51
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Liu Q, Sun Z, Santamarina JC. Self-assembled nanoparticle-coated interfaces: Capillary pressure, shell formation and buckling. J Colloid Interface Sci 2021; 581:251-261. [DOI: 10.1016/j.jcis.2020.07.110] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 11/30/2022]
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Microgels self-assembly at liquid/liquid interface as stabilizers of emulsion: Past, present & future. Adv Colloid Interface Sci 2021; 287:102333. [PMID: 33360120 DOI: 10.1016/j.cis.2020.102333] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/25/2020] [Accepted: 11/27/2020] [Indexed: 12/22/2022]
Abstract
The most recent developments on Pickering emulsions deal with the design of responsive emulsions able to undergo fast destabilization under the effect of an external stimulus. In this scenario, soft colloidal particles like microgels are considered novel class suitable emulsifiers. Microgels particles self-assemblies are highly deformable at interfaces covering higher surfaces than hard particles and their interfacial behavior strongly depends on external-stimuli. Microgels are very diverse owing to the large variety of them from the point of view of possible combinations of stimuli-responsiveness and different microstructures (crosslinking density and distribution). Herein, we illustrate the use of different types of responsive microgels not only from a structural point of view but also even from physical one. For that, the effect of different microgels parameters such as internal structure and charge density on mechanical properties of the interface will be discussed.
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53
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Bochenek S, McNamee CE, Kappl M, Butt HJ, Richtering W. Interactions between a responsive microgel monolayer and a rigid colloid: from soft to hard interfaces. Phys Chem Chem Phys 2021; 23:16754-16766. [PMID: 34319323 DOI: 10.1039/d1cp01703a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Responsive poly-N-isopropylacrylamide-based microgels are commonly used as model colloids with soft repulsive interactions. It has been shown that the microgel-microgel interaction in solution can be easily adjusted by varying the environmental parameters, e.g., temperature, pH, or salt concentration. Furthermore, microgels readily adsorb to liquid-gas and liquid-liquid interfaces forming responsive foams and emulsions that can be broken on-demand. In this work, we explore the interactions between microgel monolayers at the air-water interface and a hard colloid in the water. Force-distance curves between the monolayer and a silica particle were measured with the Monolayer Particle Interaction Apparatus. The measurements were conducted at different temperatures and lateral compressions, i.e., different surface pressures. The force-distance approach curves display long-range repulsive forces below the volume phase transition temperature of the microgels. Temperature and lateral compression reduce the stiffness of the monolayer. The adhesion increases with temperature and decreases with a lateral compression of the monolayer. When compressed laterally, the interactions between the microgels are hardly affected by temperature, as the directly adsorbed microgel fractions are nearly insensitive to temperature. In contrast, our findings show that the temperature-dependent swelling of the microgel fractions in the aqueous phase strongly influences the interaction with the probe. This is explained by a change in the microgel monolayer from a soft to a hard repulsive interface.
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Affiliation(s)
- Steffen Bochenek
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074 Aachen, Germany
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54
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Hoppe Alvarez L, Rudov AA, Gumerov RA, Lenssen P, Simon U, Potemkin II, Wöll D. Controlling microgel deformation via deposition method and surface functionalization of solid supports. Phys Chem Chem Phys 2021; 23:4927-4934. [PMID: 33620358 DOI: 10.1039/d0cp06355j] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Soft matter at solid-liquid interfaces plays an important role in multiple scientific disciplines as well as in various technological fields. For microgels, representing highly interesting soft matter systems, we demonstrate that the preparation method, i.e. the way how the microgel is applied to the specific surface, plays a key role. Focusing on the three most common sample preparation methods (spin-coating, drop-casting and adsorption from solution), we performed a comparative study of the deformation behavior of microgels at the solid-liquid interface on three different surfaces with varying hydrophilicities. For in situ visualization of the deformation of pNIPMAM microgels, we conducted highly sensitive 3D super resolution fluorescence microscopy methods. We furthermore performed complementary molecular dynamics simulations to determine the driving force responsible for the deformation depending on the surface and the deposition method. The combination of experiments and simulations revealed that the simulated equilibrium structure obtained after simulation of the completely dry microgel after deposition is retained after rehydration and subsequent fluorescent imaging.
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Affiliation(s)
- Laura Hoppe Alvarez
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056 Aachen, Germany.
| | - Andrey A Rudov
- Physics Department, Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation and DWI - Leibniz-Institute for Interactive Materials, Forckenbeckstraße 50, D-52056 Aachen, Germany
| | - Rustam A Gumerov
- Physics Department, Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation and DWI - Leibniz-Institute for Interactive Materials, Forckenbeckstraße 50, D-52056 Aachen, Germany
| | - Pia Lenssen
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056 Aachen, Germany.
| | - Ulrich Simon
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1 a, D-52056 Aachen, Germany
| | - Igor I Potemkin
- Physics Department, Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation and DWI - Leibniz-Institute for Interactive Materials, Forckenbeckstraße 50, D-52056 Aachen, Germany and National Research South Ural State University, Chelyabinsk 454080, Russian Federation
| | - Dominik Wöll
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056 Aachen, Germany.
