Study On Functionalization Of Smooth Anti-fouling Surface With Special Wettability

Since the“lotus leaf effect”was discovered,the research on special wetting anti-fouling materials has lasted half a century.Compared with conventional anti-fouling materials,the special wetting surface can be an ideal class of anti-fouling materials,which is not harmful to the environment.In addition,special wettability materials have shown a wide application prospect in many fields such as corrosion prevention,anti-icing,anti-biological adhesion,anti-fog,oil-water separation and microfluidic control.However,the environmental durability of these materials has yet to be improved in practical applications,and high light transmittance of these materials is also required for the anti-fouling of certain devices(e.g.windows and touch screens.).At present,four kinds of special wettability anti-fouling materials have been developed.The micro-nano rough structure of superhydrophobic surface,superhydrophilic surface and slippery liquid infused porous surfaces will seriously decrease the transmittance of materials,and the rough structure is easy to be damaged by mechanical failure.Moreover,superhydrophilic surface will be contaminated by oil dipped into the gaps of the rough surface if there is no water.And the slippery liquid infused porous surfaces will lose its liquid repellent with the loss of lubricating fluid.However,compared with the above three types of special wettability anti-fouling surfaces,solid smooth liquid repellent surfaces that utilize covalently grafted flexible polymer chains to provide fluid repellency are more advantageous in practical applications.This is because the avoidance of rough structure makes such surfaces more easily designed to be transparent and durable;meanwhile,the covalent linking of flexible polymer chains avoids the leakage of lubrication from slippery liquid infused porous surfaces.This paper briefly has illustrated the development,preparation and advantages and disadvantages of the four special wettability anti-fouling surfaces:superhydrophobic surface,superhydrophilic surface,slippery liquid infused porous surfaces and solid smooth liquid repellent surface.On this basis,two smooth anti-fouling coatings with special wettability were developed,which are easy to prepare on a large scale,with low cost and excellent comprehensive properties.The main research results are shown as follows:1.A coating precursor was prepared using epoxy resin and mono-aminopropyl capped polydimethylsiloxane(NH₂-PDMS)at room temperature.Then,the precursor was brushed onto glass,metal,and plastic substrates and cured at 120°C to obtain a high light transmittance(97.8%),hard(3H),and smooth anti-fouling coating.Experiments have proved that the coating possesses excellent anti-fouling and self-cleaning property.Finally,the sliding mechanism of droplets was investigated according to the sliding behavior of droplets with different surface tension coefficients on the surface of this coating.2.we used a rigorous design approach to simultaneously achieve a balance between hardness,flexibility,transparency and anti-fouling properties,and a coating is developed with excellent performances of high transparency(98.8%),anti-fouling,high hardness(8H),and flexibility simultaneously(TAHF coating).In the material design,methyl etherified melamine formaldehyde resin,hexamethylene diisocyanate trimer,and mono-aminopropyl terminated polydimethylsiloxane(NH₂-PDMS)were used as polymer matrix to provide surface hardness,a cross-linker was used to provide toughness,and omniphobic groups from NH₂-PDMS were to provide anti-fouling performance,respectively.The TAHF coating has excellent liquid repellence even after6 months of outdoor exposure,260 h of UV light exposure,1500 wear and 2000bending cycles.In addition,electrochemical impedance spectroscopy indicates that the TAHF coating has superior chemical shielding properties than a commercially available high performance fluorinated anti-corrosive paint.This design route distributes and balances several functions that are critical in practical applications,and the coating is simple and inexpensive to prepare with excellent overall performance,making the coating promising for rapid commercial application.