An Optimal Wet Friction Plate Inspired by Biological Surface Patterns

Recent progress of tree frog toe pads inspired wet adhesive materials

“…In 2018, Chang et al. prepared the tin bronze‐based bionic friction plate through laser processing technology [52]. In 2022, Shi et al.…”

“…For some samples with relatively large size, the flat‐flat contact mode can be used to measure macroscopic friction, normal adhesion and peeling force. In this mode, the friction (Figure 4b) and normal adhesion force (Figure 4c) can be measured by separating the artificial structured surface from the substrate in the transverse and normal directions respectively [13, 30, 32, 36, 44, 50, 52]. Specifically, Chen et al.…”

“…For instance, Ho et al fabricated the surface with a squared micropattern by etching silver using E-beam lithography, which was used as a template for subsequent replication [53,56]. In 2018, Chang et al prepared the tin bronze-based bionic friction plate through laser processing technology [52]. In 2022, Shi et al etched regular hexagonal microtexture on steel using a fibre laser marking machine mimicking the behaviour of tree frog toe pads in regulating body fluids [54].…”

“…Although these soft materials have an elastic modulus comparable to tree frog toe pads, it remains an intractable challenge to manufacture them at the nanoscale. In addition, tin bronze [52], silver [53], and AISI 4140 steel [54] have also been used to create adhesion surfaces that mimic tree frog toe pads. In general, the choice of materials for the construction of tree frog‐inspired adhesive surfaces is primarily based on their processability and is limited to several specific polymers.…”

“…In general, the preparation of adhesion surfaces inspired by tree frog toe pads can be divided into two categories, bottom‐up (e.g. photolithography [13, 29–35, 37, 38, 43–50, 55] and etching [52–54, 56]) and top‐down (e.g. 3D printing [51] and embossing [36–38, 49]) approaches.…”