Yin, Yixuan | Search NASA

DOE OSTI2022

The Assembly and Jamming of Nanoparticle Surfactants at Liquid–Liquid Interfaces

Abstract Using the interactions between nanoparticles (NPs) and polymeric ligands to generate nanoparticle surfactants (NPSs) at the liquid–liquid interface, the binding energy of the NP to the interface can be significantly increased, irreversibly binding the NPSs to the interface. By designing a simplified NPS model, where the NP size can be precisely controlled and the characteristic fluorescence of the NPs be used as a direct probe of their spatial distribution, we provide new insights into the attachment mechanism of NPSs at the liquid–liquid interface. We find that the binding energy of NPSs to the interface can be reduced by competitive ligands, resulting in the dissociation and disassembly of NPSs at the interface, and allowing the construction of responsive, reconfigurable all‐liquid systems. Smaller NPSs that are loosely packed (unjammed) and irreversibly bound to the interface can be displaced by larger NPSs, giving rise to a size‐dependent assembly of NPSs at the interface. However, when the smaller size NPSs are densely packed and jam at the interface, the size‐dependent assembly of NPSs at the interface can be completely suppressed.

Wang, Beibei↗

DOE OSTI2022

The Assembly and Jamming of Nanoparticle Surfactants at Liquid–Liquid Interfaces

Abstract Using the interactions between nanoparticles (NPs) and polymeric ligands to generate nanoparticle surfactants (NPSs) at the liquid–liquid interface, the binding energy of the NP to the interface can be significantly increased, irreversibly binding the NPSs to the interface. By designing a simplified NPS model, where the NP size can be precisely controlled and the characteristic fluorescence of the NPs be used as a direct probe of their spatial distribution, we provide new insights into the attachment mechanism of NPSs at the liquid–liquid interface. We find that the binding energy of NPSs to the interface can be reduced by competitive ligands, resulting in the dissociation and disassembly of NPSs at the interface, and allowing the construction of responsive, reconfigurable all‐liquid systems. Smaller NPSs that are loosely packed (unjammed) and irreversibly bound to the interface can be displaced by larger NPSs, giving rise to a size‐dependent assembly of NPSs at the interface. However, when the smaller size NPSs are densely packed and jam at the interface, the size‐dependent assembly of NPSs at the interface can be completely suppressed.

Wang, Beibei↗

DOE OSTI2021

Layer‐by‐Layer Engineered All‐Liquid Microfluidic Chips for Enzyme Immobilization

Abstract Enzyme immobilization in the confines of microfluidic chips, that promote enzyme activity and stability, has become a powerful strategy to enhance biocatalysis and biomass conversion. Here, based on a newly developed all‐liquid microfluidic chip, fabricated by the interfacial assembly of nanoparticle surfactants (NPSs) in a biphasic system, a layer‐by‐layer assembly strategy to generate polysaccharide multilayers on the surface of a microchannel, greatly enhancing the mechanical properties of the microchannel and offering a biocompatible microenvironment for enzyme immobilization, is presented. Using horseradish peroxidase and glucose oxidase as model enzymes, all‐liquid microfluidic enzymatic and cascade reactors have been constructed and the crucial role of polysaccharide multilayers on enhancing the enzyme loading and catalytic efficiency is demonstrated.

Liu, Tan↗

DOE OSTI2021

Nanoparticle/Polyelectrolyte Complexes for Biomimetic Constructs

Abstract Constructing all‐aqueous systems with tailored geometries can generate a new class of biomimetic materials, a fascinating but challenging goal to achieve. Here, by taking advantage of the interfacial complexation of a polyelectrolyte (PE) and cellulose nanocrystals (CNCs), a unique interfacial PE/CNC complex is demonstrated for the stabilization of aqueous two‐phase systems and for the fabrication of all‐aqueous double emulsions and 3D constructs. The thickness of PE/CNC complex can be effectively adjusted by tuning the osmotic stress imbalance between the two aqueous phases and, during the formation and thickening of PE/CNC complex, individual assemblies can be connected to design hierarchical all‐aqueous structures. This new platform affords tremendous potential for engineering biomimetic constructs with advanced functionality, that can be used for chemical separation, delivery, and biphasic cascading reaction vessels.

Yin, Yixuan↗