I'm interested in understanding how the Stribeck curve for two polymer brush coated surfaces might change if the refractive index of the liquid is tuned across a range of values including the value of the polymer brush.
At low normal forces does friction effectively just involve the VdW forces between the ends of the polymer chains? Presumably this force would vanish when the RI of solvent and brush match.
At high normal forces the brushes may interpenetrate but it should still be easier to slide them apart.
Any good classic tribology literature which explains this process in detail?
http://faculty.engineering.ucdavis.edu/kuhl/wp-content/uploads/sites/230/2013/02/62-Webber-Soft-Matter-ATRP.pdf
Thanks Salah, that's useful but I'm particularly interested in the effect of the refractive index of the liquid. Does anyone have information on studies where the liquid RI has been changed to match the polymer brush and compared with experiments where the two were different?
Dear Michael Smith, your question is a very profound. May be, the paper Klein J. , et al Reduction of frictional forces between solid surfaces bearing polymer brushes // Nature 1994, 370, P. 634– 636, containing some references, will be useful for you.
In my experience, the only thing that will a priori occur with the matching of refractive indices is that you will have a clear solution, dispersion, or composite. There is no necessary reason for mechanical interactions to behave in any particular fashion.
However, if you match 3D solubility parameters, then you will be directly and strongly influencing interactions.
But perhaps I'm missing something. Please elaborate.
If you match refractive indices the Van der Waals forces will be "switched off". My question is whether this is a significant effect compared to other forces.
Hi Michael,
I am very curious to know, how would the refractive index matching would switch off the Van der Waals force? Are there experimental evidences to suggest that?
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