Archive for July, 2019

Polymer Chemistry Author of the Month: Daniel Crespy

Daniel Crespy studied chemistry at the University of Strasbourg where he first came in contact with the field of heterophase polymerizations. He joined Professor Katharina Landfester in 2003 to complete a PhD in the University of Ulm where he developed novel methods to prepare nanocapsules in miniemulsion. In 2006, he held a position as project leader at Empa (Swiss Federal laboratories for Materials Research and Technology), working on stimuli-responsive materials for textile applications. He joined the department of Professor K. Landfester at the Max Planck Institute for Polymer Research (Mainz, Germany) in July 2009 as group leader. Since 2016, Daniel Crespy is an Associate Professor at the Vidyasirimedhi Institute of Science and Technology (VISTEC) in Rayong, Thailand.

What was your inspiration in becoming a polymer chemist?
Since childhood, I was fascinated by fireworks, paintings, and nature. I was interested in chemistry when I understood that movements and colors, as well as the emotions lived by the observer were produced by chemical reactions. I love chemistry because chemists can shape reality to create new materials adapted to our needs. In my view, polymer chemistry is particularly interesting because it encompasses all traditional fields of chemistry. I am definitively in debt to all the professors in chemistry and polymer science who were patient enough and enthusiastic to teach us the basics.

What was the motivation behind your most recent Polymer Chemistry article?
The aim was to create polymer nanoparticles that are decorated with cyclic carbonate groups. We demonstrated that these nanoparticles can be further functionalized with a large variety of molecules, including amino acids and proteins. The work was completed with my colleague Assist. Prof. Valerio D’Elia, who is specialist in converting CO2 to industrially important chemicals. The carbonate-functionalized particles were used as heterogeneous catalysts for carbonation reactions using CO2. Basically, we showed that a catalyst partially made from CO2 and other sustainable chemicals can be used to produce other useful chemicals from CO2. We believe that this paper will find an echo in the greater context of sustainable chemistry.

Which polymer scientist are you most inspired by?
I admire the professional achievements of Wallace Carothers who made significant contributions to both applied and fundamental research in polymer chemistry. Before my PhD studies, I was already following closely the work on heterophase polymerization of Mohamed El-Aasser, Katharina Landfester, Markus Antonietti, Klaus Tauer, Jose-Maria Asua, Bob Gilbert, Masayoshi Okubo, and Massimo Morbidelli. In parallel, I liked to read the contributions of Rolf Mulhaupt and Hans Rytger Kricheldorf on other topics of polymer chemistry. Working with Katharina Landfester had definitively a very large and positive impact on me, my working style, and my research so that I cannot be thankful enough towards her.

Can you name some up and coming polymer chemists who you think will have a big impact on the field?
I have too much respect for the work of other scientists to select people who will have a big impact on the field. We live in a time where spectacular papers are momentarily impactful but only time will truly select which contributions will stay in the classical textbooks of tomorrow. I can say that I am very impressed by the quality and quantity of talented polymer chemists from China, especially the scientists who tackle fundamental research. Finally, I do hope that my ex-students will have a big impact on the field in their future career.

How do you spend your spare time?
I am addicted to the positive sensation of collective achievement experienced when playing football. I also read a lot about Thai culture, which is for me both mysterious and fascinating. Finally, I am organizing an association to explain Thai students how to get scholarships from Germany to study in Germany.

What profession would you choose if you weren’t a chemist?

I would be geneticist, who is a kind of polymer chemist but specialized in polynucleotides.

 

Read Daniel’s recent Polymer Chemistry article now for FREE until 31st August!


