摘要
目的研究不同微结构尺寸参数和阵列形状对PMMA表面疏水性的影响。方法使用精密微铣削方式,在光滑PMMA表面加工微沟槽、方柱、圆形及椭圆形阵列,并将测量的水滴的接触角和形状作为表面疏水性的表征指标。结果当微沟槽阵列的微槽宽度B、凸台宽度C及微槽深度H分别在84.86~208.77μm、36.22~133.94μm、63.76~136.60μm变化时,垂直接触角θ_⊥分别在129.4°~143.5°、138.3°~124.0°、125.8°~141.8°变化,平行接触角θ_∥分别在62.3°~69.6°、75.0°~66.3°、81.5°~72.0°变化;当微方柱阵列的B、C、H分别在70.76~138.99μm、47.52~128.04μm、70.84~175.94μm变化时,接触角θ分别在130.3°~102.1°、114.9°~129.5°、105.7°~119.7°变化。水滴在微沟槽和椭圆形阵列表面的形状为椭球冠状,在微方柱和圆形阵列表面为球冠状。结论微结构尺寸参数和阵列形状对PMMA表面疏水性有不同影响,且θ_⊥的变化都比θ_∥的变化更为明显。钉扎效应对水滴的形状有很大的影响,对于微沟槽阵列的槽垂直方向和椭圆形、圆形阵列,钉扎效应对水滴的形状起主导作用;对于微沟槽阵列的槽平行方向和微方柱阵列,水滴形状则受钉扎效应与固液气三相接触线不连续性的共同影响。研究结果有望为设计功能可控仿生微结构提供技术支撑。
The work aims to investigate the effects of different dimensions and array shapes of microstructure on PMMA surface hydrophobicity.Microgroove,square-pillar,circular and elliptical arrays were prepared on PMMA surface through precision micro-milling.The measured contact angle and shape of water droplet were used to indicate the surface hydrophobicity.When the microgroove width B,the boss width C,and the microgroove depth H of the microgroove arrays changed from 84.86 to 208.77μm,36.22 to 133.94μm and 63.76 to 136.60μm,the vertical contact angleθ⊥changed from 129.4°to 143.5°,138.3°to 124.0°and 125.8°to 141.8°,and the parallel contact angleθ∥varied from 62.3°to 69.6°,75.0°to 66.3°,and 81.5°to 72.0°,respectively.When the B,C,and H of the micro square-pillar arrays changed from 70.76 to 138.99μm,47.52 to 128.04μm and 70.84 to 175.94μm,the contact angleθchanged from 130.3°to 102.1°,114.9°to 129.5°,and 105.7°to 119.7°,respectively.Water droplets showed elliptical droplet shape on the surfaces of microgroove and elliptical arrays,while the spherical shape on the micro square-pillar and circular arrays.The dimensions and array shapes of microstructures have different effects on the surface hydrophobicity of PMMA and theθ⊥is more sensitive to the change of dimensions thanθ∥.Moreover,the shape of water droplet is obviously influenced by pinning effect.On elliptical and circular arrays and perpendicular direction of microgroove arrays,the shape of water droplets is dominated by pinning effect.However,on the micro square-pillar arrays and the parallel direction of microgroove arrays,the shape of the water droplet is controlled by the pinning effect and the discontinuity of the solid-liquid-gas three-phase contact line.Research results are expected to support the design of the bio-functional microstructure surfaces.
作者
余剑武
陆岳托
罗红
仝瑞庆
宋金根
YU Jian-wu;LU Yue-tuo;LUO Hong;TONG Rui-qing;SONG Jin-gen(School of Mechanical and Vehicle Engineering,Hunan University,Changsha 410082,China;State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,Changsha 410082,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2021年第1期287-295,共9页
Surface Technology
基金
国家自然科学基金项目(51275165,51575174)
长沙市科技项目(kq1801007)。
关键词
微结构
表面疏水性
接触角
钉扎效应
微铣削
microstructure
surface hydrophobicity
contact angle
pinning effect
micro-milling
