Modelling mechanisms of transduction in conducting-IPN for micro-structure

PhD positions funded by the MarieSklodowska-Curie Innovative Training Network “MICACT – Microactuators” within the Horizon 2020 Programme of the European Commission.
The candidate will share his time between Institut d’Electronique de Microélectronique et de Nanotechnologies (Villeneuve d’Ascq – France)), and the Advanced Materials and Process Engineering Laboratory (Vancouver – Canada).

The PhD student will improve the understanding of the electromechanical mechanisms induced in
new micro-actuators based on electronically conducting polymer for a future integration inside soft MEMS.

First two Interpenetrating Polymer Networks (IPNs) PEO/PTHF (polyethyleneoxide /polytetrahydrofurane) and PEO/NBR (polyethyleneoxide /Nitrile Butadiene Rubber) will be rapidly optimized by combining appropriately the specific properties of each network: good ionic conductivity (PEO) and good mechanical properties (PTHF and NBR). The mechanical properties of these materials allow the synthesis of solid polymer electrolyte materials that can be elaborated and manipulated with thicknesses from 5 to 10 µm. A innovative cleanroom spin
coating process has been developed to be compatible with microsystem technology. The conducting-IPNs are synthesized from previous IPNs in which the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is weakly interpenetrated. This interface is controlled and this step will be fundamental for the electromechanical studies and for modeling. Photolithography techniques, reactive ion etching or laser ablation will be used to design conducting-IPN to obtained standardized micro-beam actuators.

The PhD student will characterize accurately the electrical and mechanical properties of these actuators to provide reliable experimental data to the model. The PhD student will establish a mathematical model to ensure on the one hand, a better understanding of the phenomena involved in the conducting IPN, and on the other hand, to predict and effectively control the mechanical performance and energy efficiency. Development of such a model to predict their behavior and quantify their performance is difficult because of the many parameters
involved (mechanical, electrical and chemical) and because of the absence of a theory clearly describing the subject. At first glance, it appears appropriate to work on a model by lumped elements (also called localized model parameters). Using the finite element method appears well suited to address this issue in particular to simulate non-linear behavior such as large displacements. In a second step, it is essential to develop a more complete and more realistic model. Thus, the model should explicitly describe not only the mechanism but also the aspects of ion conduction and electromechanical conversion.

By combining the results, the available potentialities of these new materials for soft MEMS will be
demonstrated.