摘要
微夹持器是微操作系统的重要组成部分。作为微操作系统末端执行器,微夹持器钳口端面在工作过程中容易出现磨损、吸附杂质、结冰或结霜等问题,而且目前微夹持器大多是一体化加工而成,整体更换将造成资源浪费。本文设计了一种可拆卸式微夹持器,利用中心波长为1064 nm的纳秒激光器,在执行操作的钳口端面上加工出粗糙的微纳结构,使用无毒害的硬脂酸溶液浸泡改性,获得仿生超疏水表面。通过电化学实验,测试了仿生超疏水表面在酸、盐和碱环境中的耐腐蚀性能,通过自清洁、抗结冰和抗菌实验测试了该表面的防污、防冻和防菌性能。实验结果表明:仿生超疏水表面能够有效抵抗酸、盐和碱环境中的腐蚀,具有良好的防腐性能;有效防止灰尘、水滴和细菌等杂质粘附于钳口端面,保证钳口端面的清洁与卫生;在低温环境中,有效防止端面结霜或结冰,使微夹持器能够在恶劣环境中正常工作。
Objective A microoperating microgripper is an essential part of the micromanipulation system.As the end effector of the system,the jaw end face of the microgripper is prone to wear,adsorption of impurities,ice,or frost during operation.Most traditional microgrippers are integrally machined,and the overall replacement will result in wasted resources.This study reports a detachable microgripper with superhydrophobic properties.First,a rough microstructure was machined on the end face of the jaws where the operation is performed using a nanosecond laser with a central wavelength of 1064 nm.Then,they are modified by immersing them in a nontoxic stearic acid solution.Thus,a bionic superhydrophobic surface is obtained.This surface has excellent corrosion resistance,selfcleaning,antiicing,and antibacterial properties.X-ray photoelectron spectroscopy(XPS)technique is employed to analyze the chemical composition of the pristine aluminum(Al-Ⅰ)and superhydrophobic aluminum(Al-Ⅱ)surfaces;the corrosion resistance of both surfaces in acid,salt,and alkali environments is tested using electrochemical experiments.self-cleaning,Further,the antifouling,antifreezing,and antibacterial properties of both surfaces are tested using antiicing,and antibacterial experiments.We expect that our basic strategies and findings will enhance the performance and extend the service life of the microgrippers.Methods Because the microgripper is made of 7075 space aluminum used to facilitate later observation,testing,and analysis,a 7075 aluminum sample with size and thickness of 10 mm×10 mm and 1 mm,respectively,is used for the test instead of the end face of the jaws.First,a nanosecond laser is used to etch a grid-like microstructure on the surface of the sample,and then it is immersed in a nontoxic stearic acid solution with a concentration of 0.05 mol/L for 30 min to reduce the surface free energy.Further,it is removed and placed in a drying oven at 60℃for 1 h.The sample surface will acquire the expected superhydrophobic properties using this procedure.According to the functional requirements of the microgripper,the prepared superhydrophobic sample surfaces are analyzed for surface composition and tested for corrosion resistance,self-cleaning,antiicing,and antibacterial properties.The chemical composition of Al-Ⅰand Al-Ⅱsurfaces is detected using the XPS technique.Further,the morphology of the sample surfaces before and after corrosion by acid,salt,and alkali is characterized using scanning electron microscopy.The antiicing and self-cleaning performance of the sample surfaces are evaluated using an environmental test chamber and self-designed self-cleaning experiments.The bacterial distribution and survival status of the sample surfaces are characterized using laser confocal microscopy,and the antibacterial performance is characterized using plate coating experiments to calculate the bacterial inhibition rate.Results and Discussions The lattice-like microstructures obtained from the sample surface preparation have high superhydrophobicity with average contact and rolling angles of 156.7°and 1.088°,respectively.The XPS test results show that the surface of both samples mainly contains C,O,and Al elements.After laser irradiation,the generated Al2O3 on the surface caused the O atomic number fraction to increase by 24.51%.The C 1s high-resolution spectra of the superhydrophobic samples exhibit a significant increase in C atomic number fraction following the stearic acid modification treatment,indicating that stearic acid reacted with the