Polymer Chemistry Blog

Introducing Polymer Chemistry Editorial Board Member Masami Kamigaito

23 Jan 2013

Masami Kamigaito was born in 1965 in Nagoya, Japan. He received his Ph.D. in polymer chemistry from Kyoto University under the direction of Professor Toshinobu Higashimura in 1993. After conducting postdoctoral research with Professor Mitsuo Sawamoto, he joined the faculty of Kyoto University in 1995. In 2003, he moved to Nagoya University and worked as an Associate Professor with Professor Yoshio Okamoto. In 2004, he was promoted to Professor. From 1997–1998, he worked as a visiting scientist at Stanford University with Professor Robert M. Waymouth. He was the recipient of the 2001 Arthur K. Doolittle Award of the ACS PMSE Division, the 2009 Wiley Polymer Science Award of the Society of Polymer Science, Japan, and the 2010 Japan IBM Science Award (Chemistry). His research interests include controlled radical and cationic polymerizations, the development and application of new polymerizations to precision polymer synthesis, and controlled polymerizations of renewable vinyl monomers.

His recent papers include:

Nanocellular foaming of fluorine containing block copolymers in carbon dioxide: the role of glass transition in carbon dioxide
RSC Adv., 2012,2, 2821-2827

From-syndiotactic-to-isotactic stereogradient methacrylic polymers by RAFT copolymerization of methacrylic acid and its bulky esters
Polym. Chem., 2012,3, 1750-1757

Random copolymer of styrene and diene derivatives via anionic living polymerization followed by intramolecular Friedel–Crafts cyclization for high-performance thermoplastics
Polym. Chem., 2012,3, 190-197

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Paper of the week: A functional polymer with chemically switchable crystallinity

21 Jan 2013

By Julien Nicolas, web writer.

Synthetic polymers have experienced an exponential growth over the last sixty years, in part due to their combined low density and exceptional mechanical properties. Along with chain architecture and microdomain morphology, polymer crystallinity is one of the determining parameters which control these properties. Recently, there has been a flurry of activity regarding the possibility of altering mechanical properties by changing chain architecture or microdomain morphology upon the action of a chemical stimulus, a property which can be exploited for the fabrication of mechanically adaptive objects as well as sensors.

Graphical abstract: A functional polymer with chemically switchable crystallinity

In this context, Claverie and co-workers reported a functional polymer with chemically switchable crystallinity. Linear polyethylenes containing pendant diacetone acrylamide groups were prepared using Pd phosphine sulfonate catalysts. These polymers are easily cross-linked upon reaction with hydrazine, and the cross-links can be cleaved by ozonolysis to regenerate the original polymer. The cross-linked polymer, once heated above the melting point, becomes permanently amorphous, as the crosslinks prevent the chains from packing. Crystallinity can only be recovered with the cleavage of the cross-links. Thus, the polymeric material exhibits two states (crystalline and amorphous) which are triggered upon action of simple chemicals. This study thus offers a proof of principle that crystallinity responds to the action of a chemical stimulus.

A functional polymer with chemically switchable crystallinity by Jean-Christophe Daigle, Alexandre A. Arnold, Laurence Piche and Jerome P. Claverie, Polym. Chem., 2013, 4, 449-452.

Julien Nicolas is a guest web-writer for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

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Paper of the week: Heterogeneous modification of chitosan via nitroxide-mediated polymerization

16 Jan 2013

By Julien Nicolas, web writer.

Chitosan (CS) is a natural polysaccharide which displays excellent biological properties such as biocompatibility, biodegradability, and antibacterial and wound-healing activity. CS has thus promising applications in many fields such as biomedicine, wastewater treatment, functional membranes and flocculation. In order to circumvent the main drawbacks of CS such as its solubility only in acid solutions and its poor mechanical properties compared to synthetic polymers, CS has been modified by chemical treatments and more efficiently by graft copolymerization. However, these methods of grafting do not generally allow controlling the molecular weight and the number of grafted chains. Controlled/living radical polymerization have therefore opened new prospects in this domain.

