| Superhydrophobic materials have become research hot spots because of the“louts-like”properties.Currently,superhydrophobic coatings have been applied in the fields of anti-corrosion of metals,self-cleaning of exterior glass,oil-water separation of marine oil spill,active anti icing,non-destructive water collection and drag reduction.However,most of the preparation methods of superhydrophobic coatings involve complex process and expensive instruments,so it is difficult for superhydrophobic materials to achieve large-scale application,and expensive fluorine-containing compounds are also not conducive to environmental protection.Besides,superhydrophobic coatings with only one function are difficult to meet the requirements in emerging fields.Based on these facts,simple spraying methods were conducted to prepare copper and silver nanoparticles on different fabrics to fabricate functional coatings with superhydrophobicity and conductivity.Applications of the fabrics in the rising fields such as wettability control,electromagnetic shielding and electrothermal ice melting were studied.The main research contents and results are listed as follows:(1)Non-woven cotton fabrics were selected as the substrates,the copper coated fabrics were fabricated by the spraying method,the superhydrophobicity was obtained after vacuum drying without any surface modifier.SEM results showed that accumulation of Cu NPs constituted coral-like rough micro-nano structures,forming a stable Cassie model and endowing the surface with dense charge transport pathways,thus resulting in excellent superhydrophobicity and conductivity.When sprayed 100 times,the contact angle can reach161°,while rolling angle was as low as 2.3°,and the volume resistivity was around 0.16?·cm,The fabrics prepared displayed superior waterproof and self-cleaning properties,the surface remained dry and clean even after immersion in slurry for 20 times.XPS results indicated that only small areas of surface were oxidized after long term storage in atmosphere,the surface kept superhydrophobic.In addition,the superhydrophobic and conductive coatings showed stability in air and excellent corrosion resistance,compared with hydrophilic coatings,the superhydrophobic fabrics exhibited better corrosion resistance in 3.5 wt%Na Cl solution as well as in artificial sweat.(2)A molecular grafting technology was introduced in order to improve the stability of surface microstructure.The XPS results proved the successful construction of the molecular bridge between surface and coating layers,the 3D profile and SEM results showed that the grafting technology didn't affect the surface morphology,the stacking of Cu NPs formed stable Cassie model thus low adhesion surface was obtained,which effectively prevented surfaces from water penetration.The modified fabrics were firmly connected with coatings and maintained superhydrophobicity and conductivity under large deformation such as cyclic wearing,long-term water drop impacting,cyclic bending and kneading,which would help the functional coatings to be applied to the actual sense.The superhydrophobicity endowed the fabrics with waterproof and anti-corrosion properties,so the fabrics can keep electrical conductivity when they were used in humid,weak acid,weak alkali and salt environment.When the fabrics were applied to the field of electromagnetic shielding,even after soaking in saturated Na Cl solution for 24 hours,the electromagnetic shielding effectiveness still reached44 d B.Therefore,the conductive superhydrophobic fabric could be a new electromagnetic shielding material in practical complex environment.(3)The fabrics were covered by silver nanoparticles(Ag NPs)firstly by spraying method,then the fabrics prepared were immersed into the n-hexane solution of polydimethylsiloxane(PDMS).After being cured at high temperature,conductive superhydrophobic fabrics were obtained.FTIR and XPS were employed to confirm the successfully introduction of Ag NPs and PDMS on surfaces.SEM and CA meter were utilized to study the effects of the content of PDMS on the morphology and wettability of fabric.The results showed that either low or high mass fraction of PDMS solution were not beneficial to the formation of superhydrophobic surfaces,When the mass ratio of PDMS to n-hexane was 1:12,the surface posed winkled-like microstructure,CA of the surface was around 163°and volume resistivity was 9.24×10-3?·cm.In addition to improvement of interfacial adhesion,the introduction of PDMS made the loose particles closely connect,which enhanced the stability the structure.Meanwhile,the films exhibited great electrothermal effects,which could be applied in high-speed deicing.Combined with superhydrophobicity,the electromagnetic shielding efficiency can reach 75 d B even after immersion in corrosive medium for 24 h,the fabrics also achieved long-term stable work state even in harsh environments. |
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