Archive for the ‘Author of the Month’ Category

Polymer Chemistry Author of the Month: Trang N. T. Phan

Trang N. T. Phan is an Associate Professor in the Institute of Radical Chemistry at Aix-Marseille University in France. She completed her undergraduate studies with a Masters in chemistry and then joined the PhD program in Polymers and Organic Chemistry at University of Lille 1. She received her PhD in 2000 under the supervision of Pr. M. Morcellet. During her PhD at the Macromolecular Chemistry Lab, she worked on the synthesis, characterization and water purification application of sorbents based on silica gel functionalized with β-cyclodextrin based polymers. During 2000-2002, she worked as a postdoctoral researcher at the Materials and Interfaces Chemistry Lab of University of Franche-Comté, first in the European project SILACOR and then in a project with BASF on the adsorption of polyelectrolytes on zinc oxide nanoparticles. In 2002, she joined Pr Denis Bertin’s group, firstly as a temporary lecturer and then as a postdoctoral researcher. In September 2004, she became a full associate professor at Aix-Marseille University in the group of Didier Gigmes. In 2014, she received with her colleagues (R. Bouchet and D. Gigmes) the International Prize EDF PULSE Science and Electricity. Her current research interests are in the design and the synthesis of advanced functional polymers via controlled polymerization techniques for specific applications such as solid polymer electrolytes, polymers blend compatibilizers and structure-directing agents.

 

What was your inspiration in becoming a polymer chemist?

During my Bachelors course work and internship project, I started learning about polymer chemistry. I was fascinated by the “magic” of the transformation of small molecules (monomers) to polymers which are useful functional materials. From that moment, I decided to learn more about how chemistry can help to design and synthesize (co)polymers with precise structure, functionality and composition responding to desired properties and specific applications.

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

Radical ring-opening polymerization (rROP) of cyclic monomers is an attractive method to synthesize functional polymers bearing both heteroatoms in the backbone and functional groups in the side chain. In addition, the potential applicability of rROPs for copolymerizations with vinyl monomers is a highly attractive feature. Among different cyclic monomers, vinyl cyclopropane (VCP) derivatives were the most promising compounds since their rROPs led to low-shrinkage materials with attractive applications for dental adhesives and composites. However, functional groups in the side chain of VCP polymers are usually limited to halogens, esters and nitrile functions that restrict the development of new functional VCP polymers by post-polymerization modification. During our investigation of new VCP derivatives, we have achieved a straightforward pathway for the synthesis of VCP bearing azlactone functionality. The azlactone group can react via rapid and efficient ring-opening reactions with different nucleophilic species such as primary amines, hydroxyls, and thiols. We expect that the new VCP-azlactone (co)polymers could serve widely as a reactive platform for the introduction of chemical and biological functionality.

Which polymer scientist are you most inspired by?

I am greatly interested by the work being undertaken in the group of Pr. David Mecerreyes since their research allies polymer chemistry, supramolecular chemistry and nanomaterials science to synthesize innovative polymeric materials.

How do you spend your spare time?
I like cooking and experimenting with new recipes by combining western and oriental flavors. After all, cooking is similar to chemistry. I also like hiking and reading.

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

I’d be a Scuba dive master practicing somewhere in the warm waters of tropical seas.

Read Trang’s full article now for FREE

 


Radical ring-opening polymerization of novel azlactone-functionalized vinyl cyclopropanes

Azlactone-functionalized polymers are considered powerful materials for bioconjugation and many other applications. However, the limited number of azlactone monomers available and their multistage syntheses pose major challenges for the preparation of new reactive polymers from these monomers. In this article, we report the synthesis of a new class of azlactone monomers based on vinylcyclopropane (VCP). Furthermore, the (co)polymerization of the azlactone-functionalized VCPs has been successfully demonstrated to provide new azlactone polymers by using free-radical polymerization. The ability of the resulting amine-reactive polymers to be engaged in post-polymerization modifications was demonstrated using dansylcadaverine. These new azlactone-functionalized VCP monomers and polymers are potential candidates for the synthesis of innovative (bio)materials.


About the Webwriter

Simon HarrissonSimon Harrisson is a Chargé de Recherche at the Centre National de la Recherche Scientifique (CNRS), based at the Laboratoire de la Chimie des Polymères Organiques (LCPO) in Bordeaux, France. 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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Polymer Chemistry Author of the Month: Nicholas J. Warren

Nick WarrenNick Warren  is a University Academic Fellow within the School of Chemical and Process Engineering at the University of Leeds. He was awarded an Masters in Chemistry from the University of Bristol in 2005 following which he conducted two years industrial research. He then moved to the University of Sheffield where he studied for a PhD in Polymer Chemistry within Prof Steve Armes’ research group where he focussed on synthesis of biocompatible block copolymers. Following his PhD, he continued as a postdoctoral researcher in Sheffield working in the area of polymerisation-induced self-assembly (PISA) until 2016, when he moved to Leeds to start his independent research career. His current research aims to exploit the latest advances in polymerisation techniques, combined with new reactor technologies for the design and discovery of controlled-structure polymers.

What was your inspiration in becoming a polymer chemist?

During my undergraduate masters project, I worked on development on combining pH responsive microgels with photo-responsive surfactants. I was fascinated by the ability to use chemical composition as a means of tuning physical characteristics of a material and imparting responsive behaviour. This brought on a specific interest in synthetic polymer chemistry, where there are so many synthetic routes to generating responsive materials. This was the focus of my PhD, where I gained expertise in ATRP and RAFT polymerisation which provided a convenient tool-box allowing me to design and synthesise pH responsive block copolymers.