Versatile functionalization of polymer nanoparticles with carbonate groups via hydroxyurethane linkages

Neha Yadav, Farzad Seidi, Silvano Del Gobbo, Valerio D’Elia* and Daniel Crespy*

Graphical Abstract for c9py00597h

Synthesis of polymer nanoparticles bearing pendant cyclic carbonate moieties is carried out to explore their potential as versatile supports for biomedical applications and catalysis. Nanoparticles are produced by copolymerizing glycerol carbonate methacrylate with methyl methacrylate by the miniemulsion process. The ability of the nanoparticles to serve as carriers for biomolecules was studied by reacting them with various amines, amino acids, and proteins. The functionalized nanoparticles are systematically analyzed by Fourier transform infrared spectroscopy, solid state (SS) NMR spectroscopy, and X-ray photoelectron spectroscopy. Model studies are performed to investigate the reactivity of amino acids and albumin with the pendant carbonate groups. Functionalization of the nanoparticles with dopamine led to surface coverage with catechol groups as efficient heterogeneous hydrogen bond donors for the cycloaddition of CO2 to epoxides under atmospheric pressure


About the Webwriter

Simon HarrissonSimon Harrisson is a Chargé de Recherche at the Centre National de la Recherche Scientifique (CNRS), based in the Laboratoire des IMRCP in Toulouse. His research seeks to apply a fundamental understanding of polymerization kinetics and mechanisms to the development of new materials. He is an Advisory Board member for Polymer Chemistry. Follow him on Twitter @polyharrisson

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Paper of the month: Bottom-up design of model network elastomers and hydrogels from precise star polymers

Synthetic polymer networks have attracted considerable attention owing to their exceptional mechanical properties including high resilience and toughness. Such materials are typically based on multi-arm poly(ethylene glycol) (PEG) which is a commercially available compound. However, PEG networks suffer from restricted access to higher molecular weight which limits the network dimensions. In addition, the crystalline nature of PEG does not allow for a comprehensive understanding of the mechanical behaviour in bulk network elastomers. To overcome this challenge, Walther and co-workers introduced a new class of high molecular weight star polymer building blocks for the construction of model network elastomers and hydrogels with tuneable mechanical properties. To achieve this, triethylene glycol methyl ether acrylate was successfully polymerized via light-inducted atom transfer radical polymerization and Cu(0)-wire reversible deactivation radical polymerization, yielding well-defined polymers with narrow molecular weight distributions and high end-group fidelity. Upon synthesis, functional motifs were introduced within the polymer through either post-polymerization modification of the bromine end-groups or the use of a fluorescent star initiator. In particular, the introduction of norbornene end-groups allowed for the subsequent crosslinking of the materials in presence of a photo-radical initiator. This allowed access to thermally reversible model network hydrogels based on dynamic supramolecular bonds. Overall, this work enables the simultaneous study of the mechanical behaviour of bulk network elastomers and swollen hydrogens with the same network topology. As the authors elude in their conclusions, by elegantly exploiting precision polymer chemistry, our understanding of architecture control can be enhanced leading to the rational design of functional mechanical network materials.

Graphical Abstract for c9py00731h

 

Tips/comments directly from the authors:

  1. Water-soluble star polymers with a low Tg and quantitative end-group introduction allow the simultaneous investigation of identical model networks as hydrogels and bulk elastomers.
  2. The monomer triethylene glycol methyl ether acrylate (mTEGA) yields low-Tg, water-soluble polymers. A distinct advantage over other oligo(ethylene glycol) acrylates is the absence of potential diacrylate impurities compromising polymerization control.
  3. Polymerization of mTEGA by photo-induced and Cu0-catalyzed Cu-RDRP from commercial and functional 4-arm initiators yields narrowly dispersed star polymers up to high molecular weights. In order to achieve optimal control with minimal side reactions, a balance in the initiator-to-CuBr2 ratio is necessary.
  4. Cu0-mediated Cu-RDRP is suitable for scale up, and the polymers can be isolated by precipitation into 85/15 diethyl ether/n-pentane followed by salt removal through neutral alumina.
  5. Following end-group transformation with primary amines, both excess amines and bromide salts must be removed. The former is removed through precipitation, the latter by taking the polymer up into a diethyl ether/THF mixture and removing insoluble components.
  6. Constructing hydrogels by photo-crosslinking 4-arm p(mTEGA)-norbornene with a bifunctional thiol is fast (<1 min) with the photo-radical initiator LAP and slower (>30 min) with Irgacure-2959.
  7. Supramolecular hydrogels constructed from 4-arm p(mTEGA)-terpyridine with divalent metal ions are highly dependent on the metal. ZnII yields hydrogels which are dynamic at room temperature, and increasingly so upon heating making them suitable for thermal 3D-printing.