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55
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Thamizhanban A, Balaji S, Lalitha K, Prasad YS, Prasad RV, Kumar RA, Maheswari CU, Sridharan V, Nagarajan S. Glycolipid-Based Oleogels and Organogels: Promising Nanostructured Structuring Agents. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:14896-14906. [PMID: 33284625 DOI: 10.1021/acs.jafc.0c02936] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Over the past few decades, the scientific community is actively involved in the development of edible structuring agents suitable for food, cosmetics, agricultural, pharmaceutical, and biotechnology applications. In particular, edible oil structuring using simple amphiphiles would be the best alternative for the currently used trans and saturated fatty acids, which cause deleterious health effects and cardiovascular problems. In this report, we have made an attempt to address the aforementioned consequences, by synthesizing a new class of structuring agents by a judicious combination of δ-gluconolactone and ricinoleic acid, compounds classified as GRAS, using simple steps in good yield. To our delight, the synthesized glycolipids self-assemble in a wide variety of vegetable oils and commercially viable glycerol, ethylene glycol, and polyethylene glycol via various intermolecular interactions to form a gel. The morphology of molecular gels was investigated by optical microscopy and FESEM analysis, which reveal the existence of a tubular architecture with a diameter ranging from 75 to 150 nm. Rheological studies disclosed the viscoelastic nature, thermal processability, and thixotropic behavior of both oleogels and organogels. Altogether, self-assembled oleogel and organogel reported in this paper would potentially be used in food, agricultural, cosmetics, pharmaceutical, and biotechnological applications.
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Affiliation(s)
- Ayyapillai Thamizhanban
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - Srikanth Balaji
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - Krishnamoorthy Lalitha
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - Yadavali Siva Prasad
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - R Vara Prasad
- Department of Chemistry, National Institute of Technology Warangal, Warangal 506004, Telangana, India
| | - R Arun Kumar
- Department of Chemistry, National Institute of Technology Warangal, Warangal 506004, Telangana, India
| | - C Uma Maheswari
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - Vellaisamy Sridharan
- Department of Chemistry and Chemical Sciences, Central University of Jammu, Rahya-Suchani (Bagla), District-Samba, Jammu 181143, India
| | - Subbiah Nagarajan
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
- Department of Chemistry, National Institute of Technology Warangal, Warangal 506004, Telangana, India
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56
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Schulte MF, Bochenek S, Brugnoni M, Scotti A, Mourran A, Richtering W. Stiffness Tomography of Ultra‐Soft Nanogels by Atomic Force Microscopy. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202011615] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- M. Friederike Schulte
- Institute of Physical Chemistry RWTH Aachen University Landoltweg 2 52056 Aachen Germany
| | - Steffen Bochenek
- Institute of Physical Chemistry RWTH Aachen University Landoltweg 2 52056 Aachen Germany
| | - Monia Brugnoni
- Institute of Physical Chemistry RWTH Aachen University Landoltweg 2 52056 Aachen Germany
| | - Andrea Scotti
- Institute of Physical Chemistry RWTH Aachen University Landoltweg 2 52056 Aachen Germany
| | - Ahmed Mourran
- DWI—Leibniz Institute for Interactive Materials Forckenbeckstr. 50 52056 Aachen Germany
| | - Walter Richtering
- Institute of Physical Chemistry RWTH Aachen University Landoltweg 2 52056 Aachen Germany
- DWI—Leibniz Institute for Interactive Materials Forckenbeckstr. 50 52056 Aachen Germany
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57
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Mehrabian H, Snoeijer JH, Harting J. Desorption energy of soft particles from a fluid interface. SOFT MATTER 2020; 16:8655-8666. [PMID: 32857082 DOI: 10.1039/d0sm01122c] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The efficiency of soft particles to stabilize emulsions is examined by measuring their desorption free energy, i.e., the mechanical work required to detach the particle from a fluid interface. Here, we consider rubber-like elastic as well as microgel particles, using coarse-grained molecular dynamics simulations. The energy of desorption is computed for two and three-dimensional configurations by means of the mean thermodynamic integration method. It is shown that the softness affects the particle-interface binding in two opposing directions as compared to rigid particles. On the one hand, a soft particle spreads at the interface and thereby removes a larger unfavorable liquid-liquid contact area compared to rigid particles. On the other hand, softness provides the particle with an additional degree of freedom to get reshaped instead of deforming the interface, resulting in a smaller restoring force during the detachment. It is shown that the first effect prevails so that a soft spherical particle attaches to the fluid interface more strongly than rigid spheres. Finally, we consider microgel particles both in the swollen and in the collapsed state. Surprisingly, we find that the latter has a larger binding energy. All results are rationalised using thermodynamic arguments and thereby offer detailed insights into the desorption energy of soft particles from fluid interfaces.
