Neutron Scattering from Charged Polymer Latices

1986 ◽  
Vol 79 ◽  
Author(s):  
John B. Hayter
Keyword(s):  
Ionic Strength ◽  
Neutron Scattering ◽  
Volume Fraction ◽  
Low Density ◽  
Latex Particles ◽  
Size Number ◽  
Particle Potential ◽  
Charged Polymer ◽  
Low Ionic Strength ◽  
Polymer Latex

AbstractAqueous suspensions of charged polymer latex particles exhibit several forms of ordered structure, the particular form depending on the size, number density and charge of the latex particles, and on the ionic strength of the aqueous medium. At low ionic strength, the inter-particle potential may become sufficiently long-ranged to generate crystalline order, which usually shows bcc symmetry at low density and becomes fcc above about 3% volume fraction of latex in the system. As the ionic strength increases, the crystalline structure melts, and ordered liquid structures develop. Light scattering may be used to study these structures at low density, but at higher density, where the opacity of the suspensions renders optical techniques intractable, neutron scattering must be used.This paper will review some of the recent small-angle neutron scattering experiments on polymer latex suspensions, in the light of new theoretical methods which permit in situ analysis of the particle size and charge. The discussion will also encompass new experimental methods for studying latex structures under dynamic shear conditions.

Neutron scattering studies of nucleosome structure at low ionic strength

Biochemistry ◽  
1983 ◽  
Vol 22 (21) ◽  
pp. 4916-4923 ◽  
Author(s):  
Edward C. Uberbacher ◽  
Venkatraman Ramakrishnan ◽  
Donald E. Olins ◽  
Gerard J. Bunick
Keyword(s):  
Ionic Strength ◽  
Neutron Scattering ◽  
Nucleosome Structure ◽  
Low Ionic Strength

Kinetic analysis of association processes between oppositely charged polymer latex particles

1987 ◽  
Vol 109 (22) ◽  
pp. 6641-6644 ◽  
Author(s):  
Hiromi Kitano ◽  
Satoshi Iwai ◽  
Norio Ise ◽  
Tsuneo Okubo
Keyword(s):  
Kinetic Analysis ◽  
Latex Particles ◽  
Charged Polymer ◽  
Oppositely Charged ◽  
Polymer Latex

Diffusional Deposition of Charged Latex Particles on Water−Solid Interfaces at Low Ionic Strength

Langmuir ◽  
1998 ◽  
Vol 14 (18) ◽  
pp. 5127-5132 ◽  
Author(s):  
M. Semmler ◽  
E. K. Mann ◽  
J. Rička ◽  
M. Borkovec
Keyword(s):  
Ionic Strength ◽  
Latex Particles ◽  
Low Ionic Strength

Small angle neutron scattering studies of the structure of nucleosome cores at low ionic strength

Physica B+C ◽  
1983 ◽  
Vol 120 (1-3) ◽  
pp. 436-439
Author(s):  
Kazuei Mita ◽  
Mitsuo Zama ◽  
Sachiko Ichimura ◽  
Nobuo Niimura ◽  
Keisuke Kaji ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Low Ionic Strength

Ultra-High Resolution Small-Angle Neutron Scattering Investigations of Liquid-Liquid Phase Separation in Linear Low-Density Polyethylene

1996 ◽  
Vol 461 ◽  
Author(s):  
M. M. Agamalian ◽  
R. G. Alamo ◽  
J. D. Londono ◽  
L. Mandelkern ◽  
S. Spooner ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Disperse Phase ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Volume Fraction ◽  
Amorphous Material ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Phase Volume Fraction

ABSTRACTPrevious small-angle neutron scattering (SANS) studies [1] of heterogeneous ethylene-hexene linear low-density polyethylene (LLDPE) copolymers have confirmed the existence of a dispersed minority phase (volume fraction φ ∼ 10−2) consisting of highly branched, amorphous material. However, these experiments were conducted via a pinhole SANS spectrometer with an upper resolution limit ∼ 103 Å, whereas microscopy indicates that the dimensions of the disperse phase extend to the μm-range. We have therefore complemented these investigations via a Bonse-Hart ultra-small angle neutron scattering (USANS) instrument which increases the instrumental resolution in reciprocal space by a factor - 100, and thus particle size up to 30 μm can be resolved. The sensitivity of the USANS camera has recently been increased by two orders of magnitude by using the modified channel cut crystals [2], and the performance is therefore comparable to the best x-ray Bonse-Hart cameras. Xylene extraction removes the highly branched molecules and hence the volume fraction of the disperse phase is higher (φ ∼ 0.3) in the extracted material.

scholarly journals Silica Fouling in Reverse Osmosis Systems–Operando Small-Angle Neutron Scattering Studies

