolecular Engineering) took place in Ghent, Belgium on May 21-25, 2017.  The focus of the APME2017 meeting was on macromolecular engineering for the design of advanced polymeric structures, in connection to their characterisation and recent applications.

 

Dr. Julien Nicolas (left) holding the Polymer Chemistry prize awarded by Prof. Dr. Christopher Barner-Kowollik (right)

 

 

Congratulations to Julien on his award!

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International Symposium on Ionic Polymerization – IP 2017

The 12th International Symposium on Ionic Polymerization (IP 2017) will be held at Durham University, UK from 17 – 22 September, organised and hosted by the Durham Centre for Soft Matter. 

The focus of IP 2017 will be on academic and industrial research in the areas of anionic, cationic and ring-opening polymerization mechanisms. Contributions related to other methods of living/controlled polymerization (catalytic, controlled free-radical, and step-growth polymerizations) will also be covered.

IP 2017 will feature also feature number of international leading invited speakers, as well as oral presentations, short talks for younger researchers and a poster session, supported by Polymer Chemistry, which will provide participants the opportunity to highlight their recent work. Submission deadlines for all abstracts is 31 May.

If you would like to attend, please register before 1 August in order to claim the early-bird rate. You can also read more about the symposium on the IP 2017 website.

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Paper of the month: Mild and efficient synthesis of ω,ω-heterodifunctionalized polymers and polymer bioconjugates

 

The versatile and high yielding modification of polymer end groups is a critical tool for controlling materials properties. However, when multiple different functionalities are needed, pre-installation of two different functional groups at the polymer end groups is typically a tedious requirement. Sumerlin, Castellano and co-workers managed to circumvent this by developing a mild approach that enables the efficient synthesis of ω-ω-heterodifunctionalized polymers and polymer bioconjugates. Key to this strategy is the use of the recently introduced reagent benzotrifuranone (BTF) which allows the introduction of differentially “clickable” functional groups to monomethyl ether poly(ethylene glycol) amine (mPEG amine). In contrast to conventional polymer heterofunctionalization approaches that require high temperatures, significant excess of reagents and numerous synthetic steps, BTF serves as an ideal functionalization handle that operates at ambient temperature using near-stoichiometric amounts of reagents. Importantly, following functionalization of BTF with alkyne and alkene functional groups a fluorescent (coumarin) dye and biotin could be successfully conjugated to the end of mPEG-amine. These polymer bioconjugates were then able to bind avidin while showing an unexpected disruption of avidin tetramer formation. Overall, the compatibility of BTF with a broad scope of amine nucleophiles and thermally sensitive moieties (e.g. proteins) in combination with the highly efficient and mild nature of this reagent holds great promise for more elaborate heterofunctionalization strategies.

 

 

Tips/comments directly from the authors:

 

  1. The reaction time of the first and second addition to BTF should be monitored (typically by thin layer chromatography) to ensure minimal over/under functionalization occurs.
  2. The trisubstitution products are tolerant to many reaction conditions; however, when performing reactions that include radical intermediates, higher than usual reagent equivalents may be needed due to the radical scavenging nature of the phloroglucinol
  3. When one-pot homodifunctionalizations are performed, be sure to add enough nucleophile to consume both electrophilic sites on the polymer end group and the three electrophilic sites on any unreacted BTF.
  4. Regarding BTF synthesis: 1) Using fresh polyphosphoric acid and monitoring the reaction temperature is very important for the ring-closing in the last step of the synthesis, and 2) BTF and the mono- and difuranone derivatives are sensitive to silica gel, so avoid letting the compounds reside in a column too long during purification.

 

Read this exciting research for free until 21/06/2017 through a registered RSC account.

 

Mild and efficient synthesis of ω,ω-heterodifunctionalized polymers and polymer bioconjugates
Polym. Chem., 2017,8, 2457-2461, DOI: 10.1039/C7PY00225D

 

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About the webwriterAthina Anastasaki

Dr. Athina Anastasaki is a web writer for Polymer Chemistry. She is currently a Global Marie Curie Fellow working alongside Professor Craig Hawker at the University of California, Santa Barbara (UCSB). Please visit this website for more

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Focus on: Polymer Self-Assembly

Self-assembly of block copolymers is well-known to form polymeric particles with various morphologies, for example, spherical, cylindrical and vesicular morphologies. This month we focus on three research articles published in Polymer Chemistry involving polymer self-assembly.

Polymer self-assembly is driven by the respective solubilities of the blocks of the copolymer in the solvent media present. For example, when water is the desired media the polymer is designed so that one block is water soluble and one block is water insoluble. Either post-polymerisation self-assembly, or in situ polymerisation-induced self-assembly can be employed to form a range of particle morphologies. Post-polymerisation self-assembly typically relies on a solvent switch technique whereby the block copolymer is dissolved in a good solvent for the whole polymer, and is subsequently added to another miscible solvent which is a good solvent for one block and a non-solvent for another. On the other hand, polymerisation-induced self-assembly involves the chain extension of a soluble stabiliser block with a monomer, which when polymerised is insoluble, therefore the polymerisation of the monomer drives the self-assembly process.

The first two articles here utilise polymerisation-induced self-assembly, whilst the third employs post-polymerisation self-assembly. Interestingly, all of the articles highlighted here have employed reversible addition-fragmentation chain-transfer (RAFT) polymerisation as the polymerisation technique of choice to prepared the polymers studied.

