A novel microstructure inspired from Nepenthes alata and lizard skin and its enhanced uni-directional liquid spreading property

Wetting of permeable substrates by liquids is an important phenomenon in many natural and industrial processes. Substrate heterogeneities may significantly alter liquid spreading and interface shapes, which in turn may alter liquid imbibition. A new lubrication-theory-based model for droplet spreading on permeable substrates that incorporates surface roughness is developed in this work. The substrate is assumed to be saturated with liquid, and the contact-line region is described by including a precursor film and disjoining pressure. A novel boundary condition for liquid imbibition is applied that eliminates the need for a droplet-thickness-dependent substrate permeability that has been employed in previous models. A nonlinear evolution equation describing droplet height as a function of time and the radial coordinate is derived and then numerically solved to characterize the influence of substrate permeability and roughness on axisymmetric droplet spreading. Because it incorporates surface roughness, the new model is able to describe the contact-line pinning that has been observed in experiments but not captured by previous models.

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Prevention of Liquid Spreading or Creeping

Advances in Chemistry - Contact Angle, Wettability, and Adhesion ◽

10.1021/ba-1964-0043.ch024 ◽

1964 ◽

pp. 332-340 ◽

Cited By ~ 11

Author(s):

Marianne K. Bernett ◽

William A. Zisman

Keyword(s):

Liquid Spreading

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Liquid Spreading Induced by In Situ Generation of Metallic Nanoparticles

Langmuir ◽

10.1021/acs.langmuir.0c01976 ◽

2020 ◽

Vol 36 (41) ◽

pp. 12237-12246

Author(s):

Nitish Singh ◽

Yashaswini Jain ◽

Kaushal Kishore ◽

Animangsu Ghatak

Keyword(s):

Metallic Nanoparticles ◽

Liquid Spreading ◽

In Situ Generation

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Surface-Tension-Confined Channel with Biomimetic Microstructures for Unidirectional Liquid Spreading

Micromachines ◽

10.3390/mi11110978 ◽

2020 ◽

Vol 11 (11) ◽

pp. 978

Author(s):

Yi Zhang ◽

Yang Gan ◽

Liwen Zhang ◽

Deyuan Zhang ◽

Huawei Chen

Keyword(s):

Surface Tension ◽

Underlying Mechanism ◽

Structural Features ◽

Liquid Motion ◽

Water Separation ◽

Lab On Chip ◽

Liquid Spreading ◽

Oil Water Separation ◽

On Chip ◽

The Stability

Unidirectional liquid spreading without energy input is of significant interest for the broad applications in diverse fields such as water harvesting, drop transfer, oil–water separation and microfluidic devices. However, the controllability of liquid motion and the simplification of manufacturing process remain challenges. Inspired by the peristome of Nepenthes alata, a surface-tension-confined (STC) channel with biomimetic microcavities was fabricated facilely through UV exposure photolithography and partial plasma treatment. Perfect asymmetric liquid spreading was achieved by combination of microcavities and hydrophobic boundary, and the stability of pinning effect was demonstrated. The influences of structural features of microcavities on both liquid spreading and liquid pinning were investigated and the underlying mechanism was revealed. We also demonstrated the spontaneous unidirectional transport of liquid in 3D space and on tilting slope. In addition, through changing pits arrangement and wettability pattern, complex liquid motion paths and microreactors were realized. This work will open a new way for liquid manipulation and lab-on-chip applications.

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The spreading property for a prey-predator reaction-diffusion system with fractional diffusion

Fractional Calculus and Applied Analysis ◽

10.1515/fca-2015-0035 ◽

2015 ◽

Vol 18 (3) ◽

Cited By ~ 2

Author(s):

Hongmei Cheng ◽

Rong Yuan

Keyword(s):

Fractional Laplacian ◽

Stable State ◽

Reaction Diffusion ◽

Fractional Diffusion ◽

Reaction Diffusion System ◽

Diffusion System ◽

Diffusion Term ◽

Stable Lévy Process ◽

Front Position ◽

Spreading Property

AbstractThis paper is devoted to the study of some spreading properties of a prey-predator reaction-diffusion system where the diffusion term is replaced by the fractional Laplacian. We focus on the invasion of the introduced predator in some environment which is initially well-populated of prey. In contrast with the case of the standard Laplacian where the stable state invades the unstable one at constant speed, we prove that with fractional diffusion, generated for instance by a stable Lévy process, the front position is exponential in time.

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SPREADING PROPERTY OF AZOPROTEINS IN THE DERMIS

Journal of Experimental Medicine ◽

10.1084/jem.62.2.229 ◽

1935 ◽

Vol 62 (2) ◽

pp. 229-244 ◽

Cited By ~ 9

Author(s):

Albert Claude

Keyword(s):

Molecular Weight ◽

Protein Molecule ◽

Azo Compounds ◽

Skin Permeability ◽

Low Molecular Weight ◽

Direct Proportion ◽

Rabbit Skin ◽

Aromatic Derivative ◽

Azo Group ◽

Spreading Property

1. Azoproteins are shown to have the property of spreading when introduced intradermally into the rabbit skin. 2. The aromatic derivative selected for the coupling does not affect specifically the spreading property of the azoprotein. Likewise, the type of protein has no importance, except in quantitative respects. 3. The spreading property conferred upon a protein by coupling appears to derive from the presence of the azo group. 4. The spreading power of an azoprotein preparation seems to be determined by the number of diazo groups which enter the protein molecule, and to vary in direct proportion with the concentration of the solution. 5. Azo compounds of low molecular weight fail to exhibit any significant effect on skin permeability.

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