Triplex molecular layers with nonlinear nanomechanical response

Tsukruk, Vladimir V.; Ahn, Hyo-Sok; Kim, D.; Sidorenko, Alexander

doi:10.1063/1.1486267

Cited by 21 publications

(8 citation statements)

References 28 publications

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“…12). 53,54 This model represents a complex tri-layer system with elastic modulus changing from 2000 MPa for the topmost layer to 5-10 MPa for the rubbery interlayer and to 1000 MPa for underlying organic layer on 160,000 MPa silicon substrate as was independently measured for these materials. The elastic character of deformation was tested by zooming-out the surface area probed and observing absence of the indentation marks.…”

Section: Tri-layered System: Grafted Sandwich Coatingmentioning

confidence: 99%

Nanomechanical Probing of Layered Nanoscale Polymer Films With Atomic Force Microscopy

et al. 2004

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The approach developed for the microindentation of layered elastic solids was adapted to analyze atomic force microscopy probing of ultrathin (1-100 nm-thick) polymer films on a solid substrate. The model for analyzing microindentation of layered solids was extended to construct two-and tri-step graded functions with the transition zones accounting for a variable gradient between layers. This "graded" approach offered a transparent consideration of the gradient of the mechanical properties between layers. Several examples of recent applications of this model to nanoscale polymer layers were presented. We considered polymer layers with elastic moduli ranging from 0.05 to 3000 MPa with different architecture in a dry state and in a solvated state. The most sophisticated case of a tri-layered polymer film with thickness of 20-50 nm was also successfully treated within this approach. In all cases, a complex shape of corresponding loading curves and elastic modulus depth profiles obtained from experimental data were fitted by the graded functions with nanomechanical parameters (elastic moduli and transition zone widths) close to independently determined microstructural parameters (thickness and composition of layers) of the layered materials.

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Section: Tri-layered System: Grafted Sandwich Coatingmentioning

confidence: 99%

Nanomechanical Probing of Layered Nanoscale Polymer Films With Atomic Force Microscopy

et al. 2004

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“…2͒. 21,23 Statistical analysis of the surface distribution of the molecular stiffness under small deformations clearly demonstrated the presence of three distinctive stiffness levels for surfaces covered with dendritic molecules ͑Fig. 1͒.…”

Section: Nanoscale Stiffness Of Individual Dendritic Molecules and Thmentioning

confidence: 99%

Nanoscale stiffness of individual dendritic molecules and their aggregates

Tsukruk

Shulha

Zhai

2003

Applied Physics Letters

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We demonstrate that carefully designed micromapping of the surface stiffness with nanoscale resolution could reveal quantitative data on the elastic properties of compliant, dendritic organic molecules with nanoparticulate dimensions below 3 nm. Much higher elastic modulus was observed for individual, fourth generation dendritic molecules due to their more shape persistent conformation. Large, reversible, elastic deformation is a distinct characteristic of the nanomechanical response observed for individual dendritic molecules. Such a “rubbery” response could be an indication of spatial constraints imposed on vitrification of dendritic molecules tethered to the functionalized interface. Surprisingly, an increased stiffness was also found for the third generation dendritic molecules within long aggregates.

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“…Because multilayer elastic films are common in many practical problems, [11][12][13][14] it is relevant to study the effect of a stiff bottom elastic layer on surface instability of a softer top elastic layer and the influence of a softer bottom elastic layer on surface morphology of a stiffer top elastic layer. It is often assumed that the stiff elastic layer can be approximately treated as a rigid substrate.…”

Section: Introductionmentioning

confidence: 99%

Surface instability of a bilayer elastic film due to surface van der Waals forces

Yoon

Mioduchowski

2005

Journal of Applied Physics

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The paper studies surface instability of a bilayer elastic film interacting with another flat rigid body through surface van der Waals forces under plane-strain conditions. The analysis is based on an approximate model which reduces the two-dimensional plane-strain problem of the bilayer elastic film to a one-dimensional problem on its surface. The critical value of the interaction coefficient for surface instability and the associated instability mode can be determined easily by identifying the minimum of the interaction coefficient as a function of the wavelength of the instability mode. Among others, the present analysis shows that a stiff bottom layer of a bilayer film can be approximately treated as a rigid substrate only when the surface compliance ratio of the top layer to the bottom layer exceeds a certain critical value. In contrast to a common assumption that nonequal Poisson ratios of the two layers have a minor effect, it is found that different Poisson ratio combinations could have a significant effect on the surface instability of a bilayer elastic film even when the thickness ratio and modulus ratio keep unchanged. In particular, the present study confirms that, unlike a single-layer elastic film which has only one instability mode, a bilayer elastic film can have two distinct surface instability modes when the top layer is more compliant and much thinner than the bottom layer.

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Triplex molecular layers with nonlinear nanomechanical response

Cited by 21 publications

References 28 publications

Nanomechanical Probing of Layered Nanoscale Polymer Films With Atomic Force Microscopy

Nanomechanical Probing of Layered Nanoscale Polymer Films With Atomic Force Microscopy

Nanoscale stiffness of individual dendritic molecules and their aggregates

Surface instability of a bilayer elastic film due to surface van der Waals forces

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