Pete Livermore, Deputy Editor – Polymer Chemistry Blog

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2016 Polymer Chemistry Lectureship is now open!

03 Nov 2015

Do you know an early-career researcher who deserves recognition for their contribution to the polymer chemistry field?

Now is your chance to put them forward for the accolade they deserve.

Polymer Chemistry is pleased to announce that nominations are now being accepted for its 2016 Lectureship award. This annual award was established in 2015 to honour an early-stage career scientist who has made a significant contribution to the polymer chemistry field.

Previous winners

2015 – Richard Hoogenboom, Ghent University, Belgium

Qualification

To be eligible for the Polymer Chemistry Lectureship, the candidate should be in the earlier stages of their scientific career, typically within 15 years of attaining their doctorate or equivalent degree, and will have made a significant contribution to the field.

Description

The recipient of the award will be asked to present a lecture three times, one of which will be located in the home country of the recipient. The Polymer Chemistry Editorial Office will provide the sum of £1000 to the recipient for travel and accommodation costs.

The recipient will be presented with the award at one of the three award lectures. They will also be asked to contribute a lead article to the journal and will have their work showcased on the back cover of the issue in which their article is published.

Selection

The recipient of the award will be selected and endorsed by the Polymer Chemistry Editorial Board.

Nominations

Those wishing to make a nomination should send details of the nominee, including a brief C.V. (no longer than 2 pages A4) together with a letter (no longer than 2 pages A4) supporting the nomination, to the Polymer Chemistry Editorial Office by 29^th January 2016. Self-nomination is not permitted.

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Editorial Board’s Top Picks: Ben Zhong Tang

09 Sep 2015

Ben Zhong Tang is an Associate Editor for Polymer Chemistry and a Chair Professor in the Department of Chemistry, The Hong Kong University of Science & Technology (HKUST), China. His research focuses on the synthesis of new molecules and polymers with novel structures and unique functions and the exploration of their high-tech applications as advanced materials in life science, optoelectronic devices, etc.

You can find all Editorial Board’s Top Picks papers in our web collection

Focus on Luminogenic Polymers (Associate Editor: Prof. Ben Zhong Tang, HKUST, China)

1. A fluorescent supramolecular polymer with aggregation induced emission (AIE) properties formed by crown ether-based host–guest interactions
Dong Chen, Jiayi Zhan, Mingming Zhang, Jing Zhang, Jiaju Tao, Danting Tang, Ailin Shen, Huayu Qiu and Shouchun Yin
Polym. Chem. 2015, 6, 25–29.

Supramolecular polymers are a group of novel macromolecules with their monomeric units self-assembled together through monovalent interactions. S. Yin and coworkers at Hangzhou Normal University (China) and University of Maryland (USA) have synthesized a new supramolecular polymer by utilizing crown ether-based host–guest interactions. The supramolecular polymer shows aggregation-induced emission, thanks to the tetraphenylethene units imbedded in the macromolecular chain. Its fluorescence intensity is decreased dramatically on the addition of Pd²⁺ due to the coordination of the metal ion with the triazole group, enabling the polymer to find practical application as a fluorescent chemosensor.

2. Amphiphilic fluorescent copolymers via one-pot combination of chemoenzymatic transesterification and RAFT polymerization: synthesis, self-assembly and cell imaging
Zengfang Huang, Xiqi Zhang, Xiaoyong Zhang, Changkui Fu, Ke Wang, Jinying Yuan, Lei Tao and Yen Wei
Polym. Chem. 2015, 6, 607–612.

Fluorescent organic nanoparticles (FONs) have attracted much attention. Many FONs, however, are hydrophobic particles and have been fabricated by non-covalent strategies. Z. Huang and coworkers at University of Electronic Science & Technology of China and Tsinghua University have combined radical polymerization and enzymatic transesterification processes and developed a one-pot covalent procedure for the fabrication of FONs with aggregation-induced emission (AIE) attribute. The amphiphilic chains of the obtained polymers self-assemble into spherical FONs with the hydrophobic AIE cores covered by hydrophilic poly(ethylene glycol) shells. The FONs show excellent dispersibility in aqueous media, compatibility with biological species, and performance as bioimaging reagent.

