{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/18892"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/18892","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The effect of shear flow on the Isotropic-Nematic transition in liquid crystals","abstract":"In this thesis I will discuss the effects of shear flow on the Isotropic-Nematic phase transition in liquid crystals. Shear flow has dramatic orienting effects on the rod-like constituents of nematic liquid crystals, with the general effects of (1) inducing order in the high-temperature isotropic phase, and (2) dictating a direction of alignment for the low-temperature nematic phase. Shear flow also imposes a biaxial symmetry on both the high and low temperature phases, thereby changing the nature of the symmetry-breaking at the transition. We develop coupled deterministic dynamical equations for the 5-component nematic order parameter and the fluid velocity, which may be considered generalizations of the Leslie-Ericksen and Navier-Stokes equations, respectively. We examine the stable stationary solutions to these equations to determine the nature of the nonequilibrium phases, and discuss the analogies and differences between this system and equilibrium systems. From homogeneous solutions we obtain a state diagram analogous to that of a Van der Waals fluid, including a two-state region and a discontinuous transition which terminates at a critical point. To resolve the question of the analog of the Maxwell construction to distinguish locally stable states, we construct stable inhomogeneous interfacial states. From an analysis of these states we determine a coexistence line and find exponents characterizing the shape of the coexistence curve and the interface thickness as the critical point is approached. We find mean-field critical behavior, and comment on the possibility of the analogs of spinodal decomposition and nucleation. Finally, we develop a formalism for describing light scattering from biaxial steady state, and investigate the Gaussian level fluctuations about these states. In the vicinity of the critical point we find singular behavior analogous to critical opalescence of a simple fluid at its critical point. We also find anisotropic correlations at the critical point which reflect the manner in which shear flow suppresses fluctuations, as was found by Onuki and Kawasaki in their studies of a binary fluid under shear flow. We finish by commenting on the application of these ideas to lyotropic systems, and combining flow and magnetic field effects in the same system.","abstract_html":"In this thesis I will discuss the effects of shear flow on the Isotropic-Nematic phase transition in liquid crystals. Shear flow has dramatic orienting effects on the rod-like constituents of nematic liquid crystals, with the general effects of (1) inducing order in the high-temperature isotropic phase, and (2) dictating a direction of alignment for the low-temperature nematic phase. Shear flow also imposes a biaxial symmetry on both the high and low temperature phases, thereby changing the nature of the symmetry-breaking at the transition. We develop coupled deterministic dynamical equations for the 5-component nematic order parameter and the fluid velocity, which may be considered generalizations of the Leslie-Ericksen and Navier-Stokes equations, respectively. We examine the stable stationary solutions to these equations to determine the nature of the nonequilibrium phases, and discuss the analogies and differences between this system and equilibrium systems. From homogeneous solutions we obtain a state diagram analogous to that of a Van der Waals fluid, including a two-state region and a discontinuous transition which terminates at a critical point. To resolve the question of the analog of the Maxwell construction to distinguish locally stable states, we construct stable inhomogeneous interfacial states. From an analysis of these states we determine a coexistence line and find exponents characterizing the shape of the coexistence curve and the interface thickness as the critical point is approached. We find mean-field critical behavior, and comment on the possibility of the analogs of spinodal decomposition and nucleation. Finally, we develop a formalism for describing light scattering from biaxial steady state, and investigate the Gaussian level fluctuations about these states. In the vicinity of the critical point we find singular behavior analogous to critical opalescence of a simple fluid at its critical point. We also find anisotropic correlations at the critical point which reflect the manner in which shear flow suppresses fluctuations, as was found by Onuki and Kawasaki in their studies of a binary fluid under shear flow. We finish by commenting on the application of these ideas to lyotropic systems, and combining flow and magnetic field effects in the same system.","abstract_has_math":false,"creators":["Olmsted, Peter David"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Goldbart, Paul M."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-04-27T15:57:23Z","date_published":"2011-04-27T15:57:23Z","updated_at":"2026-07-22T22:25:11Z","subjects":["shear flow","isotropic-nematic transition","liquid crytals"],"languages":["en"],"rights":["1991 Peter David Olmsted"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["3471801"],"render_values":[{"text":"3471801","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/18892","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Goldbart, Paul M."]