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Arya P, Wu Y, Wang F, Wang Z, Cadilha Marques G, Levkin PA, Nestler B, Aghassi-Hagmann J. Wetting Behavior of Inkjet-Printed Electronic Inks on Patterned Substrates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:5162-5173. [PMID: 38408752 PMCID: PMC10938881 DOI: 10.1021/acs.langmuir.3c03297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/22/2023] [Accepted: 01/18/2024] [Indexed: 02/28/2024]
Abstract
In inkjet printing technology, one important factor influencing the printing quality and reliability of printed films is the interaction of the jetted ink with the substrate surface. This short-range interaction determines the wettability and the adhesion of the ink to the solid surface and is hence responsible for the final shape of the deposited ink. Here, we investigate wetting morphologies of inkjet-printed inks on patterned substrates by carefully designed experimental test structures and simulations. The contact angles, the surface properties, and drop shapes, as well as their influence on the device variability, are experimentally and theoretically analyzed. For the simulations, we employ the phase-field method, which is based on the free energy minimization of the two-phase system with the given wetting boundary conditions. Through a systematic investigation of printed drops on patterned substrates consisting of hydrophilic and hydrophobic areas, we report that the printed morphology is related not only to the designed layout and the drop volume but also to the printing strategy and the wettability. Furthermore, we show how one can modify the intrinsic wettability of the patterned substrates to enhance the printing quality and reliability. Based on the present findings, we cast light on the improvement of the fabrication quality of thin film transistors.
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Affiliation(s)
- Pooja Arya
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Kaiserstrasse 12, Karlsruhe 76133, Germany
| | - Yanchen Wu
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Kaiserstrasse 12, Karlsruhe 76133, Germany
- Institute
for Applied Materials−Microstructure Modeling and Simulation, Karlsruhe Institute of Technology, Straße am Forum 7, Karlsruhe 76131, Germany
| | - Fei Wang
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Kaiserstrasse 12, Karlsruhe 76133, Germany
- Institute
for Applied Materials−Microstructure Modeling and Simulation, Karlsruhe Institute of Technology, Straße am Forum 7, Karlsruhe 76131, Germany
| | - Zhenwu Wang
- Institute
of Biological and Chemical Systems-Functional Molecular Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Pl. 1, Eggenstein-Leopoldshafen 76344, Germany
- Institute
of Organic Chemistry, Karlsruhe Institute
of Technology, Kaiserstraße
12, Karlsruhe 76131, Germany
| | - Gabriel Cadilha Marques
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Kaiserstrasse 12, Karlsruhe 76133, Germany
| | - Pavel A. Levkin
- Institute
of Biological and Chemical Systems-Functional Molecular Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Pl. 1, Eggenstein-Leopoldshafen 76344, Germany
- Institute
of Organic Chemistry, Karlsruhe Institute
of Technology, Kaiserstraße
12, Karlsruhe 76131, Germany
| | - Britta Nestler
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Kaiserstrasse 12, Karlsruhe 76133, Germany
- Institute
for Applied Materials−Microstructure Modeling and Simulation, Karlsruhe Institute of Technology, Straße am Forum 7, Karlsruhe 76131, Germany
- Institute
of Digital Materials Science, Karlsruhe
University of Applied Sciences, Moltkestraße 30, Karlsruhe 76133, Germany
| | - Jasmin Aghassi-Hagmann
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology, Kaiserstrasse 12, Karlsruhe 76133, Germany
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Lokesh M, Nalupurackal G, Roy S, Chakraborty S, Goswami J, Gunaseelan M, Chowdhury IU, Bhallamudi VP, Sinha Mahapatra P, Roy B. Accelerated self assembly of particles at the air-water interface with optically assisted heating due to an upconverting particle. OPTICS EXPRESS 2023; 31:5075-5086. [PMID: 36785459 DOI: 10.1364/oe.481722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/03/2023] [Indexed: 06/18/2023]
Abstract
Particles can be assembled at the air-water interface due to optically induced local heating. This induces convection currents in the water which brings particles to the surface. We improve the technique by employing an upconverting particle (UCP), which, when illuminated with 975 nm light, not only emits visible emission but also generates heat owing to the poor efficiency of the upconversion process. This induces strong convection currents which makes particles dispersed in the suspension assemble at the interface and immediately under the UCP. We show assembly of polystyrene particles of 1 μm diameter and diamonds of 500 nm diameter bearing Nitrogen-Vacancy (NV) centers around the UCP. We also show, for the first time, that the microdiamonds are assembled within about 30 nm at the bottom of the UCP by utilizing non-radiative energy transfer that reduces the lifetime of the 550 nm emission from about 90 μs to about 50 μs.
