Synthesis, photophysical properties and microphase separation of all-conjugated diblock copolymers with hydrophilic side chains

2012 ◽  
Vol 62 (2) ◽  
pp. 204-209 ◽  
Author(s):  
Xueqin Zhang ◽  
Weiwei Yang ◽  
Fan Kong ◽  
Hong Yang ◽  
Baoping Lin
Keyword(s):  
Diblock Copolymers ◽  
Microphase Separation ◽  
Photophysical Properties ◽  
Side Chains

scholarly journals Liquid Crystal Ordering in the Hexagonal Phase of Rod-Coil Diblock Copolymers

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1262
Author(s):  
Mikhail A. Osipov ◽  
Maxim V. Gorkunov ◽  
Alexander A. Antonov
Keyword(s):  
Liquid Crystal ◽  
Order Parameter ◽  
Density Functional ◽  
Diblock Copolymers ◽  
Microphase Separation ◽  
Hexagonal Phase ◽  
Orientational Order ◽  
Order Parameters ◽  
Copolymer Composition ◽  
Rigid Rod

Density functional theory of rod-coil diblock copolymers, developed recently by the authors, has been generalised and used to study the liquid crystal ordering and microphase separation effects in the hexagonal, lamellar and nematic phases. The translational order parameters of rod and coil monomers and the orientational order parameters of rod-like fragments of the copolymer chains have been determined numerically by direct minimization of the free energy. The phase diagram has been derived containing the isotropic, the lamellar and the hexagonal phases which is consistent with typical experimental data. The order parameter profiles as functions of temperature and the copolymer composition have also been determined in different anisotropic phases. Finally, the spatial distributions of the density of rigid rod fragments and of the corresponding orientational order parameter in the hexagonal phase have been calculated.

Amphiphilic diblock copolymers based on ethylene oxide and epoxides bearing aliphatic side chains

2012 ◽  
Vol 3 (8) ◽  
pp. 2148 ◽  
Author(s):  
Anne-Laure Brocas ◽  
Matthieu Gervais ◽  
Stephane Carlotti ◽  
Stergios Pispas
Keyword(s):  
Ethylene Oxide ◽  
Diblock Copolymers ◽  
Side Chains ◽  
Amphiphilic Diblock Copolymers

Mechanical and structural consequences of associative dynamic cross-linking in acrylic diblock copolymers

2021 ◽  
Author(s):  
Jacob Ishibashi ◽  
Ian Pierce ◽  
Alice Chang ◽  
Aristotelis Zografos ◽  
Bassil El-Zaatari ◽  
...  
Keyword(s):  
Viscoelastic Properties ◽  
Diblock Copolymers ◽  
Microphase Separation ◽  
Network Connectivity ◽  
Ethyl Acrylate ◽  
Cross Linking ◽  
Cross Link ◽  
Block Polymers ◽  
Link Density ◽  
Cross Link Density

<p>The composition of low-T<sub>g</sub> <i>n</i>-butylacrylate-<i>block</i>-(acetoxyaceto)ethyl acrylate block polymers is investigated as a strategy to tune the properties of dynamically cross-linked vinylogous urethane vitrimers. As the proportion of the cross-linkable block is increased, the thermorheological properties, structure, and stress relaxation evolve in ways that cannot be explained by increasing cross-link density alone. Evidence is presented that network connectivity defects such as loops and dangling ends are increased by microphase separation. The thermomechanical and viscoelastic properties of block copolymer-derived vitrimers arise from the subtle interplay of microphase separation and network defects.</p><div><br></div><p></p>

Microphase Separation in Poly(oxyethylene)−Poly(oxybutylene) Diblock Copolymers

1998 ◽  
Vol 31 (23) ◽  
pp. 8110-8116 ◽  
Author(s):  
Shao-Min Mai ◽  
J. Patrick A. Fairclough ◽  
Nicholas J. Terrill ◽  
Simon C. Turner ◽  
Ian W. Hamley ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Microphase Separation

Asymmetric diblock copolymers near the microphase separation: limitations of mean field theory

Polymer ◽  
1991 ◽  
Vol 32 (11) ◽  
pp. 1935-1942 ◽  
Author(s):  
B Holzer ◽  
A Lehmann ◽  
B Stühn ◽  
M Kowalski
Keyword(s):  
Field Theory ◽  
Diblock Copolymers ◽  
Microphase Separation ◽  
Mean Field Theory ◽  
Mean Field

scholarly journals Phase Behavior of Melts of Diblock-Copolymers with One Charged Block

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1027 ◽  
Author(s):  
Alexey A. Gavrilov ◽  
Alexander V. Chertovich ◽  
Igor I. Potemkin
Keyword(s):  
Phase Diagram ◽  
Phase Behavior ◽  
Electrostatic Interactions ◽  
Diblock Copolymers ◽  
Volume Fraction ◽  
Microphase Separation ◽  
Dissipative Particle Dynamics ◽  
Homogeneous Structure ◽  
Electrostatic Energy ◽  
Ordered Structures

