(3l) Fluidics and Ionics at the Nanoscale

Nanoscale transport is central to cellular biology as well as to applications in gas separation and water filtration. State of the art nanotechnology allows for conceiving analogs of nature’s powerful membrane transport machinery. The Kuehne laboratory will engineer solid state channels using 1D and 2D materials to investigate, exploit, and control the behavior of fluids and ions at the nanometer scale. With my background in studying ion transport in 2D and water confined to quasi 1D, I am uniquely positioned to address this topic.

With an emphasis on scalability and reproducibility, the Kuehne laboratory will fabricate devices and device arrays from nanomaterials to elucidate mass, heat, and charge transfer in statistically robust manner. Both optical and electronic characterization tools will be deployed to investigate the coupling between the different system constituents, such as electronic and ionic charge carriers or vibrational modes and fluid molecules, in order to devise pumps, logic elements, energy sources, and sensors. The proposed research will advance basic science in the field, establish new device and measurement concepts, pioneer new control modalities of matter at the nanometer scale, and enable the engineering of new solutions in energy harvesting, ion sieving, charge transport, and mass storage.

Research Experience

Postdoctoral – Massachusetts Institute of Technology (10/2018–present). Advisor: Michael S. Strano.

My work in Michael Strano’s group focuses on probing and understanding the behavior of fluids under nanoscale confinement. In particular, I synthesize individual, single-walled carbon nanotubes with diameters on the order of 1 nm for their use as well-defined single digit nanopores. As the continuum assumption for fluids inside these pores breaks down, one enters a regime of exotic transport and phase behavior that constitutes the current frontier in nanofluidics. Extreme selectivity as well as enhanced flow through these nanoscale conduits have been reported and are of immediate interest for applications in filtration and blue energy harvesting. My work contributes to ongoing efforts within the Center of Enhanced Nanofluidic Transport (CENT), a DoE Energy Frontier Research Center (EFRC), but since July 2020 is independently funded by the German Research Foundation (DFG).

Since I joined the Strano Research Group, I have developed a new platform allowing to study multiple free-standing copies of the same chirality nanotube. This enables the acquisition of statistically more robust datasets on e.g. their thermal properties, an approach targeting to increase reproducibility and to gain a better understanding of variations between different copies of the same system. I have qualified focused ion beam cutting as a new means to open these tubes to allow fluid filling, and have automated several optical spectroscopy setups to study interior fluids. A detailed Raman spectroscopy study where I compare multiple segments of the same tube in vacuum, both before and after filling with water, showed that an interior fluid impedes axial thermal transport in the system (Kuehne et al., submitted 2020). A more statistical investigation on water filling as a function of nanotube diameter is currently being finalized (Faucher, Kuehne et al., in preparation 2020). I have been contributing to other projects in the group, such as the study of hexagonal boron nitride lattice defects (Kozawa et al., arXiv:1909.11738 2019) and the use of MoS2 as Archimedean scroll Bragg reflectors (Kozawa et al., Nano Letters 2020).

Doctoral – Max Planck Institute for Solid State Research, Germany (2012–2018). Advisor: Jurgen H. Smet.

During my doctoral training, I pioneered research on the behavior of ions in single-crystalline 2D materials. To this end, I developed a novel on-chip micro-electrochemical cell architecture that allowed for the controlled integration of Li-ion conducting solid polymer electrolytes with patterned, micrometer sized flakes of 2D materials such as graphene. By engineering the substrate’s surface wettability, I spatially constrained the position of a drop cast electrolyte prior to solidification such that graphene devices were covered only partially. This enabled a series of in situ studies revealing fast lithium diffusion in bilayer graphene by magneto-transport (Kuehne et al., Nature Nanotechnology 2017), reversible superdense lithium ordering by double aberration corrected transmission electron microscopy (Kuehne et al., Nature 2018), and signatures of intercalation-induced lattice expansion by microfocused X-ray reflectivity (Zielinski, Kuehne et al., Nano Letters 2019). Part of the research was funded as a Clean Tech project of the Baden-Württemberg Foundation, the application for which I helped draft and which I regularly reported on both in oral and written form. My doctoral training also gave me the opportunity to gain experience in conducting experiments at shared particle accelerator facilities including ESRF (Grenoble), DESY (Hamburg), and ANKA (Karlsruhe).

Diploma – French National Center for Scientific Research (CNRS), France (2010–2011). Advisor: Marek Potemski.

