Ordered packing arrangements of spherical micelles of diblock copolymers in two and three dimensions

1987 ◽  
Vol 20 (11) ◽  
pp. 2934-2939 ◽  
Author(s):  
Edwin L. Thomas ◽  
David J. Kinning ◽  
David B. Alward ◽  
Chris S. Henkee
Keyword(s):  
Diblock Copolymers ◽  
Three Dimensions ◽  
Spherical Micelles

MONTE CARLO SIMULATION OF SELF-ASSEMBLED AMPHIPHILIC DIBLOCK COPOLYMER IN SOLUTION

2003 ◽  
Vol 17 (01n02) ◽  
pp. 241-244 ◽  
Author(s):  
PINGCHUAN SUN ◽  
YUHUA YIN ◽  
BAOHUI LI ◽  
QINGHUA JIN ◽  
DATONG DING
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Diblock Copolymer ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
The Self ◽  
Amphiphilic Diblock Copolymer ◽  
The Core ◽  
Spherical Micelles ◽  
The Given

In this paper, Monte Carlo method is applied to simulate the process of the self-assembly of amphiphilic diblock copolymer with a series of block lengths of the insoluble and soluble blocks. Under the given simulation conditions, the diblock copolymers form spherical micelles in solution. The dependence of the core radii of spherical micelles on both block lengths is obtained and compared with experimental results of Eisenberg and coworkers.

Effect of long-range order on craze microstructure in deformed PS/PB block copolymers

1987 ◽  
Vol 45 ◽  
pp. 524-525
Author(s):  
Chris S. Henkee ◽  
Edwin L. Thomas
Keyword(s):  
Block Copolymers ◽  
Diblock Copolymers ◽  
Local Deformation ◽  
Long Range Order ◽  
Diamond Structure ◽  
Volume Percent ◽  
Craze Growth ◽  
Stage Process ◽  
Spherical Micelles ◽  
Double Diamond

The morphology present in block copolymers is determined by the volume percent of each of the components present. When the minority component ranges from 0-20 vol%, spherical micelles of the minority component are found. From 20-35 vol%, cylindrical microdomains are observed; at volume fractions slightly greater than this (35-38%), the ordered bicontinuous double diamond structure is observed. Finally from 38-≃60 vol%, regular alternating lamellae are found. It is now well known that for polystyrene-polybutadiene (PS/PB) diblock copolymers in which the PB is the minority component forming either spheres or cylinders, that deformation takes place via crazing. The mechanism for craze growth in these polymers appears to be a two stage process; the cavitation of the PB phase, followed by the drawing of the PS matrix into fibrils spanning the region of local deformation.

Cyclic azobenzene-containing amphiphilic diblock copolymers: solution self-assembly and unusual photo-responsive behaviors

2015 ◽  
Vol 6 (16) ◽  
pp. 3009-3013 ◽  
Author(s):  
Beibei Chen ◽  
Zhao Wang ◽  
Jinjie Lu ◽  
Xian Yang ◽  
Yong Wang ◽  
...  
Keyword(s):  
Diblock Copolymer ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Amphiphilic Diblock Copolymer ◽  
Spherical Micelles ◽  
Self Assembled ◽  
Amphiphilic Diblock Copolymers

A novel amphiphilic diblock copolymer containing cyclic-azobenzene has been synthesized and self-assembled into spherical micelles which show unusual photo-responsive behaviors.

scholarly journals Solubilization of Phenol Derivatives in Polymer Micelles Formed by Cationic Block Copolymer

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Irma Fuentes ◽  
Patricio Silva ◽  
Francisco Martinez ◽  
Andrés F. Olea
Keyword(s):  
Block Copolymers ◽  
Partition Coefficients ◽  
Diblock Copolymers ◽  
Polymer Micelles ◽  
Phenol Derivatives ◽  
Fluorescence Probing ◽  
Region Model ◽  
Spherical Micelles ◽  
Self Aggregation ◽  
Side Alkyl Chain

