摘要
受仙人掌锥形刺和长嘴鸟喙单向运输液滴现象的启发,利用纳秒激光烧蚀技术,在钛片表面上制备了一种简便有效的液滴和水下气泡操控平台——超亲水不对称双轨(SHADR)。利用静态各向异性结构产生的拉普拉斯压力梯度,SHADR不仅可以实现液滴的自发单向运输,还可以实现水下气泡的单向运输。定量研究了单轨道宽度、分支角等结构参数对液滴和水下气泡运输性能的影响,并对简化的力学模型进行了分析。这种功能表面不仅操作简便,而且适用性广,可以应用于微流体和界面科学等领域。
Objective In recent years,bionic functional surfaces have played an important role in the manipulation of microfluidic dynamics.Among these,droplets and bubbles have been extensively studied as common interfacial fluids owing to their important application in fields such as droplet microreactors and cell screening.Therefore,it is highly meaningful to achieve a targeted transport and effective collection of droplets and bubbles.Researchers have achieved stable surface-wetting properties,as well as the ability to drive droplets and underwater bubbles simply and efficiently by preparing statically anisotropic structures.However,these static anisotropic structures are prepared by composite structures composed of multiple materials or by electrochemical etching.The preparation process is complex,susceptible to environmental pollution,and only a single target is considered,which significantly limits the application range.In this study,a static anisotropic superhydrophilic asymmetric double rail(SHADR)structure is prepared on the surface of a titanium sheet via nanosecond laser ablation.Based on the Laplace pressure gradient generated by the asymmetric structure,the SHADR structure achieves a spontaneous unidirectional transport of liquid droplets and underwater bubbles.This functional surface provides new ideas for microfluidic manipulation,biomedicine,and other fields.Methods The titanium sheet is ultrasonically cleaned in deionized water for 10 min to remove surface impurities before processing.A nanosecond fiber laser is used to vertically scan the surface of the titanium sheet to increase the surface roughness.Subsequently,the samples are ultrasonically cleaned once again and modified with a commercial superhydrophobic reagent to enhance the surface hydrophobicity and reduce the surface adhesion.Finally,the modified superhydrophobic surface is scanned using a nanosecond fiber laser-marking machine,and the SHADR structure with a length of 40 mm and an end spacing of 1 mm is processed.The contact angles of 5μL water droplets on the surface of the titanium sheet are measured using a contact angle measurement system to characterize the surface wettability of the titanium sheet with different structures.The optical images of the droplets and motion of bubbles are captured by a high-speed camera.Results and Discussions Inspired by the conical spines of a cactus and the long-billed beak of a bird,a simple and effective droplet and underwater bubble manipulation platform,that is,a SHADR struture,is prepared on the surface of a titanium sheet via nanosecond laser ablation(Fig.1).Using the Laplace pressure gradient generated by the static anisotropic structure,a SHADR structure achieves the spontaneous unidirectional transport of both droplets(Fig.2)and underwater bubbles(Fig.4).In this study,the effects of the structural parameters,such as the single-rail width(w)and branching angle(α),on the transport performances of the droplets and underwater bubbles are quantitatively investigated(Fig.3)and a simplified mechanical model is analyzed.Conclusions In this study,a simple and effective droplet and underwater bubble manipulation platform is prepared on the surface of a titanium sheet using nanosecond laser ablation.The SHADR struture enables the anisotropic spontaneous transport of droplets and bubbles based on the Laplace pressure difference.The droplet transport is recorded by a high-speed charge-coupled device camera,systematically quantifying the droplet transport performances in the horizontal SHADR struture under different parameters(branching angle,single rail width,and bubble volume).This functional surface is not only simple to operate but will also have wide applicability in the fields of microfluidics and interface science.
作者
顾剑锋
方金鹏
李传宗
王悦
顾志祥
肖轶
Gu Jianfeng;Fang Jinpeng;Li Chuanzong;Wang Yue;Gu Zhixiang;Xiao Yi(College of Electromechanical and Transportation Engineering,Nantong Vocational College of Science&Technology,Nantong 226000,Jiangsu,China;School of Instrument Science and Optoelectronic Engineering,Hefei University of Technology,Hefei 230009,Anhui,China;School of Computer and Information Engineering,Fuyang Normal University,Fuyang 236037,Anhui,China;College of Mechanical Engineering,Nantong Vocational University,Nantong 226000,Jiangsu,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2023年第20期187-193,共7页
Chinese Journal of Lasers
基金
中央高校基本科研基金(WK2090000035,WK2480000005)
江苏省高校“青蓝工程”项目(2019)
南通市基础科学研究项目(JC2020079)
江苏省自然科学基金面上项目(BK20191209)
江苏省优秀科技创新团队项目(2021-52)。
关键词
激光技术
纳秒激光
微纳加工
不对称结构
液滴/气泡操控
单向运输
laser technique
nanosecond laser
micro/nano processing
asymmetric structures
droplet/bubble manipulation
unidirectional transport
