Archive for the ‘Author of the Month’ Category

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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Polymer Chemistry Author of the Month: Sandra Schlögl

Dr Sandra SchloglSandra Schlögl studied Technical Chemistry at Graz University of Technology (Austria), where she obtained her Master degree in 2006. In 2006, she joined the Polymer Competence Center Leoben (PCCL), which is the leading ‘Center of Excellence’ for cooperative research in the area of polymer engineering and sciences in Austria. Two years later, she received her Ph.D. degree in Polymer Chemistry from Graz University of Technology. She was a visiting scientist at Politecnico di Torino (Italy) in the group of Prof. Marco Sangermano in 2016, and finished her habilitation (post-doctoral lecturing qualification) in Macromolecular Chemistry in 2017. Currently, she heads the ‘Chemistry of Functional Polymers’ division at PCCL. In addition, she is a lecturer at Montanuniversitaet Leoben (Austria) teaching courses at an MSc level in polymer photochemistry and in stimuli-responsive polymer materials. Her research centers on stimuli-responsive polymers, dynamic networks, elastomer chemistry and photochemistry in polymers. She is author of more than 50 peer-reviewed publications (Scopus H-index of 10), inventor of 11 patents (national and international) and has received several awards for her research (e.g. Paul Dufour Award in 2015, EARTO Innovation Award in 2016).

 

What was your inspiration in becoming a polymer chemist?

My career as a polymer chemist was not planned. In school, I always had a talent for natural-science subjects and back then, as today, I was intrigued by biological and biochemical processes of the human body. Obviously, my first plan was to study medicine and I even took Latin courses at school. However, during my voluntary work in the health care sector, I recognized that medicine is interesting in theory but hard to carry out in practice. I started to rethink my career plans, which led to my decision to study chemistry. The curriculum of the technical chemistry studies sounded promising since it also contained biochemistry, which was not so far away from medicine. However, during my studies I developed a favorite research activity: creating functional polymers. I took inspiring lectures and lab courses in polymer photochemistry, where I learned versatile and creative routes to change material properties on demand. Since then, the chemistry of polymers has me hooked.

What was the motivation behind your recent Polymer Chemistry article?

A strong focus of my working group is the synthesis of stimuli-responsive polymers, by introducing photocleavable chromophores and photoreversible binding motifs into polymer structures. These polymers change their material characteristics in response to external stimuli (such as light and temperature), which is used for numerous applications such as self-healable materials, reversible adhesives or switchable micropatterns.

Since several years, I have successfully cooperated with Marco Sangermano and Ignazio Roppolo from Politecnico di Torino on several research topics, joining the expertise of our working groups. Ignazio is not only a dedicated soccer player but also watches documentaries in his spare time. He was fascinated by the ability of desert beetles to collect humidity and transport water droplets across their skin. We discussed the topic and the idea was born to transfer the concept to photopolymer materials. Mimicking nature with synthetic materials for controlled water transport is not new, but the majority of the reported concepts rely on inorganic materials requiring time consuming and elaborate sample preparation techniques. With our recent Polymer Chemistry article, we succeeded to generate multi-gradients on polymer surfaces simply by light exposure. We introduced both a wettability gradient and a Laplace pressure gradient by a localized light-induced switching of the polarity, which is required to drive a water droplet across the photopolymer surface in a controlled way. This opens the path towards a precise movement of individual or multiple droplets on surfaces with complex topology and tailored surface polarity.

Which polymer scientist are you most inspired by?

In my field of research I am most inspired by the pioneering work of two scientists: Christopher N. Bowman (University of Colorado Boulder) and Christopher Barner-Kowollik (Queensland University of Technology). They are at the forefront of research in polymer photochemistry and their research is an important driving force for the development of new photopolymers with fascinating properties.

