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Majumder S, Basavaraj MG, Satapathy DK. Soft colloidal monolayers with reflection symmetry through confined drying. NANOSCALE ADVANCES 2024:d4na00542b. [PMID: 39139712 PMCID: PMC11317906 DOI: 10.1039/d4na00542b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Accepted: 07/17/2024] [Indexed: 08/15/2024]
Abstract
Colloidal monolayers serve as fundamental building blocks in fabricating diverse functional materials, pivotal for surface modifications, chemical reactivity, and controlled assembly of nanoparticles. In this article, we report the formation of colloidal monolayers generated by drying an aqueous droplet containing soft colloids confined between two hydrophilic parallel plates. The analysis of the kinetics of evaporation in this confined mode showed that: (i) for a significant portion of the drying time, the drops adopt a catenoid configuration; (ii) in the penultimate stage of drying, the catenoid structure undergoes division into two daughter droplets; (iii) the three-phase contact line remains pinned at a specific location while it continuously slips at all other locations. The interplay between interface-assisted particle deposition onto the solid substrate and the time evolution of particle concentration within the droplet during evaporation results in unique microstructural features in the deposited patterns. Notably, these deposit patterns exhibit reflection symmetry. The microstructural features of the dried deposits are further quantified by calculating the particle number density, inter-particle separation, areal disorder parameter, and bond orientational order parameter. The variation of these parameters for deposits formed under different conditions, such as by altering the spacing between parallel plates and the concentration of microgel particles in the droplet, is discussed.
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Affiliation(s)
- Sanjib Majumder
- Soft Material Laboratory, Department of Physics, IIT Madras Chennai-600036 India
- Centre for Soft and Biological Matter, IIT Madras Chennai-600036 India
| | - Madivala G Basavaraj
- PECS Lab, Department of Chemical Engineering, IIT Madras Chennai-600036 India
- Centre for Soft and Biological Matter, IIT Madras Chennai-600036 India
| | - Dillip K Satapathy
- Soft Material Laboratory, Department of Physics, IIT Madras Chennai-600036 India
- Centre for Soft and Biological Matter, IIT Madras Chennai-600036 India
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Othman AM, Poulos AS, Torres O, Routh AF. Liquid-Liquid Phase Separation Induced by Vapor Transfer in Evaporative Binary Sessile Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:13242-13257. [PMID: 37677134 PMCID: PMC10515642 DOI: 10.1021/acs.langmuir.3c01686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/21/2023] [Indexed: 09/09/2023]
Abstract
Drying of binary sessile droplets consisting of ethanol and octamethyltrisiloxane on a high-energy surface is investigated. During the process of evaporation, the droplets undergo liquid-liquid phase separation, resulting in the appearance of microdroplets at the liquid-air interface, which subsequently violently burst. This phase separation is attributed to water vapor transfer into the droplet, which modifies the solubility and leads to the formation of a ternary mixture. The newly formed ternary mixture may undergo nucleation and growth or spinodal decomposition, depending on the droplet composition path. By control of the relative humidity of air, phase separation can be mitigated or even eliminated. The droplets also display high mobility and complex wetting behavior due to phase separation, with two contracting and two spreading stages. The mass loss experiments reveal that the droplets undergo three distinct drying stages with an enhanced evaporation rate observed during the phase separation stage. A modified diffusion-limited model was employed to predict the evaporation rate, accounting for the physiochemical changes during evaporation and proved to be consistent with experimental observations. The findings of this work enhance our understanding of a coupled fundamental process involving the evaporation of multicomponent mixtures, wetting, and phase separation.
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Affiliation(s)
- Ahmed M. Othman
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Dr, Cambridge CB3 0AS, U.K.
| | | | - Ophelie Torres
- Unilever
R & D Port Sunlight, Quarry Road East, Wirral CH63 3JW, U.K.
| | - Alexander. F. Routh
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Dr, Cambridge CB3 0AS, U.K.
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Pham TKN, Bruffey E, Nguyen AT, Rivera-Maldonado RA, Kuo DY, Cossairt B, Lee W, Severa G, Brown JJ. Deposition of Ultrathin MgB 2 Films from a Suspension Using Cosolvent Marangoni Flow. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:3853-3861. [PMID: 36893476 DOI: 10.1021/acs.langmuir.2c02933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Magnesium diboride (MgB2) has demonstrated, theoretically and experimentally, promise as a candidate material for hydrogen storage and has thus attracted much contemporary research interest. To study hydrogen gas adsorption on MgB2 thin films using a quartz crystal microbalance (QCM)─a workhorse apparatus for this specific experiment─MgB2 must be deposited uniformly on the active surface of the QCM without damaging the quartz's performance. In work presented here, a wet-chemistry colloid synthesis and deposition process of a MgB2 thin film on a gold (Au) surface was established to avoid the extreme conditions of conventional physical deposition methods. This process also counteracts the unwanted phenomena of drying droplets on a solid surface, particularly the coffee-ring effect. To verify the normal function of the QCM after MgB2 deposition and its ability to obtain meaningful data, simple gas adsorption tests were conducted on the QCM, and the MgB2 film on the QCM was characterized with X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) for elemental analysis and surface roughness, respectively. To obtain information about the thickness and the involvement of the coffee-ring effect, the same synthesis route was applied on a similar gold substrate─an evaporated Au film on glass. XPS characterization of the film and its precursor suspension shows the potential existence of both MgB2 and its oxide forms. The film's thickness on evaporated Au was measured by scanning transmission electron microscopy (STEM) to be 3.9 nm. The resulting samples show mitigation of the coffee-ring effect through roughness measurements with AFM at two scan sizes of 50 × 50 and 1 × 1 μm2.
