Design Of Hydrophilic-Oleophobic Double-layer On The Surface Of Cotton Fabric And Its Self-cleaning Performance

Self-cleaning textiles are one of the functional textiles developed in recent years.The characteristics of self-cleaning textiles that hard-stained or easy-decontaminated are not only applicable to textile and garment,but also to industrial building materials,decorative materials,transportation,electronic equipment and other aspects.There are two ways to prepare self-cleaning textile: Photocatalysis finishing and Hydrophobic-Oleophobic finishing.Photocatalytic finishing has not been popularized because of the disadvantages of limited use conditions and damage to the matrix carrier.Hydrophobic-Oleophobic finishing achieves the self-cleaning effect by reducing the surface tension of the textile.Although the prepared textile has good Hydrophobic-Oleophobic properties,the contamination of oil is difficult to be cleaned by water and cannot meet the requirement of easy decontamination.In view of the shortcomings of the Hydrophobic-Oleophobic self-cleaning textile,we proposed to construct hydrophilic and Oleophobic self-cleaning textile which both has hard contamination and good decontamination characteristics.In this paper,the surface of cotton fabric was fabricated by fluorocarbon surfactants(f-PEG)molecular brushes which had both oil-repellent fluorinated segments and hydrophilic polyoxyethylene segments.Firstly,we coat the PAA solution and f-PEG solution on the surface of cotton fabric by using homogenizer which was controlled at the first speed of 900 r/min and the second speed of 3000 r/min,and further determined the mass fraction of PAA solution,the mass fraction of f-PEG and the molecular weight of PAA,The optimum conditions were as follows: 7%mass fraction of PAA solution,9% mass fraction of f-PEG solution and 50,000 molecular weight of PAA.The initial contact angle of hexadecane was 115.7°,and 5 minutes after the contact angle of hexadecane was 114.5°,which showed the feasible of constructing Hydrophilic and Oleophobic self-cleaning cotton textile by f-PEG.However,the double-layer structure formed on the surface of cotton fabric was stuck via Van der Waals force,which was easy broke by water scouring.So to improve the shortcomings of poor fastness,grafting method was used to construct double-layer structure on the cotton fabric surface.In this paper,SI-ARGET ATRP as grafting method was used to design a double-layer structure on the surface of cotton fabrics by grafting HEMA and tBA respectively and hydrolyzing PtBA segments 24 h to prepare Cotton-PHEMA-PAA,which was then esterifies using f-PEG in the present of EDC·HCl.The grafting time of HEMA,tBA and the esterification time of f-PEG were discussed and optimum conditions were obtained: 1h grafting time of HEMA,5h of grafting time of tBA,and 24 h of esterification of f-PEG.The results showed that the hydrolysis rate of tBA was87%,and the weight gain rate of HEMA,tBA and f-PEG were 6.4%,13.4% and 7%,respectively.The double-layer structured cotton fabric has simultaneously excellent Hydrophilic and Oleophobic performance.The FITR surface scan indicates the existence of polymers on the surface of cotton textile.The Contact Angle experiment demonstrated that the finished cotton fabric have the 125° contact angle of hexadecane and 0° contact angle of water,and also performing excellent self-cleaning property,which provides a new idea for the preparation of self-cleaning textile in future.