Polysiloxanes mésomorphes à empreinte moléculaire chirale (synthèse des squelettes et des substituants)

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Molecularly imprinted cholesteric materials for enhanced enantiomeric separation

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Synthesis and Characterization of IPNs for Electrochemical Actuators

International audienceInterpenetrating polymer networks (IPNs) have been developed for many years leading to materials with controlled properties. When an electronic conducting polymer (ECP) is incorporated into an IPN, this one becomes a conducting IPN (CIPN). The synthetic pathway ensures a non homogeneous dispersion of the ECP through the IPN thickness of the material. The system is thus similar to a layered one with the advantage that the intimate combination of the three polymers needs no adhesive interface. The last step in making the CIPN into an actuator is to ensure the ionic conductivity by incorporation of an ionic salt. The highest ionic conductivity through the IPN matrix is necessary in order to ensure the best actuation. The chosen salt is an ionic liquid, i.e. 1-ethyl-3- methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImTFSI). Based on IPN architectures electrochemical actuators have been designed and actuation in open air has been characterized

Influence of the poly(ethylene oxide)/polybutadiene IPN morphology on the ionic conductivity of ionic liquid

International audienceSolid polymer electrolytes (SPEs) were prepared by incorporating either aqueous LiClO4 or 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMITFSI) ionic liquid into Poly(ethylene oxide) (PEO)/polybutadiene (PB) Interpenetrating Polymer Networks (IPNs). With a given PEO/PB ratio, either transparent or translucent films depending on the synthesis route of these IPNs, have been investigated. TEM observations confirm that the morphology of these IPN films depends also on the PEO weight proportion whereas mechanical properties measured by DMA are only slightly modified. Measurements of ionic conductivity of SPEs are also very dependent on the IPNs morphology. For instance, EMITFSI ionic conductivity increases over four orders of magnitude from 2.2 x 10(-7) to 2.5 x 10(-3) S cm(-1) at 30 degrees C. (C) 2013 Elsevier Ltd. All rights reserved

Poly(3,4-ethylenedioxythiophene)-containing semi-interpenetrating polymer networks: a versatile concept for the design of optical or mechanical electroactive devices

International audienceThe synthesis of one-piece electronic conducting interpenetrating polymer networks is proposed as an alternative to multilayer architectures for the design of electroactive devices. The electronic conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) as active component was symmetrically distributed in a solid polymer electrolyte (SPE) matrix based on poly(ethylene oxide) which was subsequently swollen with either LiClO4 or an ionic liquid. Depending on the composition and the crosslinking density of the SPEs, the ionic conductivities vary between 0.9 × 10−3 and 2.2 × 10−3 S cm−1 at 30 °C. Controlling the PEDOT content from 0.3 to 12 wt% in the material, electrochromic, electroemissive or electromechanical properties are obtained. Typical transmissive and reflective contrast values reach 33 and 27% at 630 and 2500 nm, respectively, for free-standing films upon application of a 1.2 V bias voltage. Both bending and linear actuating devices were developed as beam-shaped or hollow fibres. The actuation occurs under low applied voltage up to 4 V and the output force ranges from 50 to 300 mN. In all cases the electroactive properties are stable over 10 000 (electroemissivity) to 3.5 × 106 (actuation) cycles in open air providing an ionic liquid is used as electrolyte