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Guo Z, Lin T, Jing D, Wang W, Sui Y. A method for real-time mechanical characterisation of microcapsules. Biomech Model Mechanobiol 2023:10.1007/s10237-023-01712-7. [PMID: 36964429 PMCID: PMC10366294 DOI: 10.1007/s10237-023-01712-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 03/09/2023] [Indexed: 03/26/2023]
Abstract
Characterising the mechanical properties of flowing microcapsules is important from both fundamental and applied points of view. In the present study, we develop a novel multilayer perceptron (MLP)-based machine learning (ML) approach, for real-time simultaneous predictions of the membrane mechanical law type, shear and area-dilatation moduli of microcapsules, from their camera-recorded steady profiles in tube flow. By MLP, we mean a neural network where many perceptrons are organised into layers. A perceptron is a basic element that conducts input-output mapping operation. We test the performance of the present approach using both simulation and experimental data. We find that with a reasonably high prediction accuracy, our method can reach an unprecedented low prediction latency of less than 1 millisecond on a personal computer. That is the overall computational time, without using parallel computing, from a single experimental image to multiple capsule mechanical parameters. It is faster than a recently proposed convolutional neural network-based approach by two orders of magnitude, for it only deals with the one-dimensional capsule boundary instead of the entire two-dimensional capsule image. Our new approach may serve as the foundation of a promising tool for real-time mechanical characterisation and online active sorting of deformable microcapsules and biological cells in microfluidic devices.
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Affiliation(s)
- Ziyu Guo
- School of Engineering and Material Science, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Tao Lin
- School of Engineering and Material Science, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Dalei Jing
- School of Engineering and Material Science, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Wen Wang
- School of Engineering and Material Science, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Yi Sui
- School of Engineering and Material Science, Queen Mary University of London, London, E1 4NS, United Kingdom.
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2
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Xie K, Gorin B, Cerbus RT, Alvarez L, Rampnoux JM, Kellay H. Activity Induced Rigidity of Liquid Droplets. PHYSICAL REVIEW LETTERS 2022; 129:138001. [PMID: 36206417 DOI: 10.1103/physrevlett.129.138001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/18/2022] [Accepted: 08/25/2022] [Indexed: 06/16/2023]
Abstract
Here we show that encapsulating active Janus particles within a drop renders it more resistant to deformation. This drop is deformed under the action of an extensional flow. Such deformation is primarily resisted by the drop interfacial tension. When the particles are active under the action of laser illumination, the deformation decreases signaling an increase in effective tension or Laplace pressure. This increase is attributed to the activity of the particles. Our results using numerous drop sizes, particle number densities, and active velocities show that the obtained increase agrees surprisingly well, over an extended range, with a standard expression for the pressure engendered by an ensemble of active particles, proposed years ago but not tested yet in three dimensions.
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Affiliation(s)
- Kaili Xie
- Université de Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - Benjamin Gorin
- Université de Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - Rory T Cerbus
- Université de Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - Laura Alvarez
- Université de Bordeaux, CNRS, CRPP, UMR 5031, 33600 Pessac, France
| | | | - Hamid Kellay
- Université de Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
- Institut Universitaire de France, 75005 Paris, France
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3
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Chachanidze R, Xie K, Lyu J, Jaeger M, Leonetti M. Breakups of Chitosan Microcapsules in Extensional Flow. J Colloid Interface Sci 2022; 629:445-454. [DOI: 10.1016/j.jcis.2022.08.169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 10/14/2022]
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4
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Chachanidze R, Xie K, Massaad H, Roux D, Leonetti M, de Loubens C. Structural characterization of the interfacial self-assembly of chitosan with oppositely charged surfactant. J Colloid Interface Sci 2022; 616:911-920. [DOI: 10.1016/j.jcis.2022.01.143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/06/2022] [Accepted: 01/22/2022] [Indexed: 11/16/2022]
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5
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Li Y, Xing B, Ding M, Shi T, Sun Z. Flow-driven competition between two capsules passing through a narrow pore. SOFT MATTER 2021; 17:9154-9161. [PMID: 34580700 DOI: 10.1039/d1sm01271a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
By incorporating a distance function into the finite element simulation, we investigate the flow-driven competition between two soft capsules passing through a narrow pore, employing the arbitrary Lagrangian-Eulerian formulation to satisfy the boundary conditions for fluid flow and capsule deformation. In our simulations, the motion and deformation of the capsules can be described in an intuitive manner, and the order in which capsules of different sizes pass through a pore can be clearly determined. Meanwhile, when the capsules are near the narrow pore, the change of the flow field is also very interesting and can be expressed intuitively. It is shown that, driven by the Poiseuille flow, the larger capsule has a stronger tendency to pass through the pore than the small one, which can be attributed to the greater resistance and the volume advantage of the larger capsule. In addition, we demonstrate that this tendency can be reversed by changing the inlet velocity and setting the initial position of the smaller capsule closer to the axis of the pore. And as long as the large one passes through first, the small one will offset the axis to the same orientation as the initial, while the large one always moves along the axis.
