Superparamagnetic colloids in viscous fluids
Abstract The influence of a magnetic field on the aggregation process of superparamagnetic colloids has been well known on short time for a few decades. However, the influence of important parameters, such as viscosity of the liquid, has received only little attention. Moreover, the equilibrium stat...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2017-08-01
|
| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-017-07917-y |
| _version_ | 1819035885446889472 |
|---|---|
| author | A. Darras E. Opsomer N. Vandewalle G. Lumay |
| author_facet | A. Darras E. Opsomer N. Vandewalle G. Lumay |
| author_sort | A. Darras |
| collection | DOAJ |
| description | Abstract The influence of a magnetic field on the aggregation process of superparamagnetic colloids has been well known on short time for a few decades. However, the influence of important parameters, such as viscosity of the liquid, has received only little attention. Moreover, the equilibrium state reached after a long time is still challenging on some aspects. Indeed, recent experimental measurements show deviations from pure analytical models in extreme conditions. Furthermore, current simulations would require several years of computing time to reach equilibrium state under those conditions. In the present paper, we show how viscosity influences the characteristic time of the aggregation process, with experimental measurements in agreement with previous theories on transient behaviour. Afterwards, we performed numerical simulations on equivalent systems with lower viscosities. Below a critical value of viscosity, a transition to a new aggregation regime is observed and analysed. We noticed this result can be used to reduce the numerical simulation time from several orders of magnitude, without modifying the intrinsic physical behaviour of the particles. However, it also implies that, for high magnetic fields, granular gases could have a very different behaviour from colloidal liquids. |
| first_indexed | 2024-12-21T07:56:44Z |
| format | Article |
| id | doaj.art-94b4514e187f40f48f0adf31bc2e1e5a |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-21T07:56:44Z |
| publishDate | 2017-08-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-94b4514e187f40f48f0adf31bc2e1e5a2022-12-21T19:10:57ZengNature PortfolioScientific Reports2045-23222017-08-01711810.1038/s41598-017-07917-ySuperparamagnetic colloids in viscous fluidsA. Darras0E. Opsomer1N. Vandewalle2G. Lumay3GRASP, CESAM - Physics Department, University of LiègeGRASP, CESAM - Physics Department, University of LiègeGRASP, CESAM - Physics Department, University of LiègeGRASP, CESAM - Physics Department, University of LiègeAbstract The influence of a magnetic field on the aggregation process of superparamagnetic colloids has been well known on short time for a few decades. However, the influence of important parameters, such as viscosity of the liquid, has received only little attention. Moreover, the equilibrium state reached after a long time is still challenging on some aspects. Indeed, recent experimental measurements show deviations from pure analytical models in extreme conditions. Furthermore, current simulations would require several years of computing time to reach equilibrium state under those conditions. In the present paper, we show how viscosity influences the characteristic time of the aggregation process, with experimental measurements in agreement with previous theories on transient behaviour. Afterwards, we performed numerical simulations on equivalent systems with lower viscosities. Below a critical value of viscosity, a transition to a new aggregation regime is observed and analysed. We noticed this result can be used to reduce the numerical simulation time from several orders of magnitude, without modifying the intrinsic physical behaviour of the particles. However, it also implies that, for high magnetic fields, granular gases could have a very different behaviour from colloidal liquids.https://doi.org/10.1038/s41598-017-07917-y |
| spellingShingle | A. Darras E. Opsomer N. Vandewalle G. Lumay Superparamagnetic colloids in viscous fluids Scientific Reports |
| title | Superparamagnetic colloids in viscous fluids |
| title_full | Superparamagnetic colloids in viscous fluids |
| title_fullStr | Superparamagnetic colloids in viscous fluids |
| title_full_unstemmed | Superparamagnetic colloids in viscous fluids |
| title_short | Superparamagnetic colloids in viscous fluids |
| title_sort | superparamagnetic colloids in viscous fluids |
| url | https://doi.org/10.1038/s41598-017-07917-y |
| work_keys_str_mv | AT adarras superparamagneticcolloidsinviscousfluids AT eopsomer superparamagneticcolloidsinviscousfluids AT nvandewalle superparamagneticcolloidsinviscousfluids AT glumay superparamagneticcolloidsinviscousfluids |