Tag: 친수성

레이저 조사 및 silanization 공정으로 제작된 micro-pillar arrays를 사용하여 초 소수성 표면에 대한 액적 영향 시뮬레이션

ZhenyanXia^a YangZhao^a ZhenYang^abc ChengjuanYang^ab LinanLi^a ShibinWang^a MengWang^ab
aSchool of Mechanical Engineering, Tianjin University, Tianjin, 300054, China
^bKey Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin, 300072, China^c
School of Engineering, University of Warwick, Coventry, CV4 7AL, UK

Received 23 September 2020, Revised 17 November 2020, Accepted 26 November 2020, Available online 11 December 2020.

Abstract

Super-hydrophobicity is one of the significant natural phenomena, which has inspired researchers to fabricate artificial smart materials using advanced manufacturing techniques. In this study, a super-hydrophobic aluminum surface was prepared by nanosecond laser texturing and FAS modification in sequence. The surface wettability turned from original hydrophilicity to super-hydrophilicity immediately after laser treatment. Then it changed to super-hydrophobicity showing a WCA of 157.6 ± 1.2° with a SA of 1.7 ± 0.7° when the laser-induced rough surface being coated with a layer of FAS molecules. The transforming mechanism was further explored from physical and chemical aspects based on the analyses of surface morphology and surface chemistry. Besides, the motion process of droplet impacting super-hydrophobic surface was systematically analyzed via the optimization of simulation calculation grid and the simulation method of volume of fluid (VOF). Based on this simulation method, the morphological changes, the inside pressure distribution and velocity of the droplet were further investigated. And the motion mechanism of the droplet on super-hydrophobic surface was clearly revealed in this paper. The simulation results and the images captured by high-speed camera were highly consistent, which indicated that the computational fluid dynamics (CFD) is an effective method to predict the droplet motion on super- hydrophobic surfaces. This paper can provide an explicit guidance for the selection of suitable methods for functional surfaces with different requirements in the industry.

Korea Abstract

초 소수성은 연구원들이 첨단 제조 기술을 사용하여 인공 스마트 재료를 제작하도록 영감을 준 중요한 자연 현상 중 하나 입니다. 이 연구에서 초 소수성 알루미늄 표면은 나노초 레이저 텍스처링과 FAS 수정에 의해 순서대로 준비되었습니다.

레이저 처리 직후 표면 습윤성은 원래의 친수성에서 초 친수성으로 바뀌 었습니다. 그런 다음 레이저 유도 거친 표면을 FAS 분자 층으로 코팅했을 때 WCA가 157.6 ± 1.2 °이고 SA가 1.7 ± 0.7 ° 인 초 소수성으로 변경되었습니다.

변형 메커니즘은 표면 형태 및 표면 화학 분석을 기반으로 물리적 및 화학적 측면에서 추가로 탐구 되었습니다. 또한, 초 소수성 표면에 영향을 미치는 물방울의 운동 과정은 시뮬레이션 계산 그리드의 최적화와 유체 부피 (VOF) 시뮬레이션 방법을 통해 체계적으로 분석되었습니다.

이 시뮬레이션 방법을 바탕으로 형태학적 변화, 내부 압력 분포 및 액 적의 속도를 추가로 조사했습니다. 그리고 초 소수성 표면에 있는 물방울의 운동 메커니즘이 이 논문에서 분명하게 드러났습니다.

시뮬레이션 결과와 고속 카메라로 캡처한 이미지는 매우 일관적 이었습니다. 이는 전산 유체 역학 (CFD)이 초 소수성 표면에서 액적 움직임을 예측하는 효과적인 방법임을 나타냅니다.

이 백서는 업계의 다양한 요구 사항을 가진 기능 표면에 적합한 방법을 선택하기 위한 명시적인 지침을 제공 할 수 있습니다.

Keywords: Laser irradiation; Wettability; Droplet impact; Simulation; VOF

Introduction

서식지에 적응하기 위해 많은 자연 식물과 동물에서 특별한 습윤 표면이 진화되었습니다 [1-3]. 연잎은 먼지에 의한 오염으로부터 스스로를 보호하기 위해 우수한 자가 청소 특성을 나타냅니다 [4]. 사막 딱정벌레는 공기에서 물을 수확할 수 있는 기능적 표면 때문에 건조한 사막에서 생존 할 수 있습니다 [5].