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

Continuous-flow techniques are well utilised in small molecule synthesis and are now becoming commonplace in polymer chemistry. In my research group, we aim to use flow-chemistry to conduct polymer synthesis and try and exploit its characteristics to develop new materials, streamline methods for optimising polymerisation processes; or for detailed online monitoring. We have already published some work conducting PISA in flow, which combined my existing expertise in PISA, with my growing interest in reactor technologies, but it became apparent that the relatively long timescales for the reactions meant that there were limited advantages over batch synthesis. We therefore looked to speed up the process, which was relatively straight-forward since our all-acrylamide PISA system was ideally suited to Seb Perrier’s ‘ultrafast’ RAFT technology. By using flow-reactors equipped with online monitoring, we were not only able to synthesise a wide range of PISA nanoparticles on short timescales, but also obtain kinetic data despite the short reaction time.

Which polymer scientist are you most inspired by?

From a synthetic perspective, the work being undertaken in Prof Brent Sumerlin’s group encompasses many of the areas I have a keen interest. I am also inspired by Prof Tanja Junkersresearch, since she is at the forefront of work into applying automation and flow chemistry to polymer synthesis.

How do you spend your spare time?

I now have two children under 3, so I spend most of my time running around after them! We spend quite a lot of time hiking in the Peak District and I also like to cook, which has recently expanded into bread making (to varying degrees of success).

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

I’d be a barista with a small coffee shop somewhere sunny.

Read Nick’s full article now for FREE

And if you are interested in reading more about PISA then check out our recent themed collection here


Rapid production of block copolymer nano-objects via continuous-flow ultrafast RAFT dispersion polymerisation

 

graphical abstract

Ultrafast RAFT polymerisation is exploited under dispersion polymerisation conditions for the synthesis of poly(dimethylacrylamide)-b-poly(diacetoneacrylamide) (PDMAmxb-PDAAmy) diblock copolymer nanoparticles. This process is conducted within continuous-flow reactors, which are well suited to fast reactions and can easily dissipate exotherms making the process potentially scalable. Transient kinetic profiles obtained in-line via low-field flow nuclear magnetic resonance spectroscopy (flow-NMR) confirmed the rapid rate of polymerisation whilst still maintaining pseudo first order kinetics. Gel permeation chromatography (GPC) reported molar mass dispersities, Đ < 1.3 for a series of PDMAmxb-PDAAmy diblock copolymers (x = 46, or 113; y = 50, 75, 100, 150 and 200) confirming control over molecular weight was maintained. Particle characterisation by dynamic light scattering (DLS) and transmission electron microscopy (TEM) indicated successful preparation of spheres and a majority worm phase at 90 °C but the formation of vesicular morphologies was only possible at 70 °C. To maintain the rapid rate of reaction at this lower temperature, initiator concentration was increased which was also required to overcome the gradual ingress of oxygen into the PFA tubing which was quenching the reaction at low radical concentrations. Ill-defined morphologies observed at PDAAm DPs close to the worm-vesicle boundary, combined with a peak in molar mass dispersity suggested poor mixing prevented an efficient morphological transition for these samples. However, by targeting higher PDAAm DPs, the additional monomer present during the transition plasticises the chains to facilitate formation of vesicles at PDAAm DPs of ≥300.


About the Webwriter

Simon HarrissonSimon Harrisson is a Chargé de Recherche at the Centre National de la Recherche Scientifique (CNRS), based at the Laboratoire de la Chimie des Polymères Organiques (LCPO) in Bordeaux, France. 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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Polymer Chemistry Author of the Month: Suhrit Ghosh

Suhrit Ghosh was born in 1976 in India. After the completion of his undergraduate education (Chemistry major) at the Presidency College (now University), Kolkata, he was admitted to the integrated PhD program (Chemical Science) at the Indian Institute of Science, Bangalore in 1997. He received his MS degree (Chemistry) in 2000 and continued for PhD until 2005 under the supervision of Professor S. Ramakrishnan. Then he moved to the group of Professor S. Thayumanavan at the University of Massachusetts, Amherst, USA, for postdoctoral studies (2005-2007). Subsequently he worked as an Alexander von Humboldt postdoctoral fellow (2007-2008) with Professor Frank Würthner at the University of Würzburg, Germany. In 2008 he joined the Indian Association for the Cultivation of Science (IACS), Kolkata, India, as an Assistant Professor where he currently holds the position of Professor and Chair of the School of Applied and Interdisciplinary Sciences.

Research interests of his group include supramolecular polymerization of donor-acceptor π-systems, H-bonding driven directional assembly of amphiphilic π-systems/macromolecules and biologically relevant stimuli responsive aggregation of amphiphilic polymers (polydisulfides, polyurethanes). He has about 100 publications in peer reviewed journals and ten PhD students have graduated from his group. He is the recipient of the B. M. Birla Science Prize in Chemistry (2014), JSPS Invitation Fellowship (long term) Japan (2014), SwarnaJayanti Fellowship (2015) from the Department of Science and Technology, Government of India, K. Kishore Memorial Award (2016) from the Society of Polymer Science, India and the Bronze medal (2017) from the Chemical Research Society of India. He has been serving as an Associate Editor for the journal RSC Advances since 2015.

What was your inspiration in becoming a polymer chemist?

