scholarly journals Multi-Technique Investigation of a Biomimetic Insect Tarsal Adhesive Fluid

2021 ◽  
Vol 7 ◽  
Author(s):  
J. Elliott Fowler ◽  
Stanislav Gorb ◽  
Joe E. Baio
Keyword(s):  
Surface Tension ◽  
Adhesive Strength ◽  
Traction Force ◽  
Surface Wetting ◽  
Bulk Properties ◽  
Sum Frequency ◽  
Characterization Techniques ◽  
Specific Order ◽  
First Time ◽  
Adhesive Fluid

There is substantial motivation to develop novel adhesives which take advantage of the superior adhesive strength and adaptability of many natural animal adhesives; however, the tools typically used to study these mechanisms are incapable of determining the precise interactions of molecules at an adhesive interface. In this study, a surface specific, order sensitive vibrational spectroscopy called sum frequency generation (SFG) is, for the first time, combined with multiple bulk characterization techniques to examine a novel, simple biomimetic adhesive fluid inspired by tarsal fluid of insects. Insects perform complex adhesive demands, including sticking, climbing vertically and running upside-down with little difficulty. Thus, we hypothesize that both bulk and surface specific properties of the fluid contribute to the success of this wet adhesive mechanism. SFG spectra of biomimetic emulsion exhibited similar hydrocarbon organization on hydrophobic and hydrophilic substrates to natural beetle fluid previously studied with the same method. Bulk characterization techniques indicated that the emulsion had a shear-thinning profile with the ability to enhance traction forces during climbing and low surface tension ideal for surface wetting on the majority of natural surfaces. Multi-technique comparisons between emulsion and pure squalane revealed that a hydrocarbon only based fluid could not replicate the traction promoting properties of the emulsion. We conclude that the insect tarsal fluid adhesive mechanism relies upon contributions from both surface-specific properties optimizing traction force and bulk properties promoting rapid surface wetting and maintaining pull-off force for fast detachment.

scholarly journals Interactions between an Associative Amphiphilic Block Polyelectrolyte and Surfactants in Water: Effect of Charge Type on Solution Properties and Aggregation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1729
Author(s):  
Patrizio Raffa
Keyword(s):  
Surface Tension ◽  
Self Assembly ◽  
Interaction Model ◽  
Industrial Applications ◽  
Molecular Organization ◽  
Different Types ◽  
Solution Rheology ◽  
Interesting Class ◽  
First Time

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

Surface Properties and Concentration Fluctuations in Sn-based Molten Alloys

2000 ◽  
Vol 55 (11-12) ◽  
pp. 967-972
Author(s):  
L. C. Prasad ◽  
V. N. Singh
Keyword(s):  
Surface Tension ◽  
Isothermal Compressibility ◽  
Reasonable Agreement ◽  
Surface Segregation ◽  
Concentration Fluctuations ◽  
Bulk Properties ◽  
Long Wavelength ◽  
Bulk Parameter ◽  
The Impact ◽  
The Ideal

Abstract A simple model based on the concept of a layered structure near the interface has been used to investigate the surface tension and surface segregation of SnPb and SnZn molten alloys. With increasing concentration of Sn, the surface tension (σ) of SnPb alloys has been found to increase, while a of SnZn alloys decreases, σ of both systems is smaller than the ideal value ΣCiσi. Our study reveals that both in SnPb and SnZn alloys the heavier atoms segregate towards the surface. The degree of segregation in SnZn alloys is greater than that in SnPb alloys. The Cahn-Hillard phenomenological model for the surface of pure liquids has been extended to binary molten mixtures and applied to the above systems. An attempt has been made to establish a link between the surface tension and the bulk properties such as concentration fluctuations in the long wavelength limit [Scc (0)] and isothermal compressibility (λT). The impact of the very sensitive bulk parameter Scc(0) has been examined. Reasonable agreement between our model and the experiment is observed for binary molten alloys such as SnPb in which the segregation is small, while for the SnZn alloys, in which the segregation is quite large, the agreement is not satisfactory.

