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Choi C, Choi J, Jo JS, Jeon GW, Lee KW, Park DH, Jang JW. Photoluminescence variations in organic fluorescent crystals by changing the surface energy of the substrate. J Colloid Interface Sci 2024; 663:379-386. [PMID: 38412723 DOI: 10.1016/j.jcis.2024.02.131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/29/2024] [Accepted: 02/16/2024] [Indexed: 02/29/2024]
Abstract
Organic fluorescent crystals were obtained using single-benzene-based diethyl 2,5-dihydroxyterephthalate (DDT) molecules through crystallization from a droplet of the DDT solution on an Au substrate. To control the size of the DDT crystals, the surface energy of the Au substrate was modified with air plasma treatment, producing a hydrophilic surface and a hydrophobic self-assembled monolayer (SAM) coating. The size of DDT crystals increased as the surface energy of the substrate decreased. The averaged cross-section area of the DDT crystals on the Au substrates increased in the order of the air-plasma-treated substrate (∼23.43 μm2) < pristine substrate (∼225.6 μm2) < hydrophobic SAM-coated substrate (∼2240 μm2). On the other hand, the main emission of the DDT crystals redshifted from blue to green as the crystal size increased, which is related to the aggregation of the DDT crystals. Moreover, the coffee-ring effect during the DDT crystallization was hindered by controlling the solvent evaporation conditions. As examples of the application of the proposed technique, patterned DDT crystals were obtained using selectively patterned hydrophobic and hydrophilic substrates.
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Affiliation(s)
- Chiwon Choi
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea
| | - Jinho Choi
- Department of Chemical Engineering, Program in Biomedical Science and Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Jeong-Sik Jo
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea
| | - Gi Wan Jeon
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea
| | - Kyu Won Lee
- Department of Physics, Korea University, Seoul 02841, Republic of Korea
| | - Dong Hyuk Park
- Department of Chemical Engineering, Program in Biomedical Science and Engineering, Inha University, Incheon 22212, Republic of Korea.
| | - Jae-Won Jang
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea.
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2
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Development of a Workflow to Engineer Tailored Microparticles Via Inkjet Printing. Pharm Res 2023; 40:281-294. [PMID: 36380170 DOI: 10.1007/s11095-022-03426-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/28/2022] [Indexed: 11/16/2022]
Abstract
PURPOSE New drug development and delivery approaches result in an ever-increasing demand for tailored microparticles with defined sizes and structures. Inkjet printing technologies could be promising new processes to engineer particles with defined characteristics, as they are created to precisely deliver liquid droplets with high uniformity. METHODS D-mannitol was used as a model compound alone or co-processed with the pore former agent ammonium bicarbonate, and the polymer polyethylene glycol 200. Firstly, a drop shape analyzer was used to characterize and understand ink/substrate interactions, evaporation, and solidification kinetics. Consequently, the process was transferred to a laboratory-scale inkjet printer and the resulting particles collected, characterized and compared to others obtained via an industrial standard technique. RESULTS The droplet shape analysis allowed to understand how 3D structures are formed and helped define the formulation and process parameters for inkjet printing. By adjusting the drop number and process waveform, spherical particles with a mean size of approximately 100 µm were obtained. The addition of pore former and polymer allowed to tailor the crystallization kinetics, resulting in particles with a different surface (i.e., spike-like surface) and bulk (e.g. porous and non-porous) structure. CONCLUSION The workflow described enabled the production of 3D structures via inkjet printing, demonstrating that this technique can be a promising approach to engineer microparticles.
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Cedeno R, Grossier R, Tishkova V, Candoni N, Flood AE, Veesler S. Evaporation Dynamics of Sessile Saline Microdroplets in Oil. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:9686-9696. [PMID: 35901237 DOI: 10.1021/acs.langmuir.2c01269] [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
The occurrence of concentration and temperature gradients in saline microdroplets evaporating directly in air makes them unsuitable for nucleation studies where homogeneous composition is required. This can be addressed by immersing the droplet in oil under regulated humidity and reducing the volume to the picoliter range. However, the evaporation dynamics of such a system is not well understood. In this work, we present evaporation models applicable for arrays of sessile microdroplets with dissolved solute submerged in a thin layer of oil. Our model accounts for the variable diffusion distance due to the presence of the oil film separating the droplet and air, the variation of the solution density and water activity due to the evolving solute concentration, and the diffusive interaction between neighboring droplets. Our model shows excellent agreement with experimental data for both pure water and NaCl solution. With this model, we demonstrate that assuming a constant evaporation rate and neglecting the diffusive interactions can lead to severe inaccuracies in the measurement of droplet concentration, particularly during nucleation experiments. Given the significance of droplet evaporation in a wide array of scientific and industrial applications, the models and insights presented herein would be of great value to many fields of interest.