 

Read the full Paper now for FREE until the 31st August! 

Bottom-up design of model network elastomers and hydrogels from precise star polymers, Polym. Chem., 2019, 10, 3740-3750, DOI: 10.1039/c9py00731h

About the web writer
Professor Athina AnastasakiDr. Athina Anastasaki is an Editorial Board Member and a Web Writer for Polymer Chemistry. Since January 2019, she joined the Materials Department of ETH Zurich as an Assistant Professor to establish her independent research group.

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Polymer Chemistry Author of the Month: Yasuhiro Kohsaka

Yasuhiro Kohsaka is an Associate Professor in the Research Initiative for Supra-Materials (RISM) and the Faculty of Textile Science and Technology (FTST) at Shinshu University. He started his academic career as a JSPS Research Fellow in 2008 researching supramolecular polymer chemistry under the supervision of Prof. Toshikazu Takata at Tokyo Tech. From 2009 to 2010 he studied as a visiting student under Prof. Timothy Swager at MIT. He received his Ph. D. degree in Engineering at 2011 from Tokyo Tech. He worked as an Assistant Professor in Prof. Tatsuki Kitayama’s group in Graduate School of Engineering Science at Osaka University. In 2015, he moved to FTST at Shinshu University as a Tenure-Track Assistant Professor supported by JST and established his own independent research group. He became an Associate Professor in 2018, and joined the RISM in 2019. Since 2019, he has started a new project on the design of new monomers and polymerization chemistry using synergetic effects of two or more functional groups. His research is always based on pure organic chemistry but proposed with practical application in mind. Therefore, he has interests in both polymer chemistry and material science. He was chosen as one of the Emerging Investigators of 2018 in Polymer Chemistry. Recently, he received a Young Researcher Award from the Society of Polymer Science, Japan (SPSJ) and the Society of Fiber Science and Technology, Japan (SFSTJ).

What was your inspiration in becoming a polymer chemist?

In childhood, my uncle often entertained me with plastic models of airplanes. This experience made me interested in science and technology. However, my favorite subjects were not chemistry but astronomy and earth science. Therefore, I attempted to join the astronomy club in the first year of middle high school, but the atmosphere was not comfortable for me. Then, my friend induced me to join chemistry club, where senior high school students were studying the synthesis of biodegradable plastics. This was my first introduction to polymer chemistry. In 2000, Prof. Hideki Shirakawa won the Nobel Prize in Chemistry for his discovery of conductive polymers. This news had a strong impact on me. I also learned that our daily life was supported by polymer materials, such as plastics, rubbers, fibers and adhesives. Then, I dreamed to develop new functional polymer materials like Prof. Shirakawa and change our life for the better. After that, I am striking out to my dream even now!

What was the motivation behind your most recent Polymer Chemistry article?

This is completely a kind of serendipity. Hemiacetal esters are interesting molecules, as they can be used for various purposes. The formation of a hemiacetal ester bond is reversible and thus it can be applied to dynamic covalent chemistry, while hemiacetal esters can also initiate living cationic polymerization of vinyl ethers. On the other hand, cyclic hemiacetal esters give two different types of polymers, polyesters and poly(hemiacetal ester)s, by ring-opening polymerization (ROP). Therefore, we have interests in the polymerization chemistry of cyclic hemiacetal esters containing polymerizable vinyl groups, as the monomers can undergo both ROP and vinyl polymerization and each product would have the respective potential application according to its residual groups. In our previous paper, therefore, we reported the vinyl polymerization of cyclic hemiacetal esters with acrylate skeleton (J. Polym. Sci. Part A: Polym. Chem. 2016, 54, 955). This monomer contains a hemiacetal ester skeleton, but we are also interested in cyclic ketene acetal esters, which provide hemiacetal ester skeletons by vinyl polymerization. That is, the vinyl polymerization changes the double bond to single bond forming a hemiacetal ester skeleton in the process. For this concept, we sought a cyclic ketene acetal ester in the database and found dehydroaspirin. Therefore, we never aimed to recycle vinyl polymers.

