Construction of hierarchical porous structure for stretchable multifunctional superhydrophobic films with high robustness
摘要
Herein, stretchable multifunctional superhydrophobic films with high robustness were fabricated using simple spraying approach. More specifically, a rigid polymer named poly(amide imide) (PAI) and an elastic polymer named thermoplastic polyurethane (TPU) were adopted to prepare stretchable substrate, which exhibited a tensile strength as high as 43 MPa and an elongation-at-break close to 240%. Encouragingly, the mechanical property of composite coating was nearly unchanged after spraying the modified silica (m-SiO2) and multiwall carbon nanotubes (MWCNTs) on the substrate surface. Hierarchical pore structure with micro/nano size was constructed, which endowed the PAI-TPU/MWCNTs/m-SiO2 composite films with excellent hydrophobicity, the water contact angle (CA) was as high as 154°, and the sliding angle (SA) was below 5°. More interestingly, intensive conductive network was formed, and thus the PAI-TPU/MWCNTs/m-SiO2 composite coating showed good electrothermal property, the temperature increased by 26 °C at a safe voltage of 36 V even it was elongated by 40%. Also, due to the good optical absorption ability of MWCNTs, the PAI-TPU/MWCNTs/m-SiO2 stretchable composite coating exhibited unique photothermal property, the equilibrium temperature increased from 16.5 to 123 °C when the intensity of optical power increased from 0.02 to 0.22 W/cm2, correspondingly. More importantly, the PAI-TPU/MWCNTs/m-SiO2 composite coating showed high robustness, the CA and SA were almost unchanged even if they were suffered from harsh treatments such as ultrasonic oscillation, sandpaper abrasion, hot-water jet impingement, UV irradiation, and immersion in strong acid or alkali solutions.
Graphical abstract