I was introduced to Polymer Chemistry by two captivating teachers (Professor Manas Chanda and Professor S. Ramakrishnan) during my Master’s Degree course work in the Indian Institute of Science, Bangalore. Subsequently I had an opportunity to carry out a year-long MS project on Polymer Chemistry under the supervision of Professor S. Ramakrishnan when I started learning more about the subject. From group discussions and seminars in the department, I learnt about the emerging topics (of the time) in Polymer Chemistry such as foldamers, molecular imprinting, conjugated polymers, helical polymers, amphiphilic polymers, supramolecular polymers and so on. I was greatly inspired by such diversity in the field and its interdisciplinary nature connecting chemistry with biology and materials science.

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

Poly(disulfide)s (PDS), although known for long time, lacked structural diversity in the absence of any generally applicable synthetic methodology. Recently we had established a mild step-growth polymerization approach to make linear functional PDS by a facile thiol-disulfide exchange reaction between commercially available 2,2′-dipyridyldisulfide and a di-thiol.  By taking a stoichiometric excess of the first monomer, telechelic PDS could be prepared with the reactive pyridyl-disulfide groups at the chain terminal which could be further functionalized by a functional thiol without disturbing the backbone disulfide groups. This motivated us to extend this approach for the synthesis of hyperbranched PDS, particularly considering the possibility of decorating such hyperbranched polymers with multiple reactive pyridyl-disulfide groups at the periphery for post-polymerization functionalization to produce a range of functional hyperbranched polymers with a fully bio-reducible disulfide backbone. We have exactly demonstrated this in our recent Polymer Chemistry paper and envisage that it might allow the screening of structurally diverse amphiphilic hyperbranched PDS for biological applications such as drug delivery.

Which polymer scientist are you most inspired by?

I am most inspired by Professor E. W. Meijer (Eindhoven University of Technology, The Netherlands), especially because of his pioneering fundamental contribution in the field of supramolecular polymers by connecting supramolecular chemistry and polymer chemistry.

How do you spend your spare time?

I like to cook, spend time with my 10-year-old daughter and socialize with like-minded people.

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

Practising literature and creative writing.

Read Suhrit’s full article now for FREE until 8th May!


Hyperbranched polydisulfides

Disulfide containing polymers have been extensively studied as responsive materials for biomedical applications such as drug delivery, gene delivery, bio-sensing and receptor-mediated cellular uptake due to the possibility of cleaving the disulfide linkage with glutathione (GSH), a tri-peptide overexpressed in cancer cells. While linear and branched polymers containing disulfide groups have been already studied and more recently polydisulfides (PDS) have come to the fore, hyperbranched polydisulfides (HBPDS) were not known. This manuscript for the first time reports a generally applicable methodology for the synthesis of HBPDS by an A2 + B3 condensation approach. The B3 monomer contains three pyridyl-disulfide (Py–Ds) groups while a di-thiol compound serves as the A2 monomer. A polycondensation reaction under very mild reaction conditions produces HBPDS (Mw = 14300 g mol−1Đ = 1.9) with a very high degree of branching (DB) value of 0.8 and more than twenty highly reactive Py–Ds groups present at the terminal or linear unit of a polymer on an average. The reactive Py–Ds groups can be completely replaced by post-polymerization functionalization using a hydrophilic thiol resulting in bio-reducible amphiphilic HBPDS. It produces micellar aggregates in water with a hydrodynamic diameter of ∼80 nm, a low critical aggregation concentration (7.0 μM) and a high dye (Nile red) loading content. The exchange dynamics of these micellar aggregates, studied by fluorescence resonance energy transfer (FRET), reveals practically no inter-micellar exchange after 6 h indicating very high non-covalent encapsulation stability. On the other hand, in the presence of glutathione, the PDS backbone can be degraded resulting in an efficient triggered release of the encapsulated dye. Dye release kinetics strongly depends on the GSH concentration and interestingly with a fixed concentration of glutathione the release kinetics appears to be much faster for the hyperbranched PDS micelle compared to its linear analogue. MTT assay with two representative cell lines indicates that the amphiphilic HBPDS is biocompatible up to 500 μg mL−1 which is further supported by hemolysis assay showing merely 6.0% hemolysis up to a polymer concentration of 500 μg mL−1.


About the Webwriter

Simon HarrissonSimon Harrisson is a Chargé de Recherche at the Centre National de la Recherche Scientifique (CNRS), based at the Laboratoire de la Chimie des Polymères Organiques (LCPO) in Bordeaux, France. 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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Polymer Chemistry Author of the Month: Stefan A F Bon

Professor Stefan A. F. Bon

Stefan A. F. Bon is a full professor in the Department of Chemistry at the University of Warwick in the United Kingdom. He studied chemical engineering at the Eindhoven University of Technology (TUe) in the Netherlands (cum laude, 1989-1993), where he also did his Ph.D. (1993-1998) in the polymer chemistry group of prof.dr.ir. Anton L. German. In April 1998 he moved to the UK  where worked as a post-doctoral research assistant in the group of prof. David M. Haddleton at the University of Warwick (1998-2000). He was appointed as Unilever Lecturer in Polymer Chemistry at the University of Warwick in January 2001. During this period of research he focused on the mechanistic aspects of living radical polymerisation in both homogeneous and heterogeneous systems, including the first ever living radical polymerization performed in emulsion. From 2005 Stefan Bon shifted his research interests from living radical polymerization to supracolloidal chemical engineering. Current research focuses on the design of assembled supracolloidal structures and the synthesis of their colloidal and macromolecular building blocks through combination of polymer chemistry, colloid science, soft matter physics, and chemical engineering. Check out www.bonlab.info for more.

What was your inspiration in becoming a polymer chemist?