3. Aggregation-induced circularly polarized luminescence of an (R)-binaphthyl-based AIE-active chiral conjugated polymer with self-assembled helical nanofibers
Shuwei Zhang, Yuan Sheng, Guo Wei, Yiwu Quan, Yixiang Cheng and Chengjian Zhu
Polym. Chem. 2015, 6, 2416–2422.

A number of polymers with atomic chirality have been found to emit circularly polarized luminescence (CPL). Polymers with axial chirality, however, have been rarely prepared. A team led by Y. Cheng and C. Zhu at Nanjing University (China) have synthesized a series of conjugated polymers containing (R)-binaphthylene and tetraphenylethene (TPE) units with axial chirality and aggregation-induced emission (AIE). All the polymers show AIE effects, thanks to the TPE units embedded in the polymer chains. When the polymers form aggregates in aqueous mixtures, a polymer with the “right” structure becomes CPL active. The aggregation-induced CPL effect of the polymer is tunable by changing the water content of the aqueous mixture.

Review article

Luminescent polymers and blends with hydrogen bond interactions
Shih-Hung Huang, Yeo-Wan Chiang and Jin-Long Hong
Polym. Chem. 2015, 6, 497–508.

Macromolecular luminogens with aggregation-induced emission (AIE) characteristics are useful functional materials because they emit strongly in the aggregate or solid state. As the restriction of intramolecular rotations of luminogens is the main cause for the AIE activity, it has been envisioned that hydrogen-bond interactions can be utilized to construct AIE-active polymers. J.-L. Hong and coworkers have summarized the research effort in the area of AIE study. Through appropriate choices of H-bonding units and sites, a variety of AIE-active polymers and blends have been conveniently generated. In the polymers containing multiple luminogen units, the entangling polymer chains and the intermolecular H-bonding interactions impose effective rotational restriction on the luminogens. In the hydrophilic polymers carrying single luminogens, ready aggregation of the hydrophobic luminogens from the phase-separated H-bonding sites reinforces the beneficial rotational restriction, resulting in AIE systems with intense light emissions. In the luminogenic polymer blends consisting of H-bonding donors and acceptors, the preferable intermolecular H-bond interactions effectively hamper the motion of the constituent components. Thanks to the effective intermolecular H-bond interactions, the blends emit more efficiently than their pure luminogen counterparts without H-bond interactions.

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Jeremiah Johnson joins the Polymer Chemistry Editorial Board

07 Sep 2015

We are delighted to announce that Dr Jeremiah Johnson has become the newest member of the Polymer Chemistry Editorial Board.

Jeremiah is Firmenich Career Development Assistant Professor in the Department of Chemistry, Massachusetts Institute of Technology, USA, having completed his PhD at Columbia University (USA) and a postdoc at California Institute of Technology (USA).

The Johnson lab focuses on researching molecular design in three primary areas: nano-scale materials synthesis, macro-scale materials synthesis, and development of new chemical methods for modifying interfaces between bulk and nanoscale objects (surface chemistry).

He was chosen by Chemical Communications as one of their Emerging Investigators of 2015. You can see his contribution to the themed issue here:

Improving photo-controlled living radical polymerization from trithiocarbonates through the use of continuous-flow techniques
Mao Chen and Jeremiah A. Johnson
Chem. Commun., 2015,51, 6742-6745

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Introducing our newest Advisory Board member: Priyadarsi De

26 Aug 2015

We are delighted to announce that Dr Priyadarsi De (Indian Institute of Science Education and Research Kolkata, India) has joined the Advisory Board of Polymer Chemistry.

Dr. Priyadarsi De is currently Associate Professor in the Department of Chemical Sciences in the Indian Institute of Science Education and Research Kolkata (IISER-K). He has held positions at University of Massachusetts Lowell, USA, where he worked as a post-doctoral fellow in the group of Professor Rudolf Faust, and in Southern Methodist University (Dallas, USA) with Professor Brent Sumerlin. He has also spent time in industry, as a Distinguished Scientist at PhaseRx Pharmaceuticals, Seattle, USA.

