Master Theses and Internships

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]. However, one class of materials remains unexplored: soft semiconductors.
In this project, we propose to study the feasibility and potential of soft semiconductors in thermally drawn fibers.

Experimental tools:

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

References:

[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.

Thanks to the multi-material thermal drawing technique, we are now able to single-step co-process soft fibers of extended length and fine architectures that can be actuated via tendon or magnetic forces. These fibers can also be weaved into functional textiles for programmed shape morphing and are envisioned to be used for assisting in rehabilitation. In addition, we can co-process magnetic materials and sensing composite to design high aspect ratio functional fibers for potential surgical tools developments. Through this project, we envision pushing the frontier of soft multi-material robotic fibers further and demonstrating magnetic textiles for rehabilitation purposes with human subjects and potential technology transfer.

We are looking to welcoming a highly motivated master’s student from Microengineering, Mechanical Engineering, Electrical and Electronic Engineering, Material Sciences and Engineering Master programs, with a strong interest in embedded design and product development. Preference will be given to students who like working on challenging interdisciplinary projects, in a serious but also friendly and very cooperative and team-work oriented environment.

Please send an email to [email protected] and [email protected] with your CV, one possible idea based on the following references, and a motivation paragraph.

Experimental and modeling tools:
• Multi-material perform fabrication and thermally drawn technique
• Mechanical properties characterization (rheology, mechanical testing, etc.)
• Materials characterization (Optical Microscopy, SEM)
• Engineering design
• Signal processing
• Motion tracking

References:

1. Qu, Yunpeng, et al. “Superelastic multimaterial electronic and photonic fibers and devices via thermal drawing.” Advanced Materials 30.27 (2018): 1707251.

2. Kim, Yoonho, and Xuanhe Zhao. “Magnetic soft materials and robots.” Chemical Reviews 122.5 (2022): 5317-5364.

3. Kim, Yoonho, et al. “Ferromagnetic soft continuum robots.” Science Robotics 4.33 (2019).

4. Kim, Yoonho, et al. “Printing ferromagnetic domains for untethered fast-transforming soft materials.” Nature 558.7709 (2018): 274-279.

5. Kim, Yoonho, et al. “Telerobotic neurovascular interventions with magnetic manipulation.” Science Robotics 7.65 (2022): eabg9907.

6. Kilic Afsar, Ozgun, et al. “OmniFiber: Integrated Fluidic Fiber Actuators for Weaving Movement Based Interactions into the ‘Fabric of Everyday Life’.” The 34th Annual ACM Symposium on User Interface Software and Technology. 2021.

Flat optics has recently emerged as a disruptive technology for fabrication of optical elements.
It consists of subwavelength nanostructuration of material with high refractive index, and enables the realization of optical elements (like lenses, beam splitters,…) with extremely reduced thickness – less than 1 micronmeter – and tunable properties [1].
This technology opens new possibilities in device miniaturization, ultrafast signal processing, augmented reality, etc…

This project aims at designing, fabricating, and characterizing a ultra-thin lens (so-called metalens), and lies at the interface of micro-fabrication, micro-optics and surface science.

Indeed, to structure the material at the nanoscale, we rely on a surface-based fabrication process developed in our laboratory [2].
In this process, a thin layer of high refractive index glass is evaporated on a pre-nanopatterned substrate and subsequently heated, to let it reflow and dewet into precise nanoshapes.
This process flow is particularly well-suited for large-area applications.

The project will involve several aspects, from computational simulations to microfabrication in EPFL cleanrooms facilities (CMi).

The experimental work will consist of extensive fabrication of a centimeter-large lens pattern with CMi tools (e-beam lithography, etching).
Replication of the pattern, glass evaporation and surface modification will also be performed.
Optical characterization of the fabricated magnifying lens could be carried as well.

The theoretical work will consist of designing the lens structure, using FDTD simulation software.

We are looking into one (or several) highly motived Master students from Microengineering, Material Sciences and Engineering, or Electrical and Electronic Engineering Master programs, with a strong interest in micro-fabrication applied preferably to optical devices.

Please send an email to [email protected] and [email protected] with your CV or description of your academic path, and a motivation paragraph.

References:
[1] T. Das Gupta, L. Martin-Monier, J. Butet, K-Y Yang et al. “Second harmonic generation in glass-based metasurfaces using tailored surface lattice resonances” Nanophotonics, vol. 10, no. 13, 2021, pp. 3465-3475.
[2] T. Das Gupta, L. Martin-Monier, W. Yan, A. Le Bris, T. Nguyen-Dang et al. “Self-assembly of nanostructured glass metasurface via templated fluid instabilities”, Nature Nanotechnology, 2019, 14, 320-327.

Rapid methods for the detection of microorganisms, contaminants and biochemical markers are in demand in many areas such as environmental monitoring, food and beverage testing, and medical diagnosis. On-site analysis in particular is becoming a key component of safety and quality monitoring, when costs, equipment, or time limitations preclude the use of conventional laboratory techniques.

Lab-on-chip systems have been extensively researched to achieve fully automated and multiplexed analysis, but still fail to be competitive in terms of price and throughput. In the opposite direction, simple, low-cost paper-based devices have found wide adoption thank to their ease of fabrication and use, but often suffer from insufficient limit-of-detection and reproducibility, or only provide semi-quantitative information.

Centered around the needs for fast results, scalable fabrication, and ease-of-use, our laboratory is developing a new platform called FiberLab: a low-cost multicapillary-format test capable of collecting and analysing µL-sized sample by colorimetric chemical assays. Where most approaches rely on cumbersome fabrication process based on the chemical post-modification of capillaries, we leverage our unique thermal drawing facility to produce ready-to-use lab-in-fiber tests at large scale and low cost.

The aim of this semester project is to expand the potential and performances of our platform by developing new sensing strategies and materials compatible with our thermal drawing process. In this perspective, the student will be involved along the entire development cycle, from the development and testing of new formulations for in-fiber chemical assay, manufacturing of the test by thermal drawing, and characterization of the final product in our laboratory setup.

This is an applied research project at the crossroad of material science, chemistry, image processing and optoelectronics, with the goal to deliver a functional demonstrator by the end of the semester.
We are looking for candidates with a background in material sciences, life or biological sciences, analytical chemistry, or pharmaceutical sciences, with a strong interest in multidisciplinary and applied research.
Please send an email to [email protected] and [email protected] with your CV or description of your academic path.