Eindhoven University of Technology in the 1990s was a fantastic place for polymer science, especially in the fields of emulsion polymerization and polymer physics and processing. We had captivating teachers, such as Alex van Herk, Anton German, and Piet Lemstra.  I was fascinated by it all as an undergrad student and hooked after my international internship at Nippon Paint where I worked on polymer colloids in the summer of 1992. I grabbed the opportunity to do my PhD on nitroxide mediated polymerizations at the end of 1993. What I love about polymer and colloid science is that you can blend chemistry, with physics, mathematics and engineering, fading out boundaries between classical disciplines.

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

In the mid 2000s we started applying the phenomenon of Pickering stabilization, the concept that particles can adhere to soft deformable interfaces, to mini-emulsion and emulsion polymerization processes. In the last decade we tried to come to a full mechanistic understanding of emulsion polymerization processes in which nanoparticles played the role of molecular surfactants. For the most part we focussed on inorganic nanoparticles, such as clay and silica sols. In 2018/2019 we asked ourselves if Pickering emulsion polymerization would be possible using polymer nanoparticles (10-40 nm), that is nanogels or crosslinked polymer micelles could be used instead. To our delight we found that using nanogels gave us the opportunity to control the morphology of the polymer colloids produced by the Pickering emulsion process. Janus, patchy and armored particles can be made. We wanted to unravel the exact mechanism. The paper in Polymer Chemistry describes a detailed mechanistic study on the effect of inert electrolyte (salt) on the emulsion polymerization process.

Which polymer scientist are you most inspired by?

On passion for emulsion polymerization I would like to mention Bob Gilbert. I know Bob since the mid 1990s, and have great respect for him. I still remember the discussions we had at Santa Margherita Ligure in 1996 on kinetics of radical polymerization and life. I love his mechanistic/kinetic approach to describe scientific concepts and have adopted this as a way of working in my team. On optimism and living larger than life, my former polymer chemistry teacher and friend Alex van Herk, who now works at A*STAR in Singapore. A big thank you to both.

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

Restricting myself to people with an academic career path I would like to mention four: Nick Ballard (POLYMAT, Spain), Athina Anastasaki (ETH Zürich, Switzerland), Stuart Thickett (UTAS, Australia), and Zhihong Nie (Fudan University, China). Why? That is simple, all four are fantastic.

How do you spend your spare time?

My husband and I bought a house in Coventry (UK) a bit over a year ago, and since then the garden is undergoing a transformation to see how many different plants we can put into the space. I think soon we will run out of space and there won’t be a single bit of traditional British lawn left. We like to cook (Chinese/Dutch fusion) , travel, and go to the theatre/concerts. We are looking forward to seeing Pink Martini soon in Birmingham. Will pick up playing the guitar again (haha, and if you wonder what style of music: Julio Iglesias of course!).

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

That is a hard question. Has to be creative and with people for sure. May be something in the area of people communication/management mediation..

Read Stefan’s full article now for FREE until the 31st March!


Effect of the addition of salt to Pickering emulsion polymerizations using polymeric nanogels as stabilizers

Graphical abstract: Effect of the addition of salt to Pickering emulsion polymerizations using polymeric nanogels as stabilizers

Nanogels made from crosslinked block copolymer micelles are used as stabilizers in the Pickering emulsion polymerization of styrene. The effect of the addition of salt, i.e. NaCl, on the emulsion polymerization is studied. It is shown that an increase in ionic strength of the dispersing medium in these polymerizations led to the formation of latexes of larger diameters. Along with an increase in size, the morphology of these polymer colloids changed from Janus to patchy with an increase in number of nanogels adsorbed on the polymer surface, as a function of the salt concentration in water. In particular, at the highest tested ionic strength, ca. 25 mM, fully armored polymeric particles surrounded by a dense layer of adsorbed stabilizing nanogels were formed. Kinetic studies carried out at varying NaCl concentrations suggested that particle formation in the reaction followed a combination of a coagulative nucleation mechanism, characterized by a clustering process of Janus precursors to form bigger aggregates, and droplet nucleation. Preliminary film formation studies on latexes made with n-butyl acrylate as a comonomer indicated the potential of this technique for the production of coherent polymer films which included a substructure of functional nanogels.


About the Webwriter

Simon HarrissonSimon Harrisson is a Chargé de Recherche at the Centre National de la Recherche Scientifique (CNRS), based at the Laboratoire de la Chimie des Polymères Organiques (LCPO) in Bordeaux, France. 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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Polymer Chemistry Author of the Month: Claude St Thomas

Claude St ThomasClaude St Thomas studied chemistry at the École Normale Supérieure, Université d’État d’Haïti, Port au Prince, Haïti. In 2008, he moved to Mexico where he obtained MSc and PhD degrees in polymer chemistry at the Centro de Investigación en Química Aplicada (CIQA) under the guidance of Dr. Ramiro Guerrero Santos. During his PhD studies, he undertook two research stays at the Laboratory of Chemistry and Processes of Polymerization (LCPP), in Lyon, France under the supervision of Prof Bernadette Charleux and Dr. Franck D’Agosto. He designed a novel dual RAFT/NMP chain transfer agent for a tandem polymerization and investigated its use for preparing the self-assembled nanoparticles. This investigation was awarded with the 2015 Rafael Illescas Frisbie prize from the Mexican Chemistry Society as the best PhD thesis. In the same year, he was promoted as a CONACYT research fellow at CIQA.

