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Yang Q, Liu Y, Jia X, Zhang T, Tian H, Fan J, Xu Q, Song F. Phase-field numerical study on the dynamic process of thermocapillary patterning. Phys Rev E 2022; 106:015111. [PMID: 35974516 DOI: 10.1103/physreve.106.015111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
It is well known that surface tension is dependent on temperature, and thus a nonuniform temperature may cause thermocapillary flow which is referred to as the Marangoni effect. For a thin liquid-air film confined between a flat hot plate and a topographical cold template, it undergoes deformation due to thermocapillary flow. This phenomenon is termed as thermocapillary patterning, and has been used to fabricate micro- and nanostructure in polymer films. In most cases, the obtained structure conforms to the template; i.e., it can be considered as a replication technique. In this paper, we developed a two-phase flow numerical model based on the phase field to study the dynamic process of thermocapillary patterning. As a remeshing-free method, the phase field enables the incorporation of thermal field and multiphase flow with free surface deformation. The numerical model was employed to study the dynamic process of thermocapillary patterning. Meanwhile, the effects of some parameters, e.g., temperature, geometry parameters, and contact angle, were also investigated.
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Affiliation(s)
- Qingzhen Yang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China
- Micro-/Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China
- Research Institute of Xi'an Jiaotong University, Hangzhou, Zhejiang 311215, People's Republic of China
| | - Yankui Liu
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin, Jilin 132012, People's Republic of China
| | - Xinmiao Jia
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China
| | - Tingting Zhang
- College of Mechanical and Electrical Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, People's Republic of China
| | - Hongmiao Tian
- Micro-/Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China
| | - Jing Fan
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin, Jilin 132012, People's Republic of China
| | - Quange Xu
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin, Jilin 132012, People's Republic of China
| | - Fenhong Song
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin, Jilin 132012, People's Republic of China
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Lv G, Tian H, Shao J, Yu D. Pattern formation in thin polymeric films via electrohydrodynamic patterning. RSC Adv 2022; 12:9681-9697. [PMID: 35424937 PMCID: PMC8959450 DOI: 10.1039/d2ra01109c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 03/21/2022] [Indexed: 11/21/2022] Open
Abstract
The free surface of a thin polymeric film is often unstable and deforms into various micro-/nano-patterns under an externally applied electric field. This paper reviews a recent patterning technique, electrohydrodynamic patterning (EHDP), a straightforward, cost-effective and contactless bottom-up method. The theoretical and numerical studies of EHDP are shown. How the characteristic wavelength and the characteristic time depend on both the external conditions (such as voltage, film thickness, template-substrate spacing) and the initial polymer properties (such as rheological property, electrical property and surface tension) is theoretically and experimentally discussed. Various possible strategies for fabricating high-aspect-ratio or hierarchical patterns are theoretically and experimentally reviewed. Aligning and ordering of the anisotropic polymers by EHDP is emphasized. A perspective, including novelty and limitations of the methods, particularly in comparison to some conventional patterning techniques, and a possible future direction of research, is presented.
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Affiliation(s)
- Guowei Lv
- School of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipments, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University Xi'an 710049 Shaanxi P. R. China
- Xi'an Aerospace Chemical Propulsion Co., Ltd. Xi'an 710025 Shaanxi P. R. China
| | - Hongmiao Tian
- State Key Laboratory of Manufacturing Systems Engineering, Xi'an Jiaotong University Xi'an 710049 Shaanxi P. R. China
| | - Jinyou Shao
- State Key Laboratory of Manufacturing Systems Engineering, Xi'an Jiaotong University Xi'an 710049 Shaanxi P. R. China
| | - Demei Yu
- School of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipments, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University Xi'an 710049 Shaanxi P. R. China
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3
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Hwang J, Park H, Lee J, Kang DJ. Parametric scheme for rapid nanopattern replication via electrohydrodynamic instability. RSC Adv 2021; 11:18152-18161. [PMID: 35480914 PMCID: PMC9033445 DOI: 10.1039/d1ra01728d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/10/2021] [Indexed: 11/21/2022] Open