His research interests include RAFT polymerization of amino acid and fatty acid based monomers, polymeric-inorganic hybrid nanomaterials, polymeric polyelectrolytes, cross-linked polymeric hydrogels and organogels, and weak-link polymers such as polyperoxides and polysulfides.

See some of Priyadarsi’s recent Polymer Chemistry papers:

Polymerization-induced self-assembly driving chiral nanostructured materials
Kamal Bauri, Amal Narayanan, Ujjal Haldar and Priyadarsi De
Polym. Chem., 2015,6, 6152-6162

POSS-induced enhancement of mechanical strength in RAFT-made thermoresponsive hydrogels
Ujjal Haldar, Mridula Nandi, Binoy Maiti and Priyadarsi De
Polym. Chem., 2015,6, 5077-5085

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Editorial Board’s Top Picks: Wei You

21 Jul 2015

Wei You is an Associate Editor for Polymer Chemistry and an Associate Professor in the Department of Chemistry, University of North Carolina Chapel Hill, USA. His research focuses on the synthesis and characterization of novel multifunctional materials for a variety of applications, predominately in electronics and photonics. Wei’s group uses an interdisciplinary approach, interfacing chemistry, physics, materials science and engineering.

You can find all Editorial Board’s Top Picks papers in our web collection

Focus on Conjugated Polymers (Associate Editor: Prof. Wei You, UNC Chapel Hill, USA)

Conjugated polymers, due to their interesting optical and electrochemical properties, have found many applications, from solar cells, to light-emitting diodes, transistors, and sensors, to name a few. Design and synthesis of novel conjugated polymers have been a very research-active area, illustrated by the fact that Polymer Chemistry has published more than 450 contributions in the past five years (~10% of the total number of publications).

In my Editorial Board’s Top Picks, I highlight four papers, and two review articles:

1. Benzodifuran-alt-thienothiophene based low band gap copolymers: substituent effects on their molecular energy levels and photovoltaic propertiesLijun Huo, Zhaojun Li, Xia Guo, Yue Wu, Maojie Zhang, Long Ye, Shaoqing Zhang and Jianhui Hou
Polym. Chem., 2013,4, 3047-3056

Conjugated polymers for solar cells is one of hottest research areas in the past decade. Hou’s group took the conjugated backbone of benzodifuran-alt-thieno[3,4-b]thiophene (BDF-alt-TT) to carry out a comprehensive study on the impact of electron-withdrawing group on the optical and electrochemical properties of the parent polymer. It is an elegant study that covers design and synthesis, physical properties, computational modeling, and photovoltaic device characteristics. Such a comprehensive study of structure-property relationship is very impressive and useful to the field of conjugated polymer for solar cells.

2. Synthesis of donor–acceptor conjugated polymers based on benzo[1,2-b:4,5-b′]dithiophene and 2,1,3-benzothiadiazole via direct arylation polycondensation: towards efficient C–H activation in nonpolar solvents
Xiaochen Wang and Mingfeng Wang
Polym. Chem., 2014,5, 5784-5792

Though most conjugated polymers are made through Stille, Suzuki type polycondensations, recently, direct-arylation cross-coupling has emerged as an economically efficient and environment-friendly approach. Wang’s group focused on a particular polymer, PBDTBT, consists of alternating benzo[1,2-b:4,5-b0]dithiophene (BDT) as an electron donor (D) and 2,1,3-benzothiadiazole (BT) as the electron acceptor (A). What is really impressive is that they systematically investigated almost all reaction factors including catalysts, solvents, ligands, bases, additives, concentration of reactants and phase transfer agents. The great efforts had a good payoff: their optimized condition was able to achieve a weight averagemolecular weight (Mw) as high as 60 kg/mol in nearly quantitative yield and excellent C–H selectivity.

3. Optical and electrical properties of dithienothiophene based conjugated polymers: medium donor vs. weak, medium, and strong acceptors
Bijitha Balan, Chakkooth Vijayakumar, Akinori Saeki, Yoshiko Koizumi, Masashi Tsuji and Shu Seki
Polym. Chem., 2013,4, 2293-2303

Donor-acceptor to create conjugated polymers is the most popular approach to control the band gap and energy level of conjugated polymers. The Seki group conducted an interesting study to investigate the strength of acceptor (weak, medium and strong) with a fixed donor, dithienothiophene in deciding optical and electrochemical properties of the resulting polymers. Furthermore, they did the computational modeling and device mobilities with different methods. An elegant work with thorough synthetic details and comprehensive study.

