Subnanometre ligand-shell asymmetry leads to Janus-like nanoparticle membranes

Jiang, Zhang; He, Jinbo; Deshmukh, Sanket A.; Kanjanaboos, Pongsakorn; Kamath, Ganesh; Wang, Yifan; Sankaranarayanan, Subramanian K. R. S.; Wang, Jin; Jaeger, Heinrich M.; Lin, Xiao‐Min

doi:10.1038/nmat4321

Cited by 75 publications

(79 citation statements)

References 34 publications

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“…The average thickness of monolayer films was found to be 80-92% of the average nanocrystal center-to-center distance, which indicates that polystyrene strands are slightly collapsed in the out-of-plane direction relative to their arrangement in the in-plane direction of the film. We believe that this asymmetry results from the unfavorable interaction of hydrophobic polystyrene with air and/or EG interfaces during superlattice self-assembly, similar to the case of the ligand shell asymmetry recently demonstrated in self-assembled superlattices formed from dodecanethiol-capped Au nanocrystals (35).…”

Section: Resultssupporting

confidence: 71%

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Tolerance to structural disorder and tunable mechanical behavior in self-assembled superlattices of polymer-grafted nanocrystals

Koshy

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Large, freestanding membranes with remarkably high elastic modulus (>10 GPa) have been fabricated through the self-assembly of ligand-stabilized inorganic nanocrystals, even though these nanocrystals are connected only by soft organic ligands (e.g., dodecanethiol or DNA) that are not cross-linked or entangled. Recent developments in the synthesis of polymer-grafted nanocrystals have greatly expanded the library of accessible superlattice architectures, which allows superlattice mechanical behavior to be linked to specific structural features. Here, colloidal self-assembly is used to organize polystyrene-grafted Au nanocrystals at a fluid interface to form ordered solids with sub-10-nm periodic features. Thin-film buckling and nanoindentation are used to evaluate the mechanical behavior of polymer-grafted nanocrystal superlattices while exploring the role of polymer structural conformation, nanocrystal packing, and superlattice dimensions. Superlattices containing 3-20 vol % Au are found to have an elastic modulus of ∼6-19 GPa, and hardness of ∼120-170 MPa. We find that rapidly self-assembled superlattices have the highest elastic modulus, despite containing significant structural defects. Polymer extension, interdigitation, and grafting density are determined to be critical parameters that govern superlattice elastic and plastic deformation.elasticity | buckling | nanocomposite | thin film | nanoindentation N anocrystal superlattices are ordered arrays of ligand-stabilized colloidal nanocrystals with unique thermal (1, 2), optical (3, 4), and electronic (5, 6) properties due to the nanoscale dimensions and periodic spacing of the inorganic crystals. Nanocrystal superlattices also exhibit superior mechanical performance: superlattice elastic modulus has been shown to rival that of lightweight structural composites (>10 GPa), and superlattice membranes are capable of withstanding repeated indents to large displacements (7)(8)(9). This is all the more remarkable because mechanical cohesion in the superlattices is attributed to van der Waals interactions between ligands on neighboring nanocrystals (10, 11), which are weak enough that the ligands are liquid at room temperature when not attached to nanocrystals. Superlattice strength and stiffness can be further elevated to values that are unprecedented for polymer nanocomposites by cross-linking the organic ligands that coat the nanocrystals (12). The unusual combination of physical properties in nanocrystal superlattices presents intriguing opportunities to use these materials as mechanically actuated optoelectronic sensors (13,14), lightweight solar sails (15), and ultrathin barriers and coatings (16,17), but warrants the development of a thorough understanding of the mechanical behavior of nanocrystal superlattices. In particular, the roles of nanocrystal packing geometry, ligand structural conformation, and ligand-ligand and ligand-nanocrystal interactions must be clarified to design multifunctional, self-assembled polymer nanocomposites with improved mechanical ...

