Semester Projects

Thermal drawing is a powerful technique to realize fibers incorporating a variety of materials into intricate structures. A few years ago, our group demonstrated the thermal drawing of thermoplastic elastomers, paving the way to new types of applications, in particular in soft robotics and wearable devices[1,2]. Based on these elastomers, several soft composites have also been developed and integrated into thermally drawn fibers to create soft actuators[3] or soft mechanical sensors[4].

In this project, we propose to explore intriguing new materials to create functional, multi-material fibers that can sense and adapt to their environment.

Typical experimental tools:

• Material and preform preparation (solution mixing, spin coating, hot pressing…) 
• Flow and mechanical properties assessment (rheology, tensile test…)
• Electronic characterization

[1] Y. Qu, T. Nguyen-Dang, A. G. Page, W. Yan, T. Das Gupta, G. M. Rotaru, R. M. Rossi, V. D. Favrod, N. Bartolomei, F. Sorin, Advanced Materials 2018, 30, 1707251.
[2] A. Leber, C. Dong, S. Laperrousaz, H. Banerjee, M. E. M. K. Abdelaziz, N. Bartolomei, B. Schyrr, B. Temelkuran, F. Sorin, Advanced Science 2023, 10, DOI 10.1002/advs.202204016.
[3] H. Banerjee, A. Leber, S. Laperrousaz, R. La Polla, C. Dong, S. Mansour, X. Wan, F. Sorin, Advanced Materials 2023, 35, DOI 10.1002/adma.202212202.
[4] A. Leber, S. Laperrousaz, Y. Qu, C. Dong, I. Richard, F. Sorin, Advanced Science 2023, DOI 10.1002/advs.202207573.

The spontaneous retraction of a liquid film from a substrate is a subject of major importance in many aspects: it can be either desired (e.g. removal of water film on windscreens) or undesired (e.g. dry eyes disease due to unstable tear film). This phenomenon, known as dewetting, is well understood on flat surfaces, but less on rough or textured substrates. This project aims to provide insights into dewetting on rough microtextured substrates, through an experimental campaign validation. It lies at the interface of Materials and surface science, fluid dynamics, and micro-fabrication. 

The project will consist in fabricating microtextured surfaces on silicon or silica, using standard lithography and etching techniques, and coating them using various thin-film methods. Dewetting of chalcogenide glass onto the fabricated substrates will also be performed and analyzed. 

This project will involve microfabrication in EPFL cleanrooms facilities (CMi) – training and regular operation on several equipment – and application of thin-film techniques in our laboratory. 

We are looking for one (or several) motivated Master students from Microengineering, Material Sciences and Engineering, or Electrical Engineering Master programs, with strong interest in micro-fabrication. Preference will be given to students who have already taken the CMi introduction course. 

Metallic nano-objects and their arrays exhibit peculiar functionalities that can be exploited in several scientific fields. Such constructs can indeed be used as catalysts for arrays of semiconducting nanowires, in light trapping and extraction systems, as efficient transparent electrodes for optoelectronic devices, and in sensing and biological applications. Their fabrication remain however difficult and costly, especially over large area substrates. In this project we propose to investigate a novel fabrication approach of these nano-structures that is simple and scalable. The objective is to demonstrate a 2D and a 3D ordered array of nano-objects using simple nano-imprint and thin-film processing approaches.