Speaker
Description
Self-propelled micropumps are the immobilized version of nanomotors, sharing similar operational principles. Pumps offer valuable insights into the key parameters governing motion, with the added advantage of being easier to probe using various experimental techniques compared to their motile counterparts. In this talk, we will explore several examples demonstrating how micropumps can be used to understand, design, and optimize nanomotors. Particular attention will be given to ion-exchange-driven pumps and swimmers.
Ion exchange is one of the most interesting processes occurring at the interface between aqueous solutions and polymers endowed with sulfonic groups, such as the well-known Nafion1. When exchanged ions possess varying diffusion coefficients, this process generates local electric fields that can be utilized to propel fluid motion1,2. we demonstrate the design and fabrication of pumps and self-propelling micro/nanoswimmers based on Nafion, powered by ion exchange and fueled by salts. These Nafion micromachines are created through different lithographic techniques (colloidal, stencil, photo or electron beam lithographies) shaping Nafion into asymmetric structures3,4. The resulting micro/nanoswimmers exhibit fascinating collective motion in water driven by the interplay of their self-generated chemical/electric fields and their capability to pump surrounding matter towards them. The pumping activity of the micro/nanoswimmers induces the formation of growing mobile clusters, whose velocity increases with size. Such dynamic structures are able to trap nearby micro/nano-objects while purifying the liquid, which acts both as the transport media and as fuel3,4. This phenomenon holds promise for potential applications in water remediation currently under development.
References
[1]M. J. Esplandiu, D. Reguera, and J. Fraxedas, Soft Matter, 16 (2020) 3717.
[2]M. J. Esplandiu et al., Acc. Chem. Res., 51 (2018) 1921
[3]M. J. Esplandiu, D. Reguera, D. Romero-Guzman, A. M. Gallardo-Moreno, and J. Fraxedas, Nat. Commun. 13 (2022) 2812.
[4]J. Fraxedas, D. Reguera, M. J. Esplandiu, Faraday discussions, 249 (2024) 424.