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Affiliation(s)
- Yingxiang Li
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Baohua Xing
- Changchun Yangzheng Senior High School, Changchun 130052, P. R. China
| | - Mingming Ding
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Tongfei Shi
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Zhaoyan Sun
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
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Honaryar H, LaNasa JA, Lloyd EC, Hickey RJ, Niroobakhsh Z. Fabricating Robust Constructs with Internal Phase Nanostructures via Liquid-in-Liquid 3D Printing. Macromol Rapid Commun 2021; 42:e2100445. [PMID: 34569682 DOI: 10.1002/marc.202100445] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/21/2021] [Indexed: 12/12/2022]
Abstract
The ability to print soft materials into predefined architectures with programmable nanostructures and mechanical properties is a necessary requirement for creating synthetic biomaterials that mimic living tissues. However, the low viscosity of common materials and lack of required mechanical properties in the final product present an obstacle to the use of traditional additive manufacturing approaches. Here, a new liquid-in-liquid 3D printing approach is used to successfully fabricate constructs with internal nanostructures using in situ self-assembly during the extrusion of an aqueous solution containing surfactant and photocurable polymer into a stabilizing polar oil bath. Subsequent photopolymerization preserves the nanostructures created due to surfactant self-assembly at the immiscible liquid-liquid interface, which is confirmed by small-angle X-ray scattering. Mechanical properties of the photopolymerized prints are shown to be tunable based on constituent components of the aqueous solution. The reported 3D printing approach expands the range of low-viscosity materials that can be used in 3D printing, and enables robust constructs production with internal nanostructures and spatially defined features. The reported approach has broad applications in regenerative medicine by providing a platform to print self-assembling biomaterials into complex tissue mimics where internal supramolecular structures and their functionality control biological processes, similar to natural extracellular matrices.
