Study On The Hydrophobic Properties Of Two-photon Polymerization Process On Bio-inspired Nepenthes Surface

Superhydrophobic surfaces are the result of the combination of the micro-nano composite structures and the wax coverage.Due to excellent waterproof,anti-fog,anti-corrosion,anti-ice or other advantages,super-hydrophobic functional surfaces have aroused intensive interests and applied to the military,civil,medical and other fields widely.Because of its special hydrophobic gradient,Nepenthes has become a heated research area.In current researches,the main approaches to obtain superhydrophobic functional surfaces include anodic oxidation,layer-by-layer self-assembly method,template method and sol-gel.etc,but most of these traditional methods mainly aim at periodic or 2.5d structure,It is difficult to prepare the complex Nepenthes-inspired microstructure.Two-photon polymerization processing has nano-scale manufacturing resolution and complex 3d structure manufacturing capability,which is an effective processing method for the bionic structure.However,there are still some problems needed to be solved in the use of two-photon polymerization to prepare the bionic structure.The main contents researches can be summarized as follows:(1)The traditional theoretical models to explain the actual wetting phenomenon will be subject to the conditions of their own conditions.They can only be used for the static analysis problem which the surface must referred to be ideal or rough.Droplets in microstructure on the surface of the advancing and receding state are used to establish a state of transient surface equation respectively.The relationship between the apparent contact angle and contact angle hysteresis are set up aiming at applying to analyze the dynamic problems,and applying it to the microstructure of the Nepenthes-inspired superhydrophobic surfaces.(2)The hydrophobic properties and the paramaters of the structures in waxy slippery zone and digestive zone are measured by Contact Angle Meter and the White-light Interferometer respectively.We use ANSYS software to simulate the mechanical properties of a lunate microstructure,then analyze the stress of the structure and the structure optimization for the lunate microstructure is carried out.The one-dimensional solid fraction and roughness factor of the surface are changed by changing the arrangement and height of the lunate microstructures on the surface of the waxy slippery zone.Meanwhile CFX is used for fluid simulation analysis aiming at obtaining the optimal design parameter.(3)The bionic lunate microstructures in different arrangement and height are prepared by using two-photon polymerization processing.The quality of Bio-inspired surface prepared is inspected by the White-light Interferometer,and the prepared surface is in accord with the dimensions of the surface designed before.It confirms that femtosecond laser two-photon polymerization processing method is an effective way to process irregular microstructures in different structure parameters.