A One-Step Strategy for End-Functionalized Donor–Acceptor Conjugated Polymers

A modular and robust method for preparing end-functionalized donor–acceptor (D–A) narrow bandgap conjugated polymers is reported that avoids multistep reactions and postpolymerization modification. The strategy is well-controlled and affords functional materials with predictable molecular weight and high end-group fidelity. To exemplify this synthetic strategy, narrow bandgap conjugated polymers based on PDPP2FT were prepared that contain perylene diimide (PDI) units at the chain-ends. Monte Carlo simulations confirm the high degree of chain-end functionalization while photoluminescence studies reveal the unique photophysical properties of the end-functional polymers with efficient charge transfer occurring between the main polymer chain and PDI end-groups that results exclusively from their covalent linkage

Supramolecular thermoplastics and thermoplastic elastomer materials with self-healing ability based on oligomeric charged triblock copolymers

Supramolecular polymeric materials constitute a unique class of materials held together by non-covalent interactions. These dynamic supramolecular interactions can provide unique properties such as a strong decrease in viscosity upon relatively mild heating, as well as self-healing ability. In this study we demonstrate the unique mechanical properties of phase-separated electrostatic supramolecular materials based on mixing of low molar mass, oligomeric, ABA-triblock copolyacrylates with oppositely charged outer blocks. In case of well-chosen mixtures and block lengths, the charged blocks are phase separated from the uncharged matrix in a hexagonally packed nanomorphology as observed by transmission electron microscopy. Thermal and mechanical analysis of the material shows that the charged sections have a T-g closely beyond room temperature, whereas the material shows an elastic response at temperatures far above this T-g ascribed to the electrostatic supramolecular interactions. A broad set of materials having systematic variations in triblock copolymer structures was used to provide insights in the mechanical properties and and self-healing ability in correlation with the nanomorphology of the materials

A One-Step Strategy for End-Functionalized Donor–Acceptor Conjugated Polymers

A modular and robust method for preparing end-functionalized donor–acceptor (D–A) narrow bandgap conjugated polymers is reported that avoids multistep reactions and postpolymerization modification. The strategy is well-controlled and affords functional materials with predictable molecular weight and high end-group fidelity. To exemplify this synthetic strategy, narrow bandgap conjugated polymers based on PDPP2FT were prepared that contain perylene diimide (PDI) units at the chain-ends. Monte Carlo simulations confirm the high degree of chain-end functionalization while photoluminescence studies reveal the unique photophysical properties of the end-functional polymers with efficient charge transfer occurring between the main polymer chain and PDI end-groups that results exclusively from their covalent linkage

Self-healing supramolecular polymers

Abstract only

Servitization of Biomass Processing for a Virtual Biorefinery: Application to the Lignocellulosic Biomass in a French Local Territory

Part 13: Digital Transformation in Food and AgribusinessInternational audienceProcessing biomass requires four major steps (pretreatment, fermentation, separation and purification) achieved by dedicated plants called biorefineries. These highly specialized structures cannot cope with the high variability of the whole biomass supply chain. Thus, providing agility to biorefineries is a key challenge to foster biomass processing. The goal is to design a virtual biorefinery as a collective network supported by the servitization of unit operations and the reuse of existing devices. In this regard, the first step described in this paper aims to gather and organize knowledge about a given local area (stakeholders, services) and the existing transformation process operations (inputs, outputs) through a framework. To this end, two metamodels are proposed: one to collect and structure the required information about the local area; one to organize the knowledge about the transformation processes. Their use is illustrated by a use case provided by a municipalities community located in South-West France

Enhanced Block Copolymer Phase Separation Using Click Chemistry and Ionic Junctions

International audienceno abstrac

Synthesis and Photophysics of Coaxial Threaded Molecular Wires: Polyrotaxanes with Triarylamine Jackets

Conjugated polyrotaxanes jacketed with hole-transport groups have been synthesized from water-soluble polyrotaxanes consisting of a polyfluorene-alt-biphenylene (PFBP) conjugated polymer threaded through β-cyclodextrin macrocycles. The hydroxyl groups of the oligosaccharides were efficiently functionalized with triphenylamine (TPA) so that every polyrotaxane molecule carries a coat of about 200 TPA units, forming a supramolecular coaxial structure. This architecture was characterized using a range of techniques, including small-angle X-ray scattering. Absorption of light by the TPA units results in excitation energy transfer (EET) and photoinduced electron transfer (ET) to the inner conjugated polymer core. These energy- and charge-transfer processes were explored by steady-state and time-resolved fluorescence spectroscopy, femtosecond transient absorption spectroscopy, and molecular modeling. The time-resolved measurements yielded insights into the heterogeneity of the TPA coat: those TPA units which are close to the central polymer core tend to undergo ET, whereas those on the outer surface of the polyrotaxane, far from the core, undergo EET. Sections of the backbone that are excited indirectly via EET tend to be more remote from the TPA units and thus are less susceptible to electron-transfer quenching. The rate of EET from the TPA units to the PFBP core was effectively modeled by taking account of the heterogeneity in the TPA-PFBP distance, using a distributed monopole approach. This work represents a new strategy for building and studying well-defined arrays of >100 covalently linked chromophores. © 2014 American Chemical Society

Synthesis and Photophysics of Coaxial Threaded Molecular Wires: Polyrotaxanes with Triarylamine jackets

peer reviewe

Application of inverse modeling methods to thermal and diffusion experiments at Mont Terri Rock laboratory

International audienc