We present a facile chemical method for fabricating bioinspired
microadhesives with significant improved reversible adhesion strength.
Four kinds of polysiloxane with gradient varying phenyl contents were
synthesized and used to fabricate microadhesives. The chemical structures
and mechanical properties, as well as surface properties of the four
microadhesives, were confirmed and characterized by ATR-FTIR, DSC,
XPS, low-field NMR, tensile tests, and SEM, respectively. The macroadhesion
test results revealed that phenyl contents showed remarkable and positive
impacts on the macroadhesion performance of microadhesives. The pull-off
adhesion strength of microadhesives with 90% phenyl content (0.851
N/cm2) was nearly 300% higher than that of pure PDMS (0.309
N/cm2). The macroadhesion mechanism analysis demonstrates
that a larger bulk energy dissipation caused by massive π–π
interaction, as well as the hydrophobic interaction and van der Waals
forces at the interface synergistically resulted in a significant
enhancement of the adhesion performance. Our results demonstrate the
remarkable impact of chemical structures on the adhesion of microadhesives,
and it is conducive to the further improvement of adhesion properties
of bioinspired microadhesives.