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Pressure Effects Revealed by Small Angle Neutron Scattering on Block Copolymer Gels

DOI: 10.1021/la801025n DOI Help

Authors: V. Castelletto (National Physical Laboratory, UK) , P. Baroni (Laboratoire Léon Brillouin) , I. W. Hamley (University of Reading) , G. E. Newby (University of Reading) , L. Noirez (Laboratoire Léon Brillouin)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Langmuir , VOL 24 (15) , PAGES 8320-8324

State: Published (Approved)
Published: June 2008

Abstract: We study the effects of hydrostatic pressure (P) on aqueous solutions and gels of the block copolymer B20E610 (E, oxyethylene; B, oxybutylene; subscripts, number of repeats), by performing simultaneous small angle neutron scattering/pressure experiments. Micellar cubic gels were studied for 9.5 and 4.5 wt % B20E610 at T = 20−80 and 35−55 °C, respectively, while micellar isotropic solutions WHERE studied for 4.5 wt % B20E610 at T > 55 °C. We observed that the interplanar distance d110 (cubic unit cell parameter a = √2d110) decreases while the correlation length of the cubic order (δ) increases, upon increasing P at a fixed T for 9.5 wt % B20E610. The construction of master curves for d110 and δ corresponding to 9.5 wt % B20E610 proved the correlation between changes in T and P. Neither d110 and δ nor the cubic−isotropic phase transition temperature was affected by the applied pressure for 4.5 wt % B20E610. The dramatic contrast between the pressure-induced behavior observed for 9.5 and 4.5 wt % B20E610 suggests that pressure induced effects might be more effectively transmitted through samples that present wider domains of cubic structure order (9.5 wt % compared to 4.5 wt % B20E610).

Subject Areas: Chemistry, Materials

Instruments: NONE-No attached Diamond beamline

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