Structure and Interactions of Block Copolymer Micelles of Brij 700 Studied by Combining Small-Angle X-ray and Neutron Scattering

Langmuir ◽  
2005 ◽  
Vol 21 (6) ◽  
pp. 2137-2149 ◽  
Author(s):  
Cornelia Sommer ◽  
Jan Skov Pedersen ◽  
Vasil M. Garamus
Keyword(s):  
Block Copolymer ◽  
Neutron Scattering ◽  
Small Angle ◽  
X Ray ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

scholarly journals Structure of PEP–PEO block copolymer micelles: exploiting the complementarity of small-angle X-ray scattering and static light scattering

2011 ◽  
Vol 44 (3) ◽  
pp. 473-482 ◽  
Author(s):  
Grethe Vestergaard Jensen ◽  
Qing Shi ◽  
María J. Hernansanz ◽  
Cristiano L. P. Oliveira ◽  
G. Roshan Deen ◽  
...  
Keyword(s):  
Light Scattering ◽  
Block Copolymer ◽  
Small Angle ◽  
Static Light Scattering ◽  
Length Scales ◽  
X Ray ◽  
X Ray Scattering ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Poly Ethylene

The structure of large block copolymer micelles is traditionally determined by small-angle neutron scattering (SANS), covering a large range of scattering vectors and employing contrast variation to determine the overall micelle morphology as well as the internal structure on shorter length scales. The present work shows that the same information can be obtained by combining static light scattering (SLS) and small-angle X-ray scattering (SAXS), which provide information on, respectively, large and short length scales. Micelles of a series of block copolymers of poly(ethylene propylene)-b-poly(ethylene oxide) (PEP–PEO) in a 70% ethanol solution are investigated. The polymers have identical PEP blocks of 5.0 kDa and varying PEO blocks of 2.8–49 kDa. The SLS contrasts of PEP and PEO are similar, providing a homogeneous contrast, making SLS ideal for determining the overall micelle morphology. The SAXS contrasts of the two components are very different, allowing for resolution of the internal micelle structure. A core–shell model with a PEP core and PEO corona is fitted simultaneously to the SAXS and SLS data using the different contrasts of the two blocks for each technique. With increasing PEO molecular weight, a transition from cylindrical to spherical micelles is observed. This transition cannot be identified from the SAXS data alone, but only from the SLS data.

Liquid Crystalline Phase Behavior of Well-Defined Cylindrical Block Copolymer Micelles Using Synchrotron Small-Angle X-ray Scattering

2015 ◽  
Vol 48 (5) ◽  
pp. 1579-1591 ◽  
Author(s):  
Dominic W. Hayward ◽  
Joe B. Gilroy ◽  
Paul A. Rupar ◽  
Laurent Chabanne ◽  
Claire Pizzey ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Phase Behavior ◽  
Small Angle ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
X Ray ◽  
X Ray Scattering ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Cylindrical Block

Structural Analysis of Bottlebrush Block Copolymer Micelles Using Small-Angle X-ray Scattering

2020 ◽  
Vol 9 (9) ◽  
pp. 1261-1266
Author(s):  
Seyoung Kim ◽  
Yunshik Cho ◽  
Jee Hyun Kim ◽  
Sanghoon Song ◽  
Jeewoo Lim ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Block Copolymer ◽  
Small Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Ray Scattering

The Morphology of Block Copolymer Micelles in Supercritical Carbon Dioxide by Small-Angle Neutron and X-ray Scattering

1997 ◽  
Vol 30 (5) ◽  
pp. 690-695 ◽  
Author(s):  
J. D. Londono ◽  
R. Dharmapurikar ◽  
H. D. Cochran ◽  
G. D. Wignall ◽  
J. B. McClain ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Block Copolymer ◽  
Small Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Environmentally Responsible ◽  
Theoretical Predictions ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Ray Scattering

Above its critical point, carbon dioxide forms a super-critical fluid, which promises to be an environmentally responsible replacement for the organic solvents traditionally used in polymerizations. Many lipophilic polymers such as polystyrene (PS) are insoluble in CO2, though polymerizations may be accomplished via the use of PS-fluoropolymer stabilizers, which act as emulsifying agents. Small-angle neutron and X-ray scattering have been used to show that these molecules form micelles with a CO2-phobic PS core and a CO2-philic fluoropolymer corona. When the PS block was fixed in length and the fluorinated corona block was varied, the number of block copolymer molecules per micelle (six to seven) remained constant. Thus, the coronal block molecular weight exerts negligible influence on the aggregation number, in accordance with the theoretical predictions of Halperin, Tirrell & Lodge [Adv. Polym. Sci. (1992), 100, 31–46]. These observations are relevant to understanding the mechanisms of micellization and solubilization in supercritical fluids.

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