双层透明耐磨超疏水膜层的制备及界面结构控制

Preparation and Interface Structure Control of Bilayer Transparent Wear Resistant Superhydrophobic Coatings

以正硅酸乙酯为前驱体,以溶胶-凝胶法制备的SiO2溶胶作为黏结剂,首先将SiO2溶胶在玻璃上旋涂成膜作为底层黏结层,再将亲水型气相SiO2纳米颗粒与SiO2溶胶混合后在底层上旋涂成膜作为上层微纳米凹凸膜层,制得双层透明耐磨微纳米凹凸膜层;同时采用KH560嫁接改性的SiO2纳米颗粒替代未处理的SiO2纳米颗粒,制得改性双层透明耐磨微纳米凹凸膜层,研究了膜层制备工艺以及SiO2纳米颗粒改性对膜层界面结构的影响。结果表明,当旋涂转速为400 r/min、膜厚为1.39μm时,底层黏结层具有优异的透光性和耐磨性;紫外臭氧照射20 min后,水接触角为0°,形成高化学活性的亲水性表面。经氟硅烷表面修饰,双层透明耐磨微纳米凹凸膜层和改性双层透明耐磨微纳米凹凸膜层的水接触角分别为151.23°、150.82°,呈现超疏水性;在1 kg/cm^2的荷载作用下,往复打磨200次后,它们的水接触角分别达到121.97°和126.45°,平均面粗糙度保持率高达51.62%和66.33%,下降幅度小,呈现优良的耐磨特性。耐磨特性与界面处的空隙、孔洞密切关联;SiO2纳米颗粒的改性能够有效地减少界面处的空隙、孔洞,提升膜层的耐磨特性。

In this paper,SiO2 sol prepared with tetraethyl orthosilicate as precursor was used as a binder.SiO2 sol was spin coated on glass as the bottom bonding layer,then hydrophilic SiO2 nanoparticles were mixed with SiO2 sol and coated on the bottom as the upper layer to prepare bilayer transparent wear-resistant coatings with micro/nano hierarchical structure.Meanwhile,KH560 modified SiO2 nanoparticles were used to replace untreated SiO2 nanoparticles to prepare modified bilayer transparent wear-resistant coatings,and the effects of the coating process and the modification of SiO2 nanoparticles on the interface structure were studied.Results show that SiO2 sol bottom layer has excellent transparency and wear resistance when the spinning speed is 400 r/min and the film thickness is 1.39μm.After 20 minutes of ultraviolet ozone irradiation,water contact angle(WCA)of SiO2 sol bottom layer is 0°,forming a hydrophilic surface with high chemical activity.The prepared bilayer and modified bilayer transparent wear-resistant coatings show superhydrophobicity,and the WCA are 151.23°and 150.82°,respectively,when modified by fluoroalkyl silane.WCA can still reach 121.97°and 126.45°after 200 cycles of mechanical abrasion under the load of 1 kg/cm^2,respectively.The average surface roughness of the coatings decreases slightly after abrasion,and the roughness retentions reach 51.62%and 66.33%respectively,sho-wing excellent wear resistance.The wear resistance of micro/nano hierarchical structural coatings is closely related to voids and holes on the interface structure,and the modification of SiO2 nanoparticles can effectively reduce the voids and holes on the interface,thus improve the wear resistance.