4. Low band-gap benzothiadiazole conjugated microporous polymers
Shijie Ren, Robert Dawson, Dave J. Adams and Andrew I. Cooper
Polym. Chem., 2013,4, 5585-5590

Conjugated microporous polymers (CMPs), combining microporosity, high surface areas with extended conjugation, can find a range of potential applications, including light-harvesting and sensing. The Cooper group created a low band gap CMP by incorporating the popular benzothiadiazole unit, via transition metal catalyzed cross-coupling polycondensation. Most interestingly, the fluorescence of one of the polymers was quenched by the inclusion of C60 in the pores, demonstrating the potential applications of such materials in efficient light harvesting or energy conversion.

Review articles:

1. Controlled polymerizations for the synthesis of semiconducting conjugated polymers
Ken Okamoto and Christine K. Luscombe
Polym. Chem., 2011,2, 2424-2434

Conjugated polymers synthesize by chain-growth mechanism (directly or indirectly), though much less explored when compared with the more popular step-growth mechanism, offer a number of unique advantages, including controlled molecular weight, low dispersity, and ease of preparing block copolymers. This review by the Luscombe group provided a rather comprehensive review (up to 2011) on this topic, covering various controlled polymerization methods to synthesize conjugated polymers, including living anion polymerization, ring-opening metathesis polymerization and chain-growth condensation polymerization.

2. Well-defined two dimensional covalent organic polymers: rational design, controlled syntheses, and potential applications
Zhonghua Xiang, Dapeng Cao and Liming Dai
Polym. Chem., 2015,6, 1896-1911

Two-dimensional (2D) covalent organic polymers (COPs) and derivatives are an emerging category of conjugated polymers, which hold great potential for a large variety of applications, including gas storage, energy conversion and storage, and sensing. The Dai group reviewed the recent progress in this exciting field of research, covering the rational design, controlled syntheses and potential applications of 2D COPs with various well-defined structures and properties. An up-to-date review on this topic with many beautiful structures.

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Paper of the Month: Rapid synthesis of ultrahigh molecular weight and low polydispersity polystyrene diblock copolymers by RAFT-mediated emulsion polymerization

26 May 2015

Truong et al. describe the synthesis of ultrahigh molecular weight and low polydispersity polystyrene diblock copolymers by RAFT-mediated emulsion polymerisation.

aper of the month: Rapid synthesis of ultrahigh molecular weight and low polydispersity polystyrene diblock copolymers by RAFT-mediated emulsion polymerization

Ultra high molecular weight (UHMW) polymers have always been an ambitious target for synthetic polymer chemists. However, synthesising these materials using controlled radical polymerisation is challenging due to high levels of bimolecular termination and chain transfer to monomer that impede the growth of polymer chains. Monomers with higher propagation rate coefficient (k_p) such as acrylamides and acrylates (and even methacrylates) have been successfully polymerised up to 10⁶ g mol^-1 but lower k_p monomers (e.g. styrene) typically present broad molecular weight distributions when high molecular weight (e.g. 10⁶ g mol^-1) is targeted.

