Fabrication And Characterization Of Superhydrophobic And Highly Oleophobic Silk Fabrics

Superhydrophobicity and oleophobicity which have been discovered from natural world are definitely anticipated to be beneficial for a large number of practical applications Imitation of nature has been the most appreciable way to develop the structural properties for coating fabrication,due to millions of creatures including botanical,insect and zoological species,which have the ability to be resistant from water and low surface tension fluids.Mechanically robust superhydrophobic and oleophobic coatings refer to the surface modification of optical materials in order to fabricate the surface roughness and reduce the low surface energy,that lead to water and oil repellent properties with several practical and industrial benefits.Nowadays,many publications have presented the preparation strategies of superhydrophobic and oleophobic surface for textile materials.However,there is a lack of ideal coating approach for superhydrophobic and oleophobic silk fabric.Furthermore,these techniques have the disadvantage of complicated procedure,time consuming,use of toxic chemicals,high cost for experiments and low effectiveness.In this master thesis,simple approaches to prepare fluorine-free superhydrophobic coating and highly hydrophobic and oleophobic coating for silk textile fabrics based on SiO2 nanoparticles and low surface energy agents are reported.SiO2 nanoparticles has naturally hydrophilic features and were functionalized by fluorine-free and/or fluorinated silanes.Due to experiment works,we successfully prepared the superhydrophobic silk fabric with water contact angle(WCA)of 152.0° and water sliding angle(WSA)of 4.2°,and highly hydrophobic silk fabric with WCA of 149.5°,which is extremely near to superhydrophobic standard.Furthermore,by the introduction of fluorinated silane,oleophobicity has been developed and oil contact angle(OCA)of modified silk fabric reached 132.0°.Effects of different particle sizes of SiO2 nanoparticles,concentration of chemicals in modification solution and the activity of fluorine-free and fluorinated low surface energy agents on wettability were investigated.The multifunctional silk fabrics show the admiring water,liquid and abrasion-resistance,excellent self-cleaning performances and high laundering durability.Moreover,the coatings have no negative influence on textile features of silk fabric.These methods are hopeful for wide-ranging production of multifunctional silk textiles.