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Section: Resultssupporting

confidence: 71%

“…S4). These cantileverlike films appear to be stable under the electron beam and their own weight, unlike dodecanethiol-Au superlattice freestanding membranes (35). AFM membrane deflection experiments were also performed on superlattice monolayers suspended on holey SiN TEM grids.…”

Section: Resultsmentioning

confidence: 99%

Tolerance to structural disorder and tunable mechanical behavior in self-assembled superlattices of polymer-grafted nanocrystals

Koshy

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…They can be coated with a wide range of ligands, which provide specific functionality in catalysis 4,5 , or define the mechanical response of nanoparticle arrays 6 . Nanoparticles are of current interest in applications concerned with thermal transport.…”

Section: Introductionmentioning

confidence: 99%

Thermal transport across nanoparticle–fluid interfaces: the interplay of interfacial curvature and nanoparticle–fluid interactions

Tascini

Armstrong

Chiavazzo

et al. 2017

Phys. Chem. Chem. Phys.

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We investigate the general dependence of the thermal transport across nanoparticle-fluid interfaces using molecular dynamics computations. We show that the thermal conductance depends strongly both on the wetting characteristics of the nanoparticle-fluid interface as well as on the nanoparticle size. Strong nanoparticle-fluid interactions, leading to full wetting states in the host fluid, result in high thermal conductances and efficient interfacial transport of heat. Weak interactions result in partial drying or full drying states and low thermal conductances. The variation of the thermal conductance with particle size is found to depend on the fluid-nanoparticle interactions. Strong interactions coupled with large interfacial curvatures lead to optimum interfacial heat transport. This complex dependence can be modelled with an equation that includes the interfacial curvature as parameter. In this way we rationalise existing experimental and computer simulation results and show that the thermal transport across nanoscale interfaces is determined by the correlations of both interfacial curvature and nanoparticle-fluid interactions.

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“…The Janus pellicle is a novel pellicle with asymmetric properties on each part [1]. As one of the pellicle materials, Janus pellicles [2][3][4][5][6] have been widely used in electrical engineering and biology due to their special structural characteristics. For example, a PVFM-based Janus pellicle is used for a highly durable Li-O 2 battery [7], a bionic Janus composite pellicle is used for a smart response actuator [8], and a hydrophobic-hydrophilic Janus pellicle is used for the mist collector [9].…”

Section: Introductionmentioning

confidence: 99%

2D double aeolotropic conductive Janus pellicle with multi-functionality then derived 3D dual-wall Janus-type tube

Qi¹,

Do²,

Xie³

et al. 2020

Express Polym. Lett.

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bilayer Janus pellicle (denoted as BJP) of concurrent double aeolotropic electrical conduction, superparamagnetism and luminescence is designed and constructed via electrospinning by using one-dimensional (1D) nanofibers and Janus nanoribbons as constructive units. The BJP comprises top-down two layers tightly bonded together. The top layer is a left-right structured Janus film which consists of Janus nanoribbons array as left and right side, and further, arrangement orientations of Janus nanoribbons in the two sides are perpendicular, leading to double aeolotropic conduction, and the conduction ratio reaches 10 8 times. The down layer is a non-array luminescent film made of nanofibers. Under the excitation by 291 and 294 nm light, red luminescence of the left side of the top layer and green luminescence of down layer in BJP are respectively achieved. The maximum saturation magnetization of the top layer can reach 21.45 (emu/g). By rolling the 2D BJP into the tube respectively with the ways of rolling from left to right or from up to down, three-dimensional (3D) dual-wall Janus-type tube with the Janus-type tube as outer or inner and the homogeneous tube as inner or outer is obtained.

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Subnanometre ligand-shell asymmetry leads to Janus-like nanoparticle membranes

Cited by 75 publications

References 34 publications

Tolerance to structural disorder and tunable mechanical behavior in self-assembled superlattices of polymer-grafted nanocrystals

Tolerance to structural disorder and tunable mechanical behavior in self-assembled superlattices of polymer-grafted nanocrystals

Thermal transport across nanoparticle–fluid interfaces: the interplay of interfacial curvature and nanoparticle–fluid interactions

2D double aeolotropic conductive Janus pellicle with multi-functionality then derived 3D dual-wall Janus-type tube

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