Governing factors in stress response of nanoparticle films on water surface

Kim, Kyungil; Leahy, Brian; Dai, Yeling; Shpyrko, Oleg; Soltau, Janet; Pelton, Matthew; Meron, Mati; Lin, Binhua

doi:10.1063/1.3661988

Cited by 12 publications

(48 citation statements)

References 31 publications

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“…[24][25][26] These studies followed the structural arrangement of NPs during the formation or compression of the NP layer and provided quantitative information on the in-plane and out-of-plane structure of the assembled NPs. [20][21][22][23][24]26 Therefore the precision of X-ray reflectivity and diffraction in elucidating the interfacial properties makes it a perfect technique for referencing the plasmon ruler. 17 In the work by Bera et al 25 voltage-tunable counterionmediated interactions between the NPs were used to control the lattice spacing of the 2D array.…”

Section: Introductionmentioning

confidence: 99%

Tuneable 2D self-assembly of plasmonic nanoparticles at liquid|liquid interfaces

et al. 2016

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Understanding the structure and assembly of nanoparticles at liquid|liquid interfaces is paramount to their integration into devices for sensing, catalysis, electronics and optics. However, many difficulties arise when attempting to resolve the structure of such interfacial assemblies. In this article we use a combination of X-ray diffraction and optical reflectance to determine the structural arrangement and plasmon coupling between 12.8 nm diameter gold nanoparticles assembled at a water|1,2-dichloroethane interface. The liquid|liquid interface provides a molecularly flat and defect-correcting platform for nanoparticles to self-assemble. The amount of nanoparticles assembling at the interface can be controlled via the concentration of electrolyte within either the aqueous or organic phase. At higher electrolyte concentration more nanoparticles can settle at the liquid|liquid interface resulting in a decrease in nanoparticle spacing as observed from X-ray diffraction experiments. The plasmonic coupling between the nanoparticles as they come closer together is observed by a red-shift in the optical reflectance spectra. The optical reflectance and the X-ray diffraction data are combined to introduce a new 'plasmon ruler'. This allows extraction of structural information from simple optical spectroscopy techniques, with important implications for understanding the structure of self-assembled nanoparticle films at liquid interfaces.

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Section: Introductionmentioning

confidence: 99%

Tuneable 2D self-assembly of plasmonic nanoparticles at liquid|liquid interfaces

et al. 2016

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“…To normalize for trough area, the isotherms are plotted in terms of ! vs surface mass density of sample.Previous X-ray and TEM experiments[3][4][5][6] indicate the pressure regimes in which the different nanoparticle films remain in the monolayer phase. We focus on comparing the compressive and shear moduli of our nanoparticle and lipid films in these regions, which are indicative of monolayer Langmuir films.Lipid Films.…”

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confidence: 99%

“…Like amphiphilic molecules, these capped nanoparticles self-assemble into 2D lattices at the air-water interface. [3][4][5][6][7][8][9][10][11][12][13][14] Nanoparticles exhibit remarkable physical properties including quantum confinement, 15 plasmon resonance 9,[16][17][18][19] and superparamagnetism 5,20 Thin films composed of nanoparticles have shown potential applications in biosensors 16,19,21 , high sensitivity resonators 14 , filtration devices 22 , magnetoresistive devices 10 , and flexible electronics. [23][24][25] Langmuir monolayers in particular have remarkable mechanical properties as two-dimensional materials that can extend into the third dimension.…”

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confidence: 99%

Comparison of the Mechanical Properties of Self-Assembled Langmuir Monolayers of Nanoparticles and Phospholipids

et al. 2013

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Nanoparticles with hydrophobic capping ligands and amphiphilic phospholipids are both found to self-assemble into monolayer films when deposited on the air/water interface. By separately measuring the anisotropic stress response of these films under uniaxial compression, we obtain both the 2D compressive and shear moduli of a range of different thin nanoparticle and phospholipid films. The compressive moduli of both nanoparticle and lipid films in the solid phase are on the same order of magnitude, whereas the shear moduli of the lipid films are found to be significantly lower. Additionally, the moduli of the nanoparticle films depended substantially on the polydispersity of the constituent particles-broader size distribution lowered the stiffness of the nanoparticle film.

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“…In contrast, films of Au-NPs collapse into the third dimension at lower surface pressures (~30 mN/m). 30,[32][33]45 This collapse occurs via a transition from a monolayer to a multilayer, as observed using optical microscopy and inferred by a decrease in the slope of the surface pressure-surface area isotherm.…”

Section: Resultsmentioning

confidence: 82%

Liquid Surface X-ray Studies of Gold Nanoparticle–Phospholipid Films at the Air/Water Interface

et al. 2016

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Amphiphilic phospholipids and nanoparticles functionalized with hydrophobic capping ligands have been extensively investigated for their capacity to self-assemble into Langmuir monolayers at the air/water interface. However, understanding of composite films consisting of both nanoparticles and phospholipids, and by extension, the complex interactions arising between nanomaterials and biological membranes, remains limited. In this work, dodecanethiol-capped gold nanoparticles (Au-NPs) with an average core diameter of 6 nm were incorporated into 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers with surface densities ranging from 0.1 to 20% area coverage at a surface pressure of 30 mN/m. High resolution liquid surface X-ray scattering studies revealed a phase separation of the DPPC and Au-NP components of the composite film, as confirmed with atomic force microscopy after the film was transferred to a substrate. At low Au-NP content, the structural organization of the phase-separated film is best described as a DPPC film containing isolated islands of Au-NPs. However, increasing the Au-NP content beyond 5% area coverage transforms the structural organization of the composite film to a long-range interconnected network of Au-NP strands surrounding small seas of DPPC, where the density of the Au-NP network increases with increasing Au-NP content. The observed phase separation and structural organization of the phospholipid and nanoparticle components in these Langmuir monolayers are useful for understanding interactions of nanoparticles with biological membranes.

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Governing factors in stress response of nanoparticle films on water surface

Cited by 12 publications

References 31 publications

Tuneable 2D self-assembly of plasmonic nanoparticles at liquid|liquid interfaces

Tuneable 2D self-assembly of plasmonic nanoparticles at liquid|liquid interfaces

Comparison of the Mechanical Properties of Self-Assembled Langmuir Monolayers of Nanoparticles and Phospholipids

Liquid Surface X-ray Studies of Gold Nanoparticle–Phospholipid Films at the Air/Water Interface

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