Tensile testing of ultra-thin films on water surface

Kim, Jae-Han; Nizami, Adeel; Huang, Yun; Jang, Beom‐Su; Lee, Hak‐Joo; Woo, Chang Su; Hyun, Seungmin; Kim, Taek‐Soo

doi:10.1038/ncomms3520

Cited by 213 publications

(214 citation statements)

References 35 publications

Supporting

Mentioning

210

Contrasting

Unclassified

Order By: Relevance

“…17c. Recently, water was used as a frictionless sliding support for the specimen to facilitate the attachment and positioning procedures of the load and actuating cells [348]. The proper alignment of the specimen is always a very critical issue as recently addressed in details by Kang and Saif [349,350] -a few degrees of misalignment invalidates the extraction of accurate elastic and plastic properties.…”

Section: Fracture Testing Methods Of Freestanding Specimensmentioning

confidence: 99%

Failure of metals III: Fracture and fatigue of nanostructured metallic materials

2016

View full text Add to dashboard Cite

a b s t r a c tPushing the internal or external dimensions of metallic alloys down to the nanometer scale gives rise to strong materials, though most often at the expense of a low ductility and a low resistance to cracking, with negative impact on the transfer to engineering applications. These characteristics are observed, with some exceptions, in bulk ultra-fine grained and nanocrystalline metals, nano-twinned metals, thin metallic coatings on substrates and freestanding thin metallic films and nanowires. This overview encompasses all these systems to reveal commonalities in the origins of the lack of ductility and fracture resistance, in factors governing fatigue resistance, and in ways to improve properties. After surveying the various processing methods and key deformation mechanisms, we systematically address the current state of the art in terms of plastic localization, damage, static and fatigue cracking, for three classes of systems: (1) bulk ultra-fine grained and nanocrystalline metals, (2) thin metallic films on substrates, and (3) 1D and 2D freestanding micro and nanoscale systems. In doing so, we aim to favour cross-fertilization between progress made in the fields of mechanics of thin films, nanomechanics, fundamental researches in bulk nanocrystalline metals and metallurgy to impart enhanced resistance to fracture and fatigue in high-strength nanostructured systems. This involves exploiting intrinsic mechanisms, e.g. to enhance hardening and rate-sensitivity so as to delay necking, or improve grain-boundary cohesion to resist intergranular cracks or voids. Extrinsic methods can also be utilized such as by hybridizing the metal with another material to delocalize the deformation -as practiced in stretchable electronics. Fatigue crack initiation is in principle improved by a fine structure, but at the expense of larger fatigue crack growth rates. Extrinsic toughening through hybridization allows arresting or bridging cracks. The content and discussions are based on experimental, theoretical and simulation results from the recent literature, and focus is laid on linking microstructure and physical mechanisms to the overall mechanical behavior.

show abstract

Section: Fracture Testing Methods Of Freestanding Specimensmentioning

confidence: 99%

Failure of metals III: Fracture and fatigue of nanostructured metallic materials

2016

View full text Add to dashboard Cite

show abstract

“…In particular, in the film transfer to a basic buffer (3‐( N ‐morpholino)propanesulfonic acid (MOPS), pH 8.0), the pH rise (from 2.8 to 8.0) induced the transition of Fe(III)–TA bis‐complex to the more durable tris‐complex. The film color changed from purple to dark brown, and the Young's modulus of the film increased from 0.73 to 1.02 GPa (Figure S11, Supporting Information), which led to the successful transfer of foldable films to the conventional solvents, such as ethanol and acetone, without film disruption (Figure c; Figure S12, Supporting Information). In addition to the pliability, we observed that the film responded to the solvent polarity anisotropically; the film rolled itself in nonpolar solvents (e.g., dichloromethane).…”

Section: Methodsmentioning

confidence: 99%

Iron Gall Ink Revisited: In Situ Oxidation of Fe(II)–Tannin Complex for Fluidic‐Interface Engineering

et al. 2018

Self Cite

View full text Add to dashboard Cite

The ancient wisdom found in iron gall ink guides this work to a simple but advanced solution to the molecular engineering of fluidic interfaces. The Fe(II)–tannin coordination complex, a precursor of the iron gall ink, transforms into interface‐active Fe(III)–tannin species, by oxygen molecules, which form a self‐assembled layer at the fluidic interface spontaneously but still controllably. Kinetic studies show that the oxidation rate is directed by the counteranion of Fe(II) precursor salts, and FeCl2 is found to be more effective than FeSO4—an ingredient of iron gall ink—in the interfacial‐film fabrication. The optimized protocol leads to the formation of micrometer‐thick, free‐standing films at the air–water interface by continuously generating Fe(III)–tannic acid complexes in situ. The durable films formed are transferable, self‐healable, pliable, and postfunctionalizable, and are hardened further by transfer to the basic buffer. This O2‐instructed film formation can be applied to other fluidic interfaces that have high O2 level, demonstrated by emulsion stabilization and concurrent capsule formation at the oil–water interface with no aid of surfactants. The system, inspired by the iron gall ink, provides new vistas on interface engineering and related materials science.

show abstract

“…Although these models have been tested experimentally for characterizing the strength of a variety of materials with different shapes, such experimental validation has not been tested on ultrathin porous membranes. While there have been several notable studies that have investigated the mechanical characterization and tensile properties of non-porous thin films, [48][49][50][51] we believe this is the first examination of the implications of introducing porosity in parylene nanomembranes. Previous studies on the mechanical properties of porous nanomembranes primarily used nanoindentation and bulge testing due to the challenge of conducting traditional tensile testing on ultrathin materials.…”

Section: Mechanical Testingmentioning

confidence: 96%

Robust and Gradient Thickness Porous Membranes forIn VitroModeling of Physiological Barriers

Gholizadeh

Allahyari

Robert

et al. 2020

Preprint

View full text Add to dashboard Cite

Porous membranes are fundamental elements for tissue-chip barrier and co-culture models. However, the exaggerated thickness of commonly available membranes impedes an accurate in vitro reproduction of the biological multi-cellular continuum as it occurs in vivo. Existing techniques to fabricate membranes such as solvent cast, spin-coating, sputtering and PE-CVD result in uniform thickness films. To understand critical separation distances for various barrier and co-culture models, a gradient thickness membrane is needed. Here, we developed a robust method to generate ultrathin porous parylene C (UPP) membranes not just with precise thicknesses down to 300 nm, but with variable gradients in thicknesses, while at the same time having porosities up to 25%. We also show surface etching and increased roughness lead to improved cell attachment. Next, we examined the mechanical properties of UPP membranes with varying porosity and thickness and fit our data to previously published models, which can help determine practical upper limits of porosity and lower limits of thickness. Lastly, we validate a straightforward approach allowing the successful integration of the UPP membranes into a prototyped 3D-printed scaffold enabling in vitro barrier modeling and investigation of cell-cell interplay over variable distances using thickness gradients.

show abstract

Tensile testing of ultra-thin films on water surface

Cited by 213 publications

References 35 publications

Failure of metals III: Fracture and fatigue of nanostructured metallic materials

Failure of metals III: Fracture and fatigue of nanostructured metallic materials

Iron Gall Ink Revisited: In Situ Oxidation of Fe(II)–Tannin Complex for Fluidic‐Interface Engineering

Robust and Gradient Thickness Porous Membranes forIn VitroModeling of Physiological Barriers

Contact Info

Product

Resources

About