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Affiliation(s)
- Ruel Cedeno
- CNRS, Aix-Marseille University, CINaM (Centre Interdisciplinaire de Nanosciences de Marseille), Campus de Luminy, Case 913, F-13288 Marseille Cedex 09, France
- Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand
| | - Romain Grossier
- CNRS, Aix-Marseille University, CINaM (Centre Interdisciplinaire de Nanosciences de Marseille), Campus de Luminy, Case 913, F-13288 Marseille Cedex 09, France
| | - Victoria Tishkova
- CNRS, Aix-Marseille University, CINaM (Centre Interdisciplinaire de Nanosciences de Marseille), Campus de Luminy, Case 913, F-13288 Marseille Cedex 09, France
| | - Nadine Candoni
- CNRS, Aix-Marseille University, CINaM (Centre Interdisciplinaire de Nanosciences de Marseille), Campus de Luminy, Case 913, F-13288 Marseille Cedex 09, France
| | - Adrian E Flood
- Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand
| | - Stéphane Veesler
- CNRS, Aix-Marseille University, CINaM (Centre Interdisciplinaire de Nanosciences de Marseille), Campus de Luminy, Case 913, F-13288 Marseille Cedex 09, France
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4
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Hierarchical Exploration of Drying Patterns Formed in Drops Containing Lysozyme, PBS, and Liquid Crystals. Processes (Basel) 2022. [DOI: 10.3390/pr10050955] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Biological systems, by nature, are highly complex. These systems exhibit diverse hierarchical spatial and temporal features when driven far from equilibrium. The generated features are susceptible to the initial conditions that largely depend on vast parameter space. Extracting information on their properties and behavior thus becomes far too complex. This work seeks to examine the drying kinetics of the drops containing a globular protein (xlysozyme (Lys)), phosphate buffer saline (PBS), and thermotropic liquid crystal (LCs). The drying evolution and the morphological crack patterns of these drops are examined using high-resolution microscopy, textural image analysis, and statistical methods. This study observes that the textural parameters can identify the (i) phase separation of the salts present in the PBS and (ii) the LCs’ birefringence during the drying evolution. This birefringence activities of the LCs slow down when the initial PBS concentration is increased from 0.25 to 1× despite using a fixed volume of LCs. To comprehend such a surprising effect, the combinations of (i) Lys+PBS and (ii) PBS+LCs are thoroughly examined. A phase diagram is established as a function of initial concentrations of Lys and PBS. The scanning electron microscopic images of Lys+PBS reveal that the tuning between lysozyme and salt concentrations in PBS plays a significant role in determining the morphological patterns. The Lys drops with and without LCs exhibit two distinct regions: the peripheral ring (“coffee-ring”) and the central ones. This phase-separated ring formation indicates that the film containing Lys and salts might have formed on top of these LCs in the central region, which reduces the optical response (birefringence) of LCs. A physical mechanism is proposed in this paper to anticipate the redistributions of LCs in a multi-component system such as Lys+PBS+LCs.
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5
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Cedeno R, Grossier R, Lagaize M, Nerini D, Candoni N, Flood A, Veesler S. Nucleation in Sessile Saline Microdroplets: Induction Time Measurement via Deliquescence-Recrystallization Cycling. Faraday Discuss 2022; 235:183-197. [DOI: 10.1039/d1fd00090j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Induction time, a measure of how long one will wait for nucleation to occur, is an important parameter in quantifying nucle-ation kinetics and its underlying mechanisms. Due to the stochastic...
