LPPI

(macro-) molecules π-conjugated or electronic conductive polymers

We use (macro) molecules π-conjugated mainly for their electron conduction or hole properties in applications often related to energy storage and conversion.

Thus, the LPPI synthesizes new molecular glasses (VM), which are semi-conductors type p and amorphous at room temperature.

What’s more, photoactive π-conjugated molecules associated with a porous TiO2 substrate allow a variation in the water contact angle on this hybrid material, both large (greater than 100°) and fast (~1 minute) during UV/visible illumination cycles illustrating a modular surface wetting.

π -conjugated macromolecules studied in the laboratory are mainly polythiophene derivatives used either alone or in combination with organic or inorganic materials. Due to their unusual electronic structure, these polymers are semi-conductive in a neutral state and conductive in an oxidized state and their optical properties are also modified during the oxidation reaction. This relation was exploited to develop electrochromic polymers. When these π -conjugated polymers are developed as thick films, they also have interesting optical properties in the infrared field. Totally opaque in this spectral domain in a neutral state, they become reflectors once oxidized. This property is used to develop variable and reversible IR reflectivity devices.

Finally, the redox process in pi-conjugated polymers involves an electronic transfer that induces movement of ion species to conserve local electroneutrality. Ion exchange between macromolecules and electrolyte induces volume variation of pi-conjugated polymer. By increasing this process, it is possible to transform electrical energy into mechanical work through the oxydo-reduction reaction: this is the domain of the actuators.

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