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Nabizadeh M, Nasirian F, Li X, Saraswat Y, Waheibi R, Hsiao LC, Bi D, Ravandi B, Jamali S. Network physics of attractive colloidal gels: Resilience, rigidity, and phase diagram. Proc Natl Acad Sci U S A 2024; 121:e2316394121. [PMID: 38194451 PMCID: PMC10801866 DOI: 10.1073/pnas.2316394121] [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: 09/26/2023] [Accepted: 12/03/2023] [Indexed: 01/11/2024] Open
Abstract
Colloidal gels exhibit solid-like behavior at vanishingly small fractions of solids, owing to ramified space-spanning networks that form due to particle-particle interactions. These networks give the gel its rigidity, and with stronger attractions the elasticity grows as well. The emergence of rigidity can be described through a mean field approach; nonetheless, fundamental understanding of how rigidity varies in gels of different attractions is lacking. Moreover, recovering an accurate gelation phase diagram based on the system's variables has been an extremely challenging task. Understanding the nature of colloidal clusters, and how rigidity emerges from their connections is key to controlling and designing gels with desirable properties. Here, we employ network analysis tools to interrogate and characterize the colloidal structures. We construct a particle-level network, having all the spatial coordinates of colloids with different attraction levels, and also identify polydisperse rigid fractal clusters using a Gaussian mixture model, to form a coarse-grained cluster network that distinctly shows main physical features of the colloidal gels. A simple mass-spring model then is used to recover quantitatively the elasticity of colloidal gels from these cluster networks. Interrogating the resilience of these gel networks shows that the elasticity of a gel (a dynamic property) is directly correlated to its cluster network's resilience (a static measure). Finally, we use the resilience investigations to devise [and experimentally validate] a fully resolved phase diagram for colloidal gelation, with a clear solid-liquid phase boundary using a single volume fraction of particles well beyond this phase boundary.
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Affiliation(s)
- Mohammad Nabizadeh
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA02215
| | - Farzaneh Nasirian
- Network Science Institute and Department of Physics, Northeastern University, Boston, MA02215
| | - Xinzhi Li
- Department of Physics, Northeastern University, Boston, MA02215
| | - Yug Saraswat
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC27606
| | - Rony Waheibi
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC27606
| | - Lilian C. Hsiao
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC27606
| | - Dapeng Bi
- Department of Physics, Northeastern University, Boston, MA02215
| | - Babak Ravandi
- Network Science Institute and Department of Physics, Northeastern University, Boston, MA02215
| | - Safa Jamali
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA02215
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Dellatolas I, Bantawa M, Damerau B, Guo M, Divoux T, Del Gado E, Bischofberger I. Local Mechanism Governs Global Reinforcement of Nanofiller-Hydrogel Composites. ACS NANO 2023; 17:20939-20948. [PMID: 37906739 DOI: 10.1021/acsnano.3c00716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
We reveal the mechanism for the strong reinforcement of attractive nanofiller-hydrogel composites. Measuring the linear viscoelastic properties of hydrogels containing filler nanoparticles, we show that a significant increase of the modulus can be achieved at unexpectedly low volume fractions of nanofillers when the filler-hydrogel interactions are attractive. Using three-dimensional numerical simulations, we identify a general microscopic mechanism for the reinforcement, common to hydrogel matrices of different compositions and concentrations and containing nanofillers of varying sizes. The attractive interactions induce a local increase in the gel density around the nanofillers. The effective fillers, composed of the nanofillers and the densified regions around them, assemble into a percolated network, which constrains the gel displacement and enhances the stress coupling throughout the system. A global reinforcement of the composite is induced as the stresses become strongly coupled. This physical mechanism of reinforcement, which relies only on attractive filler-matrix interactions, provides design strategies for versatile composites that combine low nanofiller fractions with an enhanced mechanical strength.
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Affiliation(s)
- Ippolyti Dellatolas
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Minaspi Bantawa
- Department of Physics and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, D.C. 20057, United States
| | - Brian Damerau
- Department of Physics and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, D.C. 20057, United States
| | - Ming Guo
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Thibaut Divoux
- ENSL, CNRS, Laboratoire de Physique, F-69342 Lyon, France
- MultiScale Material Science for Energy and Environment, UMI 3466, CNRS-MIT, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Emanuela Del Gado
- Department of Physics and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, D.C. 20057, United States
| | - Irmgard Bischofberger
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Vinutha HA, Diaz Ruiz FD, Mao X, Chakraborty B, Del Gado E. Stress-stress correlations reveal force chains in gels. J Chem Phys 2023; 158:114104. [PMID: 36948805 DOI: 10.1063/5.0131473] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
We investigate the spatial correlations of microscopic stresses in soft particulate gels using 2D and 3D numerical simulations. We use a recently developed theoretical framework predicting the analytical form of stress-stress correlations in amorphous assemblies of athermal grains that acquire rigidity under an external load. These correlations exhibit a pinch-point singularity in Fourier space. This leads to long-range correlations and strong anisotropy in real space, which are at the origin of force-chains in granular solids. Our analysis of the model particulate gels at low particle volume fractions demonstrates that stress-stress correlations in these soft materials have characteristics very similar to those in granular solids and can be used to identify force chains. We show that the stress-stress correlations can distinguish floppy from rigid gel networks and that the intensity patterns reflect changes in shear moduli and network topology, due to the emergence of rigid structures during solidification.
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Affiliation(s)
- H A Vinutha
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC 20057, USA
| | - Fabiola Doraly Diaz Ruiz
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC 20057, USA
| | - Xiaoming Mao
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Bulbul Chakraborty
- Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02453, USA
| | - Emanuela Del Gado
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC 20057, USA
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Sammüller F, de Las Heras D, Schmidt M. Inhomogeneous steady shear dynamics of a three-body colloidal gel former. J Chem Phys 2023; 158:054908. [PMID: 36754804 DOI: 10.1063/5.0130655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We investigate the stationary flow of a colloidal gel under an inhomogeneous external shear force using adaptive Brownian dynamics simulations. The interparticle forces are derived from the Stillinger-Weber potential, where the three-body term is tuned to enable network formation and gelation in equilibrium. When subjected to the shear force field, the system develops remarkable modulations in the one-body density profile. Depending on the shear magnitude, particles accumulate either in quiescent regions or in the vicinity of maximum net flow, and we deduce this strong non-equilibrium response to be characteristic of the gel state. Studying the components of the internal force parallel and perpendicular to the flow direction reveals that the emerging flow and structure of the stationary state are driven by significant viscous and structural superadiabatic forces. Thereby, the magnitude and nature of the observed non-equilibrium phenomena differ from the corresponding behavior of simple fluids. We demonstrate that a simple power functional theory reproduces accurately the viscous force profile, giving a rationale of the complex dynamical behavior of the system.
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Affiliation(s)
- Florian Sammüller
- Theoretische Physik II, Physikalisches Institut, Universität Bayreuth, D-95447 Bayreuth, Germany
| | - Daniel de Las Heras
- Theoretische Physik II, Physikalisches Institut, Universität Bayreuth, D-95447 Bayreuth, Germany
| | - Matthias Schmidt
- Theoretische Physik II, Physikalisches Institut, Universität Bayreuth, D-95447 Bayreuth, Germany
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Pastore R, Mensitieri G, Vlassopoulos D, Greco F. Glasses and gels: a crossroad of molecular liquids, polymers and colloids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:090401. [PMID: 34889780 DOI: 10.1088/1361-648x/ac3cf3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 11/24/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Raffaele Pastore
- Department of Chemical, Materials and Production Engineering, University of Naples 'Federico II', P.le Tecchio 80, Naples 80125, Italy
| | - Giuseppe Mensitieri
- Department of Chemical, Materials and Production Engineering, University of Naples 'Federico II', P.le Tecchio 80, Naples 80125, Italy
| | - Dimitris Vlassopoulos
- Department of Materials Science and Technology, University of Crete, and Institute of Electronic Structure and Laser, FORTH, Heraklion 70013, Greece
| | - Francesco Greco
- Department of Chemical, Materials and Production Engineering, University of Naples 'Federico II', P.le Tecchio 80, Naples 80125, Italy
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