NANOSLIP · Shear at the liquid/nano-fluid interface: Drag, slip, and friction.
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2021-09-01 → 2023-08-31
- EU contribution
- €212,934
- Participants
- 1
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
Shear at the liquid/nano-fluid interface: Drag, slip, and friction.
Aqueous Nanofluids are typically comprised of like-charged nanoparticles of silica suspended in water at high concentrations. These Nanofluids possess improved spreading properties over surfaces compared to standard liquids due to the structuring of the nanoparticles within, whereby the nanoparticles organize into layers, which are more tightly bound as they approach the surface in contact with the Nanofluid. The more stable configuration of the layers of nanoparticles nearest to the surface encourages the propagation of a nanofilm of the Nanofluid over the surface, containing 2-3 layers of nanoparticles. The Nanofluid nanofilm is capable of displacing immiscible liquids in contact with surfaces and has been a subject of research for its use in Enhanced Oil Recovery (EOC), and soil remediation. Existing methods to study the Nanofluid nanofilm confined between a surface and oil have been limited to indirect approaches, such as white light interferometry, which only enable the visualisation of the Nanofluid nanofilm, alongside determining its thickness. The objective of this project was to perform the first direct measurements of the Nanofluid nanofilm, using atomic force microscopy (AFM) at the nanofilm/oil interface. Here, the thickness of the Nanofluid nanofilm could be directly determined, and then further probed in response to shear forces which are relevant in its use in EOC and soil remediation. Through the development of this experimental platform via AFM, further investigations could be performed, enabling a deeper understanding of Nanofluids spreading properties. This project has successfully measured the presence and thickness of the Nanofluid nanofilm confined between a mica surface and fluorinated oil for the first time via AFM. The thickness of the nanofilm was larger than expected, upwards to a factor of 10, which is suspected to be due to the specific experimental set up required to achieve this feat. While there is further development required to reconcile the unexpected nanofilm thickness, this project has successfully established an experimental platform via AFM to directly study the Nanofluid nanofilm at the nanofilm/oil interface.
Data: CORDIS, © European Union
Project objective
Nano-fluids (NFs) are colloidal suspensions of nano-species (NS) that are electrostatically or sterically stabilised, with aqueous NFs including nanoparticle suspensions (silica, sulfate latex), polyelectrolytes, and self-assembled structures including micelles, polymersomes and liposomes. NFs are used in many industrial/practical applications, including controlling colloidal assembly of larger nano- and micro-sized species in solution, improving heat flux in industrial processes and solar collectors, reducing friction in oils and greases, enhanced drug delivery and as MRI contrast agents. A unique property of NFs is their modified spreading/flowing behaviour on surfaces due to internal structuring forces between NS, which enables NFs to displace immiscible liquids from surfaces. This enhanced spreading/flowing behaviour has demonstrated enhanced oil recovery compared to standard brine solutions and has been rationalised as due to a reduction of friction at the NF/oil interface. Aside from the presence of a stable nano-thin NF film beneath oil during displacement being confirmed optically via interferometry, there are no experiments to date that have probed this interface directly, and thus the friction/drag reducing properties at the liquid/NF interface remain unexplored. The scientific goal of this proposed project is to gain a better understanding of liquid flow at a liquid/NF interface, in particular, how the presence of an ultrathin film of NFs – with enhanced spreading and internal properties – can reduce drag in response to shear between an immiscible liquid and a solid surface via colloidal probe atomic force microscopy. Understanding this phenomenon will fill the current knowledge gap in the fields of NFs and boundary slip and will have direct impact on current applications of NFs in oil recovery, lubrication, heat dissipation, soil remediation, nanomedicine, and colloidal stability.
Original text from CORDIS.
Participants
- UNIVERSITY OF BRISTOL · BRISTOLCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union