Adhesive force and adhesion energy of particle-substrate detachment

The mechanics of reversible adhesion of the gecko is investigated in terms of the attachment and detachment mechanisms of the hierarchical microstructures on its toe. At the bottom of the hierarchy, we show that a spatula pad of tiny thickness can be well absorbed onto a substrate with a large surface area and a highly constrained decohesion process zone, both of which are beneficial for robust attachment. With different peeling angles, the peeling strength of a spatula pad for attachment can be 10 times larger than that for detachment. At the intermediate level of hierarchy, we show that a seta can achieve a stress level similar to that in the spatula pad by uniformly distributing adhesion forces; as a consequence, the 10 times difference in the peel-off force of a single spatula pad for attachment and detachment is magnified up to a 100 times difference in adhesion energy at the level of seta. At the top of the hierarchy, the attachment process of a gecko toe is modelled as a pad under displacement-controlled pulling, leading to an adhesive force much larger than the gecko's body weight, while the associated detachment process is modelled as a pad under peeling, resulting in a negligible peel-off force. The present work reveals, in a more systematic way than previous studies in the literature, that the hierarchical microstructures on the gecko's toe can indeed provide the gecko with robust adhesion for attachment and reversible adhesion for easy detachment at the same time.

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Determination of the attractive force, adhesive force, adhesion energy and Hamaker constant of soot particles generated from a premixed methane/oxygen flame by AFM

Applied Surface Science ◽

10.1016/j.apsusc.2017.10.030 ◽

2018 ◽

Vol 433 ◽

pp. 450-457 ◽

Cited By ~ 5

Author(s):

Ye Liu ◽

Chonglin Song ◽

Gang Lv ◽

Nan Chen ◽

Hua Zhou ◽

...

Keyword(s):

Adhesive Force ◽

Adhesion Energy ◽

Hamaker Constant ◽

Attractive Force ◽

Soot Particles ◽

Oxygen Flame

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Progressive Debonding of Multilayer Interconnect Structures

MRS Proceedings ◽

10.1557/proc-473-21 ◽

1997 ◽

Vol 473 ◽

Cited By ~ 9

Author(s):

Michael Lane ◽

Robert Ware ◽

Steven Voss ◽

Qing Ma ◽

Harry Fujimoto ◽

...

Keyword(s):

Thin Films ◽

Crack Growth ◽

Driving Force ◽

Adhesion Energy ◽

Time Dependent ◽

Multilayer Thin Films ◽

Processing Conditions ◽

Interface Morphology ◽

Entire Sample ◽

Crack Growth Velocity

ABSTRACTProgressive (or time dependent) debonding of interfaces poses serious problems in interconnect structures involving multilayer thin films stacks. The existence of such subcriticai debonding associated with environmentally assisted crack-growth processes is examined for a TiN/SiO2 interface commonly encountered in interconnect structures. The rate of debond extension is found to be sensitive to the mechanical driving force as well as the interface morphology, chemistry, and yielding of adjacent ductile layers. In order to investigate the effect of interconnect structure, particularly the effect of an adjacent ductile Al-Cu layer, on subcriticai debonding along the TiN/SiO2 interface, a set of samples was prepared with Al-Cu layer thicknesses varying from 0.2–4.0 μm. All other processing conditions remained the same over the entire sample run. Results showed that for a given crack growth velocity, the debond driving force scaled with Al-Cu layer thickness. Normalizing the data by the critical adhesion energy allowed a universal subcriticai debond rate curve to be derived.

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Nanorobots Sense Local Physiochemical Heterogeneities of Tumor Matrisome

10.26434/chemrxiv.12063420 ◽

2020 ◽

Author(s):

Debayan Dasgupta ◽

Dharma Pally ◽

Deepak K. Saini ◽

Ramray Bhat ◽

Ambarish Ghosh

Keyword(s):