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Zhang LZ, Xu SY, Wang YF, Yang YR, Zheng SF, Gao SR, Wang XD, Lee DJ. Impact Dynamics of a Single Droplet on Hydrophobic Cylinders: A Lattice Boltzmann Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11860-11872. [PMID: 36130147 DOI: 10.1021/acs.langmuir.2c01271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This study numerically investigates the effects of the Weber number (We) and cylinder-to-droplet radius ratio (R*) on the impact dynamics of a low-viscosity droplet on a hydrophobic cylinder by the lattice Boltzmann method. The intrinsic contact angle of the surface is chosen as θ0 = 122°± 2°, which ensures a representative hydrophobicity. The regime diagram of the impact dynamics in the parameter space of We versus R* is established with categories of split and nonsplit regimes. The droplet would split during impact as α = We/R* exceeds a critical value. In the nonsplit regime, the droplet bounces off the cylinder at most Weber numbers unless the impact velocity is minuscule (We < 2). The contact time of the droplet on the cylinder surface decreases with increasing R* or decreasing We, indicating bouncing is facilitated under such conditions. This can be explained by the suppressed adhesion dissipation between the droplet and surface due to a reduction in the contact area. In the split regime, sufficient kinetic energy inside the impacting droplet determines whether the whole droplet could detach from the surface. With a small cylinder (R* < 0.83) and large We (>25), the adhesion effect is weakened for the side fragments because of the small contact area, and it facilitates the dripping of fragments. For other conditions, the detachment, especially for the tiny droplet on the cylinder top, only occurs if the deformation is prominent at We > 35. Moreover, the spreading dynamics of the impacting droplet are also highlighted in this work.
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Affiliation(s)
- Ling-Zhe Zhang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Sheng-Yao Xu
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Yi-Feng Wang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Yan-Ru Yang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Shao-Fei Zheng
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Shu-Rong Gao
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Xiao-Dong Wang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Duu-Jong Lee
- Department of Mechanical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong
- Department of Chemical Engineering & Materials Science, Yuan-Ze University, Chungli 320, Taiwan
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Du J, Wang X, Li Y, Min Q, Wu X. Analytical Consideration for the Maximum Spreading Factor of Liquid Droplet Impact on a Smooth Solid Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:7582-7590. [PMID: 34114824 DOI: 10.1021/acs.langmuir.1c01076] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Based on the energy conservation approach, this study develops a universal model to predict the maximum spreading factor of liquid droplet impact on a smooth solid surface. Validated with the present simulations and experiments in the literature, this model effectively overcomes the limitation of previous models in the viscous regime and greatly reduces the computing errors from over 30% to below 6%. It is demonstrated that the underestimated maximum spreading factor by previous models results from the overestimation of viscous dissipation. By replacing the conventional model of spreading time, tm = 8D0/3U0, with a more precise one, tm = 1.47τiWe-0.44, the formulation to compute the viscous dissipation of entire spreading is improved. Finally, we examine the applicability of present model in the capillary regime and good performance is also shown.
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Affiliation(s)
- Jiayu Du
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Xiong Wang
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Yanzhi Li
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Qi Min
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Xinxin Wu
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
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Wang F, Nestler B. Wetting transition and phase separation on flat substrates and in porous structures. J Chem Phys 2021; 154:094704. [PMID: 33685148 DOI: 10.1063/5.0044914] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In contrast to the wetting phenomenon of pure substance phase, we here concentrate on the wetting behavior of immiscible fluids with two components via numerical simulations. We investigate the energetic contribution, the wall energy and the surface excess energy, to the wetting behavior of liquid solutions varying with temperature. This investigation is in accordance with Cahn's wetting transition theory, where the surface composition plays a vital role. By analyzing the energetic contributions, we reveal two different physical mechanisms of complete wetting: (i) surface tension driven complete wetting, where the wetting microstructure is achieved via the outward spreading of the triple junction, and (ii) diffusion induced complete wetting, where the wetting film is achieved through a direct deposition of the solute on the substrate. The former one is consistent with the classic theory of Young's law, and the latter one is an alternative mechanism. To indicate the broad multiplicity of the microstructural arrangements, we take porous structures to exemplarily elucidate the formation of alternative perfect wetting structures. Differing from the wetting on a flat substrate, we show that the surface composition varying with temperature leads to a distinct wetting phenomenon in porous structures. The present findings provide an alternative interpretation for complete wetting and are expected to be exploited for designing more effectively and efficiently superhydrophilic structures.