His research mainly focuses on the preparation of well-defined multiblock copolymers and the development of novel associative polymers featuring stimuli-responsive groups using reversible deactivation radical polymerization (RDRP) techniques. He is also interested in the rheological properties of polymers for applications in coatings, paints, enhanced oil recovery, and water treatment.

What was your inspiration in becoming a polymer chemist?

In my childhood, I was always fascinated by nature. At the beginning, I dreamed about becoming an agronomist. However, my interest for chemistry started in high school by the teachings from chemistry lecturer Sylvain Jean Desir. There, I understood that chemistry is the basis of life. During my MSc and PhD studies I worked with materials of common and daily use and a special interest for polymer chemistry started rising.

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

In our research group, scientific contributions related to the preparation of water-soluble copolymers have been previously published under the supervision of Dr. Enrique Javier Jiménez Regalado using free radical polymerization. In 2014, the “Consejo Nacional de Ciencía y Tecnología” (CONACYT, México) started a new program for addressing solutions to national problems, where young researchers were engaged and assigned to specific projects. Since, I started in my current position in 2015 and inspired by the versatility of the RAFT polymerization technique, my current research work focuses on the development of novel pathways for preparing well-defined water-soluble associative copolymers.

Inspired by the RDRP techniques and their feasibility for synthesizing polymeric materials with unprecedented properties, our recent contribution describes a new strategy for preparing environmentally-friendly water-soluble associative copolymers using the RAFT technique.

Which polymer scientist are you most inspired by?

A group of scientists have impacted my career. I appreciate the discipline, rigor and professional achievements of both Prof Bernadette Charleux and Dr. Franck D’Agosto. Fascinated by RDRP techniques, I am also inspired by three experts in RDRP: Prof Craig J. Hawker, Prof. San H. Thang and Prof. Krzysztof Matyjaszewski. Their publications describing processes for synthesizing polymers with specific characteristics might allow the use of these materials in different industrial applications.

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

Based on application areas of polymeric materials, it would be difficult to mention researchers who will have a big impact on the field. Notwithstanding, I select Dr. Francesco Picchioni (University of Groningen). His research on the development of chemical materials for application in Enhanced Oil Recovery (EOR) displays great interest and could impact the field. For these researches, I am also impressed by the research works of Dr. Michael F. Cunningham (Queens University) and Sébastien Perrier (University of Warwick)

How do you spend your spare time?

Outside of professional activities, I enjoy spending time with my family (wife and four year-old daughter-Nicole) and visiting natural places. My favorite sport is soccer, so I enjoy playing it with friends. I also enjoy playing guitar and reading about new scientific developments and culture.

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

Probably an agronomist due to my passion for natural sciences, because it was my first dream.

Read Claude’s full article now for FREE until the 31st January!


Preparation of hydrophobically modified associating multiblock copolymers via a one-pot aqueous RAFT polymerization

Graphical abstract: Preparation of hydrophobically modified associating multiblock copolymers via a one-pot aqueous RAFT polymerization

We describe an efficient strategy for the preparation of hydrophobically associating multiblock copolymers using the RAFT technique. Polymerization reactions were carried out by a one-pot aqueous RAFT polymerization at 70 °C using a symmetrical trithiocarbonate as a chain transfer agent (CTA) in aqueous media. The macroRAFT polyacrylamide (PAM) was synthetized and chain extended by polymerization of N,N′-dihexylacrylamide (DHAM) and acrylamide (AM), respectively. The resultant polymers were intensely characterized by size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) spectroscopy, diffusion-ordered spectroscopy (DOSY), Fourier transform-infrared (FT-IR) spectroscopy and rheology. The structure and insertion of a hydrophobic block (PDHAM) into the backbone were carefully demonstrated. The rheological measurements confirmed the effect of the hydrophobic block number on the viscosity of polymers at different concentrations and the formation of a reversible physical network of entangled polymers in aqueous media. Moreover, the incorporation of the hydrophobic block (PDHAM) was established by the oscillatory measurement.


About the Webwriter

Simon HarrissonSimon Harrisson is a Chargé de Recherche at the Centre National de la Recherche Scientifique (CNRS), based at the Laboratoire de la Chimie des Polymères Organiques (LCPO) in Bordeaux. 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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Polymer Chemistry Author of the Month: Christina Chai

Christina Chai obtained her BSc (Hons) from the University of Canter­bury, Christchurch, New Zealand and her PhD in organic chemistry from the Research School of Chemistry, Australian National University, Canber­ra under the mentorship of the late Professor Athel Beckwith, FRS. Following her PhD, she was awarded a Samuel and Violette Glasstone Research fellowship at the University of Oxford, UK. This was followed by a Faculty position in the Department of Chemis­try, Victoria University of Wellington, NZ (1991-1993) and the Department and Research School of Chemistry, Aus­tralian National University (1994-2004) where she rose to the rank of a Reader. In 2005, Christina moved to Singapore to establish a research programme on synthetic and polymer chemistry at the then newly founded Institute of Chemical and Engineering Sciences, Agency for Science Technology and Research (A*STAR). She returned to a life in academia in 2011 at the Department of Pharmacy, National University of Singapore where she has held many administrative positions. She is currently Professor and the Head of the Department of Pharmacy. Although her major research interest is on bioactive compounds, she moonlights in polymer chemistry with special interest in biomimetic materials.

What was your inspiration in becoming a scientist who works with polymers?