Abstract
Electrohydrodynamic (EHD) instability patterning exhibits substantial potential for application as a next-generation lithographic technique; nevertheless, its development continues to be hindered by the lack of process parameter controllability, especially when replicating sub-microscale pattern features. In this paper, a new parametric guide is introduced. It features an expanded range of valid parameters by increasing the pattern growth velocity, thereby facilitating reproducible EHD-driven patterning for perfect nanopattern replication. Compared with conventional EHD-driven patterning, the rapid patterning approach not only shortens the patterning time but also exhibits enhanced scalability for replicating small and geometrically diverse features. Numerical analyses and simulations are performed to elucidate the interplay between the pattern growth velocity, fidelity of the replicated features, and boundary between the domains of suitable and unsuitable parametric conditions in EHD-driven patterning. The developed rapid route facilitates nanopattern replication using EHD instability with a wide range of suitable parameters and further opens up many opportunities for device applications using tailor-made nanostructures in an effective and straightforward manner. 1/τm-dependent electrohydrodynamic replication of a hexagonally ordered hole array nanopattern by adjusting the filling ratio. As the 1/τm increases, the morphology evolves into the perfectly replicated hole features with increasing filling ratio.![]()
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Affiliation(s)
- Jaeseok Hwang
- Department of Energy Science
- Sungkyunkwan University
- Suwon
- Republic of Korea
| | - Hyunje Park
- Department of Physics
- Sungkyunkwan University
- Suwon
- Republic of Korea
| | - Jaejong Lee
- Korea Institute of Machinery and Materials (KIMM)
- Daejeon 34103
- Republic of Korea
| | - Dae Joon Kang
- Department of Physics
- Sungkyunkwan University
- Suwon
- Republic of Korea
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Nazaripoor H, Koch CR, Sadrzadeh M. Enhanced Electrically Induced Micropatterning of Confined Thin Liquid Films: Thermocapillary Role and Its Limitations. Ind Eng Chem Res 2017. [DOI: 10.1021/acs.iecr.7b02814] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hadi Nazaripoor
- Department of Mechanical
Engineering, 10-367 Donadeo Innovation Center for Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Charles R. Koch
- Department of Mechanical
Engineering, 10-367 Donadeo Innovation Center for Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Mohtada Sadrzadeh
- Department of Mechanical
Engineering, 10-367 Donadeo Innovation Center for Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
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Ravi B, Chakraborty S, Bhattacharjee M, Mitra S, Ghosh A, Gooh Pattader PS, Bandyopadhyay D. Pattern-Directed Ordering of Spin-Dewetted Liquid Crystal Micro- or Nanodroplets as Pixelated Light Reflectors and Locomotives. ACS APPLIED MATERIALS & INTERFACES 2017; 9:1066-1076. [PMID: 28026170 DOI: 10.1021/acsami.6b12182] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Chemical pattern directed spin-dewetting of a macroscopic droplet composed of a dilute organic solution of liquid crystal (LC) formed an ordered array of micro- and nanoscale LC droplets. Controlled evaporation of the spin-dewetted droplets through vacuum drying could further miniaturize the size to the level of ∼90 nm. The size, periodicity, and spacing of these mesoscale droplets could be tuned with the variations in the initial loading of LC in the organic solution, the strength of the centripetal force on the droplet, and the duration of the evaporation. A simple theoretical model was developed to predict the spacing between the spin-dewetted droplets. The patterned LC droplets showed a reversible phase transition from nematic to isotropic and vice versa with the periodic exposure of a solvent vapor and its removal. A similar phase transition behavior was also observed with the periodic increase or reduction of temperature, suggesting their usefulness as vapor or temperature sensors. Interestingly, when the spin-dewetted droplets were confined between a pair of electrodes and an external electric field was applied, the droplets situated at the hydrophobic patches showed light-reflecting properties under the polarization microscopy highlighting their importance in the development of micro- or nanoscale LC displays. The digitized LC droplets, which were stationary otherwise, showed dielectrophoretic locomotion under the guidance of the external electric field beyond a threshold intensity of the field. Remarkably, the motion of these droplets could be restricted to the hydrophilic zones, which were confined between the hydrophobic patches of the chemically patterned surface. The findings could significantly contribute in the development of futuristic vapor or temperature sensors, light reflectors, and self-propellers using the micro- or nanoscale digitized LC droplets.