},{"key":"dc:creator","label":"Author","values":["Olmsted, Peter David"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-04-27T15:57:23Z","10000-01-01","1991"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["shear flow","isotropic-nematic transition","liquid crytals"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1991 Peter David Olmsted"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["3471801","http://hdl.handle.net/2142/18892"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In this thesis I will discuss the effects of shear flow on the Isotropic-Nematic phase transition in liquid crystals. Shear flow has dramatic orienting effects on the rod-like constituents of nematic liquid crystals, with the general effects of (1) inducing order in the high-temperature isotropic phase, and (2) dictating a direction of alignment for the low-temperature nematic phase. Shear flow also imposes a biaxial symmetry on both the high and low temperature phases, thereby changing the nature of the symmetry-breaking at the transition. We develop coupled deterministic dynamical equations for the 5-component nematic order parameter and the fluid velocity, which may be considered generalizations of the Leslie-Ericksen and Navier-Stokes equations, respectively. We examine the stable stationary solutions to these equations to determine the nature of the nonequilibrium phases, and discuss the analogies and differences between this system and equilibrium systems. From homogeneous solutions we obtain a state diagram analogous to that of a Van der Waals fluid, including a two-state region and a discontinuous transition which terminates at a critical point. To resolve the question of the analog of the Maxwell construction to distinguish locally stable states, we construct stable inhomogeneous interfacial states. From an analysis of these states we determine a coexistence line and find exponents characterizing the shape of the coexistence curve and the interface thickness as the critical point is approached. We find mean-field critical behavior, and comment on the possibility of the analogs of spinodal decomposition and nucleation. Finally, we develop a formalism for describing light scattering from biaxial steady state, and investigate the Gaussian level fluctuations about these states. In the vicinity of the critical point we find singular behavior analogous to critical opalescence of a simple fluid at its critical point. We also find anisotropic correlations at the critical point which reflect the manner in which shear flow suppresses fluctuations, as was found by Onuki and Kawasaki in their studies of a binary fluid under shear flow. We finish by commenting on the application of these ideas to lyotropic systems, and combining flow and magnetic field effects in the same system.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-04-27T15:57:23Z No. of bitstreams: 1 1991_olmsted.pdf: 9402542 bytes, checksum: c53d57f741d983d9f192ea3185d677b6 (MD5)","Made available in DSpace on 2011-04-27T15:57:23Z (GMT). No. of bitstreams: 1 1991_olmsted.pdf: 9402542 bytes, checksum: c53d57f741d983d9f192ea3185d677b6 (MD5) Previous issue date: 1991","Restriction data tranferred 2014-07-01T11:12:18-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-04-27T15:57:23Z Item is restricted indefinitely.","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["The effect of shear flow on the Isotropic-Nematic transition in liquid crystals"]}]}],"canonical_facts":{"dc:contributor":["Goldbart, Paul M."],"dc:creator":["Olmsted, Peter David"],"dc:date":["2011-04-27T15:57:23Z","10000-01-01","1991"],"dc:description":["In this thesis I will discuss the effects of shear flow on the Isotropic-Nematic phase transition in liquid crystals. Shear flow has dramatic orienting effects on the rod-like constituents of nematic liquid crystals, with the general effects of (1) inducing order in the high-temperature isotropic phase, and (2) dictating a direction of alignment for the low-temperature nematic phase. Shear flow also imposes a biaxial symmetry on both the high and low temperature phases, thereby changing the nature of the symmetry-breaking at the transition. We develop coupled deterministic dynamical equations for the 5-component nematic order parameter and the fluid velocity, which may be considered generalizations of the Leslie-Ericksen and Navier-Stokes equations, respectively. We examine the stable stationary solutions to these equations to determine the nature of the nonequilibrium phases, and discuss the analogies and differences between this system and equilibrium systems. From homogeneous solutions we obtain a state diagram analogous to that of a Van der Waals fluid, including a two-state region and a discontinuous transition which terminates at a critical point. To resolve the question of the analog of the Maxwell construction to distinguish locally stable states, we construct stable inhomogeneous interfacial states. From an analysis of these states we determine a coexistence line and find exponents characterizing the shape of the coexistence curve and the interface thickness as the critical point is approached. We find mean-field critical behavior, and comment on the possibility of the analogs of spinodal decomposition and nucleation. Finally, we develop a formalism for describing light scattering from biaxial steady state, and investigate the Gaussian level fluctuations about these states. In the vicinity of the critical point we find singular behavior analogous to critical opalescence of a simple fluid at its critical point. We also find anisotropic correlations at the critical point which reflect the manner in which shear flow suppresses fluctuations, as was found by Onuki and Kawasaki in their studies of a binary fluid under shear flow. We finish by commenting on the application of these ideas to lyotropic systems, and combining flow and magnetic field effects in the same system.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-04-27T15:57:23Z No. of bitstreams: 1 1991_olmsted.pdf: 9402542 bytes, checksum: c53d57f741d983d9f192ea3185d677b6 (MD5)","Made available in DSpace on 2011-04-27T15:57:23Z (GMT). No. of bitstreams: 1 1991_olmsted.pdf: 9402542 bytes, checksum: c53d57f741d983d9f192ea3185d677b6 (MD5) Previous issue date: 1991","Restriction data tranferred 2014-07-01T11:12:18-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-04-27T15:57:23Z Item is restricted indefinitely.","Thesis","U of I Only"],"dc:identifier":["3471801","http://hdl.handle.net/2142/18892"],"dc:language":["en"],"dc:rights":["1991 Peter David Olmsted"],"dc:subject":["shear flow","isotropic-nematic transition","liquid crytals"],"dc:title":["The effect of shear flow on the Isotropic-Nematic transition in liquid crystals"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:11Z"}