Truong et al. envisaged that a high polymerisation rate for the polymer chains would be required in order to produce well-defined UHMW polystyrene, whilst at the same time termination and side reactions would need to be minimised. The authors addressed this by employing the use of novel macromolecular chain transfer agents (CTA) in reversible addition fragmentation chain transfer polymerisation (RAFT)-mediated emulsion polymerisation. N-hydroxyethyl acrylamide (HEAA) and poly(ethylene glycol) methyl ether acrylate (PEGA) were copolymerised under judiciously selected reaction conditions to identify the most effective macrostabiliser for the emulsion polymerisation. The choice of these monomers proved crucial for the polymerisation, with PEGA conferring excellent antifouling characteristics while HEAA improves the water solubility of the macromolecular CTA and reduces partitioning of the macro-stabilisers within the styrene droplets and/or at the water/droplet interfaces. Under carefully optimised conditions, UHMW polystyrene of 10⁶ g mol^-1 could be obtained with relatively low dispersity values (<1.4) and unimodal molecular weight distributions even at near-quantitative conversions (>90%). Moreover, UV-Vis analysis confirmed the presence of the CTA, further suggesting that the reversible-deactivation radical polymerisation mechanism remained operative even to this very high conversion and molecular weight. Another interesting feature of this work is the linear relationship between particle size and molecular weight in this system, which seems to depart from the packing parameter theory, typically used to explain morphology transformations during emulsion or aqueous dispersion polymerisations. TEM analysis in all samples revealed uniformly spherical nanoparticles, even when the chain length of the polystyrene core was well above the threshold for the worm and vesicle formation. These experiments suggest that the packing parameter theory cannot be applied for all polymerisation-induced self-assembly systems and that further theoretical models are potentially required to fully understand the equilibrium morphology of soft nanoparticles.

In short, this article has overcome a longstanding challenge in the synthesis of UHMW polymers and created a new nanomaterial which offers great potential in numerous applications.

Summary points from the authors:

4,4′-Azobis(4-cyanopentanoic acid (ACPA) (free radical initiator) completely dissolves in water only after stirring for about 30 min. The stock ACPA solution should be made up fresh and not be stored for later use.
To avoid the loss of styrene monomer (by evaporation) during polymerisation, there is no need to keep the emulsion polymerisation under the continuous flow of nitrogen.
Samples prepared for dynamic light scattering measurements were not filtered, and as such filtration might enable a further reduction in the particle size distribution.
The molar ratio of HEAA to PEGA in the macromolecular CTAs was optimised at 1 to 1. A higher molar ratio of HEAA to PEGA results in aggregation when targeting ultra-high molecular weight polystyrene. A lower molar ratio of HEAA to PEGA results in a higher portion of macromolecular CTAs partitioning within the styrene droplets.

Rapid synthesis of ultrahigh molecular weight and low polydispersity polystyrene diblock copolymers by RAFT-mediated emulsion polymerization by Nghia P. Truong, Marion V. Dussert, Michael R. Whittaker, John F. Quinn and Thomas P. Davis, Polym. Chem., 2015, 6, 3865-3874

Dr. Athina Anastasaki is a is a guest web-writer for Polymer Chemistry. She is currently a Warwick University (UK) and Monash University (Australia) research fellow working under the Monash Alliance. Visit the Haddleton group’s website for more information.

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2015 International Polymer Colloids Group Conference

07 Apr 2015

We are pleased to announce the 2015 International Polymer Colloids Group Conference to be held on June 28 – July 3, 2015 at The University of New Hampshire, Durham, USA.

The 2015 program will bring together world leading scientists to discuss the latest developments in the area of colloidal polymer science. The talks of the invited speakers will feature a balance of traditional and emerging applications for polymer colloids, following the themes of colloids for life, engineering colloids, and colloidal machines. You can see a list of confirmed speakers here.

You can register for the 2015 IPCG Conference here.

SCIENTIFIC COMMITTEE

Prof. Stefan Bon, Conference Chair, Warwick University, UK
Prof. Jose R. Leiza, University of the Basque Country, Spain
Dr. Willie Lau, Oriental Yuhong, CN

ORGANIZING COMMITTEE

Prof. John Tsavalas, University of New Hampshire, USA

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Polymer Chemistry Blog

Author Archive

2016 Polymer Chemistry Lectureship is now open!

Do you know an early-career researcher who deserves recognition for their contribution to the polymer chemistry field?

Editorial Board’s Top Picks: Ben Zhong Tang

Jeremiah Johnson joins the Polymer Chemistry Editorial Board

Introducing our newest Advisory Board member: Priyadarsi De

Editorial Board’s Top Picks: Wei You

Paper of the Month: Rapid synthesis of ultrahigh molecular weight and low polydispersity polystyrene diblock copolymers by RAFT-mediated emulsion polymerization

2015 International Polymer Colloids Group Conference

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