The formation of micro-protrusions atop a thermo-responsive shape memory polymer

We present an experimental investigation on a novel approach to produce micro-sized protrusive features atop a thermo-responsive shape memory polymer (SMP). This approach includes three steps, namely, indenting atop an SMP sample (using a Berkovich indenter in this study), polishing and then heating it for full shape recovery. Apart from ordinary samples, some SMP samples are pre-stretched in the in-plane direction or pre-compressed in the out-of-plane direction. The relationships between the height/shape of protrusion and the depth of indent are obtained for all indents in samples with/without pre-straining. Intrinsic relationships among the indentation depth, polishing depth and height/shape of protrusion are further revealed quantitatively in a dimensionless manner. The influence of pre-straining is discussed.