Efficient and Controlled Seeded Growth of Poly(3-hexylthiophene) Block Copolymer Nanofibers through Suppression of Homogeneous Nucleation

2021 ◽  
Author(s):  
Liam R. MacFarlane ◽  
Xiaoyu Li ◽  
Charl F. J. Faul ◽  
Ian Manners
Keyword(s):  
Block Copolymer ◽  
Homogeneous Nucleation ◽  
Seeded Growth

Seeded Growth and Solvent-Induced Fragmentation of Fiberlike Polyferrocenylsilane-Polyisoprene Block Copolymer Micelles

2010 ◽  
Vol 31 (9-10) ◽  
pp. 928-933 ◽  
Author(s):  
Jieshu Qian ◽  
Gerald Guerin ◽  
Graeme Cambridge ◽  
Ian Manners ◽  
Mitchell A. Winnik
Keyword(s):  
Block Copolymer ◽  
Seeded Growth ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

scholarly journals Self-Seeding Procedure for Obtaining Stacked Block Copolymer Lamellar Crystals in Solution

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1676
Author(s):  
Brahim Bessif ◽  
Thomas Pfohl ◽  
Günter Reiter
Keyword(s):  
Block Copolymer ◽  
Polyethylene Oxide ◽  
Homogeneous Nucleation ◽  
Diblock Copolymers ◽  
Polymer Concentration ◽  
Solubility Limit ◽  
The Self ◽  
Lateral Size ◽  
Linear Extrapolation ◽  
Lamellar Crystals

We examined the formation of self-seeded platelet-like crystals from polystyrene-block-polyethylene oxide (PS-b-PEO) diblock copolymers in toluene as a function of polymer concentration (c), crystallization temperature (TC), and self-seeding temperature (TSS). We showed that the number (N) of platelet-like crystals and their mean lateral size (L) can be controlled through a self-seeding procedure. As (homogeneous) nucleation was circumvented by the self-seeding procedure, N did not depend on TC. N increased linearly with c and decayed exponentially with TSS but was not affected significantly by the time the sample was kept at TSS. The solubility limit of PS-b-PEO in toluene (c*), which was derived from the linear extrapolation of Nc→ 0 and from the total deposited mass of the platelets per area (MCc→0), depended on TC. We have also demonstrated that at low N, stacks consisting of a (large) number (η) of uniquely oriented lamellae can be achieved. At a given TC, L was controlled by N and η as well as by ∆c=c−c∗. Thus, besides being able to predict size and number of platelet-like crystals, the self-seeding procedure also allowed control of the number of stacked lamellae in these crystals.

Morphology Control of ZnO Nanomaterials using Double Hydrophilic Block Copolymers

2005 ◽  
Vol 901 ◽  
Author(s):  
A. Mezy ◽  
C. Gérardin ◽  
D. Tichit ◽  
S. Suwanboon ◽  
D. Ravot ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Polyacrylic Acid ◽  
Sol Gel ◽  
Seeded Growth ◽  
Gel Method ◽  
Double Hydrophilic Block Copolymers ◽  
Zno Nanomaterials ◽  
Hexagonal Crystals

AbstractHighly crystalline zinc oxide (ZnO) nanomaterials are synthesized using a seeded growth sol-gel method. In order to control the morphology and the organization of the ZnO nanomaterials, a double hydrophilic block copolymer has been introduced during the seeded growth synthesis: the Polyacrylic acid-Polyacrylamide (PAA-PAM). Depending on the amount of PAA-PAM copolymers, different morphologies were obtained, such as ZnO nanostructured spheres or flat hexagonal crystals. Thus, systematic studies have been done to investigate the influence of the copolymer addition on ZnO nanomaterial morphologies and explain the mechanisms of the morphological modifications.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Lattice imaging of precipitates in Al-Zn-Mg alloy

1986 ◽  
Vol 44 ◽  
pp. 412-413
Author(s):  
C. K. Wu
Keyword(s):  
Grain Boundaries ◽  
Homogeneous Nucleation ◽  
Alloy System ◽  
Mg Alloy ◽  
List Type ◽  
Lattice Structures ◽  
Type Number ◽  
Orientation Relationships ◽  
Lattice Imaging ◽  
The Matrix

The precipitation phenomenon in Al-Zn-Mg alloy is quite interesting and complicated and can be described in the following categories:(i) heterogeneous nucleation at grain boundaries;(ii) precipitate-free-zones (PFZ) adjacent to the grain boundaries;(iii) homogeneous nucleation of snherical G.P. zones, n' and n phases inside the grains. The spherical G.P. zones are coherent with the matrix, whereas the n' and n phases are incoherent. It is noticed that n' and n phases exhibit plate-like morpholoay with several orientation relationship with the matrix. The high resolution lattice imaging techninue of TEM is then applied to study precipitates in this alloy system. It reveals the characteristics of lattice structures of each phase and the orientation relationships with the matrix.