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Affiliation(s)
- Bolleddu Ravi
- Department of Chemical Engineering, Indian Institute of Technology Guwahati , Guwahati, Assam 781039, India
| | - Snigdha Chakraborty
- Department of Chemical Engineering, Indian Institute of Technology Guwahati , Guwahati, Assam 781039, India
| | - Mitradip Bhattacharjee
- Centre for Nanotechnology, Indian Institute of Technology Guwahati , Guwahati, Assam 781039, India
| | - Shirsendu Mitra
- Department of Chemical Engineering, Indian Institute of Technology Guwahati , Guwahati, Assam 781039, India
| | - Abir Ghosh
- Department of Chemical Engineering, Indian Institute of Technology Kanpur , Kanpur, Uttar Pradesh 208016, India
| | - Partho Sarathi Gooh Pattader
- Department of Chemical Engineering, Indian Institute of Technology Guwahati , Guwahati, Assam 781039, India
- Centre for Nanotechnology, Indian Institute of Technology Guwahati , Guwahati, Assam 781039, India
| | - Dipankar Bandyopadhyay
- Department of Chemical Engineering, Indian Institute of Technology Guwahati , Guwahati, Assam 781039, India
- Centre for Nanotechnology, Indian Institute of Technology Guwahati , Guwahati, Assam 781039, India
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Yang Q, Li BQ, Tian H, Li X, Shao J, Chen X, Xu F. Deformation Hysteresis of Electrohydrodynamic Patterning on a Thin Polymer Film. ACS APPLIED MATERIALS & INTERFACES 2016; 8:17668-17675. [PMID: 27326791 DOI: 10.1021/acsami.6b04192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electrohydrodynamic patterning is a technique that enables micro/nanostructures via imposing an external voltage on thin polymer films. In this investigation, we studied the electrohydrodynamic patterning theoretically and experimentally, with special interest focused on the equilibrium state. It is found that the equilibrium structure height increases with the voltage. In addition, we have observed, and believe it to be the first time, a hysteresis phenomenon exists in the relationship between the voltage and structure height. With an increase in the voltage, a critical value (the first critical voltage) is noticed, above which the polymer film would increase dramatically until it comes into contact with the template. However, with a decrease in the voltage, a smaller voltage (the second critical voltage) is needed to detach the polymer from the template. The mismatch of the first and second critical voltages distorts the voltage-structure height curve into an "S" shape. Such a phenomenon is verified for three representative templates and also by experiments. Furthermore, the effects of some parameters (e.g., polymer film thickness and dielectric constant) on this hysteresis phenomenon are also discussed.
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Affiliation(s)
| | - Ben Q Li
- Department of Mechanical Engineering, University of Michigan-Dearborn , Dearborn, Michigan 48128, United States
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Tian H, Shao J, Hu H, Wang L, Ding Y. Role of space charges inside a dielectric polymer in the electrohydrodynamic structure formation on a prepatterned polymer (ESF-PP). RSC Adv 2016. [DOI: 10.1039/c6ra14479a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mushroom-shaped structures with a high aspect ratio are fabricated based on the action of space charges inside the dielectric polymer.
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Affiliation(s)
- Hongmiao Tian
- Micro- and Nano-technology Research Center
- State Key Laboratory for Manufacturing Systems Engineering
- Xi'an Jiaotong University
- Xi'an
- P. R. China
| | - Jinyou Shao
- Micro- and Nano-technology Research Center
- State Key Laboratory for Manufacturing Systems Engineering
- Xi'an Jiaotong University
- Xi'an
- P. R. China
| | - Hong Hu
- Micro- and Nano-technology Research Center
- State Key Laboratory for Manufacturing Systems Engineering
- Xi'an Jiaotong University
- Xi'an
- P. R. China
| | - Li Wang
- Micro- and Nano-technology Research Center
- State Key Laboratory for Manufacturing Systems Engineering
- Xi'an Jiaotong University
- Xi'an
- P. R. China
| | - Yucheng Ding
- Micro- and Nano-technology Research Center
- State Key Laboratory for Manufacturing Systems Engineering
- Xi'an Jiaotong University
- Xi'an
- P. R. China
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Nazaripoor H, Koch CR, Bhattacharjee S. Electrical perturbations of ultrathin bilayers: role of ionic conductive layer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:14734-14744. [PMID: 25419880 DOI: 10.1021/la503839x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The effect of electrostatic force on the dynamics, morphological evolution, and drainage time of ultrathin liquid bilayers (<100 nm) are investigated for perfect dielectric-perfect dielectric (PD-PD) and ionic liquid-perfect dielectric (IL-PD) bilayers. The weakly nonlinear "thin film" equation is solved numerically to obtain spatiotemporal evolution of the liquid-liquid interface responses to transverse electric field. In order to predict the electrostatic component of conjoining/disjoining pressure acting on the interface for IL-PD bilayers, an analytical model is developed using the nonlinear Poisson-Boltzmann equation. It is found that IL-PD bilayers with electric permittivity ratio of layers (lower to top), εr, greater than one remain stable under an applied electric field. An extensive numerical study is carried out to generate a map based on εr and the initial mean thickness of the lower layer. This map is used to predict the formation of various structures on PD-PD bilayer interface and provides a baseline for unstable IL-PD bilayers. The use of an ionic liquid (IL) layer is found to reduce the size of the structures, but results in polydispersed and disordered pillars spread over the domain. The numerical predictions follow similar trend of experimental observation of Lau and Russel. (Lau, C. Y.; Russel, W. B. Fundamental Limitations on Ordered Electrohydrodynamic Patterning; Macromolecules 2011, 44, 7746-7751).
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Affiliation(s)
- Hadi Nazaripoor
- Department of Mechanical Engineering, University of Alberta , Edmonton, Alberta T6G 2R3, Canada
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Tian H, Shao J, Ding Y, Li X, Liu H. Simulation of polymer rheology in an electrically induced micro- or nano-structuring process based on electrohydrodynamics and conservative level set method. RSC Adv 2014. [DOI: 10.1039/c4ra00553h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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