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6
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The Effect of Substrate Temperature on the Evaporative Behaviour and Desiccation Patterns of Foetal Bovine Serum Drops. COLLOIDS AND INTERFACES 2021. [DOI: 10.3390/colloids5040043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The drying of bio-fluid drops results in the formation of complex patterns, which are morphologically and topographically affected by environmental conditions including temperature. We examine the effect of substrate temperatures between 20 °C and 40 °C, on the evaporative dynamics and dried deposits of foetal bovine serum (FBS) drops. The deposits consist of four zones: a peripheral protein ring, a zone of protein structures, a protein gel, and a central crystalline zone. We investigate the link between the evaporative behaviour, final deposit volume, and cracking. Drops dried at higher substrate temperatures in the range of 20 °C to 35 °C produce deposits of lower final volume. We attribute this to a lower water content and a more brittle gel in the deposits formed at higher temperatures. However, the average deposit volume is higher for drops dried at 40 °C compared to drops dried at 35 °C, indicating protein denaturation. Focusing on the protein ring, we show that the ring volume decreases with increasing temperature from 20 °C to 35 °C, whereas the number of cracks increases due to faster water evaporation. Interestingly, for deposits of drops dried at 40 °C, the ring volume increases, but the number of cracks also increases, suggesting an interplay between water evaporation and increasing strain in the deposits due to protein denaturation.
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7
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Shao X, Hou Y, Zhong X. Modulation of evaporation-affected crystal motion in a drying droplet by saline and surfactant concentrations. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126701] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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8
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Oscillatory Reversible Osmotic Growth of Sessile Saline Droplets on a Floating Polydimethylsiloxane Membrane. FLUIDS 2021. [DOI: 10.3390/fluids6070232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We report a cyclic growth/retraction phenomena observed for saline droplets placed on a cured poly (dimethylsiloxane) (PDMS) membrane with a thickness of 7.8 ± 0.1 µm floating on a pure water surface. Osmotic mass transport across the micro-scaled floating PDMS membrane provided the growth of the sessile saline droplets followed by evaporation of the droplets. NaCl crystals were observed in the vicinity of the triple line at the evaporation stage. The observed growth/retraction cycle was reversible. A model of the osmotic mass transfer across the cured PDMS membrane is suggested and verified. The first stage of the osmotic growth of saline droplets is well-approximated by the universal linear relationship, whose slope is independent of the initial radius of the droplet. The suggested physical model qualitatively explains the time evolution of the droplet size. The reported process demonstrates a potential for use in industrial desalination.
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9
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Li D, Chen R, Zhu X, Liao Q, Ye D, Yang Y, Li W, Li H, Yang Y. Light-Fueled Beating Coffee-Ring Deposition for Droplet Evaporative Crystallization. Anal Chem 2021; 93:8817-8825. [PMID: 34110126 DOI: 10.1021/acs.analchem.1c00605] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Condensed deposition favors biochemical analysis, bioassays, and clinical diagnosis, but the existing strategies may suffer from low resolution, inaccurate control, cross-contamination, or miscellaneous apparatus. Herein, we propose a noncontact light strategy to enable the condensed deposition for droplet evaporative crystallization, in which the photothermal effect of a focused infrared laser is employed to induce intense evaporation. Due to the localized heating effect, not only can the droplet evaporative crystallization on the hydrophobic substrate be promoted, but also the resultant intensified Marangoni flow enables the movement of the early-formed crystals, preventing the pinning of the triple-phase contact line. Synergy of the Marangoni flow and nonuniform evaporation makes the solutes tend to accumulate near the focused light beam region, which facilitates the condensed deposition. More importantly, this light strategy not only enables condensed deposition on the hydrophobic surface with low hysteresis, but also works successfully on the hydrophilic substrate with high hysteresis via adjusting input laser power. It is demonstrated that the light strategy proposed in the present study has great potential for relevant applications.
