Archive for August, 2014

Paper of the week: White light emission of multi-chromophore photoluminescent nanoparticles

‘Fluorescence is a powerful tool in a variety of applications, ranging from optical to analytical materials (detection of small molecules and protein studies) because of its exquisite sensitivity, cost-effectiveness, facile operation, and superb spatial and temporal resolutions. Fluorescent organic nanoparticles derived from conjugated polymers have attracted significant interest due to their variable optical, electronic, and other properties such as facile preparation and functionalization. Among conjugated polymers used in organic nanoparticles, polyfluorene (PF) and its derivatives are considered to be of special interest because of their thermal/chemical stability, high fluorescence quantum yield and significant charge carrier mobility.’

Graphical abstract: White light emission of multi-chromophore photoluminescent nanoparticles using polyacrylate scaffold copolymers with pendent polyfluorene groups

In this work, Ling, Hogen-Esch and co-workers reported a styrene-type macromonomer containing polyfluorene pendent group (PFS), which allowed the convenient synthesis of well-defined copolymers of PFS with t-butyl acrylate by both RAFT and ATRP polymerization methods. After hydrolysis, the amphiphilic copolymers self-assembled into photoluminescent nanoparticles in aqueous solution. When doped with selected dyes, the nanoparticles emitted light with tunable colors as well as white via Förster energy transfer from the excited pendent polyfluorene groups.

White light emission of multi-chromophore photoluminescent nanoparticles using polyacrylate scaffold copolymers with pendent polyfluorene groups by Chao Deng, Peng Jiang, Xiaobin Shen, Jun Ling and Thieo E. Hogen-Esch, Polym. Chem. 2014, 5, 5109-5115.

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

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Author of the Month: Dr. Marlène Lejars

Dr Marlene Lejars graduated in 2009 from the National School of Chemistry, Biology and Physics (ENSCBP) of Bordeaux, France, and received a Master degree in Chemistry (Polymers and Colloids) from Bordeaux University. She obtained her PhD degree in 2012 at the University of Toulon, France (MAPIEM laboratory, A. Margaillan and C. Bressy as supervisors), working on the synthesis of new polymer binders by the RAFT polymerization for FRC/SPC hybrid antifouling coatings. Following her PhD, she continued her research work at MAPIEM with an expertise in polymer synthesis and characterization, paint formulation, and evaluation of antifouling performances. She is involved in research projects dealing with electro-active antifouling coatings, as well as antifouling coatings for drag reduction (DRACONS project 2013-2017). She is reviewer for journals in the field of polymers including Polymer Chemistry and Journal of Applied Polymer Science. She is also involved in quality and safety management at MAPIEM laboratory.

What was your inspiration in becoming a chemist?

During high school, my Chemistry teacher put me forward to compete in a French competition, called “The Olympiads of Chemistry”. This was the opportunity for me to discover several aspects of Chemistry in more detail through theoretical courses and practical experimentation. I won the first award of the competition organized in Bordeaux. Thanks to this competition, I discovered that Chemistry was a fascinating world and I decided that I would become a chemist.


What was the motivation to write your Polymer Chemistry article?

The MAPIEM laboratory is specialized on the fouling issue especially on ships hulls, and the development of antifouling coatings. There are two main types on the market: (i) Self-Polishing Coatings (SPC) based on hydrolyzable polymers which release toxic biocides into the environment, and (ii) Fouling Release Coatings which are non-adhesive poly(dimethylsiloxane) matrix coatings with no biocide. We decided to synthesize new antifouling binders by mixing both technologies through the synthesis of copolymers based on tri-alkylsilyl methacrylates (used in SPC binders) and poly(dimethylsiloxane) (used in FRC binders). The RAFT process was used to control the architecture and molecular weights of polymers. We found that the diblock copolymers exhibited much lower surface energies than the statistical copolymers.


Why did you choose Polymer Chemistry to publish your work? (DOI: 10.1039/C3PY01603J)

Polymer Chemistry is a leading journal in the field of polymer science with high quality published papers. The reviewing and publishing process is very fast.


In which upcoming conferences may our readers meet you?

Our laboratory will organize the 18th International Congress of Marine Fouling and Corrosion (ICMCF) in Toulon, France (June 19-23, 2016).


How do you spend your spare time?

I spend my spare time doing sport such as swimming, hiking and rollerblading, but also cooking or going to the cinema. I like travelling abroad to discover new cultures, cuisines and ways of life.


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

I would probably be a primary school teacher or a pastry chef as I love to prepare cakes, especially the delicious “canelés” from Bordeaux!


Graphical abstract: Synthesis and characterization of diblock and statistical copolymers based on hydrolyzable siloxy silylester methacrylate monomersRead Dr Lejars’ latest Polymer Chemistry paper:

Synthesis and characterization of diblock and statistical copolymers based on hydrolyzable siloxy silylester methacrylate monomers
Marlène Lejars, André Margaillan and Christine Bressy
Polym. Chem., 2014,5, 2109-2117 DOI: 10.1039/C3PY01603J


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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Paper of the week: Hydroxypropyl-β-cyclodextrin-grafted polyethyleneimine used as a transdermal penetration enhancer

‘The stratum corneum (SC) of skin is the main barrier against transdermal drug penetration, and poor permeability in the SC limits the usefulness of the transdermal drug administration route. Generally, drug permeation through the SC could be increased with skin permeation enhancers. Currently, enhancers most frequently used in transdermal drug delivery systems are neatly divided into three categories. One is organic solvents such as ethanol, propylene glycol and dimethyl sulfoxide. The second is surfactants such as cationic, anionic and nonionic surfactants. The last category is laurocapram and its derivative series. Nevertheless, their potential shortcomings have gradually been recognized, for their great irritation to skin or causing harm to organs. The practical use of enhancers requires the careful balancing of skin toxicity and permeation enhancement benefits’

Graphical abstract: In vitro and in vivo application of hydroxypropyl-β-cyclodextrin-grafted polyethyleneimine used as a transdermal penetration enhancer

In this work, Xing and co-workers developed a new penetration enhancer based on hydroxypropyl-β-cyclodextrin-grafted polyethyleneimine (HP-β-CD–PEI). Its penetration mechanism relied on a change of the secondary structure of keratin in the stratum corneum to enhance the transcutaneous permeation of drugs. By using a series of in vitro and in vivo methods, this cationic polymer demonstrated great biocompatibility and could be valuable for topical delivery as a penetration enhancer to improve the penetration of hydrophilic drugs.

In vitro and in vivo application of hydroxypropyl-β-cyclodextrin-grafted polyethyleneimine used as a transdermal penetration enhancer by Ke Wang, Yan Yan, Guilan Zhao, Wei Xu, Kai Dong, Cuiyu You, Lu Zhang and Jianfeng Xing, Polym. Chem. 2014, 5, 4658-4669.

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

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