Fabrication Of Transparent Nanostructures On Glass Surface And The Mechanism Of Anti-Fingerprint

Cell phones,tablet computers and other electronic products are widely used in our lives,but the fingerprints and stains are easy to remain on the glass for touch screen,then reducing users preference.At present,most of manufacturers modify the glass with anti-fingerprint oil in the factory while it still has problems of limited anti-fingerprint effect and insufficient durability.In this thesis,combining nano-metal dewetting method and reactive ion etching,we construct three types of transparent nano-protrusion arrays on glass surface for anti-fingerprint.Antifoulants are further filled in the nano-textures to improve the performance.Different anti-fingerprint mechanism of the surface are finally put forward to understand the performance according to the change of surface morphology and wettability.Taper nano-protrusion arrays were constructed on galss surface by combining Au film rapid annealing treatment and reactive ion etching method.Research showed that the obtained nano-particle templates were evenly distributed and the particle diameters were from 50 to 70 nm when the thickness of the Au film was 5 nm,the temperature was heated to 450°C by 40°C/min and maintained for 30 min.Using argon(40 sccm)and trifluoromethane(5 sccm)as reactive ion etching gases,and the best taper nano-protrusion arrays were fabricated at the etching RF(radio frequency)power of 300 W,the chamber pressure of 10 Pa,and the etching time of 10.5 min,respectively.The specific parameters were as follows: average height and bottom diameter of nano arrays were 180 nm and 140nm;average transmittance was 95%;the contact angles of treated glass for water and hexadecane were 144° and 84° after surface FAS modification,respectively.We characterized the surface fingerprint residual rate with the self-built fingerprint measurement equipment and the binary method.The result illustrated that,compared with the original glass and the anti-fingerprint oil modified glass,the fingerprint residual rate on the taper nano arrays glass surface is reduced by 45.6% and 26.8%.In order to reduce the stress concentration and damage of the taper structure,we constructed a kind of circular nano-arrays.The research showed that the diameter of the obtained circular nanoprotrusion arrays on the glass surface was about 120 nm and the spacing was about 150 nm at the etching gas pressure of 40 Pa,argon ions bombard of 30 s and the etching time of 4.5 min,respectively.Besides,the surface average transmittance was 93.5%,and the contact angles for water and hexadecane were 153° and 93°.Compared with the original glass and the anti-fingerprint oil modified glass,the fingerprint residual rate was reduced by 48.3%,30.4%.Since the increase of surface roughness could further enhance its hydrophobicity,it was our main goal to construct composite nanoprotrusion arrays with two nano structure sizes,and obtaining transparent superhydrophobic glass surface with resistant for fingerprint after surface modification.The research demonstrated that the best composite nano-protrusion arrays were fabricated when the secondary etching time was 8.5 min.Average height of first-level and second-level nano-bumps were 230 nm and 120 nm.The surface average transmittance was 95.5%,and the contact angles for water and hexadecane were 155° and101° after surface modification.Compared with the original glass and the anti-fingerprint oil modified glass,the fingerprint residual rate was reduced by 55.2%,39.7%.Further more,we investigated the influence of glass anti-fingerprint performance after filling antifoulant in the nano-textures.The results showed that the fingerprint reduction was as high as 89.4%for samples filled with the antifoulant formulated with a mixture of perfluoropolyether and acrylic varnish,although the water and hexadecanecontact angles were only 102° and 15°,respectively.In general,the transparent glass surfaces with the three types of nano-protrusion arrays all illustrated excellent non-wetting properties after modification.Meanwhile,the nano structures could reduce the contact area between the fingerprint and the substrate.For the above two reasons,the fingerprint adhesion and fingerprint deposited amount could be reduced,exhibiting excellent antifingerprint function.For the samples filled with the antifoulant formulated with mixture of perfluoropolyether and acrylic varnish,lipophilicity promoted the rapid spread of grease on the substrate surface.In this case,the original uneven fingerprints became flat and visually less sensitive.In addition,hydrophobicity could make fingerprints easy to be erased.Thus,the filled surface have excellent anti-fingerprint performance.