Observations of Interfacial Population and Organization of Surfactants with Sum Frequency Generation and Surface Tension

2011 ◽  
Vol 115 (24) ◽  
pp. 12064-12067 ◽  
Author(s):  
Yi Rao ◽  
Xia Li ◽  
Xuegong Lei ◽  
Steffen Jockusch ◽  
Michael W. George ◽  
...  
Keyword(s):  
Surface Tension ◽  
Sum Frequency Generation ◽  
Sum Frequency ◽  
Frequency Generation

Modelling the morphology of minerals by computer

1995 ◽  
Vol 59 (397) ◽  
pp. 607-615 ◽  
Author(s):  
A. L. Rohl ◽  
D. H. Gay
Keyword(s):  
Basal Plane ◽  
Computer Code ◽  
Surface Relaxation ◽  
Complete Agreement ◽  
Growth Morphology ◽  
Bulk Properties ◽  
Hartree Fock ◽  
Surfaces And Interfaces ◽  
First Time ◽  
Effect Of Surface

AbstractA new computer code (MARVIN) has been developed for the simulation of surfaces and interfaces. The models and methodologies employed within the program are briefly discussed. One application of the code, calculating crystal morphologies, is explored using zircon, quartz and α-Al2O3 as examples. The new code enables the use of covalent type force fields and the effect of surface relaxation on the growth morphology to be calculated for the first time. It is found that relaxation does affect the attachment energy but not by a large enough amount to significantly change the growth morphology for the three examples discussed here. Finally, the calculated surface relaxation for the basal plane of α-Al2O3 is found to be in complete agreement with Hartree-Fock ab initio calculations, verifying that the potentials, which are derived from bulk properties, transfer well to this surface.

Surface Wetting By A Second Phase In A Liquid Binary Alloy

1991 ◽  
Vol 238 ◽  
Author(s):  
Joud J.C
Keyword(s):  
Surface Tension ◽  
Sessile Drop ◽  
Liquid Mixture ◽  
Energy Functional ◽  
Second Phase ◽  
Surface Wetting ◽  
Free Energy Functional ◽  
Experimental Surface ◽  
Two Phases ◽  
Liquid Binary Alloy

ABSTRACTThe surface tension variations of a binary two phases liquid mixture are discussed using the square gradient approximation to the free energy functional. The case of a weakly undersaturated solution at a temperature below the critical point for which we calculate a divergence of the surface tension and the layer thickness is particulary emphasized. Applications of such considerations are proposed to discuss the experimental surface tension isotherm of the liquid Sn-O system we have studied using the sessile drop technic and A.E.S. analysis.

scholarly journals Systematic Optimization of Water Models Using Liquid/Vapor Surface Tension Data

2019 ◽  
Author(s):  
Yudong Qiu ◽  
Paul S. Nerenberg ◽  
Teresa Head-Gordon ◽  
Lee-Ping Wang
Keyword(s):  
Surface Tension ◽  
Optimization Procedure ◽  
Kinetic Properties ◽  
Molecular Liquids ◽  
Surface Tension Data ◽  
Heat Of Vaporization ◽  
Experimental Surface ◽  
Temperature Of Maximum Density ◽  
Water Models ◽  
First Time

<div> <div> <div> <p>In this work we investigate whether experimental surface tension measurements, which are less sensitive to quantum and self-polarization corrections, are able to replace the usual reliance on the heat of vaporization as experimental reference data for fitting force field models of molecular liquids. To test this hypothesis we develop the fitting protocol necessary to utilize surface tension measurements in the ForceBalance optimization procedure in order to determine revised parameters for both three-point and four-point water models, TIP3P-ST and TIP4P-ST. We find that the incorporation of surface tension in the fit results in a rigid three-point model that reproduces the correct temperature of maximum density of water for the first time, but also leads to over-structuring of the liquid and less accurate transport properties. The rigid four-point TIP4P-ST model is highly accurate for a broad range of thermodynamic and kinetic properties, with similar performance compared to recently developed four- point water models. The results show surface tension to be a useful fitting property in general, especially when self-polarization corrections or nuclear quantum corrections are not readily available for correcting the heat of vaporization as is the case for other molecular liquids. </p> </div> </div> </div>

An Analysis of how Water-Based Ink Affects the Low Energy Surface Wettability

2011 ◽  
Vol 287-290 ◽  
pp. 1383-1387
Author(s):  
Ling Jia ◽  
Bei Qing Huang ◽  
Xian Fu Wei ◽  
Na Feng
Keyword(s):  
Surface Tension ◽  
Isopropyl Alcohol ◽  
Energy Surface ◽  
Base Material ◽  
Low Energy ◽  
Wetting Agent ◽  
Surface Wettability ◽  
Surface Wetting ◽  
Water Based ◽  
Surface Contact Angle

Water-based ink in low-energy surface wetting more difficult and hinder its application. In order to solve water ink in low-energy on the surface wettability problem, change the kind of cosolvent, kind and content of surfactants prepared ink. They were tested in low-energy CD the surface contact Angle to examine wettability of ink, test the surface tension, ink affecting wettability factors were analyzed. Results show that: in water-based ink add isopropyl alcohol, flow ping agent 432 and substrate wetting agent 245, can better improve its surface wettability in low-energy, and base material wetting agent 245 content about 1.25% wet effect is good.

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