Solid surface polymer melts affective interactions

There are some uncontrollable factors affecting the determination of critical surface tension—e.g., the type of liquids used, the type of interaction between a liquid and a solid, the homogeneity of surface, etc. An ideal correlation should be made from the direct surface tension, if available, of a polymer melt. 

The above remarks point out the interest of direct measurements of the boundary condition (BC) for the fluid velocity at a fluid solid interface. To obtain reliable information on the flow velocity BC of a fluid, with a spatial resolution from the wall down to molecular sizes, is a particularly difficult challenge. Conventional velocimetry techniques (even laser velocimetry) are far from such a resolution. We have developed a near field laser velocimetry technique which allows to increase significantly the spatial resolution compared to more conventional velocimetry techniques. This technique has been used to characterize the friction between a polymer melt and a solid wall and to understand how surface modifications weakening the interactions between a solid and a given simple fluid affected the fluid -- wall friction. 

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