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 413
Author(s):  
Vitaliy Pipich ◽  
Thomas Starc ◽  
Johan Buitenhuis ◽  
Roni Kasher ◽  
Winfried Petry ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Volume Fraction ◽  
Cross Flow ◽  
Bragg Diffraction ◽  
Layer Formation ◽  
Permeate Flux ◽  
Cake Layer

We present operando small-angle neutron scattering (SANS) experiments on silica fouling at two reverse osmose (RO) membranes under almost realistic conditions of practiced RO desalination technique. To its realization, two cells were designed for pressure fields and tangential feed cross-flows up to 50 bar and 36 L/h, one cell equipped with the membrane and the other one as an empty cell to measure the feed solution in parallel far from the membrane. We studied several aqueous silica dispersions combining the parameters of colloidal radius, volume fraction, and ionic strength. A relevant result is the observation of Bragg diffraction as part of the SANS scattering pattern, representing a crystalline cake layer of simple cubic lattice structure. Other relevant parameters are silica colloidal size and volume fraction far from and above the membrane, as well as the lattice parameter of the silica cake layer, its volume fraction, thickness, and porosity in comparison with the corresponding permeate flux. The experiments show that the formation of cake layer depends to a large extent on colloidal size, ionic strength and cross-flow. Cake layer formation proved to be a reversible process, which could be dissolved at larger cross-flow. Only in one case we observed an irreversible cake layer formation showing the characteristics of an unstable phase transition. We likewise observed enhanced silica concentration and/or cake formation above the membrane, giving indication of a first order liquid–solid phase transformation.

Conformational Transitions in Escherichia coli Ribosomal RNAs as Visualized by Dedicated STEM

1988 ◽  
Vol 46 ◽  
pp. 176-177
Author(s):  
J.S. Wall ◽  
V. Maridiyan ◽  
S. Tumminia ◽  
J. Hairifeld ◽  
M. Boublik
Keyword(s):  
Ionic Strength ◽  
Three Dimensional ◽  
Conformational Transitions ◽  
Dark Field ◽  
Dimensional Structure ◽  
Ribosomal Rnas ◽  
Field Mode ◽  
Freeze Dried ◽  
High Resolution Images ◽  
Low Ionic Strength

The high contrast in the dark-field mode of dedicated STEM, specimen deposition by the wet film technique and low radiation dose (1 e/Å2) at -160°C make it possible to obtain high resolution images of unstained freeze-dried macromolecules with minimal structural distortion. Since the image intensity is directly related to the local projected mass of the specimen it became feasible to determine the molecular mass and mass distribution within individual macromolecules and from these data to calculate the linear density (M/L) and the radii of gyration.2 This parameter (RQ), reflecting the three-dimensional structure of the macromolecular particles in solution, has been applied to monitor the conformational transitions in E. coli 16S and 23S ribosomal RNAs in solutions of various ionic strength.In spite of the differences in mass (550 kD and 1050 kD, respectively), both 16S and 23S RNA appear equally sensitive to changes in buffer conditions. In deionized water or conditions of extremely low ionic strength both appear as filamentous structures (Fig. la and 2a, respectively) possessing a major backbone with protruding branches which are more frequent and more complex in 23S RNA (Fig. 2a).

An Evaluation of a Plasma Fractionation System

1960 ◽  
Vol 4 (01) ◽  
pp. 031-044
Author(s):  
George Y. Shinowara ◽  
E. Mary Ruth
Keyword(s):  
Biological Activity ◽  
Ionic Strength ◽  
Plasma Proteins ◽  
High Concentration ◽  
Significant Evidence ◽  
Native Proteins ◽  
Mobility Data ◽  
Fractionation Procedure ◽  
The Individual ◽  
Low Ionic Strength

SummaryFour primary fractions comprising at least 97 per cent of the plasma proteins have been critically appraised for evidence of denaturation arising from a low temperature—low ionic strength fractionation system. The results in addition to those referable to the recovery of mass and biological activity include the following: The high solubilities of these fractions at pH 7.3 and low ionic strengths; the compatibility of the electrophoretic and ultracentrifugal data of the individual fractions with those of the original plasma; and the recovery of hemoglobin, not hematin, in fraction III obtained from specimens contaminated with this pigment. However, the most significant evidence for minimum alterations of native proteins was that the S20, w and the electrophoretic mobility data on the physically recombined fractions were identical to those found on whole plasma.The fractionation procedure examined here quantitatively isolates fibrinogen, prothrombin and antithrombin in primary fractions. Results have been obtained demonstrating its significance in other biological systems. These include the following: The finding of 5 S20, w classes in the 4 primary fractions; the occurrence of more than 90 per cent of the plasma gamma globulins in fraction III; the 98 per cent pure albumin in fraction IV; and, finally, the high concentration of beta lipoproteins in fraction II.

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