基于润湿过渡的玻璃表面亲水微结构的理论设计与制造

Theoretical Design and Fabrication of Hydrophilic Microstructure on Glass Surface Based on Wetting Transition

目的为实现一种仿生蜂窝状的微结构的理论设计与制造,达到对接触角的理论预测,并进行试验的测量验证。方法通过建立蜂窝状微结构的理论模型,基于润湿的Cassie-Baxter态到Wenzel态的转化理论,采用数值仿真程序对该结构接触角进行预测。采用纳秒脉冲光纤激光器在玻璃表面加工出蜂窝状结构。结果通过首次建立蜂窝微结构理论模型可得到接触角的表达式,在满足物理约束(重力、拉普拉斯压力、内外压差)的条件下可得到最优的边界条件。利用数值仿真程序,得到的接触角预测值和纳秒激光技术加工后的测量值吻合良好,误差均小于5°。同时,表面接触角随着蜂窝状结构尺寸的减小而减小,在蜂窝状结构边长约为10μm时达到超亲水状态。结论基于润湿过渡理论建立的蜂窝状微结构理论模型是可行的,可以准确预测微结构的表面亲水性(表观接触角)。通过纳秒激光的吸光材料辅助烧蚀技术,可以在玻璃表面准确地加工出微米级的蜂窝结构。利用生物学仿生技术设计的蜂窝微结构,能够起到减小表观接触角的效果,从而有效地改善玻璃表面的亲水性。

In order to obtain a reliable hydrophilic microstructure that can transform from the Cassie-Baxter state to the Wenzel state,a honeycomb-like microstructure was designed.It was inspired by the natural biological structure.By establishing a theoretical model of the honeycomb microstructure and using a numerical simulation program,the contact angle of the structure was predicted.Finally,a nanosecond pulsed fiber laser is used to process a honeycomb structure on the glass surface.The results show that the contact angle expression can be obtained by establishing the theoretical model of the honeycomb microstructure for the first time.The optimal boundary conditions can be obtained under the conditions of satisfying the physical constraints.The error between the predicted value of the contact angle and the measured value after processing is less than 5°.The surface contact angle decreases as the size of the honeycomb structure decreases.When the side length of honeycomb structure is about 10μm,it reaches the super-hydrophilic state.The theoretical model of honeycomb microstructure based on wetting transition theory is feasible and can predict the surface hydrophilicity(apparent contact angle).Through nanosecond laser ablation technology assisted by light absorbing material,micron scale honeycomb structure can be accurately processed on glass surface.The honeycomb microstructure designed by bionic technology can reduce the apparent contact angle and effectively improve the hydrophilicity of glass surface.