119 Direct Measurements of Velocity Profiles in Flows of Polymer Solutions through a Microchannel
Details
Velocity profiles of polymer solutions were directly measured in a microhannel with rectangular cross sections. The test fluids are 0.2 wt% aqueous solutions of polyacrylamide whose molecular weights are 6×10^6 (fluid A) and 1.5×10^7 (fluid B). The microchannel was made of PDMS and it is mounted on the glass plate. The velocity profile in the depth direction is discussed as a function of a shear rate. Consequently, for the flows of fluid A, a symmetric profile is observed in the region between the PDMS wall and the glass wall in a low flow rate, but the velocity profile slightly becomes asymmetric with increasing the shear rate: the velocity near the PDMS wall is larger than that near the glass wall. For the flows of fluid B, a slightly asymmetric profile is observed even in the low flow rate and a largely asymmetric one in the large shear rate. The PDMS wall significantly affects the velocity profile in the flow of polymer solution through a PDMS microchannel.
