Post-doc: Development of electroactive polymers for biomedical devices

• Duration: 12 months (+12 months possible extention)

• Host Laboratory : Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI) – CY Cergy Paris Université

• Scientific topics: polymer chemistry, conducting polymers, smart materials, vitrimers, soft actuators, soft robotics

Project:

Liquid crystal elastomers (LCEs) are lightly crosslinked liquid crystal polymers, where LC units are oriented uniformly in the whole sample (monodomain). The key characteristic of monodomain LCEs is that they have the capability to deform unidirectionally, reversibly and largely (strains of 20 – 200%) upon stimulation of heat or light. However, electrical energy is the most convenient and the most in demand stimuli, because the nature does use electrical impulses between nerves and muscles/skins for actuation and sensing with extraordinary efficacy, and electrical stimulation is also more widely utilizable as driving forces in industrial devices. Unfortunately, the examples of electroactive LCEs (eLCEs) are still rare. On the other side, ionic electroactive polymers (EAPs) are typically tri-layer systems consisting of an ionically conducting membrane sandwiched by two electronically conducting polymers as electrodes. This soft ionic EAP can convert either electrical stimulation into reversible and large bending deformations under low voltage (<2V) (actuator) or convert mechanical stimulation into electrical signal (sensor). Unfortunately, large muscle-like unidirectional contraction/elongation cannot be achieved in this ionic EAP.
In the AS-LCE French Research Agency (ANR) project, we propose to develop new multifunctional eLCEs as biomimetic actuators and sensors, that comprise both LCEs and ionic EAPs. These new ionic eLCEs can perform bending and unidirectional contraction/elongation in a decoupled way or in a concomitant way, all under the control of electrical signals. This innovative combination offers more degrees of freedom and of control and could bring smart materials closer to biomimetic artificial muscles and sensors. The proof of concept of such materials has been recently published in the early stages of this project.^[1],[2]
The next objective is to implement self-healing functionalities to these smart materials thanks to the recent chemistry of Dynamic Adaptable Networks (CAN), and more specifically the subclass of vitrimers. Thanks to their dynamic exchangeable covalent crosslinks allowing reprocessing/recycling/self-healing, we demonstrated recently that it is possible to develop self-healable, stretchable and highly conducting ionogels^[3] but also to promote strong covalent co-bonding in multilayer materials.
The recruited postdoctoral fellow will have in charge the development of self-healable organic electrodes for ionic eLCE actuators and sensors as well as the fabrication and the characterization of the resulting stimuli responsive devices. The recruited postdoctoral fellow will interact strongly with a another postdoc of the project, recruited at Chimie ParisTech. He/she will also participate in project progress meetings by presenting the obtained results and will interact with the all the academic partners of the project.

[1] Electroactive Bi-Functional Liquid Crystal Elastomer Actuators, Gaoyu Liu, Yakui Deng, Bin Ni, Giao T. M. Nguyen, Cédric Vancaeyzeele, Annie Brûlet, Frédéric Vidal, Cédric Plesse, and Min-Hui Li, Small 2023, 2307565
[2] Interpenetrating Liquid Crystal Elastomer and Ionogel as Tunable Electroactive Actuators and Sensors, Yakui Deng, Gaoyu Liu, Annie Brûlet, Giao T. M. Nguyen, Daniel Dudzinski, Frédéric Vidal, Cédric Plesse, Cédric Vancaeyzeele, and Min-Hui Li, Adv. Funct. Mater. 2024, 2403892
[3] Stretchable, healable, and weldable vitrimer ionogel for ionotronic applications, Khoa Bui, Giao T.M Nguyen, Cedric Vancaeyzeele, Frederic Vidal, Xiao Hu, Chaoying Wan, Cedric Plesse, Chemical Engineering Journal 474 (2023) 145533

Candidate profile:

With a PhD in macromolecular chemistry, the highly motivated candidate will have an excellent scientific level and track records. Experience on vitrimer chemistry, electronic conducting polymers and/or rheology measurements would be a strong advantage. Moreover, the candidate will present a strong interest for multidisciplinary projects, a good adaptation capacity and excellent communication skills in English. French language can be an advantage.
 

How to apply (Limit date for application 25 October 2024) : send detailed resume, motivation letter, and ideally a recommendation letter to

• Pr. Cédric Plesse (cedric.plesse@cyu.fr)