| Based on a unique function biomimetic design of the natural materials, the developing of novel functional materials has been of universal importance in current academic research, which has also infiltrate to all aspects of natural sciences and engineering technology. As a fast-growing and renewable natural species, and one of the effective substitutes of wood, bamboo has many attractive properties, such as its high strength and toughness, perfect rigidity, good workability, and so forth. However, bamboo also suffers some defects, for example, bad dimensional stability caused by absorbing water, damage by insects, decay and mildew, discoloration by light, bad fire-resistance, and so on. The traditional methods of dipping or mechanical brush could solve the above problems, but it still exists inevitable problem, such as the uneven scatter on bamboo surface, bad interface combination with substrates, and so on. In addition, the traditional methods cannot endow the bamboo with unique and new functions. Therefore, based on traditional research results and in combination with nano manufacturing technology according to the bionic principle, the paper has designed the growth of various nanocrystals of ZnO, Ag, and CaCO3 based on bamboo surface. It provides a novelty method, which not only solves the intrinsic defects of bamboo, such as its easy deformation for moisture absorption, easy burning, easy photochromism and easy corrosion, but also renders superhydrophobicity, superoleophobicity, acid and alkali resistance, self-cleaning, electrical conductivity, degradation of organics and some other unique and new functions to the bamboo. The main results can be summarized as follows:(1) Wurtzite zinc oxide nanostructured materials with six different morphologies, namely, spheroidal nanoparticles, nanoparticles, nanoneedles, nanograsses, nanowall, nanoorchids, nanonetworks, and rose-like nanoflowers, were successfully grown on the surface of bamboo via a low-temperature hydrothermal method based on sol–gel-prepared ZnO seed layers. The morphology was strongly influenced by the hydrothermal temperature. The ZnO nanostructured materials grew at temperatures of 50 ?C and above and lost their structures at temperatures of 105 ?C and above. The appropriate concentration of OH- radicals was also vital for the nucleation and formation of the desired ZnO nanostructured materials. The specific zinc salt precursor solution used had no significant influence on the morphology of the nanostructure deposited on the bamboo surface. The appropriate conditions for ZnO perfectly growing on the bamboo surface are: 95 ?C hydrothermal temperature, 1 h reaction time, NaOH and ZnAc with molar ratio of 20: 1.(2) A novel recyclable photocatalyst was fabricated by hydrothermal method to immobilize the cross-linked ZnO nanowalls on the bamboo surface. Meanwhile, the cross-linked ZnO nanowalls modified bamboo presented a superior photocatalytic ability(similar to P25) and could be recycled at least 3 times with a photocatalytic efficiency up to 70%.(3) The large-scale rose-like ZnO nanoflowers were firstplanted on the bamboo surface by a hydrothermal method to increase the surface roughness, and then the surface was sub-sequently treated with a low surface-energy material of FAS-17. After FAS-17 film depo-sition to lower the surface energy, the resulting surface showed superamphiphobicity toward water, oil,and even certain corrosive liquids, including salt solutions and acidic and basic solutions at all pH values.The as-prepared superamphiphobic bamboo surface was durable and maintained its superhydrophobic property with water contact angles >150? when stored under ambient condition for two months orimmersed in a hydrochloric acid solution of pH 1 and a sodium hydroxide solution of pH 14 for 3 h at 50 ?C.(4) The FAS-17 treated bamboo substrate exhibited not only robust superhydrophobicity with a high contact angle of 161° but also stable repellency towards simulated acid rain(pH = 3) with a contact angle of 152?. Except for its robust superhydrophobicity, such a bamboo also presents superior water-resistant, UV-resistant, and fire-resistant properties.(5) A durable, robust superhydrophobic surface of bamboo timber with high conductivity has been successfully fabricated through a silver mirror reaction followed by hydrophobization. The compact coating of Ag NPs not only favored the construction of superhydrophobic surface but also imparted the metallic feature to the surface rendering the bamboo timber conductive. It was significant that the superhydrophobicity and conductivity were well maintained over a wide range of pH conditions and also in boiling solutions.(6) A novel continuous plate-like CaCO3 coating with hierarchical nano- and microstructures self-assembled on the surface of bamboo timber was prepared, as inspired from the biomineralization of nacre in seawater. With prenucleation treatment and immersion in simulated seawater at 50 oC for 24 h, a continuous plate-like CaCO3 coating with hierarchical nano- and microstructures was self-assembled on the surface of bamboo timber. After modification with FAS-17, the superhydrophilic CaCO3 coating transformed into a superhydrophobic one with the CA of 161o. The time of hydrothermal mineralization had a great effect on the morphologies of CaCO3 crystals, which was associated with the roughness of the coating. The obtained superhydrophobic coating showed not only super repellence towards water and common fluids, but also excellent durability under different temperatures. |
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