Projets Matériaux / Research Projects – Fall 2024
3D printing of responsive elastomers
Elastomers are three-dimensional polymeric networks that can be engineered to be soft and stretchable or stiff and brittle, depending on their composition. We recently introduced 3D printable double network granular elastomers (DNGE) that exhibit a wide range of strains and stiffnesses. However, these materials lack functionality and responsiveness.
This project aims to introduce responsive chemical groups to the 3D printable elastomeric networks to address this shortcoming. In this project, you will learn how to prepare inks that can be converted into DNGEs and study the influence of functionalities you will add to the inks on the performance of the DNGEs. You will learn how to formulate an elastomer-based ink, how to characterize its rheological properties, to print it and how to characterize the mechanical properties of the resulting material.
If you have any questions or are interested in this project, please contact [email protected].
Master Thesis – Fall 2024
Hydrogels for thermal energy storage
As the world deals with the pressing climate crisis, the focus on material innovation in the energy sector has intensified. To achieve the transition from fossil-fuel-based energy to renewable sources, intermediate thermal energy storage has emerged as a promising approach, enabling peak shifting and significantly reducing global energy consumption. To succeed in this endeavor, new materials that efficiently store energy are needed.
Within this project, you will synthesize ion-functionalized hydrogels that can be used for energy storage. In particular, you will functionalize hydrogels to render them thermally conductive. You will subsequently evaluate the possibility to convert the stored heat into other forms of energy. You will characterize your material with DSC, thermal conductivity measurement, bulk calorimetry and computer tomography.
If you have any questions or are interested in this project, please contact [email protected].
Patterning conductive tracks within hydrogel matrix for soft bioelectronics devices
Hydrogels, being highly hydrophilic polymeric networks that are filled with water, have gained significant attention in the biomedical field due to their exceptional water-retention capability, biocompatibility, and anti-biofouling properties. These versatile materials can be synthesized from a wide range of monomers and via various crosslinking routes. While hydrogels exhibit excellent ionic conductivity thanks to their high water content, their electronic conductivity remains limited. To address this limitation and broaden their applications in soft bioelectronic systems, novel approaches are required to enhance the electronic properties of hydrogels.
In this master thesis project, you will pattern conductive features within a hydrogel matrix. You will introduce noble metal nanoparticles (NPs) within the hydrogel by an in-situ synthesis approach. By combining the benefits of hydrogel substrates and the electronic properties of metal NPs, we aim to create a seamless interface between soft tissues and external electronic equipment, opening up new possibilities for manufacturing soft bioelectronic devices. In your thesis you will learn how to prepare hydrogels, pattern them using clean room facilities and how to characterize their electrical conductivity.
For more information and to discuss the next steps, please contact Lorenzo Lucherini at [email protected].
Stimuli responsive eutectogels for soft robotic applications
Smart materials can respond to environmental stimuli, an effect that can be exploited for developing soft robotic sensors and actuators. Hydrogels that are swollen with deep eutectic solvents, eutectogels, are an environmentally-friendly category of soft responsive materials. These eutectogels are typically ionically conductive at room temperature. The goal of this project is to develop environmentally friendly, low-cost sensors based on eutectogels.
Within this project, you will develop resistive sensors and actuators based on eutectogels. 3D printing will be used for integrating conductive paths in flexible substrates and producing the desired geometries. You will study the influence of the composition of the materials on the sensitivity of the sensors and their mechanical properties. You will produce a soft robotic prototype that responds to certain external stimuli.
For more information, please contact Dr. Antonia Georgopoulou [email protected].
Development steps for multi-sensory networks based on eutectogels.
Meta-Stable Particle Synthesis for Low Energy Sintering
Fabrication of brittle, non-ductile materials with high melting points – such as ceramics – requires a powder technology-based processing route with a consolidating and densifying heat treatment at the end: the sintering step. Sintering is typically done between 0.6-0.8 times the fusion temperature (in K) for several hours. This processing step therefore involves thermally activated diffusion mechanisms that may lead to rapid microstructural changes, largely affecting the mechanical, physical and chemical properties of the final material.
As a means to lower the energy needs for sintering to occur and offer new pathways for the advanced microstructure and thus property engineering of technical ceramics and minerals, synthesis of meta-stable powders is a promising research avenue for future scientific and technological breakthroughs.
In this project, we will study the effects of the crystallinity, chemistry, additives and size on the consolidation behavior of calcium carbonates, as a model material. The student will synthesize his/her own materials, varying the synthesis conditions in a controlled manner. Prior to studying the sintering behavior of the synthesized powder, thorough characterization will be performed, to learn and understand how the synthesis conditions will affect the powder properties (XRD, in-situ XRD, TGA, DSC, SEM/EDS, …). Conventional and flash sintering will be done in convention and SPS ovens, directly following in-situ the shrinkage of the samples.
We expect to build correlations of synthesis conditions and meta-stability of the particles with the sintering behavior and microstructural development of the product to build a roadmap for bringing the approach to other ceramic materials.
The project will start at EPFL with initial training and familiarization with the particle synthesis process, before following-up at Empa in Dübendorf.
For more information on this interesting opportunity in an emerging research field contact: Prof. Dr. Esther Amstad ([email protected]), and Dr. Michael Stuer ([email protected]).