Hydrogen Bond Dynamics and Phase Transitions of Water inside Carbon Nanotubes
Water dynamics in nanochannels are altered by confinement, particularly in small carbon nanotubes (CNTs). However, the mechanisms behind these effects remain unclear. To address these issues, we carried out extensive molecular dynamics (MD) simulations to investigate the structure and dynamics of wa...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-01-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/13/2/284 |
| _version_ | 1827622802287493120 |
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| author | Amit Srivastava Jamal Hassan Dirar Homouz |
| author_facet | Amit Srivastava Jamal Hassan Dirar Homouz |
| author_sort | Amit Srivastava |
| collection | DOAJ |
| description | Water dynamics in nanochannels are altered by confinement, particularly in small carbon nanotubes (CNTs). However, the mechanisms behind these effects remain unclear. To address these issues, we carried out extensive molecular dynamics (MD) simulations to investigate the structure and dynamics of water inside CNTs of different sizes (length of 20 nm and diameters vary from 0.8 nm to 5.0 nm) at different temperatures (from 200 K to 420 K). The radial density profile of water inside CNTs shows a single peak near the CNT walls for small nanotubes. For CNTs with larger sizes, water molecules are arranged into coaxial tubular sheets, the number of which increases with the CNT size. Subdiffusive behavior is observed for ultranarrow CNTs with diameters of 0.8 nm and 1 nm. As the size of CNTs increases, Fickian diffusion becomes evident. The hydrogen bond correlation function of water inside CNT decays slower than in bulk water, and the decay rate decreases as we increase the diameter of the CNTs. In large CNTs, the hydrogen bond lifetime of the innermost layer is shorter than the other layers and depends on temperature. Additional analysis of our results reveals that water molecules along the CNT axis show a non-Arrhenius to Arrhenius diffusion crossover. In general, the diffusion transition temperature is higher than that of bulk water, but it depends on the size of the CNT. |
| first_indexed | 2024-03-09T11:33:46Z |
| format | Article |
| id | doaj.art-a9532d4c8c544e7fa298850dff181fc6 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T11:33:46Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-a9532d4c8c544e7fa298850dff181fc62023-11-30T23:47:43ZengMDPI AGNanomaterials2079-49912023-01-0113228410.3390/nano13020284Hydrogen Bond Dynamics and Phase Transitions of Water inside Carbon NanotubesAmit Srivastava0Jamal Hassan1Dirar Homouz2Department of Physics, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab EmiratesDepartment of Physics, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab EmiratesDepartment of Physics, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab EmiratesWater dynamics in nanochannels are altered by confinement, particularly in small carbon nanotubes (CNTs). However, the mechanisms behind these effects remain unclear. To address these issues, we carried out extensive molecular dynamics (MD) simulations to investigate the structure and dynamics of water inside CNTs of different sizes (length of 20 nm and diameters vary from 0.8 nm to 5.0 nm) at different temperatures (from 200 K to 420 K). The radial density profile of water inside CNTs shows a single peak near the CNT walls for small nanotubes. For CNTs with larger sizes, water molecules are arranged into coaxial tubular sheets, the number of which increases with the CNT size. Subdiffusive behavior is observed for ultranarrow CNTs with diameters of 0.8 nm and 1 nm. As the size of CNTs increases, Fickian diffusion becomes evident. The hydrogen bond correlation function of water inside CNT decays slower than in bulk water, and the decay rate decreases as we increase the diameter of the CNTs. In large CNTs, the hydrogen bond lifetime of the innermost layer is shorter than the other layers and depends on temperature. Additional analysis of our results reveals that water molecules along the CNT axis show a non-Arrhenius to Arrhenius diffusion crossover. In general, the diffusion transition temperature is higher than that of bulk water, but it depends on the size of the CNT.https://www.mdpi.com/2079-4991/13/2/284carbon nanotubeswaterhydrogen bond dynamicsmolecular dynamics simulation |
| spellingShingle | Amit Srivastava Jamal Hassan Dirar Homouz Hydrogen Bond Dynamics and Phase Transitions of Water inside Carbon Nanotubes Nanomaterials carbon nanotubes water hydrogen bond dynamics molecular dynamics simulation |
| title | Hydrogen Bond Dynamics and Phase Transitions of Water inside Carbon Nanotubes |
| title_full | Hydrogen Bond Dynamics and Phase Transitions of Water inside Carbon Nanotubes |
| title_fullStr | Hydrogen Bond Dynamics and Phase Transitions of Water inside Carbon Nanotubes |
| title_full_unstemmed | Hydrogen Bond Dynamics and Phase Transitions of Water inside Carbon Nanotubes |
| title_short | Hydrogen Bond Dynamics and Phase Transitions of Water inside Carbon Nanotubes |
| title_sort | hydrogen bond dynamics and phase transitions of water inside carbon nanotubes |
| topic | carbon nanotubes water hydrogen bond dynamics molecular dynamics simulation |
| url | https://www.mdpi.com/2079-4991/13/2/284 |
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