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Intrusion and extrusion of a liquid on nanostructured surfaces.
J Phys Condens Matter 2017; 29(1):014003JP

Abstract

Superhydrophobicity is connected to the presence of gas pockets within surface asperities. Upon increasing the pressure this 'suspended' state may collapse, causing the complete wetting of the rough surface. In order to quantitatively characterize this process on nanostructured surfaces, we perform rare-event atomistic simulations at different pressures and for several texture geometries. Such an approach allows us to identify for each pressure the stable and metastable states and the free energy barriers separating them. Results show that, by starting from the superhydrophobic state and increasing the pressure, the suspended state abruptly collapses at a critical intrusion pressure. If the pressure is subsequently decreased, the system remains trapped in the metastable state corresponding to the wet surface. The liquid can be extruded from the nanostructures only at very negative pressures, by reaching the critical extrusion pressure (spinodal for the confined liquid). The intrusion and extrusion curves form a hysteresis cycle determined by the large free energy barriers separating the suspended and wet states. These barriers, which grow very quickly for pressures departing from the intrusion/extrusion pressure, are shown to strongly depend on the texture geometry.

Authors+Show Affiliations

Dipartimento di Ingegneria Meccanica e Aerospaziale, Università di Roma 'La Sapienza', Rome, Italy.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27830654

Citation

Amabili, M, et al. "Intrusion and Extrusion of a Liquid On Nanostructured Surfaces." Journal of Physics. Condensed Matter : an Institute of Physics Journal, vol. 29, no. 1, 2017, p. 014003.
Amabili M, Giacomello A, Meloni S, et al. Intrusion and extrusion of a liquid on nanostructured surfaces. J Phys Condens Matter. 2017;29(1):014003.
Amabili, M., Giacomello, A., Meloni, S., & Casciola, C. M. (2017). Intrusion and extrusion of a liquid on nanostructured surfaces. Journal of Physics. Condensed Matter : an Institute of Physics Journal, 29(1), p. 014003.
Amabili M, et al. Intrusion and Extrusion of a Liquid On Nanostructured Surfaces. J Phys Condens Matter. 2017 Jan 11;29(1):014003. PubMed PMID: 27830654.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intrusion and extrusion of a liquid on nanostructured surfaces. AU - Amabili,M, AU - Giacomello,A, AU - Meloni,S, AU - Casciola,C M, Y1 - 2016/11/10/ PY - 2016/11/11/pubmed PY - 2016/11/11/medline PY - 2016/11/11/entrez SP - 014003 EP - 014003 JF - Journal of physics. Condensed matter : an Institute of Physics journal JO - J Phys Condens Matter VL - 29 IS - 1 N2 - Superhydrophobicity is connected to the presence of gas pockets within surface asperities. Upon increasing the pressure this 'suspended' state may collapse, causing the complete wetting of the rough surface. In order to quantitatively characterize this process on nanostructured surfaces, we perform rare-event atomistic simulations at different pressures and for several texture geometries. Such an approach allows us to identify for each pressure the stable and metastable states and the free energy barriers separating them. Results show that, by starting from the superhydrophobic state and increasing the pressure, the suspended state abruptly collapses at a critical intrusion pressure. If the pressure is subsequently decreased, the system remains trapped in the metastable state corresponding to the wet surface. The liquid can be extruded from the nanostructures only at very negative pressures, by reaching the critical extrusion pressure (spinodal for the confined liquid). The intrusion and extrusion curves form a hysteresis cycle determined by the large free energy barriers separating the suspended and wet states. These barriers, which grow very quickly for pressures departing from the intrusion/extrusion pressure, are shown to strongly depend on the texture geometry. SN - 1361-648X UR - https://www.unboundmedicine.com/medline/citation/27830654/Intrusion_and_extrusion_of_a_liquid_on_nanostructured_surfaces_ L2 - https://doi.org/10.1088/0953-8984/29/1/014003 DB - PRIME DP - Unbound Medicine ER -