Graphical abstract: Heterogeneous modification of chitosan via nitroxide-mediated polymerization

In this context, Lefay and co-workers reported an efficient CS modification method based on nitroxide-mediated polymerization (NMP) under heterogeneous conditions. After introduction of acrylamide and/or acrylate functions onto the CS backbone followed by intermolecular 1,2 radical addition of the BlocBuilder alkoxyamine, methyl methacrylate in the presence of a small amount of acrylonitrile or sodium 4-styrenesulfonate was successfully polymerized by NMP under the SG1 nitroxide control. Analyses revealed that 20-30 wt% of synthetic polymers were grafted onto the CS backbone, yielding a hybrid material with potential applications such as a biocompatibilizer.

Heterogeneous modification of chitosan via nitroxide-mediated polymerization by Catherine Lefay, Yohann Guillaneuf, Guillaume Moreira, Joel J. Thevarajah, Patrice Castignolles, Fabio Ziarelli, Emily Bloch, Mohamed Major, Laurence Charles, Marianne Gaborieau, Denis Bertin and Didier Gigmes, Polym. Chem., 2013, 4, 322-328.

Julien Nicolas is a guest web-writer for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

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Author of the Week: Dr. François Tournilhac

14 Jan 2013

By Cyrille Boyer.

François Tournilhac received a Master’s degree in engineering at Ecole Centrale des Arts et Manufactures, Paris (1984) and PhD in Physical Chemistry at Université Pierre et MarieCurie, Paris (1989). Since 1989 he is a researcher at the Centre National de la Recherche Scientifique (CNRS), As a soft matter chemist, he has been working to design materials and demonstrate new effects in organic semiconductors, liquid crystals, block copolymers and composites. Presently, he is working in the team of Ludwik Leibler, Soft Matter and Chemistry at ESPCI-ParisTech, where he is developing new activities in polymer and supramolecular chemistry with a double ambition: design new materials with unusual combination of properties and in the same time identifying practical synthetic routes to make them faisible at the industrial scale.

Website of the lab: www.mmc.espci.fr

What was your inspiration in becoming a chemist?

The inspiration came to me after studying engineering without particular skills in chemistry. I wanted to do research, it seemed to me that it was a good way to remain a student during my whole life but I also wanted to make something creative by my own hands. Then I remembered these practical organic chemistry sessions of my undergraduate studies where azo dyes or aspirin are synthesized from raw material and this eventually determined my choice to launch out into chemistry.

What was the motivation to write your Polymer Chemistry article?

To the best of our knowledge, the topic of this paper, a supramolecular initiator, is a new concept. We apply it for the cationic polymerization of a commercial epoxy resin with practical application in mind but we think that this concept can be adapted to most of the polymerization processes that involve an initiation step. The motivation was also to highlight a leading work, made by a PhD student.

Why did you choose Polymer Chemistry to publish your work? (DOI: 10.1039/C2PY21140H)

Because we are ourselves readers of Polymer Chemistry and we wanted to reach a broad audience. In addition, we had excellent experience of our previous submissions to this journal: very constructive reviewers comments which helped a lot to improve the quality of the papers as well as very quick publication.

In which upcoming conferences may our readers meet you?

I will be present in Batsheva de Rothschild Seminar on Soft Matter and Biophysics in Israël in February and in the International Conference on Self Healing Materials in Belgium in June.

How do you spend your spare times?

Drawing and etching

Which profession would you choose if you were not a scientist?

Illustrator

Cyrille Boyer is a guest web-writer for Polymer Chemistry. He is currently a Senior Lecturer and an ARC-Future Fellow at the Australian Centre for NanoMedicine (School of Chemical Engineering, University of New South Wales (Australia)).

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Paper of the week: Macrocyclic regioregular poly(3-hexylthiophene)

11 Jan 2013

By Julien Nicolas, web writer.

Macrocyclic non-collapsible p-conjugated structures are known to be useful in the preparation of 1D nanotubes, 2D porous networks and 3D inclusion complexes through either unique p–p stacking or concave–convex interactions. In particular for medium to giant cyclic structures, i.e. larger than 2 nm in diameter, the p-conjugated system allows benzene, thiophene, pyridine and acetylene-based macrocycles to exhibit peculiar optical, electronic, and self-assembly properties compared to their linear homologues. Structures with fully conjugated p-systems are particularly appealing because of the absence of edge eﬀects in the p-system due to chain ends. To date, only a few examples of fully conjugated cyclic periphery have been reported. Among those, several kinds of macrocyclic oligothiophenes have attracted considerable attention since such macrocycles exhibit interesting electronic properties such as non-linear optical eﬀects.