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Affiliation(s)
- Thi Kieu Ngan Pham
- Department of Mechanical Engineering, University of Hawai'i at Ma̅noa, Honolulu, Hawai'i 96822, United States
| | - Edward Bruffey
- Department of Mechanical Engineering, University of Hawai'i at Ma̅noa, Honolulu, Hawai'i 96822, United States
- Hawaii Natural Energy Institute, University of Hawai'i at Ma̅noa, Honolulu, Hawai'i 96822, United States
| | - Anh Tuan Nguyen
- Department of Mechanical Engineering, University of Hawai'i at Ma̅noa, Honolulu, Hawai'i 96822, United States
| | | | - Ding-Yuan Kuo
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Brandi Cossairt
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Woochul Lee
- Department of Mechanical Engineering, University of Hawai'i at Ma̅noa, Honolulu, Hawai'i 96822, United States
| | - Godwin Severa
- Hawaii Natural Energy Institute, University of Hawai'i at Ma̅noa, Honolulu, Hawai'i 96822, United States
| | - Joseph J Brown
- Department of Mechanical Engineering, University of Hawai'i at Ma̅noa, Honolulu, Hawai'i 96822, United States
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Katre P, Banerjee S, Balusamy S, Sahu KC. Stability and Retention Force Factor for Binary-Nanofluid Sessile Droplets on an Inclined Substrate. Ind Eng Chem Res 2023. [DOI: 10.1021/acs.iecr.3c00160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Affiliation(s)
- Pallavi Katre
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502 284, Telangana India
| | - Sayak Banerjee
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502 284, Telangana India
| | - Saravanan Balusamy
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502 284, Telangana India
| | - Kirti Chandra Sahu
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502 284, Telangana India
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Hari Govindha A, Katre P, Balusamy S, Banerjee S, Sahu KC. Counter-Intuitive Evaporation in Nanofluids Droplets due to Stick-Slip Nature. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15361-15371. [PMID: 36459485 DOI: 10.1021/acs.langmuir.2c02590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
We experimentally investigate the evaporation characteristics of a sessile ethanol droplet containing Al2O3 and Cu nanoparticles of sizes 25 and 75 nm on a heated substrate using shadowgraphy and infrared imaging techniques. Our results demonstrate that the droplet contact line dynamics resulting from the presence of various nanoparticles plays a dominant role in the evaporation process. This is in contrast to the widely held assumption that the enhanced evaporation rate observed in sessile nanofluid droplets is due to the higher thermal conductivity of the added nanoparticles. We observe that even though the thermal conductivity of Al2O3 is an order of magnitude lower than that of Cu, droplets containing 25-nm-sized Al2O3 exhibit pinned contact line dynamics and evaporate much more rapidly than droplets containing Cu nanoparticles of both sizes and 75 nm Al2O3 nanoparticles that exhibit stick-slip behavior. We also found that the droplets with different nanoparticles display distinct thermal patterns due to the difference in contact line behavior, which alters the heat transfer inside the droplets. We establish this counter-intuitive observation by analyzing the temporal variations of the perimeter, free surface area, and deposition patterns on the substrate.
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Affiliation(s)
- A Hari Govindha
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
| | - Pallavi Katre
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
| | - Saravanan Balusamy
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
| | - Sayak Banerjee
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
| | - Kirti Chandra Sahu
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
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Moslabeh FGZ, Fouladgar F, Jafari A, Habibi N. Substrate-Free Self-Assembly of Peptides Nano-particles Through Acoustic Levitation. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.130439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kampouraki ZC, Petala M, Boumpakis A, Skordaris G, Michailidis N, Deliyanni E, Kostoglou M, Karapantsios TD. Wetting and Imbibition Characteristics of Pseudomonas fluorescens Biofilms Grown on Stainless Steel. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:9810-9821. [PMID: 35786927 DOI: 10.1021/acs.langmuir.2c00828] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This study aims to provide insights into biofilm resistance associated with their structural properties acquired during formation and development. On this account, the wetting and imbibition behavior of dehydrated Pseudomonas fluorescens biofilms grown on stainless steel electropolished substrates is thoroughly examined at different biofilm ages. A polar liquid (water) and a non-polar liquid (diiodomethane) are employed as wetting agents in the form of sessile droplets. A mathematical model is applied to appraise the wetting and imbibition performance of biofilms incorporating the evaporation of sessile droplets. The present results show that the examined biofilms are hydrophilic. The progressive growth of biofilms leads to a gradual increase of substrate surface coverage─up to full coverage─accompanied by a gradual decrease of biofilm surface roughness. It is noteworthy that just after 24 h of biofilm growth, the surface roughness increases about 6.7 times the roughness of the clean stainless steel surface. It is further found that the imbibition of liquid in the biofilm matrix is restricted only to the biofilm region under the sessile droplet. The lack of further capillary imbibition into the biofilm structure, beyond the droplet deposition region, implies that the biofilm matrix is not in the form of an extended network of interconnected micro/nanopores. All in all, the present results indicate a resilient biofilm structure to biocide penetration despite its hydrophilic nature.
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Affiliation(s)
- Zoi Christina Kampouraki
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 54124 Thessaloniki, Greece
| | - Maria Petala
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 54124 Thessaloniki, Greece
| | - Apostolos Boumpakis
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 54124 Thessaloniki, Greece
| | - Georgios Skordaris
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 54124 Thessaloniki, Greece
| | - Nikolaos Michailidis
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 54124 Thessaloniki, Greece
| | - Eleni Deliyanni
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 54124 Thessaloniki, Greece
| | - Margaritis Kostoglou
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 54124 Thessaloniki, Greece
| | - Thodoris D Karapantsios
- Division of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, University Box 116, 54124 Thessaloniki, Greece
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