Soft and Complex Materials
The Waitukaitis Group is an experimental physics lab whose research focuses on complex phenomena that arise via exotic interactions between liquids and solids. Their work is highly interdisciplinary, sitting at the intersection of soft matter physics, materials science, complex fluids, and chemistry. Under this general umbrella, their lab addresses a variety of distinct topics ranging from the nanoscale to the macroscale and involving experimental techniques ranging from atomic force microscopy to high-speed imaging.
An example at the smallest scale is the phenomenon of tribocharging – the exchange of electrical charge between objects during contact. Although well-known to anyone who has been shocked by a doorknob and described scientifically going back as far as ancient Greece, the underlying mechanism for tribocharging remains mysterious. They are particularly interested in same-material tribocharging, which counterintuitively occurs when identical materials are brought into contact. Recent results suggest that this puzzling phenomenon might result from the stochastic deposition of nanoscale islands of water on the material surface. Using atomic force microscopy to characterize surfaces and cutting-edge techniques to measure charge exchange, a major goal is to validate or nullify this hypothesis and help resolve this millennia-old mystery.
At larger scales, they are interested in the non-Newtonian dynamics that arise when colloidal-sized solid particles are suspended in liquids. Perhaps the most well-known example is a dense mixture of cornstarch particles in water, which behaves liquid-like when perturbed gently but solid-like when vigorously agitated. Previous work has centered on passive non-Newtonian suspensions such as this, but moving forward their lab will focus on smart colloidal suspensions filled with particles that can be controlled by environmental stimuli. Their long-term goal in this direction is to achieve a level of spatiotemporal control that allows us to design and build metafluids – liquids whose material properties can be changed on command.
On this site:
Mesoscale charging statistics with acoustic levitation | Macro-charging of oxide nanolayers on soft polymer substrates
Sukhov A, Hubert M, Grosjean GM, Trosman O, Ziegler S, Collard Y, Vandewalle N, Smith AS, Harting J. 2021. Regimes of motion of magnetocapillary swimmers. European Physical Journal E. 44(4), 59. View
Grosjean GM, Wald S, Sobarzo Ponce JCA, Waitukaitis SR. 2020. Quantitatively consistent scale-spanning model for same-material tribocharging. Physical Review Materials. 4(8), 082602. View
Collard Y, Grosjean GM, Vandewalle N. 2020. Magnetically powered metachronal waves induce locomotion in self-assemblies. Communications Physics. 3, 112. View
Khattak HK, Waitukaitis SR, Slepkov AD. 2019. Microwave induced mechanical activation of hydrogel dimers. Soft Matter. 15(29), 5804–5809. View
Since 2019 Assistant Professor, IST Austria
2016-2018 Veni Fellow and postdoctoral scholar at AMOLF, Amsterdam NL
2013-2016 Postdoctoral Scholar at Leiden University, Leiden NL
2007-2013 Ph.D. in physics at the University of Chicago, Chicago USA
2020 ERC Starting Grant
2018 NNV Fysica Young Speakers Award
2018 Block Prize for Outstanding Young Researcher
2016-present Veni Research Grant from the Netherlands Organization for Scientific Research
2014 The Springer Thesis Award, Springer Publishing
2012 The Bruce Winstein Prize for Instrumentation
2010-2013 Robert A. Millikan Fellowship