Graphical abstract: Macrocyclic regioregular poly(3-hexylthiophene): from controlled synthesis to nanotubular assemblies

In this study, Coulembier and co-workers have demonstrated that the preparation of giant regioregular poly(3-hexylthiophene) (P3HT) cyclics is possible with a simple but unperfected aldol reaction from a pre-formed telechelic P3HT. The four-step synthetic strategy is based on a non-metallic aldol cyclization of a designed Luscombe-type regioregular P3HT. AFM analyses highlight that linear and macrocyclic P3HTs give diﬀerent self-assembled nanostructures. Interestingly, the tubular assembly of the macrocyclic P3HT, with an estimated diameter of 5 nm, could be exploited to incorporate nano-sized structures such as carbon nanotubes or fullerenes, with potential application as a compatibilizer for bulk heterojunction photovoltaic diodes for instance.

Macrocyclic regioregular poly(3-hexylthiophene): from controlled synthesis to nanotubular assemblies by Olivier Coulembier, Gaelle Deshayes, Mathieu Surin, Julien De Winter, Florian Boon, Cecile Delcourt, Philippe Leclere, Roberto Lazzaroni, Pascal Gerbaux and Philippe Dubois, Polym. Chem., 2013, 4, 237-241.

Julien Nicolas is a guest web-writer for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher

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Paper of the week: Functionalized cyclic polymers in high yield

04 Jan 2013

By Julien Nicolas, web writer.

Although the primitive single-cyclic form conceptually represents the simplest cyclic topology, the synthetic constraints in general prevent from the clean and easy production of uniform cyclic polymers, particularly when availability of a specific functional group for further topological upgrade is desired. The common syntheses of single-cyclic polymers employ end-to-end ring-closure and ring-expansion polymerization.

Graphical abstract: Straightforward synthesis of functionalized cyclic polymers in high yield via RAFT and thiolactone–disulfide chemistry

In this study, Du Prez and co-workers reported on an efficient synthetic pathway toward cyclic polymers based on the combination of thiolactone and disulﬁde chemistry. First, heterotelechelic linear polystyrene (PS) containing an a-thiolactone (TLa) and an w-dithiobenzoate group was synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization, employing a newly designed TLa-bearing chain transfer agent (CTA). The subsequent reaction of this heterotelechelic polymer with an amine, which acts as a nucleophile for both the TLa and dithiobenzoate units, generated the a,w-thiol-telechelic PS under ambient conditions without the need for any catalyst or other additives. The arrangement of thiols under a high dilution afforded single cyclic PS (c-PS) through an oxidative disulﬁde linkage. Moreover, the authors demonstrated a controlled ring opening via either disulﬁde reduction or thiol–disulﬁde exchange to enable easy and clean topology transformation. Furthermore, to illustrate the broad utility of this synthetic methodology, different amines including functional ones were employed, allowing for the one-step preparation of functionalized cyclic polymers with high yields.

Straightforward synthesis of functionalized cyclic polymers in high yield via RAFT and thiolactone–disulfide chemistry by Milan M. Stamenović, Pieter Espeel, Eisuke Baba, Takuya Yamamoto, Yasuyuki Tezuka and Filip E. Du Prez, Polym. Chem., 2013, 4, 184-193.

Julien Nicolas is a guest web-writer for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher

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Paper of the week: Block polymer miktobrushes

02 Jan 2013

By Julien Nicolas, web writer.

Block polymers can spontaneously self-assemble into well-defined nanostructures in block selective solvents and in the bulk, offering a powerful ‘bottom up’ approach towards precisely engineered materials for many diverse applications including; microelectronics, tissue engineering, drug delivery and water purification. The increased understanding of self-assembled block polymers with varied architectures is of both fundamental and technological importance. Towards this goal, AB diblock copolymers have been studied in depth and it has been shown that adding more blocks and functional groups increases architectural and functional complexity and can lead to more exotic self-assembled morphologies.