My PhD training was in the area of free radical chemistry with one of the free radical ‘’gods’’, the late Professor Athel Beckwith. At that time, a superb team of chemists in CSIRO Australia had developed the RAFT process which was based on the principles of radical chemistry, and I was fascinated with the numerous possibilities of this process in creating new materials. Although this fascination remained after my PhD studies, I did not have the opportunity to work with polymers until I moved to A*STAR Singapore. I continue to be intrigued with clever ways of designing functional polymers for various applications.

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

When I first joined NUS, I received a grant that allowed me to work on biomimetic materials, specifically mussel-inspired coatings. I was intrigued with the claims that polydopamine (PDA) is a universal coating material, and was amazed with the reported applications of polydopamine. If one read and believed all the literature, one would imagine that PDA is the answer to all our material needs. As we worked to develop PDA functional coatings, we were hampered by the lack of information on the structure of PDA. We wanted to improve the properties of PDA but how do we improve a mystery material? So we set out to understand the oxidation chemistry of dopamine, and the process of coating and of course, to attempt to elucidate the structure of PDA. I was fortunate that my PhD student at that time, Lyu Qinghua was so obsessed with this mystery that he refused to submit his thesis until he knew the answer. I am not convinced that we have completely solved the mystery (although I did manage to persuade the student to submit his thesis) but I believe that we have made significant progress in the structural elucidation. The answer is just around the corner!

Which polymer scientist are you most inspired by?

In view of my training as a free radical chemist, I was most interested in the ability to control polymer synthesis through living free radical polymerisation methods such as ATRP and RAFT. I personally know Professor San Thang, now of Monash University, who is one of the co-inventors of RAFT, and his life story and his humility despite his successes is one of my inspiration. Professor K. Matyjaszewski, the guru of ATRP and Professor Craig Hawker, with his fascinating designs of functional polymers are also heroes in my eyes.

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

Professor Molly Stevens from Imperial College London is a name that comes to mind as her research on materials for biomedical applications will be a game changer.

How do you spend your spare time?

I love reading and travelling. I read fiction and non-fiction for pleasure. My love for travel is not about visiting places of interest but to immerse myself in a different environment and culture.  Although I am an introvert, I am interested in people-watching. People are fascinating subjects for study!

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

A doctor, a nun or a scientist – This is what I would say when I was a child when people asked me what I wanted to be when I grew up. As I doubt that I would be religious enough to qualify as a nun, this just leaves being a doctor as my alternate profession that I would choose. However I love being a scientist! I constantly worry about not having enough funds to support my research. My dream is to win the lottery so that I can support my research for the rest of my career…

Is the end in sight for the structural analysis of polydopamine? What important questions remain to be answered?

Yes, I believe that the end is in sight for the structural analysis of polydopamine. I believe that fundamental studies are important if we want to advance the applications. Without knowing the structure, how do we improve the properties of the material? There are still gaps in PDA technology that needs to be addressed. For example, one would need to know how to reproducibly control the thickness and homogeneity of the material; how to reduce the coloration and improve stability…. There is so much that we do not yet know.

 

Read Christina’s full article now for FREE until the 21st December!


Unravelling the polydopamine mystery: is the end in sight?

Graphical abstract: Unravelling the polydopamine mystery: is the end in sight?

Despite the prominence of polydopamine (PDA) in the field of polymer and materials chemistry since it was first reported by H. Lee, S. M. Dellatore, W. M. Miller and P. B. Messersmith, Science, 2007, 318, 426–430, the structure of PDA has been an unresolved and contentious issue. Current consensus favors polymers derived from the cyclized intermediate 5,6-dihydroxyindole (DHI). In this work, compelling evidence for the possible structure of PDA is shown via detailed mass spectroscopic studies using deuterium-labeled dopamine (DA) precursors. More specifically, the major component of PDA is shown to derive from dopaminochrome (DAC) and uncyclized DA components. One major intermediate, seen at m/z 402, is characterized as a combination of benzazepine + DAC + 2H-pyrrole, which has a chemical formula of C23H20N3O4. Furthermore, DAC forms stable complexes with DA, and is a key control point in the polymerization of PDA. The decay of DAC into DHI is a relatively slow process in the presence of excess DA, and plays a smaller role in PDA formation. This study shows the covalent connectivity in PDA from the starting DA monomer, and represents an important advance in elucidating the structure of PDA.


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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Polymer Chemistry Author of the Month: April Kloxin

April M. Kloxin, Ph.D., is an Associate Professor in Chemical & Biomolecular Engineering and Materials Science & Engineering at the University of Delaware (UD) and a member of the Breast Cancer Research Program at the Helen F. Graham Cancer Center and Research Institute in the Christiana Care Health System.  She obtained her B.S. and M.S. in Chemical Engineering from North Carolina State University and Ph.D. in Chemical Engineering from the University of Colorado, Boulder, as a NASA Graduate Student Research Program Fellow.  She trained as a Howard Hughes Medical Institute postdoctoral research associate at the University of Colorado before joining the faculty at UD in 2011. Her group aims to create unique materials with multiscale property control for addressing outstanding problems in human health. Her research currently focuses on the design of responsive and hierarchically structured soft materials and development of controlled, dynamic models of disease and regeneration.  Her honors include the Biomaterials Science Lectureship 2019, ACS PMSE Arthur K. Doolittle Award 2018, a Susan G. Komen Foundation Career Catalyst Research award, a NSF CAREER award, and a Pew Scholars in Biomedical Sciences award.

What was your inspiration in working with polymers?