 

 

1. In situ synthesis of a self-assembled AB/B blend of poly(ethylene glycol)-b-polystyrene/polystyrene by dispersion RAFT polymerization
Bing Yuan, Xin He, Yaqing Qu, Chengqiang Gao, Erika Eiser, Wangqing Zhang
Polym. Chem., 2017,8, 2173-2181; DOI: 10.1039/C7PY00339K

In this article, the authors present the self-assembly of diblock copolymers and homopolymers through a dispersion RAFT polymerisation. The use of a poly(ethylene glycol) macromolecular chain-transfer agent (macro-CTA) and a small molecule CTA led to the formation of various self-assembled morphologies that were considerably different from the pre-synthesised equivalent blends. Morphologies obtained include: vesicles, compartmentalized vesicles and porous nanospheres.

2. RAFT/MADIX emulsion copolymerization of vinyl acetate and N-vinylcaprolactam: towards waterborne physically crosslinked thermoresponsive particles
Laura Etchenausia, Abdel Khoukh, Elise Deniau Lejeune, Maud Save
Polym. Chem., 2017, 8, 2244-2256; DOI: 10.1039/C7PY00221A

Here, the RAFT/MADIX batch emulsion copolymerisation of vinyl acetate (VAc) and N-vinyl caprolactam (VCL) was performed using a poly(ethylene glycol) macro-CTA. The resulting particles were physically crosslinked and thermoresponsive, and particles with a core composition of VAc and VCL of 47:53 exhibited a reversible swelling-to-collapse transition with heating. The hydrolysis of VAc units to vinyl alcohol gave thermoresponsive biocompatible statistical copolymers.

3. CO2-Triggered UCST transition of amphiphilic triblock copolymers and their self-assemblies
Shaojian Lin, Jiaojiao Shang, Patrick Theato
Polym. Chem., 2017, 8, 2619-2629; DOI: 10.1039/C7PY00186J

RAFT polymerisation was used to prepare triblock copolymers consisting of poly[(ethylene glycol)methyl ether]-b-poly(acrylamide-co-acrylonitrile)-b-poly(diethylamino ethyl methacrylate), which self-assembled in water to form vesicles. As this triblock copolymer contains a temperature responsive segment and a COresponsive block, a morphological transition from vesicles to micelles could be achieved with a COpurge, and then to unimers with an increase in temperature.

Read these articles for free until June 21th


About the webwriterFiona Hatton

Dr. Fiona Hatton is a web writer for Polymer Chemistry. She is currently a postdoctoral researcher in the Armes group at the University of Sheffield, UK. Find her on Twitter: @fi_hat

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2017 Polymer Chemistry Lectureship awarded to Julien Nicolas

It is with great pleasure that we announce Dr Julien Nicolas (Université Paris Sud, France) as the recipient of the 2017 Polymer Chemistry Lectureship.

This award, now in its third year, honours an early-career researcher who has made significant contribution to the polymer chemistry field. The recipient is selected by the Polymer Chemistry Editorial Board from a list of candidates nominated by the community.

Read on to find out more about Julien…

Dr Julien Nicolas

Julien Nicolas obtained his Doctor of Philosophy in Chemistry and Physical Chemistry of Polymers in 2005 from the Laboratory of Polymer Chemistry, at the Université Pierre and Marie Curie, in Paris, France, under the supervision of Prof. Bernadette Charleux. He then joined Prof. David Haddleton’s group at the University of Warwick as a postdoctoral fellow in 2006. In 2007, he became a CNRS researcher at Institut Galien, Paris Sud, and became a Director of Research in the same institute in 2016. He has published more than 80 refereed scientific articles (h-index 36), filled 5 patents and is currently Associate Editor for Chemistry of Materials (ACS).

Julien’s current research interests are multidisciplinary and span from organic chemistry and polymer synthesis to nanoparticulate systems and biomedical applications. The current interests of his group are focused on multifunctional biodegradable nanoparticles, well-defined molecular/polymer prodrug nanoparticles and controlled polymerization techniques from both fundamental and applied standpoints, with an emphasis on their application for the synthesis of biodegradable vinyl polymers and innovative biomaterials. Awards and honours he has received to date include the French Polymer Society (GFP) / French Chemical Society (SCF) award in 2016, and the 2017 Polymer Chemistry Lectureship award.

 

 

To learn more about Julien’s research, have a look at some of his publications in Polymer Chemistry:

Structure–cytotoxicity relationship of drug-initiated polymer prodrug nanoparticles
Yinyin Bao and Julien Nicolas
Polym. Chem., 2017, DOI: 10.1039/C7PY00536A

Efficient synthesis of 2-methylene-4-phenyl-1,3-dioxolane, a cyclic ketene acetal for controlling the NMP of methyl methacrylate and conferring tunable degradability
Johanna Tran,Elise Guégain, Nada Ibrahim, Simon Harrisson and Julien Nicolas
Polym. Chem., 2016, 7, 4427-4435

On the structure–control relationship of amide-functionalized SG1-based alkoxyamines for nitroxide-mediated polymerization and conjugation
Elise Guégain, Vianney Delplace, Thomas Trimaille, Didier Gigmes, Didier Siri, Sylvain R. A. Marque, Yohann Guillaneuf and Julien Nicolas
Polym. Chem., 2015,6, 5693-5704

Recent trends in the design of anticancer polymer prodrug nanocarriers
Vianney Delplace, Patrick Couvreur and Julien Nicolas
Polym. Chem., 2014, 5, 1529-1544

We would like to thank everybody who nominated a candidate for the Lectureship; we received many excellent nominations, and the Editorial Board had a difficult task in choosing between some outstanding candidates.

Please join us in congratulating Julien on his award!

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