Graphical abstract: Synthesis of block polymer miktobrushes

In this study, Lodge and Hillmyer reported an innovative synthetic strategy towards a wide compositional range of structurally well defined “miktobrush” block terpolymers, m-A(BC)_n obtained using rather mild and facile reaction conditions with three separate polymer building blocks. The copolymers were synthesized utilizing the alternating radical copolymerization of two hydrophobic and incompatible macromonomer (MM) building blocks; a maleimide (MI) end functionalized poly(methyl-caprolactone) block (MI-PMCL) or ‘C’ and a styrene (Sty) end functionalized poly(perﬂuoro propylene oxide) block (Sty-PFPO) or ‘F’. Polymerizations were mediated by a poly(ethylene oxide) (PEO) functionalized reversible addition–fragmentation chain transfer (RAFT) agent (PEO–CTA) or ‘O’ to control the chain growth of the MMs from the O block to form O(CF)_n “miktobrush” terpolymers. The synthesis of a range of well deﬁned m-O(CF)_n terpolymers with various compositions was achieved by simply changing the feed of MMs. This new strategy offers a powerful route towards a block polymer architecture that can enable the formation of multi-domain hierarchical nanostructures with features on multiple length scales due to the incompatibility and unique connectivity of the building blocks incorporated.

Synthesis of block polymer miktobrushes by Adam O. Moughton, Takanori Sagawa, William M. Gramlich, Myungeun Seo, Timothy P. Lodge, and Marc A. Hillmyer, Polym. Chem., 2013, 4, 166-173.

Julien Nicolas is a guest web-writer for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher

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Happy holidays from Polymer Chemistry!

21 Dec 2012

By Sam Keltie, Executive Editor.

All of us in the Polymer Chemistry Editorial team would like to wish you all a merry Christmas and a happy new year! The Editorial office will be closed from 21 December 2012 and will reopen on 2 January 2013.

We’re really looking forward to 2013, which will see more high quality articles from top international polymer chemists, some great themed issues and much more.

Don’t miss out on all the journal news – follow us on twitter @PolymChem and like us on Facebook!

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Author of the Week: Dr. Massimo Benaglia

20 Dec 2012

By Cyrille Boyer.

Dr. Massimo Benaglia graduated in Pharmacy at the University of Bologna in 1995. He started his professional career in 1986 joining the CNR (National Research Council) as a Technical Assistant becoming a Full Researcher in 2006. Having already acquired a strong background in organic synthesis, he spent 2002 at the CSIRO (Commonwealth Scientific and Industrial Research Organization) in Melbourne (Australia) working as a Visiting Scientist in Dr. Rizzardo’s group studying the RAFT (Reversible Addition-Fragmentation chain Transfer) process. Realizing the enormous potentialities of this technique led him to pursue his work in the controlled radical polymerization field. In 2006 he spent another year at CSIRO studying new RAFT agents with “switchable” properties and in 2007 started studying polymeric micelles obtained through the self-assembly of “pseudo-amphiphilic” block-copolymers. His current research interests focus upon the post-polymerization modifications of poly(glycidyl methacrylate) in order to obtain materials suitable for delivery of therapeutic (drugs, nucleic acids) and/or diagnostic agents (fluorescent probes).

Website: www.isof.cnr.it/?q=content/benaglia-massimo

What was your inspiration in becoming a chemist?

As a child one of my most frequent requests as a birthday present was the “Little Chemist” but I never actually received it. Later on, however, at high school, I chose chemistry as my main subject. It was actually at school that I discovered my passion for the chemistry lab doing experiments where I could “transform” something into something else. During my studies at Uni I applied for a job at the CNR (National Research Council) and when I was 21 I found myself actually working in a lab in a research group. I consider chemistry as a way of expressing my creativity since I don’t have a great artistic predisposition. Now, through studying and applying the RAFT process, I can enjoy designing and creating new materials capable of performing special and specific functions.

What was the motivation to write your Polymer Chemistry article?

The RAFT technique is a very versatile way to synthesize functional polymers with a defined architecture. The basic problem, however, is that polymerization conditions have to be optimized for each monomer/RAFT agent system. The use of glycidyl methacrylate might provide a way of overcoming this issue. Starting from the same pre-synthesized PGMA the article shows that it is possible to obtain many different kinds of polymers whose properties depend upon the nucleophilic agent chosen.