I have always enjoyed building things and had a desire to use those skills to help people.  I discovered my passion for using chemical approaches to build soft polymeric materials possessing unique and useful properties as an undergraduate and Master’s student at North Carolina State University (NCSU).  At NCSU, I had the opportunity to work in a collaborative environment with many extraordinary friends and colleagues having great polymer science and engineering expertise, including my MS thesis advisors Profs. Rich Spontak and Stuart Cooper.  This experience helped me understand the connection between molecular design and synthetic approaches for building polymeric materials with specific properties for a desired application.  I had the opportunity to fully realize and direct this passion working at the interface between polymeric materials and biological systems under the outstanding advisement and mentorship of Prof. Kristi Anseth at the University of Colorado, Boulder, for my Ph.D. and with the many remarkable researchers in her group and at the University.


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

From a biological perspective, my group has a focus on understanding how changes in the structure, mechanical properties, and compositions of tissues in the human body that occur upon injury influence the function and fate of key cells in healing and disease.  In this context, we have been interested in building synthetic mimics of these complex systems and processes, and we wanted to establish simple yet effective approaches for controlling the density and stiffness of soft materials when and where desired for hypothesis testing.  In the Polymer Chemistry manuscript, we were inspired by the work of Prof. Matt Becker (Duke University) amongst others demonstrating how the rate of formation of water-swollen polymer networks, hydrogels, could be used to control defect formation, network heterogeneity, and thereby the mechanical properties of the resulting materials.  We hypothesized that the rate-based control of properties that others observed with catalyzed step growth reactions was translatable to a photo-polymerized system, affording the implementation of a variety of photochemical controls (e.g., wavelength, intensity, time).  In particular, by selecting a wavelength of light that was not centered at the maximum absorption of the photoinitiator, we were better able to control the rate of photopolymerization with an accessible bench-top visible light LED system and thereby defect formation.  We then saw an opportunity to exploit dangling-end defects that were generated with this rate-based approach to increase crosslink density and ‘stiffen’ these materials with a secondary photopolymerization.  We are excited about the potential that this light-triggered rate-based approach for controlling mechanical properties of polymer networks has for a number of applications, including our on-going studies of cell response to matrix stiffening.


Which polymer or materials scientists are you most inspired by?

Oh, there are so many! I am especially inspired by the work and leadership of Prof. Paula Hammond (MIT) and Prof. Kristi Anseth, who continue to blaze trials at the interface between polymers, materials, and biology to solve complex problems, and Prof. Chris Bowman (University of Colorado, Boulder) and the late Prof. Charlie Hoyle (University of Southern Mississippi), who have pioneered the use of light-triggered step growth reactions for creating polymeric materials with diverse and robust properties.


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

It is an exciting time in polymer chemistry with many excellent researchers working from different perspectives to advance not only the field of polymer chemistry, but also to make fundamental breakthroughs that have an impact in biology, medicine, and energy.  Selecting just a few is difficult in this context.  A few that come to mind at the moment whose work I find particularly inspiring are Prof. Aaron Esser Kahn (University of Chicago) in biomolecular design of polymeric materials for rewiring the immune system, Prof. Dominik Konkolewicz (Miami University Ohio) in bioconjugations and dynamic covalent chemistries with polymeric materials, Prof. Rachel A. Letteri (University of Virginia) in peptide-polymer conjugates for multi-scale and dynamic properties, and my own new colleague Prof. Laure Kayser (University of Delaware) in conducting and semiconducting polymers.


How do you spend your spare time?

I enjoy making things, from designing materials at work to preparing satisfying meals in the kitchen at home.  Breakfast foods are my favorite, and I have different recipes that I continue to hone on weekends for quick meals during the week.  I also love being outside walking, hiking, or running with my friends or my husband and our two sons, particularly in the beautiful early autumn weather we currently are having.


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

My obsession with the complexity of biological systems and improving human health would keep me in science and engineering, whether in molecular biology or bioinformatics or more applied in medicine.

 

Read April’s recent Polymer Chemistry article now for FREE until 31st October!


Rate-based approach for controlling the mechanical properties of ‘thiol–ene’ hydrogels formed with visible light

 

The mechanical properties of synthetic hydrogels traditionally have been controlled with the concentration, molecular weight, or stoichiometry of the macromolecular building blocks used for hydrogel formation. Recently, the rate of formation has been recognized as an important and effective handle for controlling the mechanical properties of these water-swollen polymer networks, owing to differences in network heterogeneity (e.g., defects) that arise based on the rate of gelation. Building upon this, in this work, we investigate a rate-based approach for controlling mechanical properties of hydrogels both initially and temporally with light. Specifically, synthetic hydrogels are formed with visible light-initiated thiol–ene ‘click’ chemistry (PEG-8-norbornene, dithiol linker, LAP photoinitiator with LED lamp centered at 455 nm), using irradiation conditions to control the rate of formation and the mechanical properties of the resulting hydrogels. Further, defects within these hydrogels were subsequently exploited for temporal modulation of mechanical properties with a secondary cure using low doses of long wavelength UV light (365 nm). The elasticity of the hydrogel, as measured with Young’s and shear moduli, was observed to increase with increasing light intensity and concentration of photoinitiator used for hydrogel formation. In situ measurements of end group conversion during hydrogel formation with magic angle spinning (MAS 1H NMR) correlated with these mechanical properties measurements, suggesting that both dangling end groups and looping contribute to the observed mechanical properties. Dangling end groups provide reactive handles for temporal stiffening of hydrogels with a secondary UV-initiated thiol–ene polymerization, where an increase in Young’s modulus by a factor of ∼2.5× was observed. These studies demonstrate how the rate of photopolymerization can be tuned with irradiation wavelength, intensity, and time to control the properties of synthetic hydrogels, which may prove useful in a variety of applications from coatings to biomaterials for controlled cell culture and regenerative medicine.

