Dilational viscoelasticity of the adsorption layers of hydrophobically modified chitosans

2005 ◽  
Vol 15 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Valery G. Babak ◽  
Jacques Desbrières
Keyword(s):  
Hydrophobically Modified ◽  
Dilational Viscoelasticity ◽  
Adsorption Layers

scholarly journals Interfacial Dilational Viscoelasticity of Adsorption Layers at the Hydrocarbon/Water Interface: The Fractional Maxwell Model

2019 ◽  
Vol 3 (4) ◽  
pp. 66 ◽  
Author(s):  
Giuseppe Loglio ◽  
Volodymyr I. Kovalchuk ◽  
Alexey G. Bykov ◽  
Michele Ferrari ◽  
Jürgen Krägel ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Maxwell Model ◽  
Water Interface ◽  
Paraffin Oil ◽  
Viscoelastic Modulus ◽  
Dilational Viscoelasticity ◽  
Span 80 ◽  
Fractional Maxwell Model ◽  
Adsorption Layers ◽  
Solution Matrix

In this communication, the single element version of the fractional Maxwell model (single-FMM or Scott–Blair model) is adopted to quantify the observed behavior of the linear interfacial dilational viscoelasticity. This mathematical tool is applied to the results obtained by capillary pressure experiments under low-gravity conditions aboard the International Space Station, for adsorption layers at the hydrocarbon/water interface. Two specific experimental sets of steady-state harmonic oscillations of interfacial area are reported, respectively: a drop of pure water into a Span-80 surfactant/paraffin-oil matrix and a pure n-hexane drop into a C13DMPO/TTAB mixed surfactants/aqueous-solution matrix. The fractional constitutive single-FMM is demonstrated to embrace the standard Maxwell model (MM) and the Lucassen–van-den-Tempel model (L–vdT), as particular cases. The single-FMM adequately fits the Span-80/paraffin-oil observed results, correctly predicting the frequency dependence of the complex viscoelastic modulus and the inherent phase-shift angle. In contrast, the single-FMM appears as a scarcely adequate tool to fit the observed behavior of the mixed-adsorption surfactants for the C13DMPO/TTAB/aqueous solution matrix (despite the single-FMM satisfactorily comparing to the phenomenology of the sole complex viscoelastic modulus). Further speculations are envisaged in order to devise combined FMM as rational guidance to interpret the properties and the interfacial structure of complex mixed surfactant adsorption systems.

Impact of Globule Unfolding on Dilational Viscoelasticity of β-Lactoglobulin Adsorption Layers

2009 ◽  
Vol 113 (40) ◽  
pp. 13398-13404 ◽  
Author(s):  
B. A. Noskov ◽  
D. O. Grigoriev ◽  
A. V. Latnikova ◽  
S.-Y. Lin ◽  
G. Loglio ◽  
...  
Keyword(s):  
Dilational Viscoelasticity ◽  
Adsorption Layers ◽  
Β Lactoglobulin

Dilational Viscoelasticity of Adsorption Layers Measured by Drop and Bubble Profile Analysis: Reason for Different Results

Langmuir ◽  
2016 ◽  
Vol 32 (22) ◽  
pp. 5500-5509 ◽  
Author(s):  
V. B. Fainerman ◽  
V. I. Kovalchuk ◽  
E. V. Aksenenko ◽  
R. Miller
Keyword(s):  
Profile Analysis ◽  
Dilational Viscoelasticity ◽  
Adsorption Layers

Influence of Polymer Charge, Temperature, and Surfactants on Surface Sizing of Liner and Greaseproof Paper With Hydrophobically Modified Starch

TAPPI Journal ◽  
2009 ◽  
Vol 8 (2) ◽  
pp. 33-38 ◽  
Author(s):  
ANNA JONHED ◽  
LARS JÄRNSTRÖM
Keyword(s):  
Phase Separation ◽  
Contact Angles ◽  
Low Ph ◽  
Hydrophobically Modified ◽  
Paper Sizing ◽  
Surface Sizing ◽  
Separation Temperature ◽  
Hydrophobic Nature ◽  
Sizing Agents ◽  
Charge Temperature

The aim of this study was to investigate the properties of hydrophobically modified (HM) quaterna-ry ammonium starch ethers for paper sizing. These starches possess temperature-responsive properties; that is, gelation or phase separation occurs at a certain temperature upon cooling. This insolubility of the HM starches in water at room temperature improved their performance as sizing agents. The contact angles for water on sized liner were substantially larger than on unsized liner. When the application temperature was well above the critical phase-separation temperature, larger contact angles were obtained for liner independently of pH compared with those at the lower application temperature. Cobb60 values for liner decreased upon surface sizing, with a low pH and high application temperature giving lower water penetration. Contact angles on greaseproof paper decreased upon sur-face sizing as compared to unsized greaseproof paper, independently of pH and temperature. Greaseproof paper showed no great difference between unsized substrates and substrates sized with HM starch at different pH. This is probably due to the already hydrophobic nature of greaseproof paper. However, the Cobb60 values increased at low pH and low application temperature. Surfactants were added to investigate how they affect the sized surface. Addition of surfactant reduces the contact angles, in spite of indications of complex formation.

Controlling porosity and density of nanocellulose aerogels for superhydrophobic light materials

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 145-153 ◽  
Author(s):  
Chengua Yu ◽  
Feng Wang ◽  
Shiyu Fu ◽  
Lucian Lucia
Keyword(s):  
Contact Angle ◽  
Freeze Drying ◽  
Engine Oil ◽  
High Porosity ◽  
Water Mixture ◽  
Waste Engine Oil ◽  
Hydrophobically Modified ◽  
Static Contact ◽  
Oil Water ◽  
Hydrophobic Material

A very low-density oil-absorbing hydrophobic material was fabricated from cellulose nanofiber aerogels–coated silane substances. Nanocellulose aerogels (NCA) superabsorbents were prepared by freeze drying cellulose nanofibril dispersions at 0.2%, 0.5%, 0.8%, 1.0%, and 1.5% w/w. The NCA were hydrophobically modified with methyltrimethoxysilane. The surface morphology and wettability were characterized by scanning electron microscopy and static contact angle. The aerogels displayed an ultralow density (2.0–16.7 mg·cm-3), high porosity (99.9%–98.9%), and superhydrophobicity as evidenced by the contact angle of ~150° that enabled the aerogels to effectively absorb oil from an oil/water mixture. The absorption capacities of hydrophobic nanocellulose aerogels for waste engine oil and olive oil could be up to 140 g·g-1 and 179.1 g·g-1, respectively.

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