Figure 1. (A) CAs, SAs,
and CA hysteresis of various test liquids on the coatings. The inset
image demonstrates the sliding behaviour of hexadecane. (B)
Anti-adhesion performance against oil-based ink exhibited by the
coatings on various substrates. (C) The tapes could be readily removed
from the coating surfaces, while were damaged and left residuals for the
uncoated substrates. (D,E) The tensile strength and shear strength
between the adhesives and the coating as well as various uncoated
substrates.
To evaluate the anti-adhesion properties of the coating, liquids with
various surface tensions such as water, diiodomethane, hexadecane, and
ethanol (72.8, 50.8, 27.5, and 22.1 mN/m, respectively at 20 °C), as
well as oils with different viscosities such as cooking oil, pump oil,
and crude oil (~80, 200, and 300 cP, respectively at 20
°C) were used for the CAs, SAs, and CA hysteresis measurements. As shown
in Fig. 1A, the coating displayed low SAs and CA hysteresis toward all
of these test liquids. These simple and complex liquids could be
repelled and readily slid off the tilted coating surfaces without
leaving any residues. When the HO-PDMS-OH was covalently linked into the
network to generate a lubricating segment, it no longer exhibited a
liquid state at the macroscopic level. Meanwhile, the glass transition
temperature of the coating as determined via differential scanning
calorimetry (DSC) experiments was ~ -35 °C, implying
that the polymer chains with abundant lubricating segments could be
stretched and rotated readily at room temperature and provide the
desired liquid-like interfacial anti-adhesion behavior (Fig. S5).
Moreover, the oil-based ink traces of Sharpie markers readily contracted
on a diverse range of coated substrates (Fig. 1B), including hard,
thermosensitive, and flexible materials such as glass, metal, wood,
paper, and polyethylene terephthalate (PET). The shrunken ink traces
could be readily wiped away with dry tissues. In contrast, it was
difficult to remove the ink from the uncoated regions of the substrates.
Noteworthy, the coating was found to exhibit low adhesion against
viscoelastic and sticky adhesives. The adhesive tapes could be readily
removed from the coating surfaces, and thus ensure the cleanability of
substrates as well as the recyclability of adhesives and advertisement
papers (Fig. 1C). Pieces of 3M Scotch® double-sided mounting tape and
adhesive tape were applied onto the coating and various uncoated
substrates to evaluate the tensile strength and shear strength (Fig
S6).21 As shown in Fig. 1D and E, these tapes could be
removed from the coatings with the tensile strength of
~42 kPa and negligible shear strength, and the values
were far lower than those estimated for the uncoated substrates.