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Affiliation(s)
- Houman Honaryar
- Department of Civil & Mechanical Engineering, University of Missouri-Kansas City, Kansas City, MO, 64110, USA
| | - Jacob A LaNasa
- Department of Materials Science & Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Elisabeth C Lloyd
- Department of Materials Science & Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Robert J Hickey
- Department of Materials Science & Engineering, Pennsylvania State University, University Park, PA, 16802, USA.,Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
| | - Zahra Niroobakhsh
- Department of Civil & Mechanical Engineering, University of Missouri-Kansas City, Kansas City, MO, 64110, USA
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Maleki M, de Loubens C, Xie K, Talansier E, Bodiguel H, Leonetti M. Membrane emulsification for the production of suspensions of uniform microcapsules with tunable mechanical properties. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2021.116567] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Dupré de Baubigny J, Perrin P, Pantoustier N, Salez T, Reyssat M, Monteux C. Growth Mechanism of Polymer Membranes Obtained by H-Bonding Across Immiscible Liquid Interfaces. ACS Macro Lett 2021; 10:204-209. [PMID: 35570784 DOI: 10.1021/acsmacrolett.0c00847] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Complexation of polymers at liquid interfaces is an emerging technique to produce all-liquid printable and self-healing devices and membranes. It is crucial to control the assembly process, but the mechanisms at play remain unclear. Using two different reflectometric methods, we investigate the spontaneous growth of H-bonded PPO-PMAA (polypropylene oxide-polymetacrylic acid) membranes at a flat liquid-liquid interface. We find that the membrane thickness h grows with time t as h ∼ t1/2, which is reminiscent of a diffusion-limited process. However, counterintuitively, we observe that this process is faster as the PPO molar mass increases. We are able to rationalize these results with a model which considers the diffusion of the PPO chains within the growing membrane. The architecture of the latter is described as a gel-like porous network, with a pore size much smaller than the radius of the diffusing PPO chains, thus inducing entropic barriers that hinder the diffusion process. From the comparison between the experimental data and the result of the model, we extract some key piece of information about the microscopic structure of the membrane. This study opens the route toward the rational design of self-assembled membranes and capsules with optimal properties.
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Affiliation(s)
- Julien Dupré de Baubigny
- Sciences et Ingénierie de La Matière Molle, UMR 7615, ESPCI Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris, France
| | - Patrick Perrin
- Sciences et Ingénierie de La Matière Molle, UMR 7615, ESPCI Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris, France
| | - Nadège Pantoustier
- Sciences et Ingénierie de La Matière Molle, UMR 7615, ESPCI Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris, France
| | - Thomas Salez
- Université Bordeaux, CNRS, LOMA, UMR 5798, 33405 Talence, France
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
| | - Mathilde Reyssat
- UMR CNRS 7083 Gulliver, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - Cécile Monteux
- Sciences et Ingénierie de La Matière Molle, UMR 7615, ESPCI Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris, France
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
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Li P, Zhang J. Similar but Distinct Roles of Membrane and Interior Fluid Viscosities in Capsule Dynamics in Shear Flows. Cardiovasc Eng Technol 2021; 12:232-249. [PMID: 33483917 DOI: 10.1007/s13239-020-00517-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/31/2020] [Indexed: 02/04/2023]
Abstract
PURPOSE The dynamics of biological capsules and red blood cells in shear flows has been studied extensively with experimental, analytical, and numerical methods. In particular, the effects of various parameters, including the shear rate or shear stress, membrane elasticity, capsule shape, and interior fluid viscosity, have been investigated carefully. The role of the membrane viscosity for capsule deformation dynamics has not been examined adequately. In previous studies, the so-called energy dissipation ratio has been used to account for the membrane viscosity effect by increasing the interior viscosity; however, the applicability and accuracy of this treatment have not been evaluated carefully. METHODS In this study, using the recently developed finite-difference scheme for immersed boundary simulations of viscoelastic membranes, we conduct comprehensive numerical simulations of the deformation processes of an originally spherical capsule in shear flows with various combinations of membrane and interior fluid viscosities. RESULTS Our results show that the membrane and interior fluid viscosity have similar however different effects on the capsule deformation dynamics. While the capsule deformation decreases with both membrane and interior fluid viscosities, a typical decrease-then-increase variation is observed for the inclination angle as the membrane viscosity increases, instead of the monotonic decrease in the inclination angle with the interior fluid viscosity increase. Also, although both large membrane and interior fluid viscosity values can introduce oscillations in the capsule deformation and inclination, larger aptitudes and slow decay processes are noticed at larger membrane viscosities. The variations of other dynamic parameters of the capsule, including the circumference, average membrane velocity, and rotation frequency, are also analyzed, and an intuitive mechanism is proposed to relate the membrane velocity and rotation frequency to the capsule deformation and inclination angle. The simple mechanism is then applied to explain the spoon-like variation patterns for membrane velocity and rotation frequency observed in our results. Furthermore, we examine the validity of the energy dissipation ratio approach based on the mathematical functional dependence. CONCLUSIONS Our results and analysis show that the dissipation ratio is a system and process dependent variable and it cannot be treated as a constant even for the same capsule. This research is valuable for a better understanding of the complex capsule dynamics in flows and also suggests that the membrane viscosity needs to be considered explicitly for accurate and reliable results in future studies.
