Effects of Adsorbing-Block Molecular Weight on the Thickness of Adsorbed Diblock Copolymers

Langmuir ◽  
1994 ◽  
Vol 10 (9) ◽  
pp. 3156-3160 ◽  
Author(s):  
Richard M. Webber ◽  
John L. Anderson
Keyword(s):  
Molecular Weight ◽  
Diblock Copolymers

Mechanical Properties of Blends of Crystallizable Polybutadienes Containing Amorphous Polybutadiene Diblock Copolymers

1994 ◽  
Vol 67 (2) ◽  
pp. 342-347
Author(s):  
Moira Marx Nir ◽  
Robert E. Cohen
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Surface Area ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Tensile Failure ◽  
Interfacial Surface ◽  
Failure Properties ◽  
Enhanced Properties

Abstract Tensile failure properties of syndiotactic 1,2 polybutadiene/trans 1,4 polybutadiene crystalline blends are improved by addition of 5–10% amorphous 1,2 polybutadiene/1,4 polybutadiene diblock copolymer. The effect of block molecular weight and microphase behavior of the diblock copolymer was investigated. Heterogeneous diblocks enhance blend properties to a greater extent than homogeneous diblocks. In blends with enhanced properties, percent coverage of interfacial surface area by diblock is on the order of 10%.

The Ordered Bicontinuous Double Diamond Structure in Binary Blends of Diblock Copolymer and Homopolymer.

1989 ◽  
Vol 171 ◽  
Author(s):  
Karen I. Winey ◽  
Edwin L. Thomas
Keyword(s):  
Molecular Weight ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Composition Range ◽  
Volume Fraction ◽  
Diamond Structure ◽  
Binary Blends ◽  
Resultant Effect ◽  
Strong Segregation ◽  
Double Diamond

ABSTRACTWe report the observation of the ordered bicontinuous double diamond (OBDD) structure in binary blends of poly(styrene-isoprene) diblock copolymer and homopolystyrene. The overall polystyrene volume fraction range is 64 - 67 PSvol% for the OBDD structure in binary blends of a lamellar diblock (SI 27/22) and a homopolymer (14.0 hPS). This composition range is approximately within the polystyrene volume fraction range established for pure diblock copolymers in the strong segregation regime having the OBDD structure. Ordered lamellae are observed at approximately 65 PSvol% when the homopolystyrene molecular weight is greater than the molecular weight of the polystyrene block of the copolymer. This observation is discussed in terms of the decreased degree of mixing between the homopolymer and the corresponding block and the resultant effect on the interfacial curvature.

scholarly journals Effects of Molecular Weight and Crystallization Temperature on the Morphology Formation in Asymmetric Diblock Copolymers with a Highly Crystalline Block

2000 ◽  
Vol 32 (7) ◽  
pp. 602-609 ◽  
Author(s):  
Awaludin Rohadi ◽  
Ryuji Endo ◽  
Satoshi Tanimoto ◽  
Shintaro Sasaki ◽  
Shuichi Nojima
Keyword(s):  
Molecular Weight ◽  
Crystallization Temperature ◽  
Diblock Copolymers

Analysis of randomly oriented structures by grazing-incidence small-angle neutron scattering

2012 ◽  
Vol 45 (2) ◽  
pp. 245-254 ◽  
Author(s):  
Denis Korolkov ◽  
Peter Busch ◽  
Lutz Willner ◽  
Emmanuel Kentzinger ◽  
Ulrich Rücker ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Small Angle ◽  
Diblock Copolymers ◽  
Weight Fraction ◽  
Grazing Incidence ◽  
Force Microscopy ◽  
Self Organized ◽  
Atomic Force ◽  
Instrumental Resolution ◽  
Evaluation Of Data

A formalism is presented which allows the quantitative evaluation of data from grazing-incidence small-angle neutron and X-ray scattering – GISANS and GISAXS – in the framework of the distorted wave Born approximation. While several aspects have been reported previously, this formalism combines solutions for scattering intensities in both reflection and transmission hemispheres, taking into account instrumental resolution effects. This formalism is applied to the case of GISANS from self-organized diblock copolymers, ordered in perpendicular lamellar structures on an Si wafer in randomly oriented short-range-ordered regions. The periodicity ofD= 85 (9) nm found for deuterated polystyrene–polybutadiene of molecular weight  Mw= 165 kg mol−1and a molecular weight fraction of the deuterated polystyrene block of 52% is consistent with atomic force microscopy and specular neutron reflectivity results.

Modification of Interfacial Properties of Polymer Blends with Diblock Copolymer

1996 ◽  
Vol 461 ◽  
Author(s):  
S. Kim ◽  
C. C. Han
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Polymer Blends ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Phase Region ◽  
Domain Growth ◽  
Two Phase ◽  
Phase Separation Kinetics ◽  
Styrene Butadiene

ABSTRACTThe effect of diblock copolymer on the phase-separation process of polymer blends has been investigated by using light scattering and optical microscopic observations. To quench the system into the two phase region, a shear-jump technique is employed instead of the conventional temperature-jump technique. The samples studied are blends of low-molecular-weight polystyrene and polybutadiene with and without added styrene-butadiene block copolymer as a compatibilizer. It was observed that the addition of diblock copolymers could accelerate the phase separation kinetics depending on the shear history. As the concentration of diblock copolymer increases, the distribution of domain sizes becomes narrower and the growth rate slows down. The extent of slowing-down depends on the molecular weight and concentration of the copolymer. The time dependence of domain growth is clearly observed with optical microscopy.

The Morphology of Symietric Diblock Copolymers as Revealed by Neutron Reflectivity

1989 ◽  
Vol 166 ◽  
Author(s):  
S. K. Satija ◽  
C. F. Majkrzak ◽  
S. H. Anastasiadis ◽  
T. P. Russell
Keyword(s):  
Molecular Weight ◽  
Concentration Gradient ◽  
Diblock Copolymers ◽  
Neutron Reflectivity ◽  
Effective Width ◽  
Hyperbolic Tangent ◽  
A Value ◽  
Specular Reflectivity ◽  
Tangent Function ◽  
Total Molecular Weight

ABSTRACTThe specular reflectivity of neutrons has been used to characterize quantitatively the microphase separated morphology of symmetric, diblock copolymers of polystyrene, PS and polymethylmethacrylate, PMMA, as a function of the total molecular weight of the copolymer where either block is perdeuterated. It is shown that the hyperbolic tangent function, as opposed to a linear or cosine squared function, most closely describes the concentration gradient at the interface between the lamellar copolymer microdomains. The effective width of the interface is found to be independent of the molecular weight of the copolymer blocks and has a value of 50 ± 3Å. This interface is also found to be identical to that of PS and PMMA, homopolymers. However, using measured values of the Flory-Huggins interaction parameter for PS and PMMA current theoretical treatments cannot describe the observed widths of the interface.

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