Fabrication Of Superhydrophobic Materials With Water Pressure Resistance

Superhydrophobic surfaces are always emphasized on the non-wetting and self-cleaning properties.However,it is still a challenge to endow water pressure resistance to the superhydrophobic surfaces for some outdoor products,such as umbrellas,tarpaulins,open tents and so forth.Superhydrophobic materials with water pressure resistance can make the surfaces easy to clean,anti-raining and anti-impacting,which will meet the requirement of multifunctional products.In this research,polyester fabrics were used as the substrates to prepare superhydrophobic materials with water pressure resistance.Hydrophobic materials were introduced onto the fiber surface based on St(?)ber reaction or blade-coating method.The water pressure resistance was improved by forming one or more layers of water barrier coatings on the surface.(1)Superhydrophobic textile materials with water pressure resistance were fabricated by St(?)ber reaction using tetraethyl orthosilicate(TEOS)and hexadecyltrimethoxysilane(HDTMS)as raw materials.The silica gel coatings were formed on the fiber surfaces,which could build micro-and nano-structures.The surface morphology of the fabrics was observed by field emission scanning electron microscope.The water pressure resistance of the surfaces was measured by water permeability tester.The surface wettability was tested by contact angle measuring instrument.The surface elements were also analyzed using an energy dispersive spectrometer.The influences of coating parameters on the water pressure resistance of the fabrics were investigated.Studies indicated that the hydrostatic pressure gradually increased with increasing the dosage of TEOS,however decreased with the increase of HDTMS.The as-prepared polyester fabrics could withstand a hydrostatic pressure of 8044 Pa and showed a water contact angle of 162°.(2)Textile materials with water pressure resistance were prepared by blade-coating method with a mixture of polydimethylsiloxane(PDMS)and silica nanoparticles,which could form hydrophobic polymer nano-composite coatings on the fiber surface to barrier the passage of water drops.Then superhydrophobic textile materials with water pressure resistance were prepared by a convenient sol-gel method using TEOS/HDTMS as raw materials to hydrophobize the coating surface.The effects of coating parameters on the wettability and water pressure resistance of the fabrics were investigated.Results revealed that the water contact angle of the fabrics changed slightly with increasing the dosage of PDMS and silica,however decreased with the increase of coating times.Increasing the dosage of PDMS and silica and coating times resulted in greater hydrostatic pressure.The as-prepared surfaces could be endowed hydrostatic pressure up to 38.4 kPa with water contact angle of 162.5° and rolling angle of 5.3°.In summary,high water pressure resistance of the superhydrophobic materials was successfully achieved by formation of hydrophobic silica gel coatings or polymer nano-composite coatings on the fibers.It is expected that the as-obtained superhydrophobic materials with water pressure resistance will open a new avenue for outdoors textile products,due to their additional excellent resistance to UV light and chemical damage.