The aggregation of cationic block copolymers formed by polystyrene (PS) and poly(ethyl-4-vinylpyridine) (PS-b-PE4VP) was studied in aqueous solution. Diblock copolymers of PS and poly(4-vinylpyridine) were synthesized by sequential anionic polymerization using BuLi as initiator. Subsequently, the 4-vinylpyridine units were quaternized with ethyl bromide to obtain cationic PS-b-PE4VP block copolymers with different quaternization degree. The self-aggregation of cationic block copolymers was studied by fluorescence probing, whereas the morphology and size of polymer micelles were determined by transmission electronic microscopy. Results indicate that spherical micelles with sizes lower than 100 nm were formed, whereas their micropolarity decreases with increasing quaternization degree. The partition of phenols between the micellar and aqueous phase was studied by using the pseudo-phase model, and the results show that the partition coefficients increase with increasing length of the side alkyl chain and are larger for star micelles. These results are discussed in terms of three-region model.

Cylindrical Micelles in Rigid-Flexible Diblock Copolymers

1991 ◽  
Vol 248 ◽  
Author(s):  
D.R.M Williams ◽  
G.H. Fredrickson
Keyword(s):  
Phase Diagram ◽  
Diblock Copolymers ◽  
Theoretical Study ◽  
Flexible Tail ◽  
Cylindrical Micelles ◽  
Rigid Rod ◽  
Spherical Micelles

AbstractWe present a theoretical study of a melt of diblock copolymers consisting of a rigid rod and a flexible tail. It is shown that in addition to the lamellax phases previously discussed, there also exist phases of “hockey puck” micelles, where the rods are packed axially into cylinders. These phases occupy most of the phase diagram previously thought to consist of monolayer lamellae. It is argued that spherical micelles probably do not exist.

High-resolution scanning electron microscopy (HRSEM) of mitochondria from various rat tissues

1988 ◽  
Vol 46 ◽  
pp. 14-15
Author(s):  
P.J. Lea ◽  
M.J. Hollenberg
Keyword(s):  
Electron Microscopy ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Rat Hepatocytes ◽  
Three Dimensions ◽  
Objective Lens ◽  
Rat Tissues ◽  
Thin Sections ◽  
Reconstruction Methods ◽  
Scanning Electron

Our current understanding of mitochondrial ultrastructure has been derived primarily from thin sections using transmission electron microscopy (TEM). This information has been extrapolated into three dimensions by artist's impressions (1) or serial sectioning techniques in combination with computer processing (2). The resolution of serial reconstruction methods is limited by section thickness whereas artist's impressions have obvious disadvantages.In contrast, the new techniques of HRSEM used in this study (3) offer the opportunity to view simultaneously both the internal and external structure of mitochondria directly in three dimensions and in detail.The tridimensional ultrastructure of mitochondria from rat hepatocytes, retinal (retinal pigment epithelium), renal (proximal convoluted tubule) and adrenal cortex cells were studied by HRSEM. The specimens were prepared by aldehyde-osmium fixation in combination with freeze cleavage followed by partial extraction of cytosol with a weak solution of osmium tetroxide (4). The specimens were examined with a Hitachi S-570 scanning electron microscope, resolution better than 30 nm, where the secondary electron detector is located in the column directly above the specimen inserted within the objective lens.

