@article{13197,
  abstract     = {Nominally identical materials exchange net electric charge during contact through a mechanism that is still debated. ‘Mosaic models’, in which surfaces are presumed to consist of a random patchwork of microscopic donor/acceptor sites, offer an appealing explanation for this phenomenon. However, recent experiments have shown that global differences persist even between same-material samples, which the standard mosaic framework does not account for. Here, we expand the mosaic framework by incorporating global differences in the densities of donor/acceptor sites. We develop
an analytical model, backed by numerical simulations, that smoothly connects the global and deterministic charge transfer of different materials to the local and stochastic mosaic picture normally associated with identical materials. Going further, we extend our model to explain the effect of contact asymmetries during sliding, providing a plausible explanation for reversal of charging sign that has been observed experimentally.},
  author       = {Grosjean, Galien M and Waitukaitis, Scott R},
  issn         = {2475-9953},
  journal      = {Physical Review Materials},
  keywords     = {Physics and Astronomy (miscellaneous), General Materials Science},
  number       = {6},
  publisher    = {American Physical Society},
  title        = {{Asymmetries in triboelectric charging: Generalizing mosaic models to different-material samples and sliding contacts}},
  doi          = {10.1103/physrevmaterials.7.065601},
  volume       = {7},
  year         = {2023},
}

@article{12697,
  abstract     = {Models for same-material contact electrification in granular media often rely on a local charge-driving parameter whose spatial variations lead to a stochastic origin for charge exchange. Measuring the charge transfer from individual granular spheres after contacts with substrates of the same material, we find instead a “global” charging behavior, coherent over the sample’s whole surface. Cleaning and baking samples fully resets charging magnitude and direction, which indicates the underlying global parameter is not intrinsic to the material, but acquired from its history. Charging behavior is randomly and irreversibly affected by changes in relative humidity, hinting at a mechanism where adsorbates, in particular, water, are fundamental to the charge-transfer process.},
  author       = {Grosjean, Galien M and Waitukaitis, Scott R},
  issn         = {1079-7114},
  journal      = {Physical Review Letters},
  keywords     = {General Physics, Electrostatics, Triboelectricity, Soft Matter, Acoustic Levitation, Granular Materials},
  number       = {9},
  publisher    = {American Physical Society},
  title        = {{Single-collision statistics reveal a global mechanism driven by sample history for contact electrification in granular media}},
  doi          = {10.1103/physrevlett.130.098202},
  volume       = {130},
  year         = {2023},
}

@article{9411,
  abstract     = {The dynamics of a triangular magnetocapillary swimmer is studied using the lattice Boltzmann method. We extend on our previous work, which deals with the self-assembly and a specific type of the swimmer motion characterized by the swimmer’s maximum velocity centred around the particle’s inverse viscous time. Here, we identify additional regimes of motion. First, modifying the ratio of surface tension and magnetic forces allows to study the swimmer propagation in the regime of significantly lower frequencies mainly defined by the strength of the magnetocapillary potential. Second, introducing a constant magnetic contribution in each of the particles in addition to their magnetic moment induced by external fields leads to another regime characterized by strong in-plane swimmer reorientations that resemble experimental observations.},
  author       = {Sukhov, Alexander and Hubert, Maxime and Grosjean, Galien M and Trosman, Oleg and Ziegler, Sebastian and Collard, Ylona and Vandewalle, Nicolas and Smith, Ana Sunčana and Harting, Jens},
  issn         = {1292895X},
  journal      = {European Physical Journal E},
  number       = {4},
  publisher    = {Springer},
  title        = {{Regimes of motion of magnetocapillary swimmers}},
  doi          = {10.1140/epje/s10189-021-00065-2},
  volume       = {44},
  year         = {2021},
}

@article{8036,
  abstract     = {When tiny soft ferromagnetic particles are placed along a liquid interface and exposed to a vertical magnetic field, the balance between capillary attraction and magnetic repulsion leads to self-organization into well-defined patterns. Here, we demonstrate experimentally that precessing magnetic fields induce metachronal waves on the periphery of these assemblies, similar to the ones observed in ciliates and some arthropods. The outermost layer of particles behaves like an array of cilia or legs whose sequential movement causes a net and controllable locomotion. This bioinspired many-particle swimming strategy is effective even at low Reynolds number, using only spatially uniform fields to generate the waves.},
  author       = {Collard, Ylona and Grosjean, Galien M and Vandewalle, Nicolas},
  issn         = {23993650},
  journal      = {Communications Physics},
  publisher    = {Springer Nature},
  title        = {{Magnetically powered metachronal waves induce locomotion in self-assemblies}},
  doi          = {10.1038/s42005-020-0380-9},
  volume       = {3},
  year         = {2020},
}

@article{8101,
  abstract     = {By rigorously accounting for mesoscale spatial correlations in donor/acceptor surface properties, we develop a scale-spanning model for same-material tribocharging. We find that mesoscale correlations affect not only the magnitude of charge transfer but also the fluctuations—suppressing otherwise overwhelming charge-transfer variability that is not observed experimentally. We furthermore propose a generic theoretical mechanism by which the mesoscale features might emerge, which is qualitatively consistent with other proposals in the literature.},
  author       = {Grosjean, Galien M and Wald, Sebastian and Sobarzo Ponce, Juan Carlos A and Waitukaitis, Scott R},
  issn         = {2475-9953},
  journal      = {Physical Review Materials},
  keywords     = {electric charge, tribocharging, soft matter, granular materials, polymers},
  number       = {8},
  publisher    = {American Physical Society},
  title        = {{Quantitatively consistent scale-spanning model for same-material tribocharging}},
  doi          = {10.1103/PhysRevMaterials.4.082602},
  volume       = {4},
  year         = {2020},
}