New generation polymer transducers for microrobotic applications
The objectives of the project are: <br />• Produce an actuator without incorporating an exogenous electrolyte. The electrolyte selected will already be grafted on the SPE resulting in a second-generation ionic actuator with no equivalent in the literature. <br />• Determine and maximise the sensitivity of the sensor mode of first and second generation conducting IPN according to the geometry of the materials and in particular their thickness. <br />• Assess the fatigue (electrical and mechanical) behaviour of these materials and undertake systematic repeatability studies (deformation amplitude, force, response time, current, etc.). Find solutions to improve these characteristics if necessary. <br />• Model the material in the form of an equivalent circuit taking into account ionic conduction and electromechanical conversion, and develop a finite elements numerical model taking into account the large displacement aspect. <br />• Combine conducting IPN with polymer substrates such as SU-8 and PDMS. <br />• Transfer the electrodes in relation to the demonstrators; design and produce the mechanical part of the demonstrators. <br />• Acquire and process the signals from the micro-actuators for closed-loop control of the demonstrators. <br />• Produce a 3D micromanipulator preferentially combining a flexible substrate, several actuators to produce an elbow movement, three fingers to pick up an object, and the related contact circuits, preferably force feedback with a zone for detecting contact with the object. <br />• Manufacture a surface topography prototype to characterise and monitor the propagation of cracks in a material using a set of parallel conducting IPN beams, preferably on a flexible substrate, including or not silicon apexes, with its signal processing electronics.
The approach is divided into four interlinked tasks.
• The first consists in developing the micro-actuators (first-generation: exogenous ionic liquid) to produce a conducting IPN which does not require the incorporation of an ionic liquid (second-generation, grafted ionic liquid). This stage will also concern the characterisation of these first and second-generation micro-transducers: comparison of forces in conjunction with geometry, sensitivity of the sensor function, and fatigue behaviour.
• The second deals with modelling this type of material, which is in its infancy at international level, and which will enable the behaviour of the actuator and a combination of these actuators to be anticipated.
• The third concerns the technological steps required to develop the demonstrators, in particular the compatibility of manufacturing transducers with structural polymers such as SU-8 and PDMS, the association with metal electrodes for signal extraction or control.
• The fourth will be devoted to implementing the electronics and evaluating the performance of the demonstrators.
-Easy fabrication of an «ionic« microactuator based on PEDOT / PSS. The elaboration will be no longer reserved for chemists alone, but will be accessible to the communities of biologists and physicists, given the simplicity of the process of elaboration.
-Synthesis of the first actuator based on ionic liquid polymers. To our knowledge, an actuator with similar architecture has not yet been published.
-The integration of micro-beams on a supple SU-8 support was realized by integrating electrical transfer contacts. This work is completely original and should be published within four months.
- We have an innovative multiphysics model of the actuator based on a finite difference Bond graph modeling which allows us to simulate the behavior of the actuator in the temporal and spatial domain as well as to analyze the energy efficiency
-The 2 sensor / actuator electronic boards are controlled with solutions based on embedded systems. The fact that this solution is dedicated will be an advantage when it is necessary to control several actuators at a time (whether for the micro-gripper or the comb structure for the surface topography)
-First analytical models of the tension measured as a function of the deformation have been proposed (a publication is being prepared on this subject). These are macro models (in addition to those obtained by finite elements at the IEMN) which will prove useful when controlling the polymers.
The main perspective is to obtain an actuator and sensor material that can be easily integrated into a microstructure. A material whose modeling will predict its behavior. A material that will incorporate devices that can be used quickly in everyday life.
1. M. Bentefrit, C. Soyer, S. Grondel, E. Cattan, J.D. Madden, A. Fannir, T. Minh Giao Nguyen, C. Plesse, F. Vidal
Soumis à smart material and structure
2.Tan Nguyen Ngoc, Kätlin Rohtlaid, Cédric Plesse, Caroline Soyer, Sébastien Grondel, Er
Research and development on electronic components compatible with flexible substrates is currently generating products with new functionalities, thus opening up new markets. However, there is little research concerning the integration of compatible, high-performance micro-transducers on these substrates at national and international level. Due to their rigidity and high manufacturing temperatures, classic micro-transducers are unsuitable for these new substrates, thus leaving the door open for the development of electroactive polymers operating as actuators or sensors for the creation of microsystems on flexible substrates.
The aim of Micro-TIP is to promote these materials, considered in the literature as artificial muscles, in the field of microsystems through the development of two demonstrators exploiting the advantages of ionic polymer materials. These materials are light, low-cost, and flexible, they can be configured in complex shapes and their properties can also be adapted on request, they can produce large bending deformations, are actuated at low voltages (1-5V) in air or in a vacuum, and are biocompatible. Micro-TIP is based on a fully mastered material (first generation) for which the integration stages in microsystems have been validated, and the creation of a new material (second generation) associating a solid electrolyte that is an unquestionable technological advance. The latter will be developed and characterised, and its potential to be integrated in microfabrication technology demonstrated. The performance is expected to be at least equivalent to that obtained with the first generation material. In Micro-TIP, we also wish to innovate with a second theme highlighting the detection capabilities of these materials brought to light with first generation macroscopic materials. Few studies have been undertaken in this field at international level. In addition, the researchers involved in Micro-TIP believe that these transducers will have the ability to adapt better to these flexible substrates (in preparation for flexible electronics) than other types of transducers, and therefore have set themselves the challenge of developing demonstrators favouring flexible and semi-flexible substrates and the appropriate technology. An innovative modelling process (mainly of actuator mode) is also proposed to provide a preliminary assessment of the behaviour of our demonstrators. These demonstrators will be manufactured using simple, low-energy, and preferably low-cost technology, and will take into account the actuator and detection capabilities of these materials in complex mechanisms, operating in air or in a vacuum, through the inclusion of control and signal processing electronics. The first will be a force feedback micromanipulator for manipulation in a restricted environment for accurately positioning optical components for MEMS instrumentation, for example. The second will be used to study materials damage and rupture using an innovative comb detector. On completion of Micro-TIP, the aim is to have sufficiently mature devices to reveal the capabilities of these artificial micro-muscles to industrialists in the fields of micro-robotics, space, and biomedicine, for example.
These conducting IPN-based microsystems can be developed with confidence thanks to the collaboration between the LPPI, the IEMN and the LISV, and through this collaboration, the entire design process will be managed: material synthesis, microfabrication and characterisation of microsystems, demonstrator design.
Monsieur Eric Cattan (Institut d'Electronique de Microélectronique et de Nanotechnologie)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
LISV- EA4048 Laboratoire d’ingénierie des systèmes de Versailles
IEMN- UMR8520 Institut d'Electronique de Microélectronique et de Nanotechnologie
LPPI Laboratoire de Physicochimie des Polymères et des Interfaces
Help of the ANR 412,164 euros
Beginning and duration of the scientific project: September 2015 - 48 Months