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Affiliation(s)
- Dongliang Li
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400030, China.,Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400030, China
| | - Rong Chen
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400030, China.,Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400030, China
| | - Xun Zhu
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400030, China.,Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400030, China
| | - Qiang Liao
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400030, China.,Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400030, China
| | - Dingding Ye
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400030, China.,Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400030, China
| | - Yang Yang
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400030, China.,Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400030, China
| | - Wei Li
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400030, China.,Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400030, China
| | - Haonan Li
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400030, China.,Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400030, China
| | - Yijing Yang
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400030, China.,Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400030, China
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10
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Tanis-Kanbur MB, Kumtepeli V, Kanbur BB, Ren J, Duan F. Transient Prediction of Nanoparticle-Laden Droplet Drying Patterns through Dynamic Mode Decomposition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2787-2799. [PMID: 33577318 DOI: 10.1021/acs.langmuir.0c03546] [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
Nanoparticle-laden sessile droplet drying has a wide impact on applications. However, the complexity affected by the droplet evaporation dynamics and particle self-assembly behavior leads to challenges in the accurate prediction of the drying patterns. We initiate a data-driven machine learning algorithm by using a single data collection point via a top-view camera to predict the transient drying patterns of aluminum oxide (Al2O3) nanoparticle-laden sessile droplets with three cases according to particle sizes of 5 and 40 nm and Al2O3 concentrations of 0.1 and 0.2 wt %. Dynamic mode decomposition is used as the data-driven learning model to recognize each nanoparticle-laden droplet as an individual system and then apply the transfer learning procedure. Along 270 s of droplet drying experiments, the training period of the first 100 s is selected, and then the rest of the 170 s is predicted with less than a 10% error between the predicted and the actual droplet images. The developed data-driven approach has also achieved the acceptable prediction for the droplet diameter with less than 0.13% error and a coffee-ring thickness over a range of 2.0 to 6.7 μm. Moreover, the proposed machine learning algorithm can recognize the volume of the droplet liquid and the transition of the drying regime from one to another according to the predicted contact line and the droplet height.
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Affiliation(s)
| | - Volkan Kumtepeli
- Energy Research Institute, Nanyang Technological University, Singapore 637371
| | - Baris Burak Kanbur
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798
| | - Junheng Ren
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798
| | - Fei Duan
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798
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11
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Ivanova N, Esenbaev T. Wetting and dewetting behaviour of hygroscopic liquids: Recent advancements. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2020.101399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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12
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Liu X, Yang F, Guo J, Fu J, Guo Z. New insights into unusual droplets: from mediating the wettability to manipulating the locomotion modes. Chem Commun (Camb) 2020; 56:14757-14788. [PMID: 33125006 DOI: 10.1039/d0cc05801g] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The ability to manipulate droplets can be utilized to develop various smart sensors or actuators, endowing them with fascinating applications for drug delivery, detection of target analytes, environmental monitoring, intelligent control, and so on. However, the stimuli-responsive superhydrophobic/superhydrophilic materials for normal water droplets cannot satisfy the requirements from some certain circumstances, i.e., liquid lenses and biosensors (detection of various additives in water/blood droplets). Stimuli-responsive wetting/dewetting behaviors of exceptional droplets are open issues and are attracting much attention from across the world. In this perspective article, the unconventional droplets are divided into three categories: ionic or surfactant additives in water droplets, oil droplets, and bubble droplets. We first introduce several classical wettability models of droplets and some methods to achieve wettability transition. The unusual droplet motion is also introduced in detail. There are four main types of locomotion modes, which are vertical rebound motion, lateral motion, self-propulsion motion, and anisotropic wettability controlled sliding behavior. The driving mechanism for the droplet motion is briefly introduced as well. Some approaches to achieve this manipulation goal, such as light irradiation, electronic, magnetic, acid-base, thermal, and mechanical ways will be taken into consideration. Finally, the current researches on unconventional droplets extending to polymer droplets and liquid metal droplets on the surface of special wettability materials are summarized and the prospect of unconventional droplet research directions in the field of on-demand transport application will be proposed.
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Affiliation(s)
- Xianchen Liu
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering and Hubei Key Laboratory of Polymer Materials, Hubei University, Wuhan 430062, People's Republic of China.
| | - Fuchao Yang
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering and Hubei Key Laboratory of Polymer Materials, Hubei University, Wuhan 430062, People's Republic of China.
| | - Jie Guo
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering and Hubei Key Laboratory of Polymer Materials, Hubei University, Wuhan 430062, People's Republic of China.
| | - Jing Fu
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering and Hubei Key Laboratory of Polymer Materials, Hubei University, Wuhan 430062, People's Republic of China. and School of Chemistry and Environment Engineering, Wuhan Institute of Technology, Wuhan 430205, People's Republic of China
| | - Zhiguang Guo
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering and Hubei Key Laboratory of Polymer Materials, Hubei University, Wuhan 430062, People's Republic of China. and State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China.
