Sorbitan Tristearate Layers at the Air/Water Interface Studied by Shear and Dilatational Interfacial Rheology

Langmuir ◽  
2005 ◽  
Vol 21 (23) ◽  
pp. 10555-10563 ◽  
Author(s):  
Philipp Erni ◽  
Peter Fischer ◽  
Erich J. Windhab
Keyword(s):  
Interfacial Rheology ◽  
Water Interface ◽  
Air Water Interface ◽  
Sorbitan Tristearate

scholarly journals Tadpole-Shaped POSS-Based Copolymers and the Aggregation Behavior at Air/Water Interface

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Lin Zhu ◽  
Fang Chen ◽  
Xiaoyan Ma ◽  
Xiu Qiang ◽  
Zhiguang Li ◽  
...  
Keyword(s):  
Thin Film ◽  
Block Copolymers ◽  
Surface Pressure ◽  
Self Assembly ◽  
Aggregation Behavior ◽  
Structure Evolution ◽  
Interfacial Rheology ◽  
Water Interface ◽  
Block Sequence ◽  
Air Water Interface

The aggregation behavior of three tadpole-shaped Polyhedral oligomeric silsesquioxane (POSS) based block copolymers using different blocks poly(methyl methacrylate) (PMMA) and poly(trifluoroethyl methacrylate) (PTFEMA) with different block sequence and ratio (POSS-PTFEMA161-b-PMMA236, POSS-PMMA277-b-PTFEMA130, and POSS-PMMA466-b-PTFEMA172) was investigated on the air-water interface. The interfacial rheology of three block copolymers was studied by surface pressure isotherm, compression modulus measurements, and compression and expansion hysteresis analysis on the Langmuir trough. The block sequence and ratio play a great role in self-assembly behavior at the interface. Based on surface pressure isotherm analysis, a thin film with low elasticity was achieved for the POSS-PTFEMA161-b-PMMA236. Moreover, for the block copolymer with same segment sequence (POSS-PMMA2-b-PTFEMA), the thin film compression capability is increased with increasing the PMMA ratio. The morphology of the deposited LB thin film was illustrated by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). We observed that a thin film was composed by crater-shaped quasi-2D micelles for POSS-PTFEMA-b-PMMA, while it was proved that only flaky texture was observed for both POSS-PMMA277-b-PTFEMA130 and POSS-PMMA466-b-PTFEMA172. The thickness and area of flaky aggregates were greatly related to PMMA ratio. The different interface self-assembly structure evolution was proposed based on the interfacial rheology and thin film morphology studies.

Jones-Ray effect on the organization of lysozyme in the presence of NaNO3 at an air/water interface: is it a cause or consequence?

RSC Advances ◽  
2015 ◽  
Vol 5 (122) ◽  
pp. 100638-100645 ◽  
Author(s):  
Maheshkumar Jaganathan ◽  
Aruna Dhathathreyan ◽  
Chellappan Selvaraju ◽  
Reinhard Miller
Keyword(s):  
Interfacial Rheology ◽  
Water Interface ◽  
Fluid Interface ◽  
Air Water Interface

Interfacial rheology confirms the Jones-Ray effect resulting from a synergy between lysozyme and NaNO3 at an air/fluid interface.

Adsorption of β-Casein–Surfactant Mixed Layers at the Air–Water Interface Evaluated by Interfacial Rheology

2012 ◽  
Vol 116 (16) ◽  
pp. 4898-4907 ◽  
Author(s):  
Armando Maestro ◽  
Csaba Kotsmar ◽  
Aliyar Javadi ◽  
Reinhard Miller ◽  
Francisco Ortega ◽  
...  
Keyword(s):  
Interfacial Rheology ◽  
Water Interface ◽  
Air Water Interface ◽  
Mixed Layers

Interfacial rheology and aggregation behaviour of amphiphilic CBABC-type pentablock copolymers at the air–water interface: effects of block ratio and chain length

RSC Advances ◽  
2015 ◽  
Vol 5 (101) ◽  
pp. 82869-82878 ◽  
Author(s):  
Zhiguang Li ◽  
Xiaoyan Ma ◽  
Duyang Zang ◽  
Xinghua Guan ◽  
Lin Zhu ◽  
...  
Keyword(s):  
Chain Length ◽  
Structure Evolution ◽  
Interfacial Rheology ◽  
Water Interface ◽  
Packing Model ◽  
Aggregation Behaviour ◽  
Air Water Interface ◽  
Pentablock Copolymers ◽  
Interface Effects

The interfacial rheology, aggregation behaviour and packing model of the structure evolution of three amphiphilic CBABC-type pentablock copolymers were investigated at the air–water interface.

scholarly journals Structure and rheology of macromolecular systems at interfaces

2015 ◽  
Author(s):  
Αντιγόνη Θεοδωράτου
Keyword(s):  
Rheological Properties ◽  
Light Stimulus ◽  
Interfacial Rheology ◽  
Water Interface ◽  
Molecular Architecture ◽  
Molecular Weights ◽  
Air Water Interface ◽  
2D Polymers ◽  
Pressure Area ◽  
Double Wall

This thesis focuses on the structural and rheological properties of viscoelastic filmsat the air-water interface. Our aim is to tailor the rheological properties of fluid interfacesand link them with their structure at the molecular scale. Langmuir quasimonolayerswere built by employing three different types of molecular systems, a seriesof semifluorinated alkanes that consist of two hydrophobic segments, a homopolymer,Poly(methyl methacrylate) (PMMA), and block copolymers of PEO-PDMS with differentmolecular architectures. The techniques employed in this thesis include LangmuirPockelstrough, to measure surface pressure/ area isotherms, and the magnetic rod interfacialstress rheometer, double wall ring fixture and bi-conical device in commercialrheometers for interfacial rheology studies. For structural studies of the films at theair-water interface we performed neutron reflectivity measurements and scanning forcemicroscopy.We observed great tunability of the structural and rheological properties of thesemifluorinated alkanes moving from simple linear molecules to more complex andbranched architectures, showing that molecular modification can change dramaticallythe viscoelastic response of the layers. Regardless of the molecular architecture effect,the external light stimulus effect was investigated for photo-sensitive semifluorinatedalkanes that could change their conformation reversibly from trans to cis. One of themain findings of this study was the transition from ordered to mixed (disordered) structureswhose onset is signaled by the drop of the interfacial storage modulus of aboutone order of magnitude.The predominantly elastic layers of PMMA were used to investigate the presence ofeven harmonics among different rheometry techniques. By analysing the strain signalin the Fourier space, it was found that the bi-conical and the double wall ring fixture do not generate even harmonics while the magnetic rod showed the presence of 2ndharmonics that are connected with asymmetry in the stress-strain profile, apparentlystemming from ununiformity in flow and the subphase contribution.Finally, the diblock and triblock copolymers of PEO-PDMS exhibit perfectly reversiblelayers at the air-water interface showing a reproducible PDMS phase transitionfor all the different molecular weights. Moreover, the average Flory radius of the polymersscale as RF∼N ν , with ν=0.56±0.01. Such result are in agreement with predictedscaling for 2D-polymers in bad solvent conditions.

Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

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