Seminars

PMMH’s weekly seminar is held every Friday at 11 am (map)

Contact :
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
responsables-seminaires (arobase) pmmh.espci.fr

PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France

Tel : (33) 1 40 79 45 22


Séminaire PMMH - Min-Hui LI (Chimie ParisTech )

Vendredi 8 mars de 11h00 à 12h00 - Salle réunion PMMH 1

Electroactive Bi-functional Liquid Crystal Elastomer Actuators

Liquid crystal elastomers (LCEs) show promising potentials as smart actuators, for example, those contracting/expanding linearly like mammalian muscles.[1] Direct heating and light illumination are the most used activation mode in LCE actuators because LCEs are based on thermotropic or phototropic liquid crystals.[1,2,3] However, in the world of actuators, electrical energy is the most convenient and the most in demand stimuli. Indeed, the nature does use electrical impulses between nerves and muscles or skins for actuation or sensing with extraordinary efficacy, and electrical stimulation is also more widely utilizable as driving forces in industrial devices. Efforts have been made to achieve electroactive LCEs (eLCEs).

In this talk, I will present a trilayer electroactive LCE (eLCE) system by combining two smart materials, LCE and ionic electroactive polymer device (i-EAD), which is bi-functional and can perform either bending or contractile deformations under low voltage stimulation.[4] By applying a voltage of ±2 V at 0.1 Hz, the redox behavior and associated ionic motion in the two conducting polymer electrodes of i-EAD provide bending deformation of the device up to a bending strain difference of 0.8% for a sample of 0.5 mm thickness. On the other hand, by applying a voltage of ± 6V at 10 Hz, the ionic current-induced Joule heating triggers the muscle-like contractile response of the central ion-conducting LCE component, a linear contraction ratio of 20% being obtained without load. Moreover, a load of 270 times of the weight of trilayer eLCE film can be left with a strain of 20%. This approach of combining two smart polymer technologies, i.e., LCE and i-EAD, in a single device, is promising for the development of smart materials with multiple degrees of freedom in soft robotics, electronic devices, and sensors.

References
[1] M.-H. Li, P. Keller P., Artificial muscles based on liquid crystal elastomers, Phil. Trans. A. 364, 2763 (2006).
[2] B. Ni, G. Liu, M. Zhang, P. Keller, M. Tatoulian, M.-H. Li, Large-Size Honeycomb-Shaped and Iris-Like Liquid Crystal Elastomer Actuators, CCS Chemistry, 4, 847 (2022).
[3] B. Ni, G. Liu, M. Zhang, M. Tatoulian, P. Keller, M.-H. Li, Customizable Sophisticated 3D Shape Changes of Large-size Liquid Crystal Elastomer Actuators, ACS Appl. Mater. Interfaces, 13, 54439 (2021).
[4] G. Liu, Y. Deng, G. Nguyen, C. Vancaeyzeele, A. Brûlet, F. Vidal, C. Plesse, M.-H. Li, Electroactive Bi-functional Liquid Crystal Elastomer Actuators, Small, 2023, 2307565.

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Recent seminars  (10)

  • Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
    Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
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  • Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
    Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
    Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
    Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…)
  • Séminaire PMMH – Daegyoum Kim (KAIST)
    Vendredi 27 juin de 11h00 à 12h00 - Salle réunion PMMH 1
  • Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
    Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
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  • Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
    Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
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    The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…)
  • Séminaire PMMH – Daniel Tam (TU Delft)
    Vendredi 13 juin de 11h00 à 12h00 - Salle réunion PMMH 1
  • Séminaire PMMH – Vincent Bertin (IUSTI, U. Aix-Marseille)
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  • Séminaire PMMH - Julien Scheibert (LTDS, EC Lyon)
    Vendredi 16 mai de 11h00 à 12h00 - Salle réunion PMMH 1
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    Many devices, including touchscreens and robotic hands, involve frictional contacts. Optimizing those devices requires fine control of the interface's friction law. We lack systematic methods to create dry contact interfaces whose frictional behaviour satisfies preset specifications. In this seminar, I will present (…)
  • Séminaire PMMH - Julien Scheibert (LTDS, EC Lyon)
    Vendredi 16 mai de 11h00 à 12h00 - Salle réunion PMMH 1
    Metainterfaces : how to design a rough contact that obeys a specific friction law ?
    Many devices, including touchscreens and robotic hands, involve frictional contacts. Optimizing those devices requires fine control of the interface's friction law. We lack systematic methods to create dry contact interfaces whose frictional behaviour satisfies preset specifications. In this seminar, I will present (…)

Information for the speakers

The audience is composed of people with rather heterogeneous backgrounds including specialists in solids, fluids, granular flows, statistical physics... so the idea is to keep your talk understandable by people not necessarily working in your field... The seminar time slot runs from 11am to noon so the best is to make the talk last around 45 minutes to leave some time for discussion.

Archive 1996-2011
Other seminars in Paris and its surroundings :

Link to cofee seminar (internal, every Thursday)


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Seminars (1)

Contact

Directeur : Ramiro GODOY DIANA
Codirecteur : Laurent DUCHEMIN
Administratrice : Frédérique AUGER (01 40 79 45 22)
Gestionnaire : Claudette BAREZ (01 40 79 58 53)
Courriel : dir (arobase) pmmh.espci.fr
Téléphone : 01 40 79 45 22