Study On Liquid Separation And Bubble Control Function Of Titanium Surface Induced By Femtosecond Laser

Femtosecond laser is widely used in the field of laser micro/nano processing because of its short pulse,high energy and small heat-affected area.Combining laser micronano processing with bionic concept is of great significance for designing micro-nano structures with special wetting functions.In this thesis,the titanium foil samples with microporous arrays were successfully prepared by reasonably designing the femtosecond laser processing parameters,and the oil-water separation and immiscible organic liquid separation were realized.At the same time,the selective bubble collection of the microporous titanium foil array can be realized by the changing of the surface tension of the solution.The thesis mainly includes the following several parts:(1)A multifunctional micropore array was produced by using one-step femtosecond laser microdrilling for oil-water and oil-oil separation.This novel method has many advantages,such as high precision,simple operation,extensible function just to name a few.The prepared foil exhibited superhydrophilic and underwater superoleophobic properties,which can be used to separate the light oil and water mixtures.After heated in dark environment 0.5 h,the prepared foil showed superhydrophobic and underwater superoleophilic properties,and can be used to separate the heavy oil and water mixtures.In addition,the heated sample also showed robust ability to separate the immiscible organic liquid mixtures,exhibiting multifunctional applications.(2)By continuously adding alcohol into pure water,the bubble contact angle on the as-prepared sample is gradually in situ tuned from superaerophilicity to superaerophobicity.This mechanism could be ascribed to the underwater competition between the air and alcohol molecules inside the micro/nanotextures induced by the variation of the solution surface tension.By utilizing the proposed strategy,we conduct a demonstrative experiment on the samples with in situ tunable bubble wettability to show the light on–off function in liquid,which can be used as an optical switch.Furthermore,a through-microholes-array titanium foil was fabricated for the selective passing/blocking of bubbles in the liquid medium.Finally,the underwater superaerophilic titanium foil could be used for collecting gas in a solution medium.