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

In my opinion, the research work of Miriam M. Unterlass (Vienna University of Technology) on hydrothermal polymerization has the potential to greatly influence future synthesis routes in polymer chemistry. Her research focuses on geomimetics, which takes inspiration from nature for generating novel synthetic materials under high pressure and with water as solvent. In one-pot reactions with low energy consumption, she is able to synthesis a great variety of materials involving polymers, dyes or inorganic-organic hybrids. I think that Miriam’s research has a great potential for the ‘green’ synthesis of new and traditional high-performance polymers; not only on a lab but also on an industrial scale.

How do you spend your spare time?

I am fond of outdoor sports, which are a good balance to my professional life, which over the past years is less and less taking place in the chemical lab but more in the office. I am a hobby racing cyclist, who tries to avoid the mountain areas, which is not an easy task in Austria and I do some running in between. I also enjoy spending time with my family and friends and in case of bad weather I like reading novels from different genres.

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

I would choose again a profession in science since I can only agree with Madame Marie Curie that ‘science has great beauty’.

 

Read her Polymer Chemistry article for FREE until June 10th!


Directed motion of water droplets on multi-gradient photopolymer surfaces

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The present work highlights the controlled directional movement of water droplets across a photopolymer surface. The movement is propelled by multi-gradients including a wettability gradient and a Laplace pressure gradient. Both gradients are conveniently adjusted by light employing a photoresponsive thiol–yne photopolymer. o-Nitrobenzyl alcohol derivatives with terminal alkyne groups are synthetized and cured across di- and tri-functional thiols upon visible light exposure. The wettability gradient is generated in a subsequent step involving an asymmetrical irradiation of the polymer surface with light in the UV-A spectral region. Polar groups are formed in the exposed areas due to the photocleavage of the chromophore and photo-oxidation reactions (upon prolonged UV exposure in air). The wettability rises with increasing exposure dose and gradient surfaces are prepared with static water contact angles ranging from 97 to 19°. By simultaneously inscribing the wettability gradient in wedge-shaped patterns, a Laplace pressure gradient is realized on the photopolymer surface, which can be easily tailored by the size and the angle of the wedge. The combination of both gradients enables a rapid and directed movement of water droplets (2 μL droplet) over a reasonable distance (up to 10 mm). Due to the high adhesion of the photopolymer surface, the droplet can be driven in a controlled way, even if the surface is inclined (20°) or turned upside down.


 

About the Web writer

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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Author of the Month: Prof. Dr. Ir. Bruno De Geest

Prof. Dr. Ir. Bruno De Geest graduated as Chemical Engineer in 2003 from Ghent University where he obtained his PhD in pharmaceutical sciences in 2006 on polyelectrolyte multilayer capsules for biomedical applications. For his PhD work he was awarded the graduate student award for pharmaceutical technology from the AAPS and the Andreas Deleenheer award from Ghent University. After 2 years of postdoctoral research at Utrecht University (The Netherlands) he returned to Ghent University at the Department of Pharmaceutics. From October 2012 onwards he is appointed as professor in Biopharmaceutical Technology.​​ Bruno De Geest has authored over 90 papers and his research group focus on the interface between materials science and life science with a particular interest in polymer chemistry, immunology and anticancer therapy.

Research website: http://brdegeest.wix.com/biopharmtech-degeest

What was your inspiration in becoming a chemist?

Chemistry offers a scientist the ability to create things using molecular scale building blocks, which appeared a very attractive concept to me. I’m a chemical engineer, thus not a hard core chemist by training. In 3rd year at university we had organic chemistry and later on polymers taught by Filip Du Prez who was then just appointed as professor. These courses awakened a strong interest in polymer chemistry and this interest still fuels the ambition of our lab to create new materials that could hopefully be of benefit for human medicine.

What was the motivation to write your Polymer Chemistry article?

