Time Dependent Lyotropic Chromonic Textures in Microfluidic Confinements
Nematic and columnar phases of lyotropic chromonic liquid crystals (LCLCs) have been long studied for their fundamental and applied prospects in material science and medical diagnostics. LCLC phases represent different self-assembled states of disc-shaped molecules, held together by noncovalent inte...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-12-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/11/1/35 |
| _version_ | 1797542999790452736 |
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| author | Anshul Sharma Irvine Lian Hao Ong Anupam Sengupta |
| author_facet | Anshul Sharma Irvine Lian Hao Ong Anupam Sengupta |
| author_sort | Anshul Sharma |
| collection | DOAJ |
| description | Nematic and columnar phases of lyotropic chromonic liquid crystals (LCLCs) have been long studied for their fundamental and applied prospects in material science and medical diagnostics. LCLC phases represent different self-assembled states of disc-shaped molecules, held together by noncovalent interactions that lead to highly sensitive concentration and temperature dependent properties. Yet, microscale insights into confined LCLCs, specifically in the context of confinement geometry and surface properties, are lacking. Here, we report the emergence of time dependent textures in static disodium cromoglycate (DSCG) solutions, confined in PDMS-based microfluidic devices. We use a combination of soft lithography, surface characterization, and polarized optical imaging to generate and analyze the confinement-induced LCLC textures and demonstrate that over time, herringbone and spherulite textures emerge due to spontaneous nematic (N) to columnar M-phase transition, propagating from the LCLC-PDMS interface into the LCLC bulk. By varying the confinement geometry, anchoring conditions, and the initial DSCG concentration, we can systematically tune the temporal dynamics of the N- to M-phase transition and textural behavior of the confined LCLC. Overall, the time taken to change from nematic to the characteristic M-phase textures decreased as the confinement aspect ratio (width/depth) increased. For a given aspect ratio, the transition to the M-phase was generally faster in degenerate planar confinements, relative to the transition in homeotropic confinements. Since the static molecular states register the initial conditions for LC flows, the time dependent textures reported here suggest that the surface and confinement effects—even under static conditions—could be central in understanding the flow behavior of LCLCs and the associated transport properties of this versatile material. |
| first_indexed | 2024-03-10T13:38:27Z |
| format | Article |
| id | doaj.art-1ef012e2a53e41bd9065e77bc8a61354 |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T13:38:27Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Crystals |
| spelling | doaj.art-1ef012e2a53e41bd9065e77bc8a613542023-11-21T03:13:07ZengMDPI AGCrystals2073-43522020-12-011113510.3390/cryst11010035Time Dependent Lyotropic Chromonic Textures in Microfluidic ConfinementsAnshul Sharma0Irvine Lian Hao Ong1Anupam Sengupta2Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162 A, Avenue de la Faïencerie, L-1511 Luxembourg, LuxembourgPhysics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162 A, Avenue de la Faïencerie, L-1511 Luxembourg, LuxembourgPhysics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162 A, Avenue de la Faïencerie, L-1511 Luxembourg, LuxembourgNematic and columnar phases of lyotropic chromonic liquid crystals (LCLCs) have been long studied for their fundamental and applied prospects in material science and medical diagnostics. LCLC phases represent different self-assembled states of disc-shaped molecules, held together by noncovalent interactions that lead to highly sensitive concentration and temperature dependent properties. Yet, microscale insights into confined LCLCs, specifically in the context of confinement geometry and surface properties, are lacking. Here, we report the emergence of time dependent textures in static disodium cromoglycate (DSCG) solutions, confined in PDMS-based microfluidic devices. We use a combination of soft lithography, surface characterization, and polarized optical imaging to generate and analyze the confinement-induced LCLC textures and demonstrate that over time, herringbone and spherulite textures emerge due to spontaneous nematic (N) to columnar M-phase transition, propagating from the LCLC-PDMS interface into the LCLC bulk. By varying the confinement geometry, anchoring conditions, and the initial DSCG concentration, we can systematically tune the temporal dynamics of the N- to M-phase transition and textural behavior of the confined LCLC. Overall, the time taken to change from nematic to the characteristic M-phase textures decreased as the confinement aspect ratio (width/depth) increased. For a given aspect ratio, the transition to the M-phase was generally faster in degenerate planar confinements, relative to the transition in homeotropic confinements. Since the static molecular states register the initial conditions for LC flows, the time dependent textures reported here suggest that the surface and confinement effects—even under static conditions—could be central in understanding the flow behavior of LCLCs and the associated transport properties of this versatile material.https://www.mdpi.com/2073-4352/11/1/35lyotropic chromonic liquid crystalsmicrofluidicssurface anchoringphase transitionherringbonespherulite |
| spellingShingle | Anshul Sharma Irvine Lian Hao Ong Anupam Sengupta Time Dependent Lyotropic Chromonic Textures in Microfluidic Confinements Crystals lyotropic chromonic liquid crystals microfluidics surface anchoring phase transition herringbone spherulite |
| title | Time Dependent Lyotropic Chromonic Textures in Microfluidic Confinements |
| title_full | Time Dependent Lyotropic Chromonic Textures in Microfluidic Confinements |
| title_fullStr | Time Dependent Lyotropic Chromonic Textures in Microfluidic Confinements |
| title_full_unstemmed | Time Dependent Lyotropic Chromonic Textures in Microfluidic Confinements |
| title_short | Time Dependent Lyotropic Chromonic Textures in Microfluidic Confinements |
| title_sort | time dependent lyotropic chromonic textures in microfluidic confinements |
| topic | lyotropic chromonic liquid crystals microfluidics surface anchoring phase transition herringbone spherulite |
| url | https://www.mdpi.com/2073-4352/11/1/35 |
| work_keys_str_mv | AT anshulsharma timedependentlyotropicchromonictexturesinmicrofluidicconfinements AT irvinelianhaoong timedependentlyotropicchromonictexturesinmicrofluidicconfinements AT anupamsengupta timedependentlyotropicchromonictexturesinmicrofluidicconfinements |