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13
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McBride SA, Skye R, Varanasi KK. Differences between Colloidal and Crystalline Evaporative Deposits. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:11732-11741. [PMID: 32937070 DOI: 10.1021/acs.langmuir.0c01139] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Evaporative deposits from drops are widely studied due to their numerous applications in low-effort self-assembly, including for inkjet printing, microscale separations, and sensing/diagnostics. This phenomenon has been broadly explored for drops containing suspended colloidal particles but has been less quantified for drops with dissolved solutes. When a drop of solute/solvent mixture is evaporated on a substrate, nonvolatile solutes become supersaturated as the solvent evaporates, which then leads to crystal nucleation at the substrate-drop contact line. Emerging crystals alter the local wettability and fundamentally alter the dynamics of evaporation, which, in turn, influences the resultant evaporative deposit. Here we investigate the role of interactions between the substrate, crystals, and solution by comparing the evaporative deposition of three different salts as solutes against an evaporating colloidal solution. We show that nucleation effects can cause crystalline deposits to have a temperature relationship that is opposite to that of colloidal deposits and demonstrate how a balance between the contact-line pinning force and nucleation controls the deposit size.
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Affiliation(s)
- Samantha A McBride
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Rachael Skye
- Department of Materials Science Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Kripa K Varanasi
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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14
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Liu L, Zhang K, Kong S, Wang X, Yong L, Mi M. Evaporation and crystallization process for sessile saline droplets during depressurization. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2020; 43:36. [PMID: 32524432 DOI: 10.1140/epje/i2020-11956-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
The evaporation and crystallization process for sessile saline droplets during depressurization is experimentally studied. The relationship between ambient pressure and the crystallization pattern is primarily discussed. When the ambient pressure is low, salt particles are easily formed at the droplet contact line. In contrast, when the ambient pressure is similar to atmospheric pressure, it is more likely for cubic crystals to be formed inside the droplet. By analysing the contact angle fluctuation during crystallization, the experimental results show that the growth of a cubic salt crystal under high ambient pressure or low salt concentration leads to a greater deformation of the liquid-gas interface and a larger contact angle fluctuation. Finally, the Peclet number Pe is introduced to reflect the ratio of the rate of ion advection to the rate of diffusion. The Pe number is larger at lower ambient pressure, which means that the external mass transfer and convection effect is more significant under low pressure, with salt particles easily formed at the droplet contact line. The effect of concentration diffusion inside the droplet increases at higher ambient pressure, thereby, making it easy for cubic crystals to be formed inside the droplet.
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Affiliation(s)
- Lu Liu
- Department of Power Engineering, North China Electric Power University, No. 619 Yonghuabei Street, 071003, Baoding, China.
| | - Kaiqi Zhang
- Department of Power Engineering, North China Electric Power University, No. 619 Yonghuabei Street, 071003, Baoding, China
| | - Shuxian Kong
- Department of Power Engineering, North China Electric Power University, No. 619 Yonghuabei Street, 071003, Baoding, China
| | - Xilin Wang
- Department of Power Engineering, North China Electric Power University, No. 619 Yonghuabei Street, 071003, Baoding, China
| | - Libo Yong
- Department of Power Engineering, North China Electric Power University, No. 619 Yonghuabei Street, 071003, Baoding, China
| | - Menglong Mi
- Department of Power Engineering, North China Electric Power University, No. 619 Yonghuabei Street, 071003, Baoding, China
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15
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Efstratiou M, Christy J, Sefiane K. Crystallization-Driven Flows within Evaporating Aqueous Saline Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4995-5002. [PMID: 32319295 DOI: 10.1021/acs.langmuir.0c00576] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Using micro-PIV (particle image velocimetry), we observe for the first time, the direct correlation between crystallization and hydrodynamics in evaporating microliter saline (1 M NaCl) sessile drops. The relationship is demonstrated by a remarkable jet of liquid along the base of the drops, induced by, and directed at the point of nucleation and subsequent crystal growth. Prior to nucleation, the flow is more uniformly outward with the magnitude of the velocity decreasing with time. From calculations and the flow measurements in the two observed stages of evaporation (prior to nucleation and during crystallization), this jet can be explained on the basis of competition between solutal Marangoni convection and mass conservation flow. The jet of fluid leads to vortices on either side of the crystal in which the salt concentration is reduced, providing a potential explanation as to why NaCl deposits as a sequence of discrete crystals rather than as a continuous ring for such drops.