surface Al to form low surface energy aluminum stearate during the chemical modification process.The C—C(H)content is as high as 82.81%,the occupying strongest peak,which indicates that the long-chain molecules of stearic acid have successfully adhered to the surface of the Al-Ⅱsample in the form of aluminum stearate(Fig.5).Electrochemical experiments and SEM results show that the corrosion resistance of the superhydrophobic surface in a salt solution is better than its resistance to acids and bases;the total impedance modulus of superhydrophobic Al-Ⅱis better than that of pristine Al-Ⅰsample sample.This implies that the superhydrophobic surface with a rough microstructure can significantly enhance the corrosion inhibition of aluminum materials(Figs.6--8,Table 1).The self-cleaning test results show that the droplets can effectivelyremove the impurities from the surface of the Al-Ⅱsample,indicatingthat the superhydrophobic surface has a good self-cleaning ability(Fig.10).The results of the twenty-minute antiicing experiments show that the Al-Ⅱsamplehas excellent superhydrophobicity with low adhesion ability and no significant icing occurred during the test,whereas the adhering ice layer on the surface of the Al-Ⅰsamplehas a mass of 1.283 g and shows poor antiicingperformancein the cryogenic environment(Fig.11).The results of laser confocal microscope characterization in the antibacterial experiment show that the number of strains adhering to the surface of the Al-Ⅱsampleis significantly lower than that of the Al-Ⅰsample,indicatingthat the prepared superhydrophobic sample has a strong resistance to bacterial adhesion(Fig.12).Further,the results of the plate-coating experiment show that the antibacterial rate of the Al-Ⅱsampleis 3.8 times higher than that of the original Al-Ⅰsample,which proves that the aluminum-based superhydrophobic surface with lattice-like microstructure has certain bactericidal properties(Table2).Conclusions Inthis study,we design and construct a detachable microgripper with a bionic superhydrophobic structure in the jaw end of the gripper body,which addresses several problems of the traditional microgripper.The main research contents and innovations are as follows:1)the microgripper’sbase body and the left and right clampingbodies are designed separately and connected by bolts.This design increases the flexibility of the microgripper,which can replace the corresponding body based on different clamping objects and working conditions.When the jaw end face is damaged by repeated use,it is unnecessary to replace the whole microgripper;however,onlythe body part can be replaced.2)The laser-textured jaw end faces are soaked in a low surface energy stearic acid solution to obtain superhydrophobic properties.The surface obtained through this method has a rough microstructure and low surface energy,thus forming an air layer between the material and the liquid;it effectively prevents the contact of the material surface with corrosive solutions,common water droplets,and bacterial solutions inhibiting the adhesion of droplets.This enables the jaw end faces to acquire self-cleaning,anticorrosion,antiicing,and antifrost properties,thus effectively enhancing the clamping performance of the microgripper.
作者
杨成娟
杨雪
王蒙
王福军
时贝超
朱鑫垚
Yang Chengjuan;Yang Xue;Wang Meng;Wang Fujun;Shi Beichao;Zhu Xinyao(School of Mechanical Engineering,Tianjin University,Tianjin 300072,China;Key Laboratory of Mechanism Theory and Equipment Design,Ministry of Education,School of Mechanical Engineering,Tianjin University,Tianjin 300072,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2022年第10期217-230,共14页
Chinese Journal of Lasers
基金
国家重点研发计划—政府间国际科技创新合作重点专项(2017YFE0112100)
国家重点研发计划(2017YFB1104700)。
关键词
激光技术
表面加工
仿生超疏水表面
微夹持器
耐腐蚀
自清洁
抗结冰
抗菌
laser technique
surface processing
bionic superhydrophobic surface
microgripper
corrosion resistance
self-cleaning
antiicing
antibacterial
