Thermally-induced all-damage-healable superhydrophobic surface with photocatalytic performance from hierarchical BiOCl

Abstract

Preparation of superhydrophobic surfaces capable of recovering both the surface chemistry and hierarchical structure is still a challenge. In this work, all-damage-healable superhydrophobic surface was fabricated by assembly of superhydrophobic and hierarchical BiOCl on lignocellulosic substrates. Fibers having thermally responsive behavior, the main component of lignocellulosic materials, act as the underlying movable substrates. By a simple heating treatment, fibers can convey the undamaged neighbored superhydrophobic coating to the damaged area. In 2 this way, the loss of superhydrophobicity caused by rigorous mechanical destructions, even deep cuts of one hundred of micrometers wide, can be restored, mimicking the self-healing mechanism of human skin. Superior self-healing ability in surface chemistry was also confirmed. Meanwhile, the as-prepared superhydrophobic surfaces demonstrated reliable photocatalytic ability, a useful property for resisting organic contaminations. Interestingly, it was found that the photocatalytic activity can be enhanced by tuning the surface wettability. This work reported the first use of substrate material's inherently thermally responsive property to demonstrate self-healing superhydrophobic surface with photoctalyticity, which not only promotes the application of superhydrophobic materials in complex environment, but also opens up a new perspective in designing durable superhydrophobic materials.

Trends in Chemical Wood Surface Improvements and Modifications: A Review of the Last Five Years

“…The hydrophobization of the micro-/nanoscale architecture could also be achieved by replacing the resins with low surface free energy components [113][114][115][116][117][118][119][120][121][122][123][124][125][126][127][128][129][130][131][132]. As a general rule, these coatings showed superhydrophobicity (contact angle > 150 • , roll-off angle < 10 • ), high resistance to mechanical wear (abrasion, cutting, etc.…”

“…These methods were adopted in different publications presented in this review to improve the characteristics of the wood surfaces, such as mechanical properties, thermal stability, dimensional stability and resistance to biodegradation. They were particularly prevalent to cast inorganic [115][116][117][118]121,122,132,147,148,150,151,153,154,[156][157][158][160][161][162][163][164][165][166]170,172] and organicinorganic composite [87,88,103,[105][106][107][109][110][111][112][113][114][125][126][127][129][130][131][134][135][136][137]…”

“…A solution to the generally poor durability of superhydrophobic coating may be found in self-healing, as the restoration of the micro-/nanoscale architecture following mechanical damage can revert the loss of hydrophobicity [21]. Accordingly, different workers developed superhydrophobic coatings with self-healing capacities over the last five years, although some of them require a thermal stimulus for the actual healing to take place [110,116]. Conversely, a self-healing coating prepared by Wang et al with SiO 2 and perfluorooctyltriethoxysilane could not only self-repair upon taking damage without needing any external stimulus, but its self-healing ability could be replenished by spraying a coating solution [133].…”

All-organic fluorine-free superhydrophobic bulk material with mechanochemical robustness and photocatalytic functionality

“…However, the as-prepared bulk composite features the ability of regeneration of superhydrophobicity even after oily dirt contamination due to its photocatalytic self-cleaning functionality. [42,43] To investigate the photocatalytic self-cleaning properties of the obtained bulk material, we contaminated the sample with oleic acid as a model of oily dirt. The regeneration of superhydrophobicity was examined by measuring the changes in ƟCA and ƟSA of the contaminated bulk composite before and after visible light irradiation.…”

Development of highly durable superhydrophobic and UV-resistant wood by E-beam radiation curing

“…Through investigation, it has been realized that amelioration on wooden substrates can explicitly contain two aspects: (i) the existence of an interface binding force between the superhydrophobic layer and wood substrate and (ii) the strength of the micro/nano-roughness structure itself ). Based on these perceptions, considerable design strategies have been developed to construct robust superhydrophobic surfaces, such as using pretreated wood surfaces with stable hydrophobic material, creating a self-healing (light irradiation, high temperature) superhydrophobic coating and enhancing the adhesion between the superhydrophobic layer and wooden substrates (increasing the adhesive layer) (Jia et al 2019;Tu et al 2018;Yang et al 2021). Although these strategies have been proven to improve the abrasion resistance and durability of superhydrophobic wood surfaces, the cumbersome procedure, high stimulus requirements, and the smooth adhesive layer surface exposed after multiple abrasions, make them undesirable for practical applications.…”