Adsorption Free Energy of Cellulose Nanocrystal on Water–Oil Interface
To investigate the amphiphilicity of cellulose, a series of molecular dynamics simulations were performed with a cellulose nanocrystal and a water–octane interfacial system. Assuming that the axis of cellulose is parallel to the water–octane interface, the freedoms of motion of the nanocrystal were...
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MDPI AG
2022-04-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/12/8/1321 |
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| author | Kenya Ito Mitsuhiro Matsumoto |
| author_facet | Kenya Ito Mitsuhiro Matsumoto |
| author_sort | Kenya Ito |
| collection | DOAJ |
| description | To investigate the amphiphilicity of cellulose, a series of molecular dynamics simulations were performed with a cellulose nanocrystal and a water–octane interfacial system. Assuming that the axis of cellulose is parallel to the water–octane interface, the freedoms of motion of the nanocrystal were restricted to two, the distance from the interface and the orientation around the axis. The mean force and the mean torque on the nanocrystal were evaluated with sufficiently long simulation at each crystal configuration, and their numerical integration gave a smooth free energy surface as the potential of mean force. The cellulose sample used here was found to be much more hydrophilic than oleophilic with the free energy difference <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>Δ</mo><msub><mi>F</mi><mrow><mi mathvariant="normal">w</mi><mo>→</mo><mi mathvariant="normal">o</mi></mrow></msub><mo>=</mo><mn>318</mn></mrow></semantics></math></inline-formula> kcal/mol. Three adsorption states with local minimum of adsorption free energy are distinguished in the free energy surface—the direct contact type which is similar to previously reported one, the hydrophilic-surface/water/octane type where a thin water layer is sandwiched between the surface and the octane phase, and the oleophilic/water/octane type where a thin water layer also exists. Water molecules in these water layers contribute to stabilize the adsorption states by taking a special orientational order and slow self-diffusion. |
| first_indexed | 2024-03-09T10:31:02Z |
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| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T10:31:02Z |
| publishDate | 2022-04-01 |
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| spelling | doaj.art-4f720dd706f14e8d9da38483bcd777b82023-12-01T21:16:52ZengMDPI AGNanomaterials2079-49912022-04-01128132110.3390/nano12081321Adsorption Free Energy of Cellulose Nanocrystal on Water–Oil InterfaceKenya Ito0Mitsuhiro Matsumoto1Graduate School of Engineering, Kyoto University, Kyoto 615-8540, JapanGraduate School of Engineering, Kyoto University, Kyoto 615-8540, JapanTo investigate the amphiphilicity of cellulose, a series of molecular dynamics simulations were performed with a cellulose nanocrystal and a water–octane interfacial system. Assuming that the axis of cellulose is parallel to the water–octane interface, the freedoms of motion of the nanocrystal were restricted to two, the distance from the interface and the orientation around the axis. The mean force and the mean torque on the nanocrystal were evaluated with sufficiently long simulation at each crystal configuration, and their numerical integration gave a smooth free energy surface as the potential of mean force. The cellulose sample used here was found to be much more hydrophilic than oleophilic with the free energy difference <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>Δ</mo><msub><mi>F</mi><mrow><mi mathvariant="normal">w</mi><mo>→</mo><mi mathvariant="normal">o</mi></mrow></msub><mo>=</mo><mn>318</mn></mrow></semantics></math></inline-formula> kcal/mol. Three adsorption states with local minimum of adsorption free energy are distinguished in the free energy surface—the direct contact type which is similar to previously reported one, the hydrophilic-surface/water/octane type where a thin water layer is sandwiched between the surface and the octane phase, and the oleophilic/water/octane type where a thin water layer also exists. Water molecules in these water layers contribute to stabilize the adsorption states by taking a special orientational order and slow self-diffusion.https://www.mdpi.com/2079-4991/12/8/1321cellulose nanocrystalamphiphilicityadsorption free energypotential of mean forceconfined liquidmolecular dynamics simulation |
| spellingShingle | Kenya Ito Mitsuhiro Matsumoto Adsorption Free Energy of Cellulose Nanocrystal on Water–Oil Interface Nanomaterials cellulose nanocrystal amphiphilicity adsorption free energy potential of mean force confined liquid molecular dynamics simulation |
| title | Adsorption Free Energy of Cellulose Nanocrystal on Water–Oil Interface |
| title_full | Adsorption Free Energy of Cellulose Nanocrystal on Water–Oil Interface |
| title_fullStr | Adsorption Free Energy of Cellulose Nanocrystal on Water–Oil Interface |
| title_full_unstemmed | Adsorption Free Energy of Cellulose Nanocrystal on Water–Oil Interface |
| title_short | Adsorption Free Energy of Cellulose Nanocrystal on Water–Oil Interface |
| title_sort | adsorption free energy of cellulose nanocrystal on water oil interface |
| topic | cellulose nanocrystal amphiphilicity adsorption free energy potential of mean force confined liquid molecular dynamics simulation |
| url | https://www.mdpi.com/2079-4991/12/8/1321 |
| work_keys_str_mv | AT kenyaito adsorptionfreeenergyofcellulosenanocrystalonwateroilinterface AT mitsuhiromatsumoto adsorptionfreeenergyofcellulosenanocrystalonwateroilinterface |