 


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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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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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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Polymer Chemistry Author of the Month: Bumjoon Kim

Professor Bumjoon KimBumjoon Kim is a Professor in the Department of Chemical and Biomolecular Engineering at KAIST since 2008 where he is appointed as the KAIST Endowed Chair Professor. He completed his doctorate under the guidance of Prof. Edward Kramer at UCSB. Then, he worked with Prof. Jean Fréchet at UC Berkeley. His research interests include development of block copolymer-based functional materials including shape-tunable particles, colorimetric sensors, and design of new electroactive polymers for all-polymer solar cells with high stability. He has published more than 170 peer-reviewed papers and 50 issued/pending patents. He was appointed as the Ewon Assistant Professor at KAIST (2010-2013). Also, he received the KAIST Academic Excellence Award (2015) and Shimgye Science Award (2017), and he was selected as 2013 Young Scientist by the World Economic Forum (DAVOS Forum) and appointed as the KAIST Endowed Chair Professor (2018). He currently serves as an editorial advisory board member of Macromolecules, ACS Macro Letters, Chemistry of Materials (ACS), J. Mater. Chem. A (RSC) and BMC Energy (Springer Nature).

 

What was your inspiration in becoming a polymer chemist?

I’m not sure what would be the best way to simply describe it. I was educated both as a chemical engineer and a polymer scientist, not a hard core chemist. During my senior year in college, I first learned about polymers in a class named “Introduction to Polymer Engineering” taught by Prof. Kookheon Char at Seoul National University. This course gave me a strong interest in polymer science and motivated me to study polymer science further. Also, I believe I was very fortunate to receive a well-balanced education in both polymer physics and chemistry during my time at graduate school and postdoctoral studies from Profs. Edward Kramer, Craig Hawker (UCSB), and Jean Fréchet (UC Berkeley). These interests and backgrounds have led me to pursue the development of new polymer-based materials that may benefit our lives and society.

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

Particle shape is one of the most fundamental and essential features that determines the function of polymeric particles. For example, anisotropically shaped particles can exhibit unique optical properties, packing structures, and rheological behaviors. For the last few years, our group has made contributions to the development of the principles dictating the shape of block copolymer (BCP) particles from the evaporative emulsions. For example, I would like to highlight the papers including JACS 2014, 9982; Adv. Funct. Mater. 2018, 1802961; Macromolecules 2019, 1150. This understanding is synergistically combined with a technique called “membrane emulsification” to produce the particles of the same size and shape in a large batch (also see ACS Nano 2017, 2133; Chem. Mater. 2018, 6277), which enables the use of these particles for the various applications described above. In this Polymer Chemistry article, we describe the development of a series of non-spherical Janus particles with interesting cone-shapes. Systematic control of particle shape is achieved by programming the phase-separation of the blend of BCP and newly-synthesized copolymers confined in emulsion droplets. We also have developed a theoretical model to explain the shape of the cone-shaped particles.

Which polymer scientist are you most inspired by?

As I mentioned in the answer to the first question, people who are world-leading polymer scientists as well as great teachers have inspired me and helped a lot to develop my career and do my current research. In particular, I have learned a lot from Prof. Edward Kramer, who was my Ph.D. advisor, on many aspects, such as how to conduct research and attitudes towards students. I believe his patience and inspiration for science have greatly influenced my choice of work as a teacher and professor.

How do you spend your spare time?

I like traveling and walking/driving near the seaside. I spend enough time relaxing and refreshing outside the office. This helps me to think more clearly. Also, I enjoy spending time with my 7-year-old daughter, Jaeyeon.

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

I would like to be a teacher or a cook. Since I like teaching, I would spend time teaching young students if I were not a chemist. Also, I like cooking, so I think becoming a cook can be a great choice for me. I think there are many connections between cooking and doing experiments.

 

Read his Polymer Chemistry article for FREE until 15th July


graphical abstract

Block copolymers (BCPs) under colloidal confinement can provide an effective route to produce non-spherical particles. However, the resulting structures are typically limited to spheroids, and it remains challenging to achieve a higher level of control in the particle shape with different symmetries. Herein, we exploit the blend of BCPs and statistical copolymers (sCPs) within emulsion droplets to develop a series of particles with different symmetries (i.e. Janus-sphere and cone-shaped particles). The particle shape is tunable by controlling the phase behavior of the polymer blend consisting of a poly(styrene-block-1,4-butadiene) (PS-b-PB) BCP and a poly(methylmethacrylate-statistical-(4-acryloylbenzophenone)) (P(MMA-stat-4ABP)) sCP. A key strategy for controlling the phase separation of the polymer blend is to systematically tune the incompatibility between the BCP and sCP by varying the composition of the sCPs (ϕ4ABP, mole fraction of 4ABP). As a result, a sequential morphological transition from a prolate ellipsoid, to a Janus-sphere, to a cone-shaped particle is observed with the increase of ϕ4ABP. We further demonstrate that the shape-anisotropy of cone-shaped particles can be tailored by controlling the particle size and the Janusity, which is supported by quantitative calculation of the particle shape-anisotropy from the theoretical model. Also, the importance of the shape control of the cone-shaped particles with high uniformity in a batch is demonstrated by investigating their coating properties, in which the deposited coating pattern is a strong function of the shape-anisotropy of the particles.


About the webwriters

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

 

 

 

Professor Athina Anastasaki

 

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

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