Geometry and Nanolength Scales versus Interface Interactions: Water Dynamics in AOT Lamellar Structures and Reverse Micelles

2009 ◽  
Vol 131 (23) ◽  
pp. 8318-8328 ◽  
Author(s):  
David E. Moilanen ◽  
Emily E. Fenn ◽  
Daryl Wong ◽  
M. D. Fayer
Keyword(s):  
Reverse Micelles ◽  
Water Dynamics ◽  
Lamellar Structures

scholarly journals A theoretical study on the expression of enzymic activity in reverse micelles

1989 ◽  
Vol 259 (2) ◽  
pp. 355-361 ◽  
Author(s):  
R Bru ◽  
A Sánchez-Ferrer ◽  
F Garcia-Carmona
Keyword(s):  
Reverse Micelle ◽  
Reverse Micelles ◽  
Structural Model ◽  
Dynamic Equilibrium ◽  
Free Water ◽  
Continuous Phase ◽  
Enzymic Activity ◽  
Water Dynamics ◽  
Polar Phase ◽  
Catalytic Constant

The present work deals with a theoretical model of catalysis by enzymes entrapped in reverse micelles. Three aspects of the enzyme-reverse-micelle system have been considered: structure, dynamics and enzyme distribution and catalysis in reverse micelles. A proposed structural model of reverse micelles [El Seoud (1984) in Reverse Micelles (Luisi, P. L. & Straub, B. E., eds.), p. 81, Plenum Press, New York] consists of three domains: surfactant apolar tails, bound water and free water. Dynamics are based on a dynamic equilibrium of association-dissociation that lead one to consider the dispersed polar phase as a pseudo-continuous phase [Luisi, Giomini, Pileni & Robinson (1988) Biochim. Biophys. Acta 947, 207-246]. Enzyme is distributed among the reverse-micelle domains and it expresses a catalytic constant for each one of them. The overall activity is calculated taking into account the volume in which enzyme is solubilized, and expressed as a function of the whole volume (V). The characteristic parameters of reverse micelles, omega 0 (= [H2O]/[surfactant]) and theta (= % water, v/v), were investigated as modulators of enzymic activity. Three basic patterns of modulation by omega 0 were found depending on which domain the enzyme expressed the highest catalytic constant. Combinations of those basic patterns lead to other modulation types that can be found experimentally, such as superactivation. Other combinations predict behaviour patterns not described to date, such as superinhibition. Dependence of catalytic activity on theta was only stated at omega 0 values around a critical value, which coincides with the appearance of free water.

scholarly journals Water Dynamics at the Interface in AOT Reverse Micelles

2009 ◽  
Vol 113 (25) ◽  
pp. 8560-8568 ◽  
Author(s):  
David E. Moilanen ◽  
Emily E. Fenn ◽  
Daryl Wong ◽  
M. D. Fayer
Keyword(s):  
Reverse Micelles ◽  
Water Dynamics ◽  
Aot Reverse Micelles

scholarly journals Water dynamics in large and small reverse micelles: From two ensembles to collective behavior

2009 ◽  
Vol 131 (1) ◽  
pp. 014704 ◽  
Author(s):  
David E. Moilanen ◽  
Emily E. Fenn ◽  
Daryl Wong ◽  
Michael D. Fayer
Keyword(s):  
Collective Behavior ◽  
Reverse Micelles ◽  
Water Dynamics

SEM/FESEM imaging of lamellar structures in melt extruded polyethylene films

1992 ◽  
Vol 50 (2) ◽  
pp. 1142-1143
Author(s):  
R.T. Chen ◽  
M.G. Jamieson ◽  
R. Callahan
Keyword(s):  
Imaging Techniques ◽  
Membrane Surface ◽  
High Stress ◽  
Extrusion Direction ◽  
Polymeric Membranes ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Crystalline Polymers ◽  
Lamellar Structures ◽  
Resolution Imaging

“Row lamellar” structures have previously been observed when highly crystalline polymers are melt-extruded and recrystallized under high stress. With annealing to perfect the stacked lamellar superstructure and subsequent stretching in the machine (extrusion) direction, slit-like micropores form between the stacked lamellae. This process has been adopted to produce polymeric membranes on a commercial scale with controlled microporous structures. In order to produce the desired pore morphology, row lamellar structures must be established in the membrane precursors, i.e., as-extruded and annealed polymer films or hollow fibers. Due to the lack of pronounced surface topography, the lamellar structures have typically been investigated by replica-TEM, an indirect and time consuming procedure. Recently, with the availability of high resolution imaging techniques such as scanning tunneling microscopy (STM) and field emission scanning electron microscopy (FESEM), the microporous structures on the membrane surface as well as lamellar structures in the precursors can be directly examined.The materials investigated are Celgard® polyethylene (PE) flat sheet membranes and their film precursors, both as-extruded and annealed, made at different extrusion rates (E.R.).

Infrared investigation of water encapsulated in non ionic reverse micelles

2000 ◽  
Vol 10 (PR7) ◽  
pp. Pr7-215-Pr7-218 ◽  
Author(s):  
J.-B. Brubach ◽  
A. Mermet ◽  
A. Filabozzi ◽  
P. Colavita ◽  
A. Gerschel ◽  
...  
Keyword(s):  
Reverse Micelles

Method application of optimal multi-parameter analysis to assess the distribution of water masses as an example of CTD data of the Barents Sea in summer 2017

2019 ◽  
pp. 38-51
Author(s):  
Valeriy G. Yakubenko ◽  
Anna L. Chultsova
Keyword(s):  
Barents Sea ◽  
Field Measurements ◽  
Structural Similarity ◽  
Water Masses ◽  
Parameter Analysis ◽  
Water Dynamics ◽  
Phosphorus Concentration ◽  
Nitrogen And Phosphorus ◽  
The Barents Sea ◽  
Expert Assessments

Identification of water masses in areas with complex water dynamics is a complex task, which is usually solved by the method of expert assessments. In this paper, it is proposed to use a formal procedure based on the application of the method of optimal multiparametric analysis (OMP analysis). The data of field measurements obtained in the 68th cruise of the R/V “Academician Mstislav Keldysh” in the summer of 2017 in the Barents Sea on the distribution of temperature, salinity, oxygen, silicates, nitrogen, and phosphorus concentration are used as a data for research. A comparison of the results with data on the distribution of water masses in literature based on expert assessments (Oziel et al., 2017), allows us to conclude about their close structural similarity. Some differences are related to spatial and temporal shifts of measurements. This indicates the feasibility of using the OMP analysis technique in oceanological studies to obtain quantitative data on the spatial distribution of different water masses.

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