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Affiliation(s)
- Fei Wang
- Institute of Applied Materials - Computational Materials Science, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131 Karlsruhe, Germany
| | - Britta Nestler
- Institute of Applied Materials - Computational Materials Science, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131 Karlsruhe, Germany
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6
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Suo S, Gan Y. Rupture of Liquid Bridges on Porous Tips: Competing Mechanisms of Spontaneous Imbibition and Stretching. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13642-13648. [PMID: 33147041 DOI: 10.1021/acs.langmuir.0c02479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Liquid bridges are commonly encountered in nature and the liquid transfer induced by their rupture is widely used in various industrial applications. In this work, with the focus on the porous tip, we studied the impacts of capillary effects on the liquid transfer induced by the rupture through numerical simulations. To depict the capillary effects of a porous tip, a time scale ratio, RT, is proposed to compare the competing mechanisms of spontaneous imbibition and external drag. In terms of RT, we then develop a theoretical model for estimating the liquid retention ratio considering the geometry, porosity, and wettability of tips. The mechanism presented in this work provides a possible approach to control the liquid transfer with better accuracy in microfluidics or microfabrications.
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Affiliation(s)
- Si Suo
- School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Yixiang Gan
- School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia
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Xu D, Ba Y, Sun J, Fu X. A Numerical Study of Micro-Droplet Spreading Behaviors on Wettability-Confined Tracks Using a Three-Dimensional Phase-Field Lattice Boltzmann Model. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:340-353. [PMID: 31851519 DOI: 10.1021/acs.langmuir.9b02731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Wettability-confined tracks have been extensively used in open-surface microfluidic devices for their high capacity of transporting droplet pumplessly. Inspired by the experimental work of Sen et al. [ Langmuir 2018 , 34 , 1899 - 1907 ], in the present study, a three-dimensional phase-field lattice Boltzmann model is developed and used to investigate the spreading behaviors of microdroplet on a series of wettability-confined tracks. The experimental findings are successfully reproduced through our simulation, where three distinct stages of droplet spreading on the horizontal wettability-confined diverging track are fairly exhibited, that is, the initial stage with droplet front spreading quickly, the intermediate stage with both droplet front and bulge moving forward at a constant speed, and the final stage with droplet front decelerating gradually. Moreover, a parametric study of track divergence angle is further performed, and the influential mechanism of track divergence angle on droplet spreading is further revealed. It is demonstrated that track divergence is responsible for the Laplace pressure gradient and capillary force inside the droplet, which drives the droplet bulge to move forward on the diverging track. With an increase in divergence angle, the capillary force increases linearly, which increases the droplet spreading speed at the initial and intermediate stages, while the peak capillary force comes earlier, and consequently the final decelerating stage comes earlier. On the basis of the parametric study and droplet volume conservation rule, a power law relation between track divergence angle and droplet spreading is proposed, which helps to identify the start of final decelerating stage. Finally, the droplet spreading over various inclined tracks is explored, which can be achieved only when the capillary force at the beginning is larger than the droplet gravity component along the inclined track surface.
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Affiliation(s)
- Da Xu
- School of Energy and Power Engineering , Xi'an Jiaotong University , 28 West Xianning Road , Xi'an 710049 , China
| | - Yan Ba
- School of Astronautics , Northwestern Polytechnical University , 127 West Youyi Road , Xi'an 710072 , China
| | - Jinju Sun
- School of Energy and Power Engineering , Xi'an Jiaotong University , 28 West Xianning Road , Xi'an 710049 , China
| | - Xiaojin Fu
- School of Energy and Power Engineering , Xi'an Jiaotong University , 28 West Xianning Road , Xi'an 710049 , China
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Wu Y, Wang F, Selzer M, Nestler B. Droplets on chemically patterned surface: A local free-energy minima analysis. Phys Rev E 2019; 100:041102. [PMID: 31770894 DOI: 10.1103/physreve.100.041102] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Indexed: 06/10/2023]
Abstract
Droplet wetting on solid surfaces is a ubiquitous phenomenon in nature and applications. The wetting behavior of droplets on homogeneous surfaces has been accurately elucidated by the quintessential Young's law. However, on heterogeneous substrates, due to the energy barriers and contact line pinning effect, more than one equilibrated droplet pattern exists, which is more close to reality. Here, we propose a concise mathematical-physical model to delineate the droplet patterns on chemically patterned surfaces: stripe, "chocolate," and "chessboard." The present concept is capable of predicting the number as well as the morphologies of the equilibrated droplets on chemically patterned surfaces. We anticipate that the current work can be applied to fabricate programmable surfaces involving droplet manipulation in integrated circuits, biochips, and smart microelectronics.
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Affiliation(s)
- Yanchen Wu
- Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology, Straße am Forum 7, 76131 Karlsruhe, Germany
| | - Fei Wang
- Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology, Straße am Forum 7, 76131 Karlsruhe, Germany
| | - Michael Selzer
- Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology, Straße am Forum 7, 76131 Karlsruhe, Germany and Institute of Digital Materials Science, Karlsruhe University of Applied Sciences, Moltkestraße 30, 76133 Karlsruhe, Germany
| | - Britta Nestler
- Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology, Straße am Forum 7, 76131 Karlsruhe, Germany and Institute of Digital Materials Science, Karlsruhe University of Applied Sciences, Moltkestraße 30, 76133 Karlsruhe, Germany
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