One of the main focuses of our research group in nanoparticulate vaccine delivery. While endeavoring to attach vaccine antigens to polymeric nanoparticles we noticed that the efficiency of conjugating a polymer to a protein is disappointingly low. Therefore we decided at comparing head-to-head different conjugation chemistries based on functional RAFT chain transfer agents for grafting-onto protein conjugation. The message of our paper is twofold. Firstly it gives a guide to which chemistries as more efficient than others, at least for the specific cases we have tested. Secondly, it urges the need for more efficient polymer-protein conjugation strategies.

Why did you choose Polymer Chemistry to publish your work? (DOI: 10.1039/C4PY01224K)

Polymer Chemistry has high visibility in the chemical and materials science community and publishes a high number of papers dealing with topics on controlled radical polymerization and biomedical applications. In addition, the paper will be published as part of the upcoming Emerging Investigator Issue. I’m delighted to contribute especially with this paper as it is a signature paper for our current research line.

In which upcoming conferences may our readers meet you?

I’m attending the ACS Spring Meeting in Denver in March where together with Prof. Aaron Esser-Kahn we are organizing a POLY symposium on ‘Interacting with the immune system using polymeric systems’.

How do you spend your spare times?

I’m a keen cyclist and a love to ride with my race bike trough the Flemish Ardennes. This region south of Ghent towards the Walloon border is well known for the spring cycling classics and it is a privilege to ride the same roads and climb the same cobblestone hills as the pro cyclists.

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

I think I would have studied sciences anyway, but in stead of becoming a researcher I would like be a teacher. I have always enjoyed working together with young people.


Polymer-protein conjugation via a ‘grafting to’ approach – a comparative study of the performance of protein-reactive RAFT chain transfer agents

N. Vanparijs,   S. Maji,   B. Louage,   L. Voorhaar,   D. Laplace,   Q. Zhang,   Y. Shi,   W. E. Hennink,   R. Hoogenboom and   B. G. De Geest

Abstract: Efficient polymer-protein conjugation is a crucial step in the design of many therapeutic protein formulations including nanoscopic vaccine formulations, antibody-drug conjugates and to enhance the in vivo behaviour of proteins. Here we aimed at preparing well-defined polymers for conjugation to proteins by reversible addition–fragmentation chain transfer (RAFT) polymerization of both acrylates and methacrylamides with protein-reactive chain transfer agents (CTAs). These RAFT agents contain either a N-hydroxysuccinimide (NHS) or pentafluorophenyl (PFP) ester moiety that can be conjugated to lysine residues, and alternatively a maleimide (MAL) or pyridyl disulfide (PDS) moiety that can be conjugated to cysteine residues. Efficiency of the bioconjugation of these polymers to bovine and avian serum albumin was investigated as a function of stoichiometry, polymer molecular weight and the presence of reducing agents. A large molar excess of polymer was required to obtain an acceptable degree of protein conjugation. However, protein modification with N-succinimidyl-S-acetylthiopropionate (SATP) to introduce sulfhydryl groups onto primary amines, significantly increased conjugation efficiency with MAL- and PDS-containing polymers.


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


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Author of the Month: Professor Takeshi Endo

Takeshi Endo is a Professor of Molecular Engineering Institute (MEI) at Kinki University and an Emeritus Professor at Tokyo Institute of Technology (TIT). He is also Director of MEI and Vice President of Kinki University. He became an Assistant Professor at TIT in 1969, Associate Professor in 1982 and a Professor in 1986. He was Director of Chemical Resources Laboratory at TIT from 1991 until his retirement from TIT in 2000. Then he moved to Yamagata University, and became Vice President of Yamagata University until his retirement from Yamagata University in 2005. He moved to Kinki University in 2005. He was awarded the award of the Society of Polymer Science, Japan (1984), the Chemical Society of Japan Award for Creative Work (1989), and the Chemical Society of Japan Award for Technical Development (2000). From 2008, he has been an Honorary Member of the Society of Polymer Science, Japan.

Institute Website: Molecular Engineering Institute (MEI)

What was your inspiration in becoming a chemist?