Why did you choose Polymer Chemistry to publish your work? (DOI:10.1039/C2PY20646C)

Polymer Chemistry is a journal that highlights all the novel aspects of polymer synthesis. Here, it is possible to follow the state of the art in this field. When I first came across the journal I was impressed by the high quality of the papers. Another great advantage is the very rapid review process.

In which upcoming conferences may our readers meet you?

I haven’t decided yet which conferences I will attend in 2013. I usually find small/medium-sized conferences more fruitful in terms of scientific interactions and my choice will probably depend upon this aspect.

How do you spend your spare time?

Mostly with my relatives and friends. I like music and movies, but I also like food. Therefore, besides resting after tiring days, I go out to the cinema or to listen to live music or enjoy good food/wine in the company of friends.

Which profession would you choose if you were not a scientist?

I didn’t mention that I also like cooking and I would definitely have been a chef. I consider the “art” of cooking another very interesting way of expressing creativity with the advantage of the results being promptly verifiable, especially in a convivial way.

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Paper of the week: In situ stereocomplexing polymerization of methyl methacrylate

17 Dec 2012

By Julien Nicolas, web writer.

Stereocomplex poly(methyl methacrylate), sc-PMMA, is a crystalline material formed via van der Waals interactions between diastereomeric, isotactic (it) and syndiotactic (st), PMMA chains. It represents a rare example of helical supramolecular structures derived from a commodity polymer and is typically obtained in a 1/2 it/st ratio either in the solid state, when annealed, or in suitable solvents, when crystallized. In this study, Chen and co-workers hypothesized that, with the advent of stereospeciﬁc and living coordination polymerization by chiral metallocene catalysts, it is possible to combine the synthesis of highly stereoregular PMMAs with the fabrication of their crystalline stereocomplex into a one-step procedure, thereby producing such important crystalline materials in a rapid and cost/energy-saving fashion.

Graphical abstract: In situ stereocomplexing polymerization of methyl methacrylate by diastereospecific metallocene catalyst pairs

The authors demonstrate the ﬁrst in situ stereocomplexing polymerization of MMA using a pair of diastereospeciﬁc coordination polymerization catalysts for rapid, high-yield, ambient-temperature production of crystalline sc-PMMA. The diastereospeciﬁc catalyst pair is conveniently generated by in situ activation of a mixture of C2- and Cs -ligated metallocene bis(ester enolate)s with [Ph₃C][B(C₆F₅)₄], which is highly active, stereospeciﬁc, and controlled for coordination–addition polymerization of MMA. The isotactic/syndiotactic (it/st) composition of the sc-PMMA materials can be modulated by simply adjusting the relative ratio of the diastereospeciﬁc catalysts. The dynamic light scattering (DLS) results of the in situ stereocomplexing polymerization by a diastereospeciﬁc catalyst pair, obtained by monitoring the reaction in real time with DLS, indicate that stereocomplexation occurs as the diastereomeric PMMA chains are continuously growing. The presence of nanocages such as POSS and C60, which can be encapsulated by st-PMMA, in the stereocomplexing MMA polymerization system can completely disrupt or have no effect on the stereocomplexation, or enable both stereocomplexation and inclusion complexation processes to occur, depending on the type of nanocage employed.

In situ stereocomplexing polymerization of methyl methacrylate by diastereospeciﬁc metallocene catalyst pairs by Nicole C. Escudé, Yalan Ning and Eugene Y.-X. Chen, Polym. Chem., 2012, 3, 3247-3255.

Julien Nicolas is a guest web-writer for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher

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Polymer Chemistry Blog

Introducing Polymer Chemistry Editorial Board Member Masami Kamigaito

Paper of the week: A functional polymer with chemically switchable crystallinity

Paper of the week: Heterogeneous modification of chitosan via nitroxide-mediated polymerization

Author of the Week: Dr. François Tournilhac

Paper of the week: Macrocyclic regioregular poly(3-hexylthiophene)

Paper of the week: Functionalized cyclic polymers in high yield

Paper of the week: Block polymer miktobrushes

Happy holidays from Polymer Chemistry!

Author of the Week: Dr. Massimo Benaglia

Paper of the week: In situ stereocomplexing polymerization of methyl methacrylate

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