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

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.

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.

scholarly journals Crystallization and Phase Behavior in Block Copolymer Solution: An in Situ Small Angle X-ray Scattering Study

2019 ◽  
Vol 37 (11) ◽  
pp. 1162-1168
Author(s):  
Hong-Yan Zhu ◽  
Feng Tian ◽  
Xiu-Hong Li ◽  
Hui-Bin Qiu ◽  
Jie Wang
Keyword(s):  
Block Copolymer ◽  
Phase Behavior ◽  
Small Angle ◽  
Copolymer Solution ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

Styrene/butadiene block copolymer micelles in heptane

1985 ◽  
Vol 63 (1) ◽  
pp. 249-252 ◽  
Author(s):  
T. L. Bluhm ◽  
M. D. Whitmore
Keyword(s):  
Block Copolymer ◽  
Radius Of Gyration ◽  
X Ray ◽  
X Ray Scattering ◽  
Micelle Core ◽  
Theoretical Predictions ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Styrene Butadiene ◽  
Good Agreement

The radius of gyration of poly(styrene-b-butadiene) block copolymer micelles in n-heptane is measured by small angle X-ray scattering (SAXS). The results are compared with theoretical predictions, and good agreement is found, particularly for the appropriate scaling relations. It is argued that the radius of gyration of the micelles depends on both the molecular weight and the composition of the copolymers. The dominant factors which determine the micelle core and corona dimensions are identified.

Thermotropic behavior of sodium cholesteryl carbonate

2009 ◽  
Vol 24 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Rabkwan Chuealee ◽  
Timothy S. Wiedmann ◽  
Teerapol Srichana
Keyword(s):  
Phase Behavior ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Wave Number ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
C Nmr

Sodium cholesteryl carbonate ester (SCC) was synthesized, and its phase behavior was studied. The chemical structure was assessed by solid-state infrared spectroscopy based on vibration analysis. The wave number at 1705 and 1276 cm−1 corresponds to a carbonyl carbonate and O–C–O stretching of SCC, respectively. Molecular structure of SCC was further investigated with 1H and 13C NMR spectroscopy. The chemical shift, for the carbonyl carbonate resonance appeared at 155.5 ppm. A molecular mass of SCC was at m/z of 452. Differential scanning calorimetry (DSC), video-enhanced microscopy (VEM) together with polarized light microscopy, and small-angle x-ray scattering (SAXS) were used to characterize the phase behavior as a function of temperature of SCC. Liquid crystalline phase was formed with SCC. Based on the thermal properties and x-ray diffraction, it appears that SCC forms a structure analogous to the type II monolayer structure observed with cholesterol esters.

Small-Angle X-ray Scattering of Concentration Dependent Structures in Block Copolymer Solutions

2014 ◽  
Vol 47 (22) ◽  
pp. 7978-7986 ◽  
Author(s):  
Soo-Hyung Choi ◽  
Frank S. Bates ◽  
Timothy P. Lodge
Keyword(s):  
Block Copolymer ◽  
Small Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering
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