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Affiliation(s)
- Marina Efstratiou
- Institute of Multiscale Thermofluids, School of Engineering, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3FD, U.K
| | - John Christy
- Institute of Multiscale Thermofluids, School of Engineering, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3FD, U.K
| | - Khellil Sefiane
- Institute of Multiscale Thermofluids, School of Engineering, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3FD, U.K
- Tianjin Key Lab of Refrigeration Technology, Tianjin University of Commerce, Tianjin City 300134, PR China
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16
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Lama H, Satapathy DK, Basavaraj MG. Modulation of Central Depletion Zone in Evaporated Sessile Drops via Substrate Heating. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4737-4744. [PMID: 32259450 DOI: 10.1021/acs.langmuir.0c00785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this article, we report the influence of substrate temperature (Tsub) on the evaporation driven patterning of colloids on solid substrates. When the drops are dried in an environment maintained at temperature, Tenv, lower than Tsub, the temperature difference between the drop apex and the three-phase contact line leads to thermal Marangoni flow. We show that the interplay between the radial capillary flow, the thermal Marangoni flow, and the descending rate of the drop surface can be tuned to modulate the spatial distribution of colloids in the dried deposits. At ΔT (=Tsub - Tenv) ≥ 45 °C, the distribution of particles in the interior region of the pattern is nearly uniform with a significant decrease in concentration of particles in the ring-like deposit at the edge. The deposits formed at 15 °C ≤ ΔT ≤ 40 °C are accompanied by a particle depleted zone in the center, which has not been reported to date. The formation of the central depletion zone arises from the suppression of the thermal Marangoni flow at the penultimate stage of drying and the interplay between the radial capillary flow and the descending rate of the drop surface. At ΔT < 15 °C, the dried deposits are found to exhibit coffee-ring-like stains.
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Affiliation(s)
- Hisay Lama
- Soft Materials Laboratory, Department of Physics, IIT Madras, Chennai-600036, India
- PECS Laboratory, Department of Chemical Engineering, IIT Madras, Chennai-600036, India
| | - Dillip K Satapathy
- Soft Materials Laboratory, Department of Physics, IIT Madras, Chennai-600036, India
| | - Madivala G Basavaraj
- PECS Laboratory, Department of Chemical Engineering, IIT Madras, Chennai-600036, India
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Li X, Sanderson AR, Allen SS, Lahr RH. Tap water fingerprinting using a convolutional neural network built from images of the coffee-ring effect. Analyst 2020; 145:1511-1523. [PMID: 31934695 DOI: 10.1039/c9an01624d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A low-cost tap water fingerprinting technique was evaluated using the coffee-ring effect, a phenomenon by which tap water droplets leave distinguishable "fingerprint" residue patterns after water evaporates. Tap waters from communities across southern Michigan dried on aluminum and photographed with a cell phone camera and 30× loupe produced unique and reproducible images. A convolutional neural network (CNN) model was trained using the images from the Michigan tap waters, and despite the small size of the image dataset, the model assigned images into groups with similar water chemistry with 80% accuracy. Synthetic solutions containing only the majority species measured in Detroit, Lansing, and Michigan State University tap waters did not display the same residue patterns as collected waters; thus, the lower concentration species also influence the tap water "fingerprint". Residue pattern images from salt mixtures with an array of sodium, calcium, magnesium, chloride, bicarbonate, and sulfate concentrations were analyzed by measuring features observed in the photographs as well as using principal component analysis (PCA) on the image files and particles measurements. These analyses together highlighted differences in the residue patterns associated with the water chemistry in the sample. The results of these experiments suggest that the unique and reproducible residue patterns of tap water samples that can be imaged with a cell phone camera and a loupe contain a wealth of information about the overall composition of the tap water, and thus, the phenomenon should be further explored for potential use in low-cost tap water fingerprinting.
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Affiliation(s)
- Xiaoyan Li
- Department of Civil & Environmental Engineering, Michigan State University, 1449 Engineering Research Ct., East Lansing, MI 48824, USA.