I have been interested in the nature science from a young age, especially, photosynthesis that is essential to grow foods such as rice and sweet potato that I can see around my house. The interests let me to study the chemistry at university.

What was the motivation to write your Polymer Chemistry article?

Our group recently reported on synthesis of polypeptide through polycondensation of N-phenoxycarbonyl derivative of a-amino acid with the elimination of phenol and CO2. During the course of investigation about polymethionine(oxides), we have achieve the facile route for the synthesis of well-defined poly polymethionine(oxides) in terms of molecular weigh and terminal structure through polycondensation of the corresponding urethane derivative. In addition, we found that oligo(methionine sulfoxide)-base polymer offers a excellent antifouling property against biological matters. We expect that the synthetic method could be used widely to construct polypeptide-based polymer for biomedical application.

Why did you choose Polymer Chemistry to publish your work?

Polymer Chemistry is one of the most attractive journals in the field of polymer chemistry and many readers working on the related fields will have a lot of interesting.

In which upcoming conference may our readers meet you?

I will attend the 11th International Conference on Advanced Polymers via Macromolecular Engineering (APME 2015), which is held at Yokohama in Japan from 18th to 22nd October 2015 as a member of organizing committee (Chairman). The conference is now announced at http://www.apme2015.jp/index.html. I am looking forward to seeing you at Yokohama in Japan.

How do you spend your spare times?

I enjoy watching TVs about baseball, soccer and tennis game.

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

I would choose a SF writer.


Facile synthesis of polymethionine oxides through polycondensation of activated urethane derivative of α-amino acid and their application to antifouling polymer against proteins and cells

Shuhei Yamada,   Kazuhiro Ikkyu,   Kazuhiro Iso,   Mitsuaki Goto and   Takeshi Endo

We have developed a facile route for the synthesis of poly(methionine) and poly(methionine oxide), including poly(methionine sulfoxide), and poly(methionine sulfone) through polycondensation of the corresponding N-phenoxycarbonyl derivatives of α-amino acids in the presence of amines. These urethane derivatives were readily synthesized through N-carbamylation of onium salt of methionine with diphenyl carbonate. Oxidation of sulfide on the urethane derivative with a hydrogen peroxide selectively provided the corresponding sulfoxide and sulfone in high yield. Heating of their urethane derivative 60 °C successfully obtained the corresponding polypeptide through polycondensation accompanying the elimination of phenol and CO2 in high yield. The molecular weight of polypeptide was adjusted by varying the feed ratio of urethane derivative to amine. MALDI-TOF mass analysis revealed that the added amine was successfully incorporated into the terminal end of the polypeptide. Taking advantage of our facile synthetic route to synthesize a polypeptide, we have synthesized a polystyrenes bearing oligo(L-methionine sulfoxide) in the side chain, and investigated their application as a surface-coating polymer that leads to antifouling property against proteins and cells. The polystyrene was readily synthesized through polycondensation of a urethane derivative of L-methionine sulfoxide in the presence of 4-vinylbenzylamine, followed by radical polymerization with water-soluble azo initiator. The inhibition of protein (hRP-IgG) adsorption and F9 cells adhesion was observed on the surface of the polymer-coated PS plate because of the hydrophilic nature of L-methionine sulfoxide segment. In addition, the result of CCK-8 assay reveals a low cytotoxicity against F9 cells, indicating that the polymer possesses a high biocompatibility.


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


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Author of the Month: Prof. Nathaniel A. Lynd

Nate studied chemistry at Michigan State University, and attended graduate school at the University of Minnesota where he worked in the laboratory of Prof. Marc A. Hillmyer on the effects of polydispersity on block polymer self-assembly. After graduating in late 2007, Nate moved to the Materials Research Laboratory at the University of California in Santa Barbara and worked in the groups of Glenn H. Fredrickson, Edward J. Kramer, and Craig J. Hawker. During nearly six years of research at the MRL, Nate published work in areas of polymer science encompassing a broad range of synthetic, physical, and theoretical topics. After UCSB, Nate became a staff scientist at Lawrence Berkeley National Laboratory in the Materials Sciences Division and became a project leader at the Joint Center for Artificial Photosynthesis. In April 2014, Nate was appointed as an assistant professor in the McKetta Department of Chemical Engineering at the University of Texas at Austin.