Cell Lines ◽

Cancer Cell ◽

Cancer Cell Lines ◽

Adhesive Force ◽

Surrounding Tissue ◽

Quantitative Measurements ◽

Malignant Breast Tumor ◽

Malignant Breast ◽

Cancer Dissemination

The dissemination of cancer is brought about by continuous interaction of malignant cells with their surrounding tissue microenvironment. Understanding and quantifying the remodeling of local extracellular matrix (ECM) by invading cells can therefore provide fundamental insights into the dynamics of cancer dissemination. In this paper, we use an active and untethered nanomechanical tool, realized as magnetically driven nanorobots, to locally probe a 3D tissue culture microenvironment consisting of cancerous and non-cancerous epithelia, embedded within reconstituted basement membrane (rBM) matrix. Our assay is designed to mimic the in vivo histopathological milieu of a malignant breast tumor. We find that nanorobots preferentially adhere to the ECM near cancer cells: this is due to the distinct charge conditions of the cancer-remodeled ECM. Surprisingly, quantitative measurements estimate that the adhesive force increases with the metastatic ability of cancer cell lines, while the spatial extent of the remodeled ECM was measured to be approximately 40 μm for all cancer cell lines studied here. We hypothesized and experimentally confirmed that specific sialic acid linkages specific to cancer-secreted ECM may be a major contributing factor in determining this adhesive behavior. The findings reported here can lead to promising applications in cancer diagnosis, quantification of cancer aggression, in vivo drug delivery applications, and establishes the tremendous potential of magnetic nanorobots for fundamental studies of cancer biomechanics.

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Oxidation Behavior of Maraging 300 Alloy Exposed to Nitrogen/Water Vapor Atmosphere at 500 °C

Metals ◽

10.3390/met11071021 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1021

Author(s):

Mauro Andres Cerra Florez ◽

Gemma Fargas Ribas ◽

Jorge Luiz Cardoso ◽

Antonio Manuel Mateo García ◽

Joan Josep Roa Rovira ◽

...

Keyword(s):

Water Vapor ◽

Oxide Layer ◽

Magnetic Layer ◽

Adhesive Force ◽

Point Of View ◽

Maraging Steels ◽

Cobalt Spinel ◽

Water Vapor Atmosphere ◽

Iron Nickel ◽

Ferrite Cobalt

Aging heat treatments in maraging steels are fundamental to achieve the excellent mechanical properties required in several industries, i.e., nuclear, automotive, etc. In this research, samples of maraging 300 alloy were aged using a novel procedure that combines different steps with two atmospheres (nitrogen and water vapor) for several hours. The oxidized surface layer was chemical, microstructural and micromechanically characterized. Due to the thermodynamic and kinetic conditions, these gases reacted and change the surface chemistry of this steel producing a thin iron-based oxide layer of a homogeneous thickness of around 500 nm. Within the aforementioned information, porosity and other microstructural defects showed a non-homogeneous oxide, mainly constituted by magnetite, nickel ferrite, cobalt ferrite, and a small amount of hematite in the more external parts of the oxide layer. In this sense, from a chemical point of view, the heat treatment under specific atmosphere allows to induce a thin magnetic layer in a mixture of iron, nickel, and cobalt spinel ferrites. On the other hand, the oxide layer presents an adhesive force 99 mN value that shows the capability for being used for tribological applications under sliding contact tests.

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Nanoscale Evaluation of Multi-Walled Carbon Nanotube’s Performance on Resisting Oxidization of Asphalt

Materials Science Forum ◽

10.4028/www.scientific.net/msf.982.195 ◽

2020 ◽

Vol 982 ◽

pp. 195-200

Author(s):

Abdullah Al Mamun ◽

Okan Sirin

Keyword(s):

Adhesive Force ◽

Force Microscopy ◽

Modified Asphalt ◽

Atomic Force ◽

Resistance To Oxidation ◽

Pavement Engineering ◽

Multi Walled Carbon Nanotubes ◽

Polymer Modified Asphalt ◽

Styrene Butadiene ◽

Walled Carbon Nanotubes

Nanotechnology has contributed significantly to different subfields of the construction industry, including asphalt pavement engineering. The improved properties and new functionalities of the nanomaterials have provided different desired properties of asphalt. In this study, the effectiveness of multi-walled carbon nanotubes (MWCNT) in resisting the oxidation of polymer-modified asphalt was measured. A total of three different percentages (0.5%, 1%, and 1.5%) of MWCNT were used to modify the Styrene-Butadiene (SB) and styrene–butadiene–styrene (SBS) modified asphalt (4% and 5%). The laboratory oxidized asphalt samples were evaluated by an atomic force microscopy machine. The oxidation of the polymer-MWCNT modified asphalt is measured by simulating the existing functional group of the asphalt and as a function of the adhesive force. It is observed that the use of MWCNT in SB and SBS can increase the resistance to oxidation.

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