A Design And Research On Passive Anti-Frosting/Anti-Icing Transparent Films

Traditional defrost/deicing methods have many drawbacks such as high energy consumption,high cost and low efficiency,and the surface of the object is easily dam-aged in the process of defrosting.Therefore,researchers have turned their attention to passive anti-frost/anti-ice strategies,and based on bionanotechnology research,super-hydrophobic surfaces（SHS）prepared from the lotus leaf effect and slippery liquid in-fused porous surfaces（SLIPS）that further developed from SHS are widely used for passive frost/ice protection.However,both SHS and SLIPS still have non-negligible drawbacks,for example,the rough structure of SHS can lead to frost pinning and freez-ing during application,and the lubricating liquid in SLIPS can be continuously lost and cause environmental problems.This experiment combines the"humidity sink"effect with the superhydrophobic anti-frost/anti-ice mechanism,and uses a KBr hygroscopic crystal sheet as a substrate to prepare a porous Si O₂ superhydrophobic coating film with precisely controllable pore size and distance,and combines the two to obtain a porous superhydrophobic anti-frost/anti-ice film,the anti-frost/ice performance of the film surface is investigated and analyzed,and the"humidity sink"effect was used to design a surface with other practical applications:（1）the film surface around a single hygroscopic pore can form a region of inhibited condensation and condensation frosting（RIC）,thus playing a frost inhibition effect.（2）The frost inhibition effect around the hygroscopic pore is related to the size of the hygroscopic pore and the surface temperature.It can be assumed that the larger the ratio of the frost inhibition area（S_δ）to the hygroscopic pore area（S_R）,the higher the frost inhibition efficiency under the corresponding conditions.When the sur-face supercooling temperature is-5℃and-10℃,the S_δ/S_R value corresponding to the smallest pore size（R=100μm）is the largest,which is 6.58 and 4.58 respectively,and the frost inhibition effect is the best at this time;when the surface temperature decreases to-15℃,the frost inhibition fails;（3）choose the best size of hygroscopic pore,and reasonably regulate the spacing of hygroscopic pores,so that the frost inhibition area overlaps with each other,high efficiency large area frost inhibition can be achieved.（4）In addition to frost inhibition,this porous superhydrophobic anti-frost film surface also has good super hydrophobicity,with a contact angle of 155.3°and a rolling angle of about 3.5°,and water drops can be quickly popped up on the surface when they fall,greatly reducing the contact time between the two,which greatly shortens the contact time between the two and helps prevent the nail and frozen damage to the surface caused by freezing rain;（5）At the same time,this anti-frost surface has good transpar-ency and light transmittance,in the visible light range,the light transmittance can reach60%overall,and in the yellow-orange light region（577-622 nm）,the light transmit-tance can reach 80%,using this advantage of the anti-frost surface can be applied to the solar panel surface anti-frost;when the surface can still maintain the hydrophobic state after five times of tape peeling,indicating that the surface has good stability;in addition,the surface temperature above-10℃can delay the complete frosting time to at least 30 minutes,which proves that the surface also has delayed frosting performance.