{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/15563"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/15563","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Molecular understanding of osmosis and a multiscale framework to investigate confined fluid properties","abstract":"Understanding the fluid structure and behavior in nanoscale confinements is of major importance in a wide variety of applications including biological and engineering devices. A critical biological application in which the physics at the nanoscale is important is osmosis. Critical functions of life as well as technology to develop better water filtration systems depends on a fundamental understanding of osmosis. In this thesis, first, a molecular understanding of osmosis in uncharged and charged semi-permeable membranes is developed using Molecular Dynamics (MD) simulation studies. Specifically, we identify key inter-molecular forces that initiate osmosis in uncharged and charged membranes and explain the significance of various inter-molecular forces as the system evolves to a steady-state. We also investigate the effect of size-asymmetric electrolytes on osmosis through uncharged semi-permeable membranes. Second, we develop a multiscale framework to investigate fluids in confinement. Since the atomistic simulations are extremely computational, they become intractable at very large length scales. Also, the classical continuum theory breaks down at the atomistic level. Towards the goals of bridging the two scales, we formulate a semi-classical framework to predict the concentration and potential profiles of LJ fluids confined in channels of widths ranging from 2 sigma to 100 sigma (sigma is the fluid-fluid LJ parameter). The semi-classical framework utilizes the Nernst-Planck equation coupled with a theoretical potential formulation to obtain the accurate concentration and potential profiles in a channel. The results obtained from the semi-classical framework are then compared with results obtained from MD simulations in the channel.","abstract_html":"Understanding the fluid structure and behavior in nanoscale confinements is of major importance in a wide variety of applications including biological and engineering devices. A critical biological application in which the physics at the nanoscale is important is osmosis. Critical functions of life as well as technology to develop better water filtration systems depends on a fundamental understanding of osmosis. In this thesis, first, a molecular understanding of osmosis in uncharged and charged semi-permeable membranes is developed using Molecular Dynamics (MD) simulation studies. Specifically, we identify key inter-molecular forces that initiate osmosis in uncharged and charged membranes and explain the significance of various inter-molecular forces as the system evolves to a steady-state. We also investigate the effect of size-asymmetric electrolytes on osmosis through uncharged semi-permeable membranes. Second, we develop a multiscale framework to investigate fluids in confinement. Since the atomistic simulations are extremely computational, they become intractable at very large length scales. Also, the classical continuum theory breaks down at the atomistic level. Towards the goals of bridging the two scales, we formulate a semi-classical framework to predict the concentration and potential profiles of LJ fluids confined in channels of widths ranging from 2 sigma to 100 sigma (sigma is the fluid-fluid LJ parameter). The semi-classical framework utilizes the Nernst-Planck equation coupled with a theoretical potential formulation to obtain the accurate concentration and potential profiles in a channel. The results obtained from the semi-classical framework are then compared with results obtained from MD simulations in the channel.","abstract_has_math":false,"creators":["Raghunathan, Anjan V."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Aluru, Narayana R.","Georgiadis, John G.","Ravaioli, Umberto","Tajkhorshid, Emad"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010-05-14T20:50:33Z","date_published":"2010-05-14T20:50:33Z","updated_at":"2026-07-22T22:25:08Z","subjects":["Multiscale simulations","Nanofluidics","Osmosis"],"languages":["en"],"rights":["Copyright 2010 Anjan V Raghunathan"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/15563","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Aluru, Narayana R.","Georgiadis, John G.","Ravaioli, Umberto","Tajkhorshid, Emad"]},{"key":"dc:creator","label":"Author","values":["Raghunathan, Anjan V."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2010-05-14T20:50:33Z","2012-05-15T10:00:32Z","2010-5"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Multiscale simulations","Nanofluidics","Osmosis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2010 Anjan V Raghunathan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/15563"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Understanding the fluid structure and behavior in nanoscale confinements is of major importance in a wide variety of applications including biological and engineering devices. 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Also, the classical continuum theory breaks down at the atomistic level. Towards the goals of bridging the two scales, we formulate a semi-classical framework to predict the concentration and potential profiles of LJ fluids confined in channels of widths ranging from 2 sigma to 100 sigma (sigma is the fluid-fluid LJ parameter). The semi-classical framework utilizes the Nernst-Planck equation coupled with a theoretical potential formulation to obtain the accurate concentration and potential profiles in a channel. The results obtained from the semi-classical framework are then compared with results obtained from MD simulations in the channel.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2010-04-22T20:18:39Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 Raghunathan_Anjan.zip: 2896757 bytes, checksum: d87260a7b86af73885fd8492d3f5ee97 (MD5) Raghunathan_Anjan.pdf: 890607 bytes, checksum: f8827a27fca34a8a739e76ce6aeb182d (MD5)","Made available in DSpace on 2010-05-14T20:50:33Z (GMT). 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A critical biological application in which the physics at the nanoscale is important is osmosis. Critical functions of life as well as technology to develop better water filtration systems depends on a fundamental understanding of osmosis. In this thesis, first, a molecular understanding of osmosis in uncharged and charged semi-permeable membranes is developed using Molecular Dynamics (MD) simulation studies. Specifically, we identify key inter-molecular forces that initiate osmosis in uncharged and charged membranes and explain the significance of various inter-molecular forces as the system evolves to a steady-state. We also investigate the effect of size-asymmetric electrolytes on osmosis through uncharged semi-permeable membranes. Second, we develop a multiscale framework to investigate fluids in confinement. Since the atomistic simulations are extremely computational, they become intractable at very large length scales. Also, the classical continuum theory breaks down at the atomistic level. Towards the goals of bridging the two scales, we formulate a semi-classical framework to predict the concentration and potential profiles of LJ fluids confined in channels of widths ranging from 2 sigma to 100 sigma (sigma is the fluid-fluid LJ parameter). The semi-classical framework utilizes the Nernst-Planck equation coupled with a theoretical potential formulation to obtain the accurate concentration and potential profiles in a channel. 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