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Affiliation(s)
- Ping Li
- Bharti School of Engineering, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada
| | - Junfeng Zhang
- Bharti School of Engineering, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.
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10
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A microwave-triggered opening of the multifunctional polyelectrolyte capsules with nanodiamonds in the shell composition. POLYMER 2021. [DOI: 10.1016/j.polymer.2020.123299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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11
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Puri V, Sharma A, Kumar P, Singh I. Thiolation of Biopolymers for Developing Drug Delivery Systems with Enhanced Mechanical and Mucoadhesive Properties: A Review. Polymers (Basel) 2020; 12:E1803. [PMID: 32796741 PMCID: PMC7464630 DOI: 10.3390/polym12081803] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 01/09/2023] Open
Abstract
Biopolymers are extensively used for developing drug delivery systems as they are easily available, economical, readily modified, nontoxic, biodegradable and biocompatible. Thiolation is a well reported approach for enhancing mucoadhesive and mechanical properties of polymers. In the present review article, for the modification of biopolymers different thiolation methods and evaluation/characterization techniques have been discussed in detail. Reported literature on thiolated biopolymers with enhanced mechanical and mucoadhesive properties has been presented conspicuously in text as well as in tabular form. Patents filed by researchers on thiolated polymers have also been presented. In conclusion, thiolation is an easily reproducible and efficient method for customization of mucoadhesive and mechanical properties of biopolymers for drug delivery applications.
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Affiliation(s)
- Vivek Puri
- Chitkara College of Pharmacy, Chitkara University, Punjab 140401, India; (V.P.); (A.S.)
- Chitkara University School of Pharmacy, Chitkara University, Himachal Pradesh 174103, India
| | - Ameya Sharma
- Chitkara College of Pharmacy, Chitkara University, Punjab 140401, India; (V.P.); (A.S.)
- Chitkara University School of Pharmacy, Chitkara University, Himachal Pradesh 174103, India
| | - Pradeep Kumar
- Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa;
| | - Inderbir Singh
- Chitkara College of Pharmacy, Chitkara University, Punjab 140401, India; (V.P.); (A.S.)
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Li P, Zhang J. A finite difference method with subsampling for immersed boundary simulations of the capsule dynamics with viscoelastic membranes. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3200. [PMID: 30884167 DOI: 10.1002/cnm.3200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 02/05/2019] [Accepted: 03/09/2019] [Indexed: 06/09/2023]
Abstract
The membrane or interfacial viscosity is an important property in many multiphase and biofluidic situations, such as the red blood cell dynamics and emulsion stability. The immersed boundary method (IBM), which incorporates the dynamic flow-membrane interaction via force distribution and velocity interpolation, has been extensively employed in simulations of such systems. Unfortunately, direct implementation of membrane viscosity in IBM suffers severe numerical instability, which causes an IBM calculation to break down before generating any useful results. Few attempts have been recently reported; however, several concerns exist in these attempts, such as the inconsistency to the classical definition of membrane viscosity, the inability to model the shear and dilatational viscosities separately, the unjustified mathematical formulations, and the complicated algorithms and computation. To overcome these concerns, in this paper, we propose a finite difference approach for implementing membrane viscosity in immersed boundary simulations. The viscous stress is obtained via finite difference approximations to the differential strain-stress relationship, with the help of a subsampling scheme to reduce the numerical noise in the calculated strain rates. This simple method has also avoided the complicated matrix calculations in previous attempts, and hence, a better computational efficiency is expected. Detailed mathematical description of the method and key steps for its implementation in immersed boundary programs are provided. Validation and illustration calculations are performed, and our results are compared with analytical solutions and previous publications with satisfactory agreement. The influences of membrane mesh resolution and simulation time step are also examined; and the results show no indication that our finite difference method has downgraded the general IBM accuracy. Based on these simulations and analysis, we believe that our method would be a better choice for future IBM simulations of capsule dynamics with viscoelastic membranes.
