am1c03272_si_003.mp4 (3.57 MB)
Ultrafast Flame-Induced Pyrolysis of Poly(dimethylsiloxane) Foam Materials toward Exceptional Superhydrophobic Surfaces and Reliable Mechanical Robustness
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posted on 2021-05-06, 14:35 authored by Guo-Dong Zhang, Zhi-Hao Wu, Qiao-Qi Xia, Yong-Xiang Qu, Hong-Tao Pan, Wan-Jun Hu, Li Zhao, Kun Cao, Er-Yu Chen, Zhou Yuan, Jie-Feng Gao, Yiu-Wing Mai, Long-Cheng TangSuperhydrophobic surfaces are imperative
in flexible polymer foams
for diverse applications; however, traditional surface coatings on
soft skeletons are often fragile and can hardly endure severe deformation,
making them unstable and highly susceptible to cyclic loadings. Therefore,
it remains a great challenge to balance their mutual exclusiveness
of mechanical robustness and surface water repellency on flexible
substrates. Herein, we describe how robust superhydrophobic surfaces
on soft poly(dimethylsiloxane) (PDMS) foams can be achieved using
an extremely simple, ultrafast, and environmentally friendly flame
scanning strategy. The ultrafast flame treatment (1–3 s) of
PDMS foams produces microwavy and nanosilica rough structures bonded
on the soft skeletons, forming robust superhydrophobic surfaces (i.e.,
water contact angles (WCAs) > 155° and water sliding angles
(WSAs)
< 5°). The rough surface can be effectively tailored by simply
altering the flame scanning speed (2.5–15.0 cm/s) to adjust
the thermal pyrolysis of the PDMS molecules. The optimized surfaces
display reliable mechanical robustness and excellent water repellency
even after 100 cycles of compression of 60% strain, stretching of
100% strain, and bending of 90° and hostile environmental conditions
(including acid/salt/alkali conditions, high/low temperatures, UV
aging, and harsh cyclic abrasion). Moreover, such flame-induced superhydrophobic
surfaces are easily peeled off from ice and can be healable even after
severe abrasion cycles. Clearly, the flame scanning strategy provides
a facile and versatile approach for fabricating mechanically robust
and surface superhydrophobic PDMS foam materials for applications
in complex conditions.