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Affiliation(s)
- Hadi Mehrabian
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Physics of Fluids Group and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands and Chemical Engineering Department, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jacco H Snoeijer
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Physics of Fluids Group and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jens Harting
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Physics of Fluids Group and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands and Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, Forschungszentrum Jülich, Fürther Str. 248, 90429 Nürnberg, Germany. and Department of Chemical and Biological Engineering and Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fürther Straße 248, 90429 Nürnberg, Germany
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58
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Schmidt MM, Bochenek S, Gavrilov AA, Potemkin II, Richtering W. Influence of Charges on the Behavior of Polyelectrolyte Microgels Confined to Oil-Water Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:11079-11093. [PMID: 32845643 DOI: 10.1021/acs.langmuir.0c02081] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The role of electrostatics on the interfacial properties of polyelectrolyte microgels has been discussed controversially in the literature. It is not yet clear if, or how, Coulomb interactions affect their behavior under interfacial confinement. In this work, we combine compression isotherms, atomic force microscopy imaging, and computer simulations to further investigate the behavior of pH-responsive microgels at oil-water interfaces. At low compression, charged microgels can be compressed more than uncharged microgels. The in-plane effective area of charged microgels is found to be smaller in comparison to uncharged ones. Thus, the compressibility is governed by in-plane interactions of the microgels with the interface. At high compression, however, charged microgels are less compressible than uncharged microgels. Microgel fractions located in the aqueous phase interact earlier for charged than for uncharged microgels because of their different swelling perpendicular to the interface. Therefore, the compressibility at high compression is controlled by out-of-plane interactions. In addition, the size of the investigated microgels plays a pivotal role. The charge-dependent difference in compressibility at low compression is only observed for small but not for large microgels, while the behavior at high compression does not depend on the size. Our results highlight the complex nature of soft polymer microgels as compared to rigid colloidal particles. We clearly demonstrate that electrostatic interactions affect the interfacial properties of polyelectrolyte microgels.
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Affiliation(s)
| | - Steffen Bochenek
- Institute of Physical Chemistry, RWTH Aachen University, 52074 Aachen, Germany
| | - Alexey A Gavrilov
- Physics Department, Lomonosov Moscow State University, Moscow 119991, Russian Federation
| | - Igor I Potemkin
- Physics Department, Lomonosov Moscow State University, Moscow 119991, Russian Federation
- DWI - Leibniz Institute for Interactive Materials, 52074 Aachen, Germany
- National Research South Ural State University, Chelyabinsk 454080, Russian Federation
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, 52074 Aachen, Germany
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59
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60
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Wang D, Zhu YL, Zhao Y, Li CY, Mukhopadhyay A, Sun ZY, Koynov K, Butt HJ. Brownian Diffusion of Individual Janus Nanoparticles at Water/Oil Interfaces. ACS NANO 2020; 14:10095-10103. [PMID: 32662990 PMCID: PMC7458482 DOI: 10.1021/acsnano.0c03291] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Janus nanoparticles could exhibit a higher interfacial activity and adsorb stronger to fluid interfaces than homogeneous nanoparticles of similar sizes. However, little is known about the interfacial diffusion of Janus nanoparticles and how it compares to that of homogeneous ones. Here, we employed fluorescence correlation spectroscopy to study the lateral diffusion of ligand-grafted Janus nanoparticles adsorbed at water/oil interfaces. We found that the diffusion was significantly slower than that of homogeneous nanoparticles. We carried out dissipative particle dynamic simulations to study the mechanism of interfacial slowdown. Good agreement between experimental and simulation results has been obtained only provided that the flexibility of ligands grafted on the nanoparticle surface was taken into account. The polymeric ligands were deformed and oriented at an interface so that the effective radius of Janus nanoparticles is larger than the nominal one obtained by measuring the diffusion in bulk solution. These findings highlight further the critical importance of the ligands grafted on Janus nanoparticles for applications involving nanoparticle adsorption at an interface, such as oil recovery or two-dimensional self-assembly.
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Affiliation(s)
- Dapeng Wang
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, People’s Republic of China
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - You-Liang Zhu
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, People’s Republic of China
| | - Yuehua Zhao
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, People’s Republic of China
| | - Christopher Y. Li
- Department
of Materials Science and Engineering, Drexel
University, Philadelphia, Pennsylvania 19104, United States
| | - Ashis Mukhopadhyay
- Department
of Physics, Wayne State University, Detroit, Michigan 48201, United States
| | - Zhao-Yan Sun
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, People’s Republic of China
| | - Kaloian Koynov
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Hans-Jürgen Butt
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
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61
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Tsujinoue H, Nozawa T, Arai N. Cylindrical defect structures formed by chiral nematic liquid crystals in quasi-one-dimensional systems. Phys Chem Chem Phys 2020; 22:16896-16904. [PMID: 32666995 DOI: 10.1039/d0cp01526a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Blue phases are three-dimensional self-assembly structures of liquid crystals with a lattice of line defects. They have attracted considerable interest as photonic materials. It is well known that blue phases occur in cholesteric liquid crystals (CLCs) under certain thermodynamic conditions; however, recent studies have indicated that confining surfaces may induce distinctive structural changes. For example, in a previous study, a quasi-two-dimensional (Q2D) confinement system was investigated with the aid of numerical calculations, and a stable Q2D Skyrmion structure was attained. Here, we performed molecular simulations to investigate the CLC phase behavior at the molecular scale for a quasi-one-dimensional (Q1D) nanotube system. Various morphological behaviors of CLCs were observed by changing the temperature and the radius of the nanotubes. In particular, we discovered a self-assembled structure with cylindrical (or ring-like) defects rather than lines by introducing a novel local orientation analysis. Our simulation results show that the self-assembly of CLCs offers a guide to control the intensity in Q1D systems and fundamental knowledge for their application to optical devices.
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Affiliation(s)
- Hiroaki Tsujinoue
- Department of Mechanical Engineering, Keio University, Yokohama 223-8522, Japan.
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62
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Grishina VS, Vikhrenko VS, Ciach A. Triangular lattice models for pattern formation by core-shell particles with different shell thicknesses. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:405102. [PMID: 32498052 DOI: 10.1088/1361-648x/ab9979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
Triangular lattice models for pattern formation by hard-core soft-shell particles at interfaces are introduced and studied in order to determine the effect of the shell thickness and structure. In model I, we consider particles with hard-cores covered by shells of cross-linked polymeric chains. In model II, such inner shell is covered by a much softer outer shell. In both models, the hard cores can occupy sites of the triangular lattice, and nearest-neighbor repulsion following from overlapping shells is assumed. The capillary force is represented by the second or the fifth neighbor attraction in model I or II, respectively. Ground states with fixed chemical potentialμor with fixed fraction of occupied sitescare thoroughly studied. ForT> 0, theμ(c) isotherms, compressibility and specific heat are calculated by Monte Carlo simulations. In model II, 6 ordered periodic patterns occur in addition to 4 phases found in model I. These additional phases, however, are stable only at the phase coexistence lines at the (μ,T) diagram, which otherwise looks like the diagram of model I. In the canonical ensemble, these 6 phases and interfaces between them appear in model II for large intervals ofcand the number of possible patterns is much larger than in model I. We calculated line tensions for different interfaces, and found that the favorable orientation of the interface corresponds to its smoothest shape in both models.
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Affiliation(s)
- V S Grishina
- Belarusian State Technological University, 13a Sverdlova str., 220006 Minsk, Belarus
| | - V S Vikhrenko
- Belarusian State Technological University, 13a Sverdlova str., 220006 Minsk, Belarus
| | - A Ciach
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland
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63
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Self-templating assembly of soft microparticles into complex tessellations. Nature 2020; 582:219-224. [DOI: 10.1038/s41586-020-2341-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 03/17/2020] [Indexed: 01/19/2023]
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64
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Arismendi-Arrieta DJ, Moreno AJ. Deformability and solvent penetration in soft nanoparticles at liquid-liquid interfaces. J Colloid Interface Sci 2020; 570:212-222. [DOI: 10.1016/j.jcis.2020.02.102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 12/29/2022]
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65
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Bushuev NV, Gumerov RA, Bochenek S, Pich A, Richtering W, Potemkin II. Compression and Ordering of Microgels in Monolayers Formed at Liquid-Liquid Interfaces: Computer Simulation Studies. ACS APPLIED MATERIALS & INTERFACES 2020; 12:19903-19915. [PMID: 32248678 DOI: 10.1021/acsami.0c01600] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Monolayers of polymer microgels adsorbed at the liquid interfaces were studied by dissipative particle dynamics simulations. The results demonstrated that the compressibility of the monolayers can be widely tuned by varying the cross-linking density of the microgels and their (in)compatibility with the immiscible liquids. In particular, the compression of the monolayers (increase of 2D concentration of the microgels) leads to the decrease of their lateral size. Herewith, the shape of the individual soft particles gradually changes from oblate (diluted 2D system) to nearly spherical (compressed monolayer). The polymer concentration profiles plotted along the normal to the interface reveal a nonmonotonous shape with a sharp maximum at the interface. This is a consequence of the shielding effect: saturation of the interface by monomer units of the subchains is driven by minimization of unfavorable contacts between the immiscible liquids and is opposed by elasticity of the network. The decrease of the interfacial tension upon concentration (compression) of the monolayer is quantified. It has been demonstrated that the interfacial tension significantly differs if the solubility of the polymer chains of the microgel network in the liquids changes. These results correlate well with experimental data. The examination of the microgels' crystalline ordering in monolayers demonstrated a nonmonotonous dependency on the compression degree (microgel concentration). Finally, the worsening of the solvent quality leads to the collapse of the microgels in monolayer and nonmonotonous behavior of the interfacial tension.
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Affiliation(s)
- Nikita V Bushuev
- Physics Department, Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation
| | - Rustam A Gumerov
- Physics Department, Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation
- DWI-Leibniz Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen 52056, Germany
| | - Steffen Bochenek
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, Aachen 52056, Germany
| | - Andrij Pich
- DWI-Leibniz Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen 52056, Germany
- Aachen Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, Urmonderbaan 22, Geleen 6167 RD, The Netherlands
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, Aachen 52056, Germany
| | - Igor I Potemkin
- Physics Department, Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation
- DWI-Leibniz Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen 52056, Germany
- National Research South Ural State University, Chelyabinsk 454080, Russian Federation
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66
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Rey M, Fernandez-Rodriguez MA, Karg M, Isa L, Vogel N. Poly- N-isopropylacrylamide Nanogels and Microgels at Fluid Interfaces. Acc Chem Res 2020; 53:414-424. [PMID: 31940173 DOI: 10.1021/acs.accounts.9b00528] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The confinement of colloidal particles at liquid interfaces offers many opportunities for materials design. Adsorption is driven by a reduction of the total free energy as the contact area between the two liquids is partially replaced by the particle. From an application point of view, particle-stabilized interfaces form emulsions and foams with superior stability. Liquid interfaces also effectively confine colloidal particles in two dimensions and therefore provide ideal model systems to fundamentally study particle interactions, dynamics, and self-assembly. With progress in the synthesis of nanomaterials, more and more complex and functional particles are available for such studies. In this Account, we focus on poly(N-isopropylacrylamide) nanogels and microgels. These are cross-linked polymeric particles that swell and soften by uptaking large amounts of water. The incorporated water can be partially expelled, causing a volume phase transition into a collapsed state when the temperature is increased above approximately 32 °C. Soft microgels adsorbed to liquid interfaces significantly deform under the influence of interfacial tension and assume cross sections exceeding their bulk dimensions. In particular, a pronounced corona forms around the microgel core, consisting of dangling chains at the microgel periphery. These polymer chains expand at the interface and strongly affect the interparticle interactions. The particle deformability therefore leads to a significantly more complex interfacial phase behavior that provides a rich playground to explore structure formation processes. We first discuss the characteristic "fried-egg" or core-corona morphology of individual microgels adsorbed to a liquid interface and comment on the dependence of this interfacial morphology on their physicochemical properties. We introduce different theoretical models to describe their interfacial morphology. In a second part, we introduce how ensembles of microgels interact and self-assemble at liquid interfaces. The core-corona morphology and the possibility to force these elements into overlap upon compression results in a complex phase behavior with a phase transition between microgels with extended and collapsed coronae. We discuss the influence of the internal particle architecture, also including core-shell microgels with rigid cores, on the phase behavior. Finally, we present new routes for the realization of more complex structures, resulting from multiple deposition protocols and from engineering the interaction potential of the individual particles.
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Affiliation(s)
- Marcel Rey
- Institute of Particle Technology (LFG), Friedrich-Alexander University Erlangen-Nürnberg, Cauerstrasse 4, 91058 Erlangen, Germany
- Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander University Erlangen-Nürnberg, Haberstrasse 9a, 91058 Erlangen, Germany
| | - Miguel Angel Fernandez-Rodriguez
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Matthias Karg
- Institut für Physikalische Chemie I: Kolloide und Nanooptik, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany
| | - Lucio Isa
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Nicolas Vogel
- Institute of Particle Technology (LFG), Friedrich-Alexander University Erlangen-Nürnberg, Cauerstrasse 4, 91058 Erlangen, Germany
- Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander University Erlangen-Nürnberg, Haberstrasse 9a, 91058 Erlangen, Germany
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67
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Bochenek S, Scotti A, Ogieglo W, Fernández-Rodríguez MÁ, Schulte MF, Gumerov RA, Bushuev NV, Potemkin II, Wessling M, Isa L, Richtering W. Effect of the 3D Swelling of Microgels on Their 2D Phase Behavior at the Liquid-Liquid Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16780-16792. [PMID: 31782927 DOI: 10.1021/acs.langmuir.9b02498] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We investigate soft, temperature-sensitive microgels at fluid interfaces. Though having an isotropic, spherical shape in bulk solution, the microgels become anisotropic upon adsorption. The structure of microgels at interfaces is described by a core-corona morphology. Here, we investigate how changing temperature across the microgel volume phase transition temperature, which leads to swelling/deswelling of the microgels in the aqueous phase, affects the phase behavior within the monolayer. We combine compression isotherms, atomic force microscopy imaging, multiwavelength ellipsometry, and computer simulations. At low compression, the interaction between adsorbed microgels is dominated by their highly stretched corona and the phase behavior of the microgel monolayers is the same. The polymer segments within the interface lose their temperature-sensitivity because of the strong adsorption to the interface. At high compression, however, the portions of the microgels that are located in the aqueous side of the interface become relevant and prevail in the microgel interactions. These portions are able to collapse and, consequently, the isostructural phase transition is altered. Thus, the temperature-dependent swelling perpendicular to the interface ("3D") affects the compressibility parallel to the interface ("2D"). Our results highlight the distinctly different behavior of soft, stimuli-sensitive microgels as compared to rigid nanoparticles.
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Affiliation(s)
- Steffen Bochenek
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , 52056 Aachen , Germany
| | - Andrea Scotti
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , 52056 Aachen , Germany
| | - Wojciech Ogieglo
- Chemical Process Engineering , RWTH Aachen University , Forckenbeckstrasse 51 , 52064 Aachen , Germany
| | - Miguel Ángel Fernández-Rodríguez
- Laboratory for Soft Materials and Interfaces, Department of Materials , ETH Zurich , Vladimir-Prelog-Weg 1-5/10 , 8093 Zurich , Switzerland
| | - M Friederike Schulte
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , 52056 Aachen , Germany
| | - Rustam A Gumerov
- Physics Department , Lomonosov Moscow State University , Moscow 119991 , Russian Federation
- DWI-Leibniz Institute for Interactive Materials , Forckenbeckstrasse 50 , Aachen 52056 , Germany
| | - Nikita V Bushuev
- Physics Department , Lomonosov Moscow State University , Moscow 119991 , Russian Federation
| | - Igor I Potemkin
- Physics Department , Lomonosov Moscow State University , Moscow 119991 , Russian Federation
- DWI-Leibniz Institute for Interactive Materials , Forckenbeckstrasse 50 , Aachen 52056 , Germany
- National Research South Ural State University , Chelyabinsk 454080 , Russian Federation
| | - Matthias Wessling
- Chemical Process Engineering , RWTH Aachen University , Forckenbeckstrasse 51 , 52064 Aachen , Germany
- DWI-Leibniz Institute for Interactive Materials , Forckenbeckstrasse 50 , Aachen 52056 , Germany
| | - Lucio Isa
- Laboratory for Soft Materials and Interfaces, Department of Materials , ETH Zurich , Vladimir-Prelog-Weg 1-5/10 , 8093 Zurich , Switzerland
| | - Walter Richtering
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , 52056 Aachen , Germany
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68
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Hoppe Alvarez L, Eisold S, Gumerov RA, Strauch M, Rudov AA, Lenssen P, Merhof D, Potemkin II, Simon U, Wöll D. Deformation of Microgels at Solid-Liquid Interfaces Visualized in Three-Dimension. NANO LETTERS 2019; 19:8862-8867. [PMID: 31642321 DOI: 10.1021/acs.nanolett.9b03688] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Solid-liquid interfaces play an important role for functional devices. Hence, a detailed understanding of the interaction of soft matter objects with solid supports and of the often concomitant structural deformations is of great importance. We address this topic in a combined experimental and simulation approach. We investigated thermoresponsive poly(N-isopropylmethacrylamide) microgels (μGs) at different surfaces in an aqueous environment. As super-resolution fluorescence imaging method, three-dimensional direct stochastical optical reconstruction microscopy (dSTORM) allowed for visualizing μGs in their three-dimensional (3D) shape, for example, in a "fried-egg" conformation depending on the hydrophilicity of the surface (strength of adsorption). The 3D shape, as defined by point clouds obtained from single-molecule localizations, was analyzed. A new fitting algorithm yielded an isosurface of constant density which defines the deformation of μGs at the different surfaces. The presented methodology quantifies deformation of objects with fuzzy surfaces and allows for comparison of their structures, whereby it is completely independent from the data acquisition method. Finally, the experimental data are complemented with mesoscopic computer simulations in order to (i) rationalize the experimental results and (ii) to track the evolution of the shape with changing surface hydrophilicity; a good correlation of the shapes obtained experimentally and with computer simulations was found.
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Affiliation(s)
- Laura Hoppe Alvarez
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , D-52056 Aachen , Germany
| | - Sabine Eisold
- Institute of Inorganic Chemistry , RWTH Aachen University , Landoltweg 1 a , D-52056 Aachen , Germany
| | - Rustam A Gumerov
- Physics Department , Lomonosov Moscow State University , Leninskie Gory 1-2 , Moscow 119991 , Russian Federation
- DWI - Leibniz-Institute for Interactive Materials , Forckenbeckstraße 50 , D-52056 Aachen , Germany
| | - Martin Strauch
- Institute of Imaging and Computer Vision , RWTH Aachen University , Kopernikusstraße 16 , 52074 Aachen , Germany
| | - Andrey A Rudov
- Physics Department , Lomonosov Moscow State University , Leninskie Gory 1-2 , Moscow 119991 , Russian Federation
- DWI - Leibniz-Institute for Interactive Materials , Forckenbeckstraße 50 , D-52056 Aachen , Germany
| | - Pia Lenssen
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , D-52056 Aachen , Germany
| | - Dorit Merhof
- Institute of Imaging and Computer Vision , RWTH Aachen University , Kopernikusstraße 16 , 52074 Aachen , Germany
| | - Igor I Potemkin
- Physics Department , Lomonosov Moscow State University , Leninskie Gory 1-2 , Moscow 119991 , Russian Federation
- DWI - Leibniz-Institute for Interactive Materials , Forckenbeckstraße 50 , D-52056 Aachen , Germany
- National Research South Ural State University , Chelyabinsk 454080 , Russian Federation
| | - Ulrich Simon
- Institute of Inorganic Chemistry , RWTH Aachen University , Landoltweg 1 a , D-52056 Aachen , Germany
| | - Dominik Wöll
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , D-52056 Aachen , Germany
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69
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Schulte MF, Scotti A, Brugnoni M, Bochenek S, Mourran A, Richtering W. Tuning the Structure and Properties of Ultra-Low Cross-Linked Temperature-Sensitive Microgels at Interfaces via the Adsorption Pathway. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14769-14781. [PMID: 31638406 DOI: 10.1021/acs.langmuir.9b02478] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The structure of poly(N-isopropylacrylamide) (PNIPAM) microgels adsorbed onto a solid substrate is investigated in the dry and hydrated states by means of atomic force microscopy (AFM). We compare two different systems: a regularly cross-linked microgel containing 5 mol % cross-linker and ultra-low cross-linked microgels (ULC) prepared without a dedicated cross-linker. Furthermore, we compare three different adsorption processes: (i) in situ adsorption from solution, (ii) spin-coating, and (iii) Langmuir-Blodgett deposition from an oil-water interface. The results demonstrate that the morphology and the temperature-induced collapse of microgels adsorbed onto a solid substrate are very different for ultra-low cross-linked microgels as compared to regularly cross-linked microgels, despite the fact that their general behavior in solution is very similar. Furthermore, the morphology of ULC microgels can be controlled by the adsorption pathway onto the substrate. Absorbed ULC microgels are strongly deformed when being prepared either by spin-coating or by Langmuir-Blodgett deposition from an oil-water interface. After rehydration, the ULC microgels cannot collapse as entire objects, instead small globules are formed. Such a strong deformation can be avoided by in situ adsorption onto the substrate. Then, the ULC microgels exhibit half-ellipsoidal shapes with a smooth surface in the collapsed state similar to the more cross-linked microgels. As ULC microgels can be selectively trapped either in a more particle-like or in a more polymer-like behavior, coatings with strongly different topographies and properties can be prepared by one and the same ultra-low cross-linked microgel. This provides new opportunities for the development of smart polymeric coatings.
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Affiliation(s)
- M Friederike Schulte
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , 52056 Aachen , Germany
- DWI-Leibniz Institute for Interactive Materials , Forckenbeckstr. 50 , 52056 Aachen , Germany
| | - Andrea Scotti
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , 52056 Aachen , Germany
| | - Monia Brugnoni
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , 52056 Aachen , Germany
| | - Steffen Bochenek
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , 52056 Aachen , Germany
| | - Ahmed Mourran
- DWI-Leibniz Institute for Interactive Materials , Forckenbeckstr. 50 , 52056 Aachen , Germany
| | - Walter Richtering
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , 52056 Aachen , Germany
- DWI-Leibniz Institute for Interactive Materials , Forckenbeckstr. 50 , 52056 Aachen , Germany
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70
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Ninarello A, Crassous JJ, Paloli D, Camerin F, Gnan N, Rovigatti L, Schurtenberger P, Zaccarelli E. Modeling Microgels with a Controlled Structure across the Volume Phase Transition. Macromolecules 2019; 52:7584-7592. [PMID: 31656322 PMCID: PMC6812067 DOI: 10.1021/acs.macromol.9b01122] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/20/2019] [Indexed: 12/13/2022]
Abstract
![]()
Thermoresponsive microgels are soft
colloids that find widespread
use as model systems for soft matter physics. Their complex internal
architecture, made of a disordered and heterogeneous polymer network,
has been so far a major challenge for computer simulations. In this
work, we put forward a coarse-grained model of microgels whose structural
properties are in quantitative agreement with results obtained with
small-angle X-ray scattering experiments across a wide range of temperatures,
encompassing the volume phase transition. These results bridge the
gap between experiments and simulations of individual microgel particles,
paving the way to theoretically address open questions about their
bulk properties with unprecedented nano- and microscale resolution.
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Affiliation(s)
- Andrea Ninarello
- CNR-ISC Uos Sapienza, Piazzale A. Moro 2, IT-00185 Roma, Italy.,Department of Physics, Sapienza Università di Roma, Piazzale A. Moro 2, IT-00185 Roma, Italy
| | - Jérôme J Crassous
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, DE-52074 Aachen, Germany.,Physical Chemistry, Department of Chemistry, Lund University, Naturvetarvägen 14, SE-22100 Lund, Sweden
| | - Divya Paloli
- Physical Chemistry, Department of Chemistry, Lund University, Naturvetarvägen 14, SE-22100 Lund, Sweden
| | - Fabrizio Camerin
- CNR-ISC Uos Sapienza, Piazzale A. Moro 2, IT-00185 Roma, Italy.,Department of Basic and Applied Sciences for Engineering, Sapienza Università di Roma, via A. Scarpa 14, IT-00161 Roma, Italy
| | - Nicoletta Gnan
- CNR-ISC Uos Sapienza, Piazzale A. Moro 2, IT-00185 Roma, Italy.,Department of Physics, Sapienza Università di Roma, Piazzale A. Moro 2, IT-00185 Roma, Italy
| | - Lorenzo Rovigatti
- Department of Physics, Sapienza Università di Roma, Piazzale A. Moro 2, IT-00185 Roma, Italy.,CNR-ISC Uos Sapienza, Piazzale A. Moro 2, IT-00185 Roma, Italy
| | - Peter Schurtenberger
- Physical Chemistry, Department of Chemistry, Lund University, Naturvetarvägen 14, SE-22100 Lund, Sweden
| | - Emanuela Zaccarelli
- CNR-ISC Uos Sapienza, Piazzale A. Moro 2, IT-00185 Roma, Italy.,Department of Physics, Sapienza Università di Roma, Piazzale A. Moro 2, IT-00185 Roma, Italy
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71
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Harrer J, Rey M, Ciarella S, Löwen H, Janssen LMC, Vogel N. Stimuli-Responsive Behavior of PNiPAm Microgels under Interfacial Confinement. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10512-10521. [PMID: 31304759 DOI: 10.1021/acs.langmuir.9b01208] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The volume phase transition of microgels is one of the most paradigmatic examples of stimuli-responsiveness, enabling a collapse from a highly swollen microgel state into a densely coiled state by an external stimulus. Although well characterized in bulk, it remains unclear how the phase transition is affected by the presence of a confining interface. Here, we demonstrate that the temperature-induced volume phase transition of poly(N-isopropylacrylamide) microgels, conventionally considered an intrinsic molecular property of the polymer, is in fact largely suppressed when the microgel is adsorbed to an air/liquid interface. We further observe a hysteresis in the core morphology and interfacial pressure between heating and cooling cycles. Our results, supported by molecular dynamics simulations, reveal that the dangling polymer chains of microgel particles, spread at the interface under the influence of surface tension, do not undergo any volume phase transition. The balance in free energy responsible for the volume phase transition is fundamentally altered by interfacial confinement. These results imply that important technological properties of such systems, including the temperature-induced destabilization of emulsions, do not occur via a decrease in the interfacial coverage of the microgels.
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Affiliation(s)
- Johannes Harrer
- Institute of Particle Technology , Friedrich-Alexander University Erlangen-Nürnberg , Cauerstrasse 4 , 91058 Erlangen , Germany
| | - Marcel Rey
- Institute of Particle Technology , Friedrich-Alexander University Erlangen-Nürnberg , Cauerstrasse 4 , 91058 Erlangen , Germany
| | - Simone Ciarella
- Theory of Polymers and Soft Matter, Department of Applied Physics , Eindhoven University of Technology , P.O. Box 513, 5600MB Eindhoven , The Netherlands
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie , Heinrich-Heine-Universität , D-40225 Düsseldorf , Germany
| | - Liesbeth M C Janssen
- Theory of Polymers and Soft Matter, Department of Applied Physics , Eindhoven University of Technology , P.O. Box 513, 5600MB Eindhoven , The Netherlands
| | - Nicolas Vogel
- Institute of Particle Technology , Friedrich-Alexander University Erlangen-Nürnberg , Cauerstrasse 4 , 91058 Erlangen , Germany
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72
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Rovigatti L, Gnan N, Ninarello A, Zaccarelli E. Connecting Elasticity and Effective Interactions of Neutral Microgels: The Validity of the Hertzian Model. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00099] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Lorenzo Rovigatti
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Roma, Italy
- CNR-ISC, Uos Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
| | - Nicoletta Gnan
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Roma, Italy
- CNR-ISC, Uos Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
| | - Andrea Ninarello
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Roma, Italy
- CNR-ISC, Uos Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
| | - Emanuela Zaccarelli
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Roma, Italy
- CNR-ISC, Uos Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
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73
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Scotti A, Denton AR, Brugnoni M, Houston JE, Schweins R, Potemkin II, Richtering W. Deswelling of Microgels in Crowded Suspensions Depends on Cross-Link Density and Architecture. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00729] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Andrea Scotti
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - Alan R. Denton
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050 United States
| | - Monia Brugnoni
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - Judith E. Houston
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85748 Garching, Germany
- European Spallation
Source ERIC, Box 176, SE-221 00 Lund, Sweden
| | - Ralf Schweins
- Institut Laue-Langevin
ILL DS/LSS, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - Igor I. Potemkin
- Physics Department, Lomonosov Moscow State University, 119991 Moscow, Russian Federation
- DWI - Leibniz
Institute
for Interactive Materials, Aachen 52056, Germany
- National Research South
Ural State University, Chelyabinsk 454080, Russian Federation
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
- JARA, Jülich Aachen
Research Alliance, 52056 Aachen, Germany
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74
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Gumerov RA, Filippov SA, Richtering W, Pich A, Potemkin II. Amphiphilic microgels adsorbed at oil-water interfaces as mixers of two immiscible liquids. SOFT MATTER 2019; 15:3978-3986. [PMID: 31025694 DOI: 10.1039/c9sm00389d] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Amphiphilic microgels adsorbed at an oil-water interface were studied by means of dissipative particle dynamics (DPD) simulations. The hydrophobic (A) and hydrophilic (B) monomer units in the polymer network are considered to be randomly distributed. Effects of the crosslinking density, interfacial tension between the liquids, their selectivity as solvents towards species A and B, and the degree of incompatibility between the A and B units on the internal microgel structure and distribution of the liquids are considered. The most important predictions are that (i) two immiscible liquids can homogeneously be mixed within the microgels and (ii) the adsorbed microgels contain a high fraction of the liquids (they are swollen at the interface). Simultaneous fulfillment of these two conditions can have a high impact on the design of new and efficient catalytic systems. In particular, such microgels can mix immiscible reactants dissolved in water and oil and trigger chemical reactions in the presence of a catalyst embedded into the microgel.
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Affiliation(s)
- Rustam A Gumerov
- Physics Department, Lomonosov Moscow State University, Moscow 119991, Russian Federation.
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75
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Volk K, Deißenbeck F, Mandal S, Löwen H, Karg M. Moiré and honeycomb lattices through self-assembly of hard-core/soft-shell microgels: experiment and simulation. Phys Chem Chem Phys 2019; 21:19153-19162. [DOI: 10.1039/c9cp03116b] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Moiré and honeycomb lattices result from the sequential double deposition of monolayers of core/shell microgels in dependence of the drying conditions.
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Affiliation(s)
- Kirsten Volk
- Institut für Physikalische Chemie I: Kolloide und Nanooptik
- Heinrich-Heine-Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Florian Deißenbeck
- Institut für Theoretische Physik II: Weiche Materie
- Heinrich-Heine-Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Suvendu Mandal
- Institut für Theoretische Physik II: Weiche Materie
- Heinrich-Heine-Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie
- Heinrich-Heine-Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Matthias Karg
- Institut für Physikalische Chemie I: Kolloide und Nanooptik
- Heinrich-Heine-Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
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