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18
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Zhong X, Ren J, Chong KSL, Ong KS, Duan F. Wetting Transition at a Threshold Surfactant Concentration of Evaporating Sessile Droplets on a Patterned Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:4509-4517. [PMID: 30865459 DOI: 10.1021/acs.langmuir.9b00170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Wetting transitions induced by varying the components in a solution of a drying droplet can lead to its evolving shape on a textured surface. It can provide new insights on liquid pattern control through manipulating droplet solutions. We show the pronounced transitions of wetting for surfactant solution droplets drying on a micropyramid-patterned surface. At low initial surfactant concentrations, the droplet maintains an octagonal shape until the end of drying. At intermediate initial surfactant concentrations, the early octagon spreads to a square, which later evolves to a stretched rectangle. At high initial surfactant concentrations, the droplet mainly exhibits the "octagon-to-square" transition, and the square shape is maintained until the end. The octagon-to-square transition occurs at similar temporal volume-averaged surfactant concentrations for the various initial surfactant concentrations. It results from the dependence of the surface energy change of spread over the micropyramid structure on the temporal volume-averaged surfactant concentration. At high initial surfactant concentrations, the accumulation of the surfactant near the contact line driven by outward flows could raise the local viscosity and enhance the pinning effect, leading to the great suppression of the "square-to-rectangle" transition.
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Affiliation(s)
- Xin Zhong
- School of Mechanical and Aerospace Engineering , Nanyang Technological University , 50 Nanyang Avenue , Singapore 639798 , Singapore
- State Key Laboratory of Multiphase Flow in Power Engineering , Xi'an Jiaotong University , Xi'an 710049 , P. R. China
| | - Junheng Ren
- School of Mechanical and Aerospace Engineering , Nanyang Technological University , 50 Nanyang Avenue , Singapore 639798 , Singapore
| | - Karen Siew-Ling Chong
- Institute of Materials Research and Engineering, A*Star , 2 Fusionopolis Way, Innovis, Level 9 , Singapore 138634 , Singapore
| | - Kian-Soo Ong
- Institute of Materials Research and Engineering, A*Star , 2 Fusionopolis Way, Innovis, Level 9 , Singapore 138634 , Singapore
| | - Fei Duan
- School of Mechanical and Aerospace Engineering , Nanyang Technological University , 50 Nanyang Avenue , Singapore 639798 , Singapore
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Basu N, Mukherjee R. Morphology modulation in evaporative drying mediated crystallization of sodium chloride solution droplet with surfactant. SOFT MATTER 2018; 14:7883-7893. [PMID: 30229795 DOI: 10.1039/c8sm01370e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report the evaporative drying of an aqueous droplet containing a dilute solution of sodium chloride (NaCl) on a hydrophobic substrate made of cross-linked poly-dimethyl siloxane (PDMS). The salt concentration Cn was varied between 0.08 molar (M) and 2.0 M. The contact line of the evaporating droplets shows significant initial retraction for all Cn, before they get pinned. While the final morphology comprises a few small NaCl crystals deposited around the pinned contact line, in droplets with a low Cn (<0.5 M), it transforms to a single large salt crystal when Cn > 0.7 M with no peripheral deposition. We further show that the deposition morphology drastically changes when an anionic surfactant, sodium dodecyl sulfate (SDS), is added into the salt-solutions. Even in the surfactant-laden droplets, the final deposition morphology changes significantly as a function of Cn. It transforms from a thick SDS ring surrounding a fractal-like deposit of NaCl crystallites at lower Cn to a peripheral deposit of NaCl crystals at higher Cn due to competition between micelle formation and crystallization. However, the crystallographic orientation of the deposited NaCl crystals remains unaltered irrespective of the presence of surfactant.
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Affiliation(s)
- Nandita Basu
- Instability and Soft Patterning Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Pin 721 302, West Bengal, India.
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Parsa M, Harmand S, Sefiane K. Mechanisms of pattern formation from dried sessile drops. Adv Colloid Interface Sci 2018; 254:22-47. [PMID: 29628116 DOI: 10.1016/j.cis.2018.03.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 02/06/2018] [Accepted: 03/19/2018] [Indexed: 10/17/2022]
Abstract
The formation of patterns after the evaporation of colloidal droplets deposited on a solid surface is an everyday natural phenomenon. During the past two decades, this topic has gained broader audience due to its numerous applications in biomedicine, nanotechnology, printing, coating, etc. This paper presents a detailed review of the experimental studies related to the formation of various deposition patterns from dried droplets of complex fluids (i.e., nanofluids, polymers). First, this review presents the fundamentals of sessile droplet evaporation including evaporation modes and internal flow fields. Then, the most observed dried patterns are presented and the mechanisms behind them are discussed. The review ends with the categorisation and exhaustive investigation of a wide range of factors affecting pattern formation.
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