Light scattering with evanescent waves: Intermolecular interference and the structure factor for an ideal flexible chain at an interacting interface

1990 ◽  
Vol 93 (4) ◽  
pp. 2785-2800 ◽  
Author(s):  
Jun Gao ◽  
Karl F. Freed ◽  
Stuart A. Rice
Keyword(s):  
Light Scattering ◽  
Structure Factor ◽  
Evanescent Waves ◽  
Flexible Chain

Rheo-Optiics for Multicomponent Liquids

1991 ◽  
Vol 248 ◽  
Author(s):  
G. Fuller ◽  
J. van Egmond ◽  
J. Zawada ◽  
L. Archer
Keyword(s):  
Light Scattering ◽  
Structure Factor ◽  
Uniaxial Extension ◽  
Chemical Species ◽  
Polymer Melt ◽  
Orientation Distribution ◽  
Quantitative Information ◽  
Dioctyl Phthalate ◽  
Multicomponent Systems ◽  
Relaxation Dynamics

AbstractThe application of techniques in optical rheometry for the study of multicomponent systems is reviewed. Small angle light scattering (SALS) patterns are related to the structure of concentration fluctuations with length scales of the order of the wavelength of light. Scattering techniques such as SALS and scattering dichroism have been applied to monitor the transient evolution of anisotropic concentration fluctuation enhancement during simple shear induced phase separation in a semi-dilute solution of polystyrene (PS) in dioctyl phthalate(DOP). Furthermore, the Onuki- Doi theory relating scattering dichroism and structure factor has been used to verify the consistency between scattering dichroism and anisotropy in structure factor. Infrared polarimetry is a useful technique in probing the transient microstructural orientation of individual chemical species in multicomponent systems. The simultaneous measurement of intrinsic infrared dichroism and birefringence is particularly effective and has been employed to monitor component relaxation dynamics in miscible blends of poly(ethylene oxide) and poly(methyl methacrylate). Polarization Modulated Laser Raman Scattering (PMLRS) has been successfully employed to study the orientation dynamics of a polymer melt subjected to transient uniaxial extension. PMLRS provides quantitative information about the time evolution of both the second and fourth moments of the orientation distribution function of molecular segments.

Light-scattering and depolarization in biopolymers: Distinction between flexible chain models

Biopolymers ◽  
1978 ◽  
Vol 17 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. G. Shkorbatov ◽  
B. I. Verkin ◽  
I. O. Kulik
Keyword(s):  
Light Scattering ◽  
Flexible Chain

Analysis of light scattering in the evanescent waves area by a cylindrical nanohole in a noble-metal film

2008 ◽  
Vol 281 (13) ◽  
pp. 3581-3586 ◽  
Author(s):  
Elena Eremina ◽  
Yuri Eremin ◽  
Natalia Grishina ◽  
Thomas Wriedt
Keyword(s):  
Light Scattering ◽  
Noble Metal ◽  
Metal Film ◽  
Evanescent Waves

scholarly journals Algorithms and methods for analysis of the optical structure factor of fractal aggregates

2012 ◽  
Vol 19 (3) ◽  
pp. 459-470 ◽  
Author(s):  
Janusz Mroczka ◽  
Mariusz Woźniak ◽  
Fabrice R.A. Onofri
Keyword(s):  
Fractal Dimension ◽  
Light Scattering ◽  
Structure Factor ◽  
Single Particles ◽  
Particle Agglomeration ◽  
Simple Method ◽  
Large Size ◽  
Particle Aggregates ◽  
Reproducible Analysis ◽  
Optical Structure

Abstract We introduce numerical methods and algorithms to estimate the main parameters of fractal-like particle aggregates from their optical structure factor (i.e. light scattering diagrams). The first algorithm is based on a direct and simple method, but its applicability is limited to aggregates with large size parameter and intermediate fractal dimension. The second algorithm requires to build calibration curves based on accurate particle agglomeration and particle light scattering models. It allows analyzing the optical structure factor of much smaller aggregates, regardless of their fractal dimension and the size of the single particles. Therefore, this algorithm as well as the introduction of a criterial curve to detect the different scattering regimes, are thought to be powerful tools to perform reliable and reproducible analysis.

scholarly journals Conformation of Flexible and Semiflexible Chains Confined in Nanoposts Array of Various Geometries

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1064 ◽  
Author(s):  
Zuzana Benková ◽  
Lucia Rišpanová ◽  
Peter Cifra
Keyword(s):  
Structure Factor ◽  
Volume Fraction ◽  
Occupation Number ◽  
Chain Extension ◽  
Coarse Grained ◽  
Square Lattice ◽  
Structural Behavior ◽  
Single Chain ◽  
Flexible Chain ◽  
Two Factors

The conformation and distribution of a flexible and semiflexible chain confined in an array of nanoposts arranged in parallel way in a square-lattice projection of their cross-section was investigated using coarse-grained molecular dynamics simulations. The geometry of the nanopost array was varied at the constant post diameter dp and the ensuing modifications of the chain conformation were compared with the structural behavior of the chain in the series of nanopost arrays with the constant post separation Sp as well as with the constant distance between two adjacent post walls (passage width) wp. The free energy arguments based on an approximation of the array of nanopost to a composite of quasi-channels of diameter dc and quasi-slits of height wp provide semiqualitative explanations for the observed structural behavior of both chains. At constant post separation and passage width, the occupation number displays a monotonic decrease with the increasing geometry ratio dc/wp or volume fraction of posts, while a maximum is observed at constant post diameter. The latter finding is attributed to a relaxed conformation of the chains at small dc/wp ratio, which results from a combination of wide interstitial volumes and wide passage apertures. This maximum is approximately positioned at the same dc/wp value for both flexible and semiflexible chains. The chain expansion from a single interstitial volume into more interstitial volumes also starts at the same value of dc/wp ratio for both chains. The dependence of the axial chain extension on the dc/wp ratio turns out to be controlled by the diameter of the interstitial space and by the number of monomers in the individual interstitial volumes. If these two factors act in the same way on the axial extension of chain fragments in interstitial volumes the monotonic increase of the axial chain extension with the dc/wp in the nanopost arrays is observed. At constant wp, however, these two factors act in opposite way and the axial chain extension plotted against the dc/wp ratio exhibits a maximum. In the case of constant post diameter, the characteristic hump in the single chain structure factor whose position correlates with the post separation is found only in the structure factor of the flexible chain confined in the nanopost array of certain value of Sp. The structure factor of the flexible chain contains more information on the monomer organization and mutual correlations than the structure factor of the semiflexible chain. The stiffer chain confined in the nanopost array is composed of low number of statistical segments important for the presence of respective hierarchical regimes in the structure factor.

Short-time behavior of the dynamic structure factor for flexible-chain molecules

1982 ◽  
Vol 15 (6) ◽  
pp. 1609-1611 ◽  
Author(s):  
Manfred Schmidt ◽  
W. H. Stockmayer ◽  
Marc L. Mansfield
Keyword(s):  
Structure Factor ◽  
Dynamic Structure ◽  
Dynamic Structure Factor ◽  
Time Behavior ◽  
Flexible Chain ◽  
Chain Molecules ◽  
Short Time
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