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Affiliation(s)
- Ping Li
- Bharti School of Engineering, Laurentian University, Sudbury, Canada
| | - Junfeng Zhang
- Bharti School of Engineering, Laurentian University, Sudbury, Canada
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Puri S, Thaokar RM. Study of dependence of elasticity on the microstructure of microcapsules using electro-deformation technique. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.02.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Trégouët C, Salez T, Monteux C, Reyssat M. Microfluidic probing of the complex interfacial rheology of multilayer capsules. SOFT MATTER 2019; 15:2782-2790. [PMID: 30887970 DOI: 10.1039/c8sm02507j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Encapsulation of chemicals using polymer membranes enables control of their transport and delivery for applications such as agrochemistry or detergency. To rationalize the design of polymer capsules, it is necessary to understand how the membranes' mechanical properties control the transport and release of the cargo. In this article, we use microfluidics to produce model polymer capsules and study in situ their behavior in controlled divergent flows. Our model capsules are obtained by assembling polymer mono and hydrogen-bonded bilayers at the surface of an oil droplet in water. We also use microfluidics to probe in situ the mechanical properties of the membranes in a controlled divergent flow generated by introducing the capsules through a constriction and then in a larger chamber. The deformation and relaxation of the capsules depend on their composition and especially on the molecular interactions between the polymer chains that form the membranes and the anchoring energy of the first layer. We develop a model and perform numerical simulations to extract the main interfacial properties of the capsules from the measurement of their deformations in the microchannels.
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Affiliation(s)
- Corentin Trégouët
- UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France. and UMR CNRS SIMM 7615, ESPCI Paris, PSL Research University, 75005 Paris, France.
| | - Thomas Salez
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France and Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
| | - Cécile Monteux
- UMR CNRS SIMM 7615, ESPCI Paris, PSL Research University, 75005 Paris, France. and Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
| | - Mathilde Reyssat
- UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France.
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Hegemann J, Boltz HH, Kierfeld J. Elastic capsules at liquid-liquid interfaces. SOFT MATTER 2018; 14:5665-5685. [PMID: 29946629 DOI: 10.1039/c8sm00316e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigate the deformation of elastic microcapsules adsorbed at liquid-liquid interfaces. An initially spherical elastic capsule at a liquid-liquid interface undergoes circumferential stretching due to the liquid-liquid surface tension and becomes lens- or discus-shaped, depending on its bending rigidity. The resulting elastic capsule deformation is qualitatively similar, but distinct from the deformation of a liquid droplet into a liquid lens at a liquid-liquid interface. We discuss the deformed shapes of droplets and capsules adsorbed at liquid-liquid interfaces for a whole range of different surface elasticities: from droplets (only surface tension) deforming into liquid lenses, droplets with a Hookean membrane (finite stretching modulus, zero bending modulus) deforming into elastic lenses, to microcapsules (finite stretching and bending modulus) deforming into rounded elastic lenses. We calculate capsule shapes at liquid-liquid interfaces numerically using shape equations from nonlinear elastic shell theory. Finally, we present theoretical results for the contact angle (or the capsule height) and the maximal capsule curvature at the three phase contact line. These results can be used to infer information about the elastic moduli from optical measurements. During capsule deformation into a lens-like shape, surface energy of the liquid-liquid interface is converted into elastic energy of the capsule shell giving rise to an overall adsorption energy gain by deformation. Soft hollow capsules exhibit a pronounced increase of the adsorption energy as compared to filled soft particles and, thus, are attractive candidates as foam and emulsion stabilizers.
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Affiliation(s)
- Jonas Hegemann
- Physics Department, TU Dortmund University, 44221 Dortmund, Germany.
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