In this work, we investigated the phase behavior of melts of block-copolymers with one charged block by means of dissipative particle dynamics with explicit electrostatic interactions. We assumed that all the Flory–Huggins χ parameters were equal to 0. We showed that the charge- correlation attraction solely can cause microphase separation with a long-range order; a phase diagram was constructed by varying the volume fraction of the uncharged block and the electrostatic interaction parameter λ (dimensionless Bjerrum length). The obtained phase diagram was compared to the phase diagram of “equivalent” neutral diblock-copolymers with the non-zero χ-parameter between the beads of different blocks. The neutral copolymers were constructed by grafting the counterions to the corresponding co-ions of the charged block with further switching off the electrostatic interactions. Surprisingly, the differences between these phase diagrams are rather subtle; the same phases in the same order are observed, and the positions of the order-disorder transition ODT points are similar if the λ-parameter is considered as an “effective” χ-parameter. Next, we studied the position of the ODT for lamellar structure depending on the chain length N. It turned out that while for the uncharged diblock copolymer the product χcrN was almost independent of N, for the diblock copolymers with one charged block we observed a significant increase in λcrN upon increasing N. This can be attributed to the fact that the counterion entropy prevents the formation of ordered structures, and its influence is more pronounced for longer chains since they undergo the transition to ordered structures at smaller values of λ, when the electrostatic energy becomes comparable to kbT. This was supported by studying the ODT in diblock-copolymers with charged blocks and counterions cross-linked to the charged monomer units. The ODT for such systems was observed at significantly lower values of λ, with the difference being more pronounced at longer chain lengths N. The fact that the microphase separation is observed even at zero Flory–Huggins parameter can be used for the creation of “high-χ” copolymers: The incorporation of charged groups (for example, ionic liquids) can significantly increase the segregation strength. The diffusion of counterions in the obtained ordered structures was studied and compared to the case of a system with the same number of charged groups but a homogeneous structure; the diffusion coefficient along the lamellar plane was found to be higher than in any direction in the homogeneous structure.

Functionalized polynorbornenes with organosilicon groups in the side chains. Synthesis and photophysical properties

2016 ◽  
Vol 86 (1) ◽  
pp. 116-124 ◽  
Author(s):  
Е. О. Platonova ◽  
Т. А. Kovylina ◽  
Е. V. Baranov ◽  
А. V. Arapova ◽  
L. N. Bochkarev
Keyword(s):  
Photophysical Properties ◽  
Side Chains

Solid State Structure and Photoluminescence properties of poly(2,5-dialkoxy-p-phenyleneethynylene)s

1995 ◽  
Vol 413 ◽  
Author(s):  
Christoph Weder ◽  
Michael J. Wagner ◽  
Mark S. Wrighton
Keyword(s):  
Solid State ◽  
Long Range ◽  
Photophysical Properties ◽  
Significant Degree ◽  
Range Order ◽  
Quantum Yields ◽  
Side Chains ◽  
Long Range Order ◽  
Rigid Rod ◽  
Covalently Linked

ABSTRACTIn an effort to better understand the relationship between molecular structure and photophysical properties, we have prepared and investigated a series of novel poly(2,5-dialkoxy-p-phenyleneethynylene)s. Wide angle X-ray diffraction measurements show that the supramolecular structure can be easily and significantly influenced by the nature of substituents covalently linked to the rigid-rod polymer main chains. Polymers which have sterically hindered side chains are essentially amorphous, while those with only linear side chains can form lamellar structures with a significant degree of long-range order. High photoluminescence quantum yields, up to 0.86 in solution and 0.36 in the solid state, have been measured. While the solution quantum yields are independent of the functionalization, solid state quantum efficiencies were found to be related to the degree of long-range order in the samples. In samples with a high degree of long-range order, the close proximity of the coplanar oriented polymer backbones is assumed to lead to the formation of eximer complexes which provide non emissive decay channels and, hence, result in comparable low photoluminescence quantum yields. In samples that adopt only a small extent of long-range order, the rigid-rod conjugated polymer backbones behave as if they were ‘dissolved’ in a hydrocarbon solvent and consequently high quantum efficiencies are obtained. Preliminary results indicate the suitability of these polymers as the emitting layer in electroluminescent devices.

Computer Design of Copolymers with Desired Functionalities: Microphase Separation in Diblock Copolymers with Amphiphilic Block

2007 ◽  
Author(s):  
Alexei R. Khokhlov ◽  
Yury A. Kriksin ◽  
Igor Ya. Erukhimovich ◽  
Pavel G. Khalatu ◽  
George Maroulis ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Microphase Separation ◽  
Computer Design
Sign in / Sign up

Export Citation Format

Share Document