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Chevreux S.,University of Reims Champagne Ardenne | Allain C.,CNRS Supramolecular and Macromolecular Photophysics and Photochemistry | Wilbraham L.,CNRS Paris Research Institute of Chemistry | Nakatani K.,CNRS Supramolecular and Macromolecular Photophysics and Photochemistry | And 3 more authors.
Faraday Discussions | Year: 2015

Phen-PENMe2 has recently been proposed as a promising new molecule displaying solvent-tuned dual emission, highlighting an original and newly-described charge transfer model. The study of the photophysical behaviour of this molecule was extended to include protic solvents. The effects of polarity and hydrogen bonding lead to an even more evident dual emission associated with a large multi-emission band in some solvents like methanol, highlighting Phen-PENMe2 as a promising candidate for white light emission. © 2015 The Royal Society of Chemistry. Source


Schmitt J.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Schmitt J.,CNRS Organic, Bioorganic and Macromolecular Chemistry Laboratory | Blanchard N.,CNRS Organic, Bioorganic and Macromolecular Chemistry Laboratory | Poly J.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Poly J.,CNRS Mulhouse Institute of Materials Science
Polymer Chemistry | Year: 2011

An original xanthate possessing a vinyl ester polymerizable function, namely vinyl 2-[(ethoxycarbonothioyl)sulfanyl]propanoate (Xa2), was synthesized. It was implemented as a chain transfer agent (CTA) to design branched polymers based on vinyl acetate (VAc) by self-condensing vinyl copolymerization (SCVC) by reversible addition-fragmentation chain transfer (RAFT). The branching density as well as the length of the branches were efficiently tuned by adjusting the total initial concentration of polymerizable functions C0 = [VAc]0 + [Xa2]0 and the ratio C0/[Xa2] 0. Additionally, Xa2 was also homopolymerized to provide hyperbranched oligomers. These precursors were used as multifunctional CTAs to control a subsequent polymerization of VAc, affording starlike poly(vinyl acetate)s (PVAcs). All the products were characterized by 1H NMR spectroscopy, quadruple detection size exclusion chromatography and differential scanning calorimetry. Reference samples consisted of linear PVAcs which were synthesized using a homologue non-polymerizable xanthate. As expected, the intrinsic viscosity and the glass transition temperature increased when either the number of branches or their length increased. © 2011 The Royal Society of Chemistry. Source


De Paz-Simon H.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Chemtob A.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Croutxe-Barghorn C.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Rigolet S.,Upper Alsace University | And 3 more authors.
Langmuir | Year: 2013

Over the past ten years, understanding the self-assembly process within mesostructured silica films has been a major concern. Our characterization approach relies on two powerful and complementary techniques: in situ time-resolved FTIR spectroscopy and ex situ solid-state NMR. As model systems, three silica/surfactant films displaying various degrees of mesostructuration were synthesized using an amphiphilic block copolymer (PEO-b-PPO-b-PEO) via a UV light induced self-assembly process. The key idea is that the hydration state of the hydrophobic PPO chain is expected to be different depending upon whether the sample is amorphous (blend) or mesostructured (segregated). With real-time FTIR experiments, we show that the methyl deformation mode can act as a signature for the PPO microenvironment so as to trace the progressive copolymer self-association throughout the irradiation time. In 1H solid-state NMR, the dependence of the 1H chemical shift on the PPO hydration state has been exploited to evidence the extent of mesostructuration. © 2013 American Chemical Society. Source


Ni L.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Chemtob A.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Croutxe-Barghorn C.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Brendle J.,CNRS Mulhouse Institute of Materials Science | And 2 more authors.
Journal of Physical Chemistry C | Year: 2012

Organosilane self-assembly is a widely studied template-free approach to design organic-inorganic hybrids structured at the nanometer scale. The main emphasis has been focused so far on novel precursor architectures and sol-gel preparation methods to drive the self-assembly. This feature attempts for the first time a thermodynamic, kinetic, and dynamic description of the organosilane supramolecular assembly. Condensation and hydrolysis rates are the main kinetic parameters impacting the self-assembly, while organic moiety, alkoxy head, temperature, or relative humidity determine essentially the energetic contributions of the self-association, and therefore, form part of a thermodynamic description. In terms of dynamics, the gradual conversion of the isotropic precursor into a cross-linked hybrid nanostructure was assessed by time-resolved infrared spectroscopy combined with small-angle X-ray scattering. To reveal the mechanism of self-assembly, our system is simplified to the main ingredients: n-dodecyltrimethoxysilane (C12H25Si(OCH 3)3) as a model organosilane building block and a photoacid generator ((C12H25) 2Φ2I+ SbF6 -), deposited as a photolatent micrometric film. UV light governs the sol-gel polymerization kinetics through the controlled liberation of Brönsted superacids. © 2012 American Chemical Society. Source


Chemtob A.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Ni L.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Croutxe-Barghorn C.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | Demarest A.,CNRS Laboratory of Macromolecular Photochemistry and Engineering | And 3 more authors.
Langmuir | Year: 2011

We describe a novel solvent- and water-free sol-gel process for n-octadecyltriclorosilane (C18H37SiCl3) film catalyzed by photogenerated Brönsted acids. Driven by hydrophobic van der Waals interactions, a photoinduced self-assembly process occurs to afford a long-range ordered lamellar mesostructure, characterized by X-ray diffraction and transmission electron microscopy. Real-time Fourier transform IR spectroscopy was instrumental to probe the fast hydrolysis kinetics and assess the change of conformational behavior of the alkyl chains during UV irradiation. A unique combination of different solid-state NMR techniques (29Si, 13C, 1H) provided an insight into the supramolecular organization of this hybrid film. © 2011 American Chemical Society. Source

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