As final project of my double-diploma studies at the Grenoble Institute of Technology (Grenoble INP, France) and Karlsruhe Institutes of Technology (Germany), I spent a year working on magneto-optics at the CNRS National High Magnetic Field Laboratory (LNCMI). I conducted experiments especially on epitaxial graphene on SiC and graphite. At the time, little was known about the interactions between electronic and vibrational excitations in these materials. Using magneto-Raman scattering, we revealed the coupling between inter-Landau level excitations and the Raman active E2g phonon, and determined selection rules for the different modes (Kuehne et al., Phys. Rev. B 2012). Throughout my stay, I contributed to a number of related projects that resulted in three additional co-authored publications.

Selected Publications

1. Kuehne, S. Faucher, M. Liew, Z. Yuan, S. X. Li, T. Ichihara, Y. Zeng, P. Gordiichuk, V. B. Koman, D. Kozawa, A. Majumdar, M. S. Strano. Interior fluid filling impedes thermal conduction in isolated, free-standing single-walled carbon nanotubes. Submitted (2020).
2. Zielinski, M. Kuehne, D. Kaercher, F. Paolucci, P. Wochner, S. Fecher, J. Drnec, R. Felici, J. H. Smet. Probing exfoliated graphene layers and their lithiation with microfocused X-rays. Nano Letters 19, 3634–3640 (2019).
3. Kuehne, F. Boerrnert, S. Fecher, M. Ghorbani-Asl, J. Biskupek, D. Samuelis, A. V. Krasheninnikov, U. Kaiser, J. H. Smet. Reversible superdense ordering of lithium between two graphene sheets. Nature 564, 234–239 (2018). // European Microscopy Society (EMS) 2018 Outstanding Paper Award
4. Kuehne, F. Paolucci, J. Popovic, P. M. Ostrovsky, J. Maier, J. H. Smet. Ultrafast lithium diffusion in bilayer graphene. Nature Nanotechnology 12, 895–900 (2017).
5. Kuehne, C. Faugeras, P. Kossacki, A. A. L. Nicolet, M. Orlita, Yu. I. Latyshev, M. Potemski. Polarization-resolved magneto-Raman scattering of graphenelike domains on natural graphite. Physical Review B 85, 195406 (2012).

Teaching Interests

Good teaching is when students leave the class feeling inspired, still actively discussing the subject matter, and wanting to learn more. I intend to provoke this situation as much as possible and to this end create an inclusive learning environment for all students, irrespective of their background or long-term goals. I understand my role as a facilitator for active learning, enabling students to succeed in their career by taking ownership of the subject matter. As a graduate of MIT’s Kaufman Teaching Certificate Program, I have acquired skills centered around research-based strategies for teaching and learning that I will build on and continuously improve. I am currently co-developing a nanopore sequencing module as an educational initiative at MIT, a project partially funded by the Alumni Class Funds ($41,000).

My Physics and Nanoscience background allows me to teach related topics both at an undergraduate and at a graduate level, but my teaching interests also include topics more at the heart of Chemical Engineering Education such as fluid mechanics, heat and mass transport, and thermodynamics. I highly value interdisciplinary approaches, which I consider essential especially for future advances in nanotechnology engineering, and I am enthusiastic to develop an elective course on that subject. I will leverage my mentoring experience gained during both my doctoral and my postdoctoral training to help students excel in the lab, in solving problems, and in presenting and communicating their research.

Teaching experience

MIT, Department of Chemical Engineering

• Consultant for 10.26 Chemical Engineering Project Labs, Nanopore DNA Sequencing (Spring 2020, Lecturer: Michael S. Strano).
• Guest lecturer in 10.585 Nanotechnology Engineering (Fall 2019, Lecturer: Michael S. Strano).
• Mentored 2 undergraduate students (2019–2020).

Max Planck Institute for Solid State Research, Germany

• Mentored 1 PhD & 5 undergraduate students (2012–2018).

University of Stuttgart, Germany, Faculty 8 - Mathematics and Physics

• Teaching assistant for Advanced Physical Laboratory, Scanning Tunneling Microscopy (Summer 2014, 2015, Lecturer: Bruno Gompf).

Karlsruhe Institute of Technology (KIT), Germany, Faculty of Physics

• Teaching assistant for Physics IV - Atoms and Molecules (Summer 2012, Lecturer: Wim de Boer).
• Teaching assistant for Physics III – Optics and Thermodynamics (Winter 2011, Lecturer: G. Ulrich Nienhaus).