Nate’s research efforts are focused on creating and utilizing new functional and reactive macromolecular materials. Newer work is built on a foundation of techniques for advanced copolymer structure determination and detailed mechanistic understanding which facilitate the compositional control of structure-property-processing relationships. Specifically, we are currently engaged in gaining further understanding of compositional control in polyether materials, degradable biomedical materials, membranes for carbon capture, and understanding ion transport in polymer electrolytes and membranes.

Research group: http://lynd.che.utexas.edu/

What was your inspiration in becoming a chemist?

I always had an interest in science as a kid. I was (and still am!) very interested in geology, paleontology, and space exploration like many. My interest narrowed to chemistry with a very inspirational honors chemistry teacher in high school (Mr. John Wheeler, Batavia High School). In undergraduate, I took organic chemistry from Dr. Gregory L. Baker, a polymer chemist. I was fascinated by the possibilities of polymers, and did undergraduate research in Dr. Baker’s lab on the stereospecific synthesis of substituted lactides. This was how I got started in polymer science.

What was the motivation to write your Polymer Chemistry article?

Functional, mono-sized polymer particles are enabling to a range of applications. Our interest in this was motivated by a one very specific application, but we focused on the underlying chemistry for the article.

Why did you choose Polymer Chemistry to publish your work?

I’ve had a very positive experience with the journal, and I think it’s the right venue for rapidly reporting new developments. Additionally, I believe it reaches the right audience. As such, I’ve selected Polymer Chemistry to publish several other articles as well.

In which upcoming conferences may our readers meet you?

I will be a several upcoming conferences. I’ll be at an ECI conference on membranes in Syracuse, Italy in February, also the upcoming American Chemical Society Meeting in Denver. Additionally, I’ll be at the upcoming Gordon Research Conference on Polymers in June, and will attend the International Symposium on Ionic Polymerization in Bordeaux this July.

How do you spend your spare time?

I enjoy reading science fiction, spending time with my family, and running whenever I get a chance. I enjoy cooking and especially barbecue. Lately, I’ve been working on my central Texas style BBQ’ing skills!

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

I would probably enjoy being a scientific illustrator, or a software engineer.


A synthetic strategy for the preparation of sub-100 nm functional polymer particles of uniform diameter

Kato L. Killops,   Christina G. Rodriguez,   Pontus Lundberg,   Craig J. Hawk and   Nathaniel A. Lynd

Abstract: An amphiphilic block copolymer surfactant is used to impart peripheral surface functionality to polymer nanoparticles synthesized via emulsion polymerization. Particles ranged in size from ca. 55 nm by SEM (ca. 82 nm by DLS) to just over 200 nm. Particles displaying latent functionality were readily functionalized directly after polymerization using a fluorescent dye.


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


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Author of the Month: Dr Daniel Klinger

Daniel obtained his degree in chemistry from the Johannes Gutenberg University in Mainz, Germany. During his diploma studies under the guidance of Prof. Dr. Patrick Theato, he worked on the development of photo-switchable block copolymers using controlled radical polymerization methods. He then moved to the group of Katharina Landfester at the Max Planck Institute for Polymer Research in Mainz where he received his PhD at the end of 2011. During this time he focused on the development of responsive microgels and polymeric nanoparticles for enzymatic and light-triggered release applications. In, early 2012, Daniel joined the group of Craig J. Hawker at the University of California in Santa Barbara as a postdoctoral researcher and started working on surfactant-directed block copolymer self-assembly in nanoparticles.