Which polymer scientist are you most inspired by?

Since I am interested in the principles of step-growth polymerization, Prof. Mitsuru Ueda’s (NTU) early papers such as group-selective polycondensation and synthesis of regio-regular polymers always give me a good inspiration. As I conduct a project on ring-opening polymerization, I am also inspired by Prof. Marc Hillmyer (University of Minnesota).

Can you name some up and coming polymer chemists who you think will have a big impact on the field?

I respect Prof. Koji Takagi’s (Nagoya Institute of Technology) energetic activity. He proposes unique and sophisticated approaches in polymer synthesis and collaborates with many young professors to advance his research. His molecular design is simple, but his deep insight and wide viewpoint present the importance of intelligence and dreams of polymer chemistry to our young generations. Speaking about our generations, my best friends, Prof. Hiroaki Imoto (Kyoto Institute of Technology), and Prof. Fumitaka Ishiwari (Tokyo Tech), my junior in school, are the closest but farthest researchers. Their motivation is very pure, and thus, the impacts of the completed results are always strong.

How do you spend your spare time?

As I work away from my family due to business reason, I enjoy driving home to spend the weekend with my wife and children. I like to play with my daughter (four years old) and son (two years old) with my children’s mind. On weekdays, I play and watch Shogi, a Japanese traditional board game like a chess. The way of thinking in Shogi is similar to that in organic chemistry, as the construction and motion of cooperated pieces (atoms) are the keys to winning. I also like to watch sports, particularly baseball and Formula One (F1).

What profession would you choose if you weren’t a chemist?

Earth scientist or astronomer, as they are my first dream in childhood. As it turns out, I am a natural scientist!

 

Read Yasuhiro’s recent Polymer Chemistry article for FREE until 19th August!


Radical polymerization of ‘dehydroaspirin’ with the formation of a hemiacetal ester skeleton: a hint for recyclable vinyl polymers

Graphic Abstract for C9PY00474B

A vinyl polymer with a cyclic hemiacetal ester skeleton was synthesized via the radical polymerization of 2-methylene-4H-benzo[d][1,3]dioxin-4-one (MBDO; so-called ‘dehydroaspirin’). This material could be decomposed to acetic acid and salicylic acid (the raw ingredients for MBDO) by acid hydrolysis, and thus has potential as a recyclable vinyl polymer.


About the webwriter

Simon HarrissonSimon Harrisson is a Chargé de Recherche at the Centre National de la Recherche Scientifique (CNRS), based in the Laboratoire des IMRCP in Toulouse. His research seeks to apply a fundamental understanding of polymerization kinetics and mechanisms to the development of new materials. He is an Advisory Board member for Polymer Chemistry. Follow him on Twitter @polyharrisson

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Polydays 2019 – Polymer Science and Engineering in View of Digitalization

The Polydays 2019 conference, taking place in Berlin on the 11th – 13th September, will focus on the transformation of material research by digital technologies, initiated by the Berlin-Brandenburg Association of Polymer Research (BVP) and organized by the Helmholtz-Zentrum Geesthacht (HZG). The conference will be chaired by Prof. Andreas Lendlein (Institute of Biomaterial Science, HZG) and co-chaired by Prof. Hans Börner (Institute of Chemistry, Humboldt-Universität zu Berlin).

Confirmed plenary speakers:
– Amanda Barnard, CSIRO, Melbourne, Australia
– Andrew I. Cooper, University of Liverpool, UK
– Jean-François Lutz, CNRS-Institute Charles Sadron, Strasbourg, France
– E. W. (Bert) Meijer, Eindhoven University of Technology, Netherlands
– Roeland Nolte, Radboud University, The Netherlands
– H. Jerry Qi, Georgia Institute of Technology, Atlanta, USA

Key dates
12th July – abstract submission deadline
31st July – early bird registration deadline

For more information please refer to the conference webpage:  www.hzg.de/polydays2019

Polydays flyer

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