Inelastic Electron Scattering from Valence Electrons in Aluminum

1976 ◽  
Vol 34 ◽  
pp. 462-463
Author(s):  
P. E. Batson ◽  
C. H. Chen ◽  
J. Silcox
Keyword(s):  
Electron Scattering ◽  
Single Scattering ◽  
Three Dimensions ◽  
Inelastic Electron ◽  
Weak Beam ◽  
Scattering Spectrum ◽  
Valence Electrons ◽  
Diffraction Patterns ◽  
Electronic Scattering

We wish to report in this paper measurements of the inelastic scattering component due to the collective excitations (plasmons) and single particlehole excitations of the valence electrons in Al. Such scattering contributes to the diffuse electronic scattering seen in electron diffraction patterns and has recently been considered of significance in weak-beam images (see Gai and Howie) . A major problem in the determination of such scattering is the proper correction for multiple scattering. We outline here a procedure which we believe suitably deals with such problems and report the observed single scattering spectrum.In principle, one can use the procedure of Misell and Jones—suitably generalized to three dimensions (qx, qy and #x2206;E)--to derive single scattering profiles. However, such a computation becomes prohibitively large if applied in a brute force fashion since the quasi-elastic scattering (and associated multiple electronic scattering) extends to much larger angles than the multiple electronic scattering on its own.

Advantages of Complementary Stereo Images as Viewed with the Low-Temperature Field-Emission SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1314-1315
Author(s):  
William P. Wergin ◽  
Eric F. Erbe
Keyword(s):  
Fold Increase ◽  
Horizontal Displacement ◽  
Three Dimensions ◽  
Stereo Image ◽  
Stereo Pair ◽  
Sem Micrograph ◽  
Left And Right ◽  
The Common ◽  
The Brain ◽  
Pair Analysis

The eye-brain complex allows those of us with normal vision to perceive and evaluate our surroundings in three-dimensions (3-D). The principle factor that makes this possible is parallax - the horizontal displacement of objects that results from the independent views that the left and right eyes detect and simultaneously transmit to the brain for superimposition. The common SEM micrograph is a 2-D representation of a 3-D specimen. Depriving the brain of the 3-D view can lead to erroneous conclusions about the relative sizes, positions and convergence of structures within a specimen. In addition, Walter has suggested that the stereo image contains information equivalent to a two-fold increase in magnification over that found in a 2-D image. Because of these factors, stereo pair analysis should be routinely employed when studying specimens.Imaging complementary faces of a fractured specimen is a second method by which the topography of a specimen can be more accurately evaluated.

convergent-beam diffraction from surfaces

1987 ◽  
Vol 45 ◽  
pp. 30-33
Author(s):  
J. A. Eades ◽  
A. E. Smith ◽  
D. F. Lynch
Keyword(s):  
Reciprocal Lattice ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
Three Dimensions ◽  
Plane Figure ◽  
Transmission Electron ◽  
Convergent Beam ◽  
Beam Patterns ◽  
Beam Diffraction

It is quite simple (in the transmission electron microscope) to obtain convergent-beam patterns from the surface of a bulk crystal. The beam is focussed onto the surface at near grazing incidence (figure 1) and if the surface is flat the appropriate pattern is obtained in the diffraction plane (figure 2). Such patterns are potentially valuable for the characterization of surfaces just as normal convergent-beam patterns are valuable for the characterization of crystals.There are, however, several important ways in which reflection diffraction from surfaces differs from the more familiar electron diffraction in transmission.GeometryIn reflection diffraction, because of the surface, it is not possible to describe the specimen as periodic in three dimensions, nor is it possible to associate diffraction with a conventional three-dimensional reciprocal lattice.

3-D reconstruction and analysis of mammalian mitotic spindle structure

1992 ◽  
Vol 50 (1) ◽  
pp. 578-579
Author(s):  
Kent McDonald ◽  
David Mastronarde ◽  
Rubai Ding ◽  
Eileen O'Toole ◽  
J. Richard McIntosh
Keyword(s):  
Cross Sections ◽  
Mitotic Spindle ◽  
Experimental Studies ◽  
Video Camera ◽  
Three Dimensions ◽  
Mitotic Spindles ◽  
Black And White ◽  
Reconstruction Methods ◽  
Spindle Structure ◽  
Tissue Culture Line

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.

Sign in / Sign up

Export Citation Format

Share Document