Visualization of Wave Propagation and Fine Structure in Frictional Motion of Unconstrained Soft Microstructured Tapes

We performed friction experiments of soft microstructured tapes, which adhere to a smooth and rigid substrate without further constraint. One side of the tapes was pulled parallel to the substrate allowing the tapes to be stretched, thus changing the frictional dynamics. This essentially differs from previous friction tests of microstructured elastomers fixed onto a rigid support, allowing only for shear deformations of surface microstructures and the backing layer, but not for stretching of the entire sample. Three different types of microstructured tapes were tested and their frictional behavior compared to results from numerical simulations. In both experimental and numerical cases, visualization of wave propagation and fine structure in friction is obtained.