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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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Xu XY, Xu Z, Wang XD, Qin SC, Qian YW, Wang LD, Liu JS. Loading a High-Viscous Droplet via the Cone-Shaped Liquid Bridge Induced by an Electrostatic Force. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2334-2340. [PMID: 33529533 DOI: 10.1021/acs.langmuir.0c03154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In transfer printing, the loaded droplet on the probe has a significant influence on the dispensing resolution. A suitable loading approach for a high-viscous liquid is highly required. Herein, a novel electrostatic loading method is presented, in which the main aim is to control precisely the formation and breaking of a cone-shaped liquid bridge. An experimental device is developed. The influence of electrical and geometric parameters on the feature size of the liquid bridge is investigated in detail. In the formation of the liquid bridge, the increase of voltage or the decrease of the air gap can enhance the electric field intensity, thus reducing the formation period and increasing the initial cone tip diameter of the liquid cone. After the liquid bridge is formed, both the circuit current implying the liquid wetted area on the probe surface and the lifting velocity of the probe are utilized to further regulate the volume of the loaded droplet. Loaded droplets ranging from 60 to 600 pL are obtained via the method with a standard deviation of 4 to 30 pL. Moreover, a dot array is transferred with different loaded droplets. The minimum diameter of the printed dots is about 140 μm with a variation less than 5%. The advantages include the reduced risk of contamination, the droplet-size independent of the size of the probe, and the low cost of the device.
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Affiliation(s)
- Xiao-Yu Xu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Zheng Xu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Xiao-Dong Wang
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Shao-Chun Qin
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Yan-Wen Qian
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Li-Ding Wang
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Jun-Shan Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
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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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Nazaripoor H, Koch CR, Sadrzadeh M, Bhattacharjee S. Compact micro/nano electrohydrodynamic patterning: using a thin conductive film and a patterned template. SOFT MATTER 2016; 12:1074-1084. [PMID: 26574883 DOI: 10.1039/c5sm02258d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The influence of electrostatic heterogeneity on the electric-field-induced destabilization of thin ionic liquid (IL) films is investigated to control spatial ordering and to reduce the lateral dimension of structures forming on the films. Commonly used perfect dielectric (PD) films are replaced with ionic conductive films to reduce the lateral length scales to a sub-micron level in the EHD pattering process. The 3-D spatiotemporal evolution of a thin IL film interface under homogenous and heterogeneous electric fields is numerically simulated. Finite differences in the spatial directions using an adaptive time step ODE solver are used to solve the 2-D nonlinear thin film equation. The validity of our simulation technique is determined from close agreement between the simulation results of a PD film and the experimental results in the literature. Replacing the flat electrode with the patterned one is found to result in more compact and well-ordered structures particularly when an electrode with square block protrusions is used. This is attributed to better control of the characteristic spatial lengths by applying a heterogeneous electric field by patterned electrodes. The structure size in PD films is reduced by a factor of 4 when they are replaced with IL films, which results in nano-sized features with well-ordered patterns over the domain.
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Affiliation(s)
- Hadi Nazaripoor
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, CanadaT6G2G8.
| | - Charles R Koch
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, CanadaT6G2G8.
| | - Mohtada Sadrzadeh
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, CanadaT6G2G8.
| | - Subir Bhattacharjee
- Water Planet Engineering, 721 Glasgow Ave, Unit D, Inglewood, California 90301, USA
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