Dependence of the OBDD morphology on diblock copolymer molecular weight in copolymer/homopolymer blends

A wide range of morphologies and thereby physical properties can be achieved in block copolymer/homopolymer blends by varying the copolymer composition, copolymer concentration and molecular weights. Recently we investigated micelle shape transitions in diblock copolymer with homopolymer blends at low copolymer concentration. In this paper we study the microstructure over a wider concentration range for a polystyrene-polybutadiene (PS/PB) diblock copolymer of molecular weight 20.5 × 103/20.5 × 103 blended with 17.2 × 103 molecular weight homopolystyrene (hPS).Figure 1 shows schematically a possible spectrum of microdomain structures dependent on the copolymer concentration of a lamellar PS/PB and hPS. Below the critical micelle concentration (CMC) the block copolymer is molecularly dispersed in the homopolymer exhibiting a homogeneous phase. As diblock concentration increases the minority (i.e. PB) forms spherical and/or cylindrical micelles randomly dispersed in the hPS. Further increases in diblock concentration induces long range ordering of various microdomains. In addition three biphasic regions are proposed in which two phases coexist: isotropic cylinders with ordered cylinders, ordered cylinders with ordered bicontinuous double diamond (OBDD), and OBDD with swollen lamellae.

Download Full-text

Synthesis of poly(methyl methacrylate)-b-poly(acrylic acid) by DPE method

e-Polymers ◽

10.1515/epoly.2008.8.1.1051 ◽

2008 ◽

Vol 8 (1) ◽

Cited By ~ 2

Author(s):

Dong Chen ◽

Ruixue Liu ◽

Zhifeng Fu ◽

Yan Shi

Keyword(s):

Molecular Weight ◽

Acrylic Acid ◽

Methyl Methacrylate ◽

Diblock Copolymer ◽

Self Assembly ◽

Gel Permeation Chromatography ◽

Amphiphilic Diblock Copolymer ◽

Poly Methyl Methacrylate ◽

Copolymer Poly ◽

Poly Acrylic Acid

AbstractAmphiphilic diblock copolymer poly(methyl methacrylate)-b-poly(acrylic acid) (PMMA-b-PAA) was prepared by 1,1-diphenylethene (DPE) method. Firstly, free radical polymerization of methyl methacrylate was carried out with AIBN as initiator in the presence of DPE, giving a DPE-containing PMMA precursor with controlled molecular weight. tert-Butyl acrylate (tBA) was then polymerized in the presence of the PMMA precursor, and PMMA-b-PtBA diblock copolymer with controlled molecular weight was prepared. Finally, amphiphilic diblock copolymer PMMA-b-PAA was obtained by hydrolysis of PMMA-b-PtBA. The formation of PMMA-b-PAA was confirmed by 1H NMR spectrum and gel permeation chromatography. Transmission electron microscopy and dynamic light scattering were used to detect the self-assembly behavior of the amphiphilic diblock polymers in methanol.

Download Full-text

Swelling of lamellar diblock copolymer by homopolymer: influences of homopolymer concentration and molecular weight

Macromolecules ◽

10.1021/ma00023a020 ◽

1991 ◽

Vol 24 (23) ◽

pp. 6182-6188 ◽

Cited By ~ 160

Author(s):

Karen I. Winey ◽

Edwin L. Thomas ◽

Lewis J. Fetters

Keyword(s):

Molecular Weight ◽

Diblock Copolymer

Download Full-text

Control of Alignment Regularity and Density of Nanodots by Changing Concentration and Molecular Weight of Self-Assembling Diblock Copolymer

Japanese Journal of Applied Physics ◽

10.1143/jjap.45.l20 ◽

2005 ◽

Vol 45 (1) ◽

pp. L20-L22 ◽

Cited By ~ 7

Author(s):

Tsuyoshi Matsuyama ◽

Yoshimasa Kawata

Keyword(s):

Molecular Weight ◽

Diblock Copolymer ◽

Self Assembling

Download Full-text

Fluctuation theory of diblock copolymer/homopolymer blends and its effects on the Lifshitz point

The Journal of Chemical Physics ◽

10.1063/1.474235 ◽

1997 ◽

Vol 107 (14) ◽

pp. 5588-5608 ◽

Cited By ~ 45

Author(s):

L. Kielhorn ◽

M. Muthukumar

Keyword(s):

Diblock Copolymer ◽

Fluctuation Theory ◽

Lifshitz Point ◽

Homopolymer Blends

Download Full-text

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

Rubber Chemistry and Technology ◽

10.5254/1.3538679 ◽

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%.

Download Full-text

Diblock Copolymer Surfactants in Immiscible Homopolymer Blends: Swollen Micelles and Interfacial Tension

Macromolecules ◽

10.1021/ma060481s ◽

2006 ◽

Vol 39 (22) ◽

pp. 7746-7756 ◽

Cited By ~ 12

Author(s):

Kwanho Chang ◽

David C. Morse

Keyword(s):

Interfacial Tension ◽

Diblock Copolymer ◽

Homopolymer Blends

Download Full-text

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

MRS Proceedings ◽

10.1557/proc-171-255 ◽

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.

Download Full-text