Amorphous silica coating on α-alumina particles

1995 ◽  
Vol 53 ◽  
pp. 210-211
Author(s):  
J. W. Mellowes ◽  
C. M. Chun ◽  
I. A. Aksay
Keyword(s):  
Amorphous Silica ◽  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Silica Coating ◽  
Full Density ◽  
Optimal Conditions ◽  
Fine Grained ◽  
Alumina Particles ◽  
Complete Mullitization ◽  
Powder Compacts

Mullite (3Al2O32SiO2) can be fabricated by transient viscous sintering using composite particles which consist of inner cores of a-alumina and outer coatings of amorphous silica. Powder compacts prepared with these particles are sintered to almost full density at relatively low temperatures (~1300°C) and converted to dense, fine-grained mullite at higher temperatures (>1500°C) by reaction between the alumina core and the silica coating. In order to achieve complete mullitization, optimal conditions for coating alumina particles with amorphous silica must be achieved. Formation of amorphous silica can occur in solution (homogeneous nucleation) or on the surface of alumina (heterogeneous nucleation) depending on the degree of supersaturation of the solvent in which the particles are immersed. Successful coating of silica on alumina occurs when heterogeneous nucleation is promoted and homogeneous nucleation is suppressed. Therefore, one key to successful coating is an understanding of the factors such as pH and concentration that control silica nucleation in aqueous solutions. In the current work, we use TEM to determine the optimal conditions of this processing.

Crystal structure-size relationship in ultrafine metallic particles

1989 ◽  
Vol 47 ◽  
pp. 266-267
Author(s):  
Jun Liu ◽  
Mehmet Sarikaya ◽  
Ilhan A. Aksay
Keyword(s):  
Ultrafine Particles ◽  
Carbon Film ◽  
Lattice Defects ◽  
Careful Examination ◽  
Seeded Growth ◽  
Gold Particles ◽  
Metallic Particles ◽  
Interfacial Structures ◽  
Typical Particle ◽  
Many Particles

Ultrafine particles usually have unique physical properties. This study illustrates how the lattice defects and interfacial structures between particles are related to the size of ultrafine crystalline gold particles.Colloidal gold particles were produced by reducing gold chloride with sodium citrate at 100°C. In this process, particle size can be controlled by changing the concentration of the reactant. TEM samples are prepared by transferring a small amount of solution onto a thin (5 nm) carbon film which is suspended on a copper grid. In this work, all experiments were performed with Philips 430T at 300 kV.With controlled seeded growth, particles of different sizes are produced, as shown in Figure 1. By a careful examination, it can be resolved that very small particles have lattice defects with complex interfaces. Some typical particle structures include multiple twins, resulting in a five-fold symmetry bicrystals, and highly disordered regions. Many particles are too complex to be described by simple models.

MACROSCOPIC " SINGLE CRYSTALS " OF AN S-B-S THREE BLOCK COPOLYMER

1971 ◽  
Vol 32 (C5) ◽  
pp. C5a-295-C5a-300
Author(s):  
A. KELLER ◽  
J. DLUGOSZ ◽  
M. J. FOLKES ◽  
E. PEDEMONTE ◽  
F. P. SCALISI ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Single Crystals

Preparation of La-doped TiO$lt;inf$gt;2$lt;/inf$gt; Ultrafiltration Membrane by Templating of Block Copolymer

2015 ◽  
Vol 30 (2) ◽  
pp. 171 ◽  
Author(s):  
CHEN Tao-Tao ◽  
LI Dan ◽  
JING Wen-Heng ◽  
FAN Yi-Qun ◽  
XING Wei-Hong
Keyword(s):  
Block Copolymer ◽  
Ultrafiltration Membrane ◽  
La Doped
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