In his current position as project leader in the Materials Research Laboratory at UCSB, he combines the areas of block copolymer self-assembly, with his existing experience in the fields of stimuli-responsive materials and colloidal chemistry. He currently focuses on the development of functional nanomaterials from the controlled assembly of tailor-made polymeric building blocks. Among other areas, he is interested in phase-separated block copolymer nanoparticles, stimuli-responsive micro- and nano gels and new polymers and composite materials for applications in photonics, optoelectronics and thermal conductors.

What was your inspiration of becoming a chemist?

From early on, I was always interested in understanding how things around me work and constantly asked the questions, “Why is it like this?” and “How come it does that?” It was my father – a chemistry teacher – who first showed me that all these interesting phenomena could be explained by the interaction of atoms and molecules. I became hooked on the subject in high school when I learned that these physical and chemical principles could be used to develop entirely new materials of my own design. It is this process of developing new materials by combining a theoretical understanding with the handicraft of an actual experiment that still excites me and drives my research.  The ability to transform an abstract idea on paper into a reality in the lab is highly rewarding to me.

What was the motivation to write your Polymer Chemistry article?

To me, stimuli-responsive microgels have long been an interesting class of materials. Adjusting the swelling and degradation profiles via macromolecular design allows for precise tuning of their loading and release behavior. However, the utilization and efficiency of such nanoparticles in actual biomedical applications crucially depends on various structural parameters such as surface chemistry, size and size distribution. Since investigations on new responsive particles normally come with variations in these factors, accurately comparing the biological efficiency of different approaches is difficult. To overcome this limitation, I wanted to develop a synthetic platform that could investigate different response mechanisms while keeping the structural and morphological parameters constant, and the approach presented here is a first step towards realizing this goal.

Why did you choose Polymer Chemistry to publish your work?

Polymer Chemistry is a great platform for the rapid publication of studies that are not only focusing on macromolecular synthesis but also combine new polymeric materials with a variety of different research fields and applications. Since our presented research is based on combining polymer chemistry with the area of functional colloids, the interdisciplinary character of the journal makes our work accessible to a broad readership and thereby enhances its exposure.

In which upcoming conferences may our readers meet you?

Most likely, I will attend the fall ACS meeting in Boston 2015.

How do you spend your spare times?

I really like travelling and exploring new countries, cultures and foods around the world. I am especially happy if I am able to combine this with spending time in nature. I love being active outdoors and enjoy hiking, rock climbing and camping in the wilderness where simple things like sitting around the campfire can be the best reward after a long day.

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

Being a chemist, I enjoy mixing things together to make new and interesting products. If I were not a scientist, I would combine this excitement with my passion for food to become a chef. I am just not sure whether a lot of people would enjoy these “experiments”.


A robust platform for functional microgels via thiol–ene chemistry with reactive polyether-based nanoparticles

Carolin Fleischmann,   Jeffrey Gopez,   Pontus Lundberg,   Helmut Ritter,   Kato L. Killops,   Craig J. Hawker and   Daniel Klinger

We herein report the development of crosslinked polyether particles as a reactive platform for the preparation of functional microgels. Thiol–ene crosslinking of poly(allyl glycidyl ether) in miniemulsion droplets – stabilized by a surface active, bio-compatible polyethylene glycol block copolymer – resulted in colloidal gels with a PEG corona and an inner polymeric network containing reactive allyl units. The stability of the allyl groups allows the microgels to be purified and stored before a second, subsequent thiol–ene functionalization step allows a wide variety of pH- and chemically-responsive groups to be introduced into the nanoparticles. The facile nature of this synthetic platform enables the preparation of microgel libraries that are responsive to different triggers but are characterized by the same size distribution, surface functionality, and crosslinking density. In addition, the utilization of a crosslinker containing cleavable ester groups renders the resulting hydrogel particles degradable at elevated pH or in the presence of esterase under physiological conditions.


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


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