자연 세계에서 영감을 받아 고체 기질의 표면 습윤성을 수정하는데 더 많은 관심이 집중되었습니다 [6-7]. 기능성 표면의 우수한 성능은 고유 한 표면 습윤성에 기인하며, 이는 고체 표면에서 액체의 확산 능력을 반영하는 중요한 특성 중 하나입니다 [8].

일반적으로 물 접촉각 (WCA) 값에 따라 90 °는 친수성과 소수성의 경계로 간주됩니다. WCA가 90 ° 이상인 소수성 표면, WCA가 90 ° 미만인 친수성 표면 [9 ]. 특히 고체 표면은 WCA가 10 ° 미만의 슬라이딩 각도 (SA)에서 150 °를 초과 할 때 특별한 초 소수성을 나타냅니다 [10-11].

<내용 중략> ……

References

[1] H.W. Chen, P.F. Zhang, L.W. Zhang, Y. Jiang, H.L. Liu, D.Y. Zhang, Z.W. Han, L.
Jiang, Continuous directional water transport on the peristome surface of Nepenthes
alata, Nature 532 (2016) 85-89.
[2] Y. Liu, K.T. Zhang, W.G. Yao, J.A. Liu, Z.W. Han, L.Q. Ren, Bioinspired
structured superhydrophobic and superoleophilic stainless steel mesh for efficient oilwater separation, Colloids Surf., A 500 (2016) 54-63.
[3] Y.X. Liu, W.L. Liu, G.L. Wang, J.C. Hou, H. Kong, W.L. Wang, A facile one-step
approach to superhydrophilic silica film with hierarchical structure using
fluoroalkylsilane, Colloids Surf., A 539 (2018) 109-115.
[4] F.P. Wang, S. Li, L. Wang, Fabrication of artificial super-hydrophobic lotus-leaflike bamboo surfaces through soft lithography, Colloids Surf., A 513 (2017) 389-395.
[5] W. Huang, X.Y. Tang, Z. Qiu, W.X. Zhu, Y.G. Wang, Y.L. Zhu, Z.F. Xiao, H.G.
Wang, D.X. Liang, Jian, L. Y.J Xie, Cellulose-based Superhydrophobic Surface
Decorated with Functional Groups Showing Distinct Wetting Abilities to Manipulate
Water Harvesting, ACS Appl. Mater. Interfaces DOI: 10.1021/acsami.0c12504.
[6] M.Y. Zhang, L.J. Ma, Q. Wang, P. Hao, X. Zheng, Wettability behavior of
nanodroplets on copper surfaces with hierarchical nanostructures, Colloids Surf., A
604 (2020) 125291.
[7] A.F. Pan, W.J. Wang, X.S. Mei, K.D. Wang, X.B. Yang, Rutile TiO2 flocculent
ripples with high antireflectivity and superhydrophobicity on the surface of titanium
under 10 ns laser irradiation without focusing, Langmuir 33 (2017) 9530-9538.
[8] M. Li, X.H. Liu, N. Liu, Z.H. Guo, P.K. Singh, S.Y. Fu, Effect of surface
wettability on the antibacterial activity of nanocellulose-based material with
quaternary ammonium groups, Colloids Surf., A 554 (2018) 122-128.
[9] T.C. Chen, H.T. Liu, H.F. Yang, W. Yan, W. Zhu, H. Liu, Biomimetic fabrication
of robust self-assembly superhydrophobic surfaces with corrosion resistance
properties on stainless steel substrate, RSC Adv. 6 (2016) 43937-43949.
[10] P. Zhang, F.Y. Lv, A review of the recent advances in superhydrophobic surfaces
and the emerging energy-related applications, Energy 82 (2015) 1068-1087.
[11] Z. Yang, X.P. Liu, Y.L. Tian, Novel metal-organic super-hydrophobic surface
fabricated by nanosecond laser irradiation in solution, Colloids Surf., A 587 (2020)
124343.
[12] J.Y. Peng, X.J. Zhao, W.F. Wang, X. Gong, Durable Self-Cleaning Surfaces with
Superhydrophobic and Highly Oleophobic Properties, Langmuir, 35 (2019) 8404-
8412.
[13] Z. Yang, X.P. Liu, Y.L. Tian, A contrastive investigation on anticorrosive
performance of laser-induced super-hydrophobic and oil-infused slippery coatings,
Prog. Org. Coat. 138 (2020) 105313.
[14] J.L. Yong, F. Chen, Q. Yang, J.L. Huo, X. Hou, Superoleophobic Surfaces,
Chem. Soc. Rev. 46 (2017) 4168-4217.
[15] D.W. Li, H.Y. Wang, Y. Liu, D.S. Wei, Z.X. Zhao, Large-Scale Fabrication of
Durable and Robust Super-Hydrophobic Spray Coatings with Excellent Repairable
and Anti-Corrosion Performance, Chem. Eng. J. 367 (2019) 169-179.
[16] R.J. Liao, Z.P. Zuo, C. Guo, Y. Yuan, A.Y. Zhuang, Fabrication of
superhydrophobic surface on aluminum by continuous chemical etching and its antiicing property, Appl. Surf. Sci. 317 (2014) 701-709.
[17] Z. Yang. X.P. Liu, Y.L. Tian, Hybrid laser ablation and chemical modification for
fast fabrication of bio-inspired super-hydrophobic surface with excellent selfcleaning, stability and corrosion resistance, J Bionic Eng 16 (2019) 13-26.
[18] Z. Yang, Y.L. Tian, Y.C. Zhao, C.J. Yang, Study on the fabrication of superhydrophobic surface on Inconel alloy via nanosecond laser ablation, Materials 12
(2019) 278.
[19] Y. Wang, X. Gong, Superhydrophobic Coatings with Periodic Ring Structured
Patterns for Self-Cleaning and Oil-Water Separation, Adv. Mater. Interfaces 4 (2017)
1700190.
[20] N. Chik, W.S.W.M. Zain, A.J. Mohamad, M.Z. Sidek, W.H.W. Ibrahim, A. Reif,
J.H. Rakebrandt, W. Pfleging, X. Liu, Bacterial adhesion on the titanium and
stainless-steel surfaces undergone two different treatment methods: Polishing and ultrafast laser treatment, IOP Conf. Ser.: Mater. Sci. Eng.358 (2018) 012034.
[21] N.K.K. Win, P. Jitareerat, S. Kanlayanarat, S. Sangchote, Effects of cinnamon
extract, chitosan coating, hot water treatment and their combinations on crown rot
disease and quality of banana fruit, Postharvest Biol. Technol. 45 (2007) 333–340.
[22] A. Yarin, Drop impact dynamics: splashing, spreading, receding, bouncing, Annu.
Rev. Fluid Mech. 38 (2006) 159–192.
[23] N. Wang, L.L. Tang, Y.F. Cai, W. Tong, D.S. Xiong, Scalable superhydrophobic
coating with controllable wettability and investigations of its drag reduction, Colloids
Surf. A 555 (2018) 290–295.
[24] R. Fürstner, W. Barthlott, C. Neinhuis, P. Walzel, Wetting and self-cleaning
properties of artificial superhydrophobic surfaces, Langmuir 21 (2005) 956–61.
[25] U. Trdan, M. Hočevar, P. Gregorčič, Transition from superhydrophilic to
superhydrophobic state of laser textured stainless steel surface and its effect on
corrosion resistance, Corros. Sci. 123 (2017) 21–44.
[26] A.L. Biance, C. Clanet, D. Quere, First steps in the spreading of a liquid droplet,
Phys. Rev. E 69 (2004) 016301.
[27] S. Kulju, L. Riegger, P. Koltay et al, Fluid flow simulations meet high-speed
video: computer vision comparison of droplet dynamics, J. Colloid Interface Sci. 522
(2018) 48.
[28] C.J. Yong, B. Bhushan, Dynamic effects of bouncing water droplets on
superhydrophobic surfaces, Langmuir 24.12 (2008) 6262–6269.
[29] G. Karapetsas, N.T. Chamakos, A.G. Papathanasiou, Efficient modelling of
droplet dynamics on complex surfaces, J. Phys.: Condens. Matter 28.8 (2016) 085101.
[30] D. Khojasteh, N.M. Kazerooni, S. Salarian et al, Droplet impact on
superhydrophobic surfaces: a review of recent developments, J. Ind. Eng. Chem. 42
(2016) 1–14.
[31] S.H. Kim, Y. Jiang, H. Kim, Droplet impact and LFP on wettability and
nanostructured surface, Exp. Therm. Fluid Sci. 99 (2018) 85–93.
[32] M. Rudman, Volume‐Tracking Methods for Interfacial Flow Calculations, Int.
J. Numer. Methods Fluids 24.7 (1997) 671-691.