{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/82437"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/82437","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Conformation and Rheology of Semiflexible Macromolecules Using Non-Equilibrium Brownian Dynamics and Monte Carlo Simulations","abstract":"Non-Equilibrium Brownian Dynamics Simulations (NEBD) and Configuration-Biased Monte Carlo (CBMC) methods are used to model the dynamics of semi-flexible macromolecules and polyelectrolytes undergoing shear and extensional flow. The mathematical model utilizes a discretized version of the Kratky-Porod wormlike (or persistent) chain as the building block, generalized to include flow. This discrete chain contains beads which interact through stretching and bending forces, and for polyelectrolytes a screened Debye-Huckel potential is also present. The Fokker-Planck equation describing this chain is converted to a Stochastic Differential Equation (SDE) from which the simulation algorithm for the NEBD is obtained. In steady, potential flows, the solution of the Fokker-Planck equation exists and is used in the generation of trial and acceptance moves in the CBMC scheme. Various conformational and rheological quantities are monitored, under both steady-state and transient conditions, with the primary independent variables being the $flexibility\\ parameter\\ \\beta ,$ the bending constant of the chain, and for polyelectrolytes, the salt concentration (parametrized through the Debye length) and the strength of interaction q, related to the degree of ionization of the chain. The model qualitatively describes many of the experimentally-observed effects in such systems, most notably birefringence overshoots, cessation effects, and various steady-state effects. The crucial advantage of the NEBD over an analytical treatment is its ability to incorporate (analytically intractable) effects such as hydrodynamic interactions and its (natural) ability to obtain transient information, a facet useful in comprehending the differing dynamics of molecules of varying rigidity. In addition, excluded volume effects on transient orientational and rheological behavior is studied.","abstract_html":"Non-Equilibrium Brownian Dynamics Simulations (NEBD) and Configuration-Biased Monte Carlo (CBMC) methods are used to model the dynamics of semi-flexible macromolecules and polyelectrolytes undergoing shear and extensional flow. The mathematical model utilizes a discretized version of the Kratky-Porod wormlike (or persistent) chain as the building block, generalized to include flow. This discrete chain contains beads which interact through stretching and bending forces, and for polyelectrolytes a screened Debye-Huckel potential is also present. The Fokker-Planck equation describing this chain is converted to a Stochastic Differential Equation (SDE) from which the simulation algorithm for the NEBD is obtained. In steady, potential flows, the solution of the Fokker-Planck equation exists and is used in the generation of trial and acceptance moves in the CBMC scheme. Various conformational and rheological quantities are monitored, under both steady-state and transient conditions, with the primary independent variables being the <span class=\"etd-inline-math\">flexibility parameter &beta; ,</span> the bending constant of the chain, and for polyelectrolytes, the salt concentration (parametrized through the Debye length) and the strength of interaction q, related to the degree of ionization of the chain. The model qualitatively describes many of the experimentally-observed effects in such systems, most notably birefringence overshoots, cessation effects, and various steady-state effects. The crucial advantage of the NEBD over an analytical treatment is its ability to incorporate (analytically intractable) effects such as hydrodynamic interactions and its (natural) ability to obtain transient information, a facet useful in comprehending the differing dynamics of molecules of varying rigidity. In addition, excluded volume effects on transient orientational and rheological behavior is studied.","abstract_has_math":true,"creators":["Andrews, Naveen Chandy"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemical Engineering","degree_department":null,"school":null,"contributors":["McHugh, A.J."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-25T20:44:03Z","date_published":"2015-09-25T20:44:03Z","updated_at":"2026-07-22T22:26:18Z","subjects":["Engineering, Chemical"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI9812520"],"render_values":[{"text":"(MiAaPQ)AAI9812520","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/82437","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["McHugh, A.J."]},{"key":"dc:creator","label":"Author","values":["Andrews, Naveen Chandy"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T20:44:03Z","10000-01-01","1997"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemical 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":["Engineering, Chemical"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/82437","(MiAaPQ)AAI9812520"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Non-Equilibrium Brownian Dynamics Simulations (NEBD) and Configuration-Biased Monte Carlo (CBMC) methods are used to model the dynamics of semi-flexible macromolecules and polyelectrolytes undergoing shear and extensional flow. The mathematical model utilizes a discretized version of the Kratky-Porod wormlike (or persistent) chain as the building block, generalized to include flow. This discrete chain contains beads which interact through stretching and bending forces, and for polyelectrolytes a screened Debye-Huckel potential is also present. The Fokker-Planck equation describing this chain is converted to a Stochastic Differential Equation (SDE) from which the simulation algorithm for the NEBD is obtained. In steady, potential flows, the solution of the Fokker-Planck equation exists and is used in the generation of trial and acceptance moves in the CBMC scheme. Various conformational and rheological quantities are monitored, under both steady-state and transient conditions, with the primary independent variables being the $flexibility\\ parameter\\ \\beta ,$ the bending constant of the chain, and for polyelectrolytes, the salt concentration (parametrized through the Debye length) and the strength of interaction q, related to the degree of ionization of the chain. The model qualitatively describes many of the experimentally-observed effects in such systems, most notably birefringence overshoots, cessation effects, and various steady-state effects. The crucial advantage of the NEBD over an analytical treatment is its ability to incorporate (analytically intractable) effects such as hydrodynamic interactions and its (natural) ability to obtain transient information, a facet useful in comprehending the differing dynamics of molecules of varying rigidity. In addition, excluded volume effects on transient orientational and rheological behavior is studied.","Made available in DSpace on 2015-09-25T20:44:03Z (GMT). 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The mathematical model utilizes a discretized version of the Kratky-Porod wormlike (or persistent) chain as the building block, generalized to include flow. This discrete chain contains beads which interact through stretching and bending forces, and for polyelectrolytes a screened Debye-Huckel potential is also present. The Fokker-Planck equation describing this chain is converted to a Stochastic Differential Equation (SDE) from which the simulation algorithm for the NEBD is obtained. In steady, potential flows, the solution of the Fokker-Planck equation exists and is used in the generation of trial and acceptance moves in the CBMC scheme. Various conformational and rheological quantities are monitored, under both steady-state and transient conditions, with the primary independent variables being the $flexibility\\ parameter\\ \\beta ,$ the bending constant of the chain, and for polyelectrolytes, the salt concentration (parametrized through the Debye length) and the strength of interaction q, related to the degree of ionization of the chain. The model qualitatively describes many of the experimentally-observed effects in such systems, most notably birefringence overshoots, cessation effects, and various steady-state effects. The crucial advantage of the NEBD over an analytical treatment is its ability to incorporate (analytically intractable) effects such as hydrodynamic interactions and its (natural) ability to obtain transient information, a facet useful in comprehending the differing dynamics of molecules of varying rigidity. In addition, excluded volume effects on transient orientational and rheological behavior is studied.","Made available in DSpace on 2015-09-25T20:44:03Z (GMT). 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