Structure and phase behavior of polymer-linked colloidal gels

Abstract

Low-density "equilibrium" gels that consist of a percolated, kinetically arrested network of colloidal particles and are resilient to aging can be fabricated by restricting the number of effective bonds that form between the colloids. Valence-restricted patchy particles have long served as one archetypal example of such materials, but equilibrium gels can also be realized through a synthetically simpler and scalable strategy that introduces a secondary linker, such as a small ditopic molecule, to mediate the bonds between the colloids. Here, we consider the case where the ditopic linker molecules are low-molecular-weight polymers and demonstrate using a model colloid-polymer mixture how macroscopic properties such as the phase behavior as well as the microstructure of the gel can be designed through the polymer molecular weight and concentration. The low-density window for equilibrium gel formation is favorably expanded using longer linkers, while necessarily increasing the spacing between all colloids. However, we show that blends of linkers with different sizes enable wider variation in microstructure for a given target phase behavior. Our computational study suggests a robust and tunable strategy for the experimental realization of equilibrium colloidal gels.

arXiv comment11 pages, 8 figures

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Cited by in corpus (9)

• Universal Gelation of Metal Oxide Nanocrystals via Depletion Attractions
• Effects of linker flexibility on phase behavior and structure of linked colloidal gels
• Using patchy particles to prevent local rearrangements in models of non-equilibrium colloidal gels
• Wertheim's thermodynamic perturbation theory with double-bond association and its application to colloid-linker mixtures
• Percolation in binary mixtures of linkers and particles: chaining {\it {vs}} branching
• Comparative Study of Covalent and van der Waals CdS Quantum Dot Assemblies from Many-Body Perturbation Theory
• Dynamics of equilibrium linked colloidal gels
• Odd elasticity in disordered chiral active materials
• Effects of Ligand vs